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Sample records for human beta-2 adrenergic

  1. Astrocytic beta(2)-adrenergic receptors: from physiology to pathology.

    PubMed

    Laureys, Guy; Clinckers, Ralph; Gerlo, Sarah; Spooren, Anneleen; Wilczak, Nadine; Kooijman, Ron; Smolders, Ilse; Michotte, Yvette; De Keyser, Jacques

    2010-07-01

    Evidence accumulates for a key role of the beta(2)-adrenergic receptors in the many homeostatic and neuroprotective functions of astrocytes, including glycogen metabolism, regulation of immune responses, release of neurotrophic factors, and the astrogliosis that occurs in response to neuronal injury. A dysregulation of the astrocytic beta(2)-adrenergic-pathway is suspected to contribute to the physiopathology of a number of prevalent and devastating neurological conditions such as multiple sclerosis, Alzheimer's disease, human immunodeficiency virus encephalitis, stroke and hepatic encephalopathy. In this review we focus on the physiological functions of astrocytic beta(2)-adrenergic receptors, and their possible impact in disease states. PMID:20138112

  2. An insilico approach to high altitude pulmonary edema - Molecular modeling of human beta2 adrenergic receptor and its interaction with Salmeterol & Nifedipine.

    PubMed

    Chandramoorthi, Gayathri Devi; Piramanayagam, Shanmughavel; Marimuthu, Parthiban

    2008-09-01

    Knowledge of the three-dimensional structures of protein targets from genomic data has the potential to accelerate researches pertaining to drug discovery. Human beta(2) adrenergic receptor is a G-protein-coupled receptor with seven transmembrane helices, and is important in pharmaceutical targeting on pulmonary and cardiovascular diseases. The human beta(2) adrenergic receptor has been found to play a very important role in the pathogenesis of high altitude pulmonary edema (HAPE). In the present study, a high quality of protein 3D structure has been predicted for the human beta(2) adrenergic receptor sequence with primary accession number P07550. Homologous template protein sequence with known 3D structure was identified and the template-query protein sequence validation was done by multiple sequence alignment method. The homology model was performed through Modeller and depended on the quality of the sequence alignment by BLAST, template structure and the consolidated result performed by Gene silico meta-server. The statistical verification of the generated model was evaluated by PROCHECK which revealed that the structure modeled through Modeller to be of good quality with 84.1% of residues in the most favored region. Docking studies were carried out after modeling with two well known ligands namely Salmeterol and Nifedipine, and the fitness score revealed that Salmeterol has a higher fitness score than Nifedipine. Estimation of binding affinity by X-Score revealed that Salmeterol had -10.40 binding affinity while Nifedipine showed -9.62 binding affinity. From the present study, it can be concluded that the generated model of human beta(2) adrenergic receptor can be used for further studies related to this receptor and Salmeterol was found to have a high binding affinity with human beta(2) adrenergic receptor. PMID:18512086

  3. Genetic variation of the beta2-adrenergic receptor is associated with differences in lung fluid accumulation in humans.

    PubMed

    Snyder, Eric M; Beck, Kenneth C; Turner, Stephen T; Hoffman, Eric A; Joyner, Michael J; Johnson, Bruce D

    2007-06-01

    The beta2-adrenergic receptors (beta2AR) play an important role in lung fluid regulation. Previous research has suggested that subjects homozygous for arginine at amino acid 16 of the beta2AR (Arg16) may have attenuated receptor function relative to subjects homozygous for glycine at the same amino acid (Gly16). We sought to determine if the Arg16Gly polymorphism of the beta2AR influenced lung fluid balance in response to rapid saline infusion. We hypothesized that subjects homozygous for Arg at amino acid 16 (n=14) would have greater lung fluid accumulation compared with those homozygous for Gly (n=15) following a rapid intravenous infusion of isotonic saline (30 ml/kg over 17 min). Changes in lung fluid were determined using measures of lung density and tissue volume (computerized tomography imaging) and measures of pulmonary capillary blood volume (Vc) and alveolar-capillary conductance (DM, determined from the simultaneous assessment of the diffusing capacities of the lungs for carbon monoxide and nitric oxide). The saline infusion resulted in elevated catecholamines in both genotype groups (Arg16 283+/-117% vs. Gly16 252+/-118%, P>0.05). The Arg16 group had a larger decrease in DM and increase in lung tissue volume and lung water after saline infusion relative to the Gly16 group (DM -13+/-14 vs. 0+/-26%, P<0.05; lung tissue volume 13+/-11 vs. 3+/-11% and lung water +90+/-66 vs. +48+/-144 ml, P=0.10, P<0.05, for Arg vs. Gly16, respectively, means+/-SD). These data suggest that subjects homozygous for Arg at amino acid 16 of the beta2AR have a greater susceptibility for lung fluid accumulation relative to subjects homozygous for Gly at this position. PMID:17347382

  4. The beta 2-adrenergic receptors of human epidermoid carcinoma cells bear two different types of oligosaccharides which influence expression on the cell surface.

    PubMed Central

    Cervantes-Olivier, P; Delavier-Klutchko, C; Durieu-Trautmann, O; Kaveri, S; Desmandril, M; Strosberg, A D

    1988-01-01

    The beta 2-adrenergic receptors of the human epidermoid carcinoma A431 cells reside on two polypeptide chains revealed by photoaffinity labelling with [125I]iodocyanopindolol-diazirine. These proteins correspond to two distinct populations of N-asparagine-linked glycoproteins: the 55-52 kDa molecules are associated with complex carbohydrate chain(s), the 65-63 kDa component with polymannosidic carbohydrate chain(s). Both types of receptors are present in preconfluent cells, but only the polymannosidic type is found in the postconfluent cells. Moreover, complex chains appear to be associated with the receptors with the highest affinity for (-)-isoproterenol and polymannosidic chains with the receptors with the lowest affinity for this agonist. the carbohydrate moiety of the beta-adrenergic receptor is involved in the expression and function of the beta 2-adrenergic receptors at the surface of the A431 cells, since tunicamycin and monensin, complete and partial inhibitors of glycosylation respectively, diminish the number of binding sites at the cell surface and increase the total number of sites in the cell. In these conditions a diminution of cyclic AMP accumulation is also observed. Images Fig. 5. PMID:2895638

  5. Transformation of human ciliary epithelial cells by simian virus 40: induction of cell proliferation and retention of beta 2-adrenergic receptors.

    PubMed Central

    Coca-Prados, M; Wax, M B

    1986-01-01

    Ciliary epithelial cells derived from human eye were successfully propagated through many generations after transformation with simian virus 40. The cell clone 8-SVHCE was isolated and characterized by immunoprecipitation and pharmacological studies that demonstrated the presence of several functional properties observed in the parent cells of this tissue. Immunoprecipitation revealed the presence of large tumor (T) antigen, and Southern blot analysis showed the incorporation of viral DNA into high molecular weight ciliary epithelial cell DNA. The presence of beta-adrenergic receptors was demonstrated by direct binding of a radiolabeled antagonist, [125I]iodopindolol, to membrane preparations of 8-SVHCE cells (Kd = 41.8 pM and Bmax = 67.1 fmol/mg of protein). Competition experiments with [125I]iodopindolol and selective drugs suggested that the receptors are of the beta 2-adrenergic subtype. Studies of catecholamine-stimulated cellular cAMP production and of isoproterenol-dependent protein phosphorylation of vimentin in 8-SVHCE indicated the functional conservation of beta-adrenergic receptor-mediated processes that are thought to be important in the regulation of aqueous humor production by the ciliary epithelium in vivo. Images PMID:3022303

  6. Human-Specific SNP in Obesity Genes, Adrenergic Receptor Beta2 (ADRB2), Beta3 (ADRB3), and PPAR γ2 (PPARG), during Primate Evolution

    PubMed Central

    Takenaka, Akiko; Nakamura, Shin; Mitsunaga, Fusako; Inoue-Murayama, Miho; Udono, Toshifumi; Suryobroto, Bambang

    2012-01-01

    Adrenergic-receptor beta2 (ADRB2) and beta3 (ADRB3) are obesity genes that play a key role in the regulation of energy balance by increasing lipolysis and thermogenesis. The Glu27 allele in ADRB2 and the Arg64 allele in ADRB3 are associated with abdominal obesity and early onset of non-insulin-dependent diabetes mellitus (NIDDM) in many ethnic groups. Peroxisome proliferator-activated receptor γ (PPARG) is required for adipocyte differentiation. Pro12Ala mutation decreases PPARG activity and resistance to NIDDM. In humans, energy-expense alleles, Gln27 in ADRB2 and Trp64 in ADRB3, are at higher frequencies than Glu27 and Arg64, respectively, but Ala12 in PPARG is at lower frequency than Pro12. Adaptation of humans for lipolysis, thermogenesis, and reduction of fat accumulation could be considered by examining which alleles in these genes are dominant in non-human primates (NHP). All NHP (P. troglodytes, G. gorilla, P. pygmaeus, H. agilis and macaques) had energy-thrifty alleles, Gly16 and Glu27 in ADRB2, and Arg64 in ADRB3, but did not have energy-expense alleles, Arg16, Gln27 and Trp64 alleles. In PPARG gene, all NHP had large adipocyte accumulating type, the Pro12 allele. Conclusions These results indicate that a tendency to produce much more heat through the energy-expense alleles developed only in humans, who left tropical rainforests for savanna and developed new features in their heat-regulation systems, such as reduction of body hair and increased evaporation of water, and might have helped the protection of entrails from cold at night, especially in glacial periods. PMID:22937051

  7. Novel Confocal Microscopic and Flow Cytometric Based Assays to Visualize and Detect the (Beta)2-Adrenergic Receptor in Human Lymphocyte and Mononuclear Cell Populations

    NASA Technical Reports Server (NTRS)

    Salicru, A. N.; Crucian, B. E.; Nelman, M. A.; Sams, C. F.; Actor, J. K.; Marshall, G. D.

    2006-01-01

    The data show that immunophenotyping of leukocyte populations with (beta)2AR is possible with the commercially available Ab, although the FC assay is limited to the IST as a result of the Ab binding site to the intracellular C-terminus of the 2AR. The FC assay has applications for measuring alterations in total (beta)2AR in human leukocyte populations as changes in fluorescence. In addition, CM confirms that both surface and intracellular compartments stain positively for the (beta)2AR and can be used for qualitative assays that screen for changes in receptor compartmentalization and localization.

  8. Comparative biochemical and pharmacological characterization of the mouse 5HT5A 5-hydroxytryptamine receptor and the human beta2-adrenergic receptor produced in the methylotrophic yeast Pichia pastoris.

    PubMed

    Weiss, H M; Haase, W; Michel, H; Reiländer, H

    1998-03-15

    Over the last few years, Pichia pastoris has been developed into a powerful expression system for a multitude of foreign genes. Here, we demonstrate that the P. pastoris expression system has similar power to the baculovirus expression system in high-level production of two G-protein-coupled receptors, the mouse 5HT5A 5-hydroxtryptamine receptor and the human beta2-adrenergic receptor. Different expression plasmids were constructed in which the cDNAs of the two receptors were cloned under the transcriptional control of the highly inducible promoter of the P. pastoris alcohol oxidase 1 (AOX1) gene. In three expression plasmids, the receptors were fused to the Saccharomyces cerevisiae alpha-factor prepropeptide and also to the c-myc tag or the FLAG tag to permit immunological detection of the receptors. After transformation into P. pastoris strains KM71 and SMD 1163, recombinant clones were selected and tested for the production of the 5HT5A receptor and the beta2-adrenergic receptor by radioligand binding using [N-methyl-3H]lysergic acid diethylamide and [5,7-3H](-)CGP-12177 respectively. The production level of the 5HT5A receptor was improved by a factor of three by fusion with the alpha-factor prepropeptide. Also, the higher gene dosage resulting from multiple insertions of the expression cassette led to an improvement in production by a factor of two for both receptors. The addition of the adrenergic antagonist alprenolol to the culture medium had a positive effect on the number of specific binding sites detectable in clones producing the beta2-adrenergic receptor. For the 5HT5A receptor the addition of yohimbine resulted in a similar but smaller effect. Binding assays revealed that approx. 25 pmol of beta2-adrenergic receptor and approx. 40 pmol of 5HT5A receptor per mg of membrane protein in crude membrane preparations were produced. The pharmacological profiles for the heterologously produced receptors, estimated by ligand-displacement analysis using certain

  9. Beta 2-adrenergic agonist as adjunct therapy to levodopa in Parkinson's disease.

    PubMed

    Alexander, G M; Schwartzman, R J; Nukes, T A; Grothusen, J R; Hooker, M D

    1994-08-01

    We studied the effect of the beta 2-adrenergic agonist albuterol on Parkinson's disease (PD) patients receiving chronic levodopa treatment. The albuterol-treated patients demonstrated reduced parkinsonian symptoms and an increased ability to tap their index finger between two points 20 cm apart, and were able to perform a "walk test" in 70% of their control time. Three patients currently on chronic albuterol therapy still show amelioration of their parkinsonian symptoms, and two have reduced their daily levodopa dose. This study suggests that beta 2-adrenergic agonists as adjunct therapy to levodopa may be beneficial in PD. PMID:8058159

  10. Beta-2 adrenergic receptor genotypes and haplotypes in different ethnic groups.

    PubMed

    Maxwell, Taylor J; Ameyaw, Margaret-Mary; Pritchard, Stuart; Thornton, Nadia; Folayan, Gbolahan; Githang'a, Jessie; Indalo, Anne; Tariq, Mohammed; Mobarek, Abeer; Evans, David A; Ofori-Adjei, David; Templeton, Alan R; McLeod, Howard L

    2005-10-01

    The human beta-2 adrenergic receptor (beta2AR) is responsible for the binding of endogenous catecholamines and their exogenously administered agonists and antagonists. Three functional polymorphisms in codons 16, 27 and 164 have been described which have clinical importance for several diseases, including asthma, hypertension, heart failure, cystic fibrosis and obesity, as well as response to beta-agonist therapy. These were evaluated in 726 individuals from 8 distinct ethnic populations (Chinese, Filipino, Southwest Asian, Saudi, Ghanaian, Kenyan, Sudanese, and European from Scotland). The results show that most haplotypes are shared among all populations, yet there are marked differences in their frequency distributions geographically. The genetic distance tree is different from standard human population distance trees, implying a different mode of evolution for this locus than that for human population gene-flow history. The multilocus frequency differences between the observed clusters of populations correspond to historical haplotype groupings that have been found to be functionally different with respect to multiple medically related phenotypes. Further studies are needed to see if functional relationships are the same across populations. PMID:16142389

  11. Beta2-adrenergic receptor stimulation inhibits nitric oxide generation by Mycobacterium avium infected macrophages.

    PubMed

    Boomershine, C S; Lafuse, W P; Zwilling, B S

    1999-11-01

    Catecholamine regulation of nitric oxide (NO) production by IFNgamma-primed macrophages infected with Mycobacterium avium was investigated. Epinephrine treatment of IFNgamma-primed macrophages at the time of M. avium infection inhibited the anti-mycobacterial activity of the cells. The anti-mycobacterial activity of macrophages correlated with NO production. Using specific adrenergic receptor agonists, the abrogation of mycobacterial killing and decreased NO production by catecholamines was shown to be mediated via the beta2-adrenergic receptor. Elevation of intracellular cAMP levels mimicked the catecholamine-mediated inhibition of NO in both M. avium infected and LPS stimulated macrophages. Specific inhibitors of both adenylate cyclase and protein kinase A prevented the beta2-adrenoceptor-mediated inhibition of nitric oxide production. Beta2-adrenoreceptor stimulation at the time of M. avium infection of IFNgamma-primed macrophages also inhibited expression of iNOS mRNA. These observations show that catecholamine hormones can affect the outcome of macrophage-pathogen interactions and suggest that one result of sympathetic nervous system activation is the suppression of the capacity of macrophages to produce anti-microbial effector molecules. PMID:10580815

  12. Dephosphorylation of the beta 2-adrenergic receptor and rhodopsin by latent phosphatase 2

    SciTech Connect

    Yang, S.D.; Fong, Y.L.; Benovic, J.L.; Sibley, D.R.; Caron, M.G.; Lefkowitz, R.J.

    1988-06-25

    Recent evidence suggests that the function of receptors coupled to guanine nucleotide regulatory proteins may be controlled by highly specific protein kinases, e.g. rhodopsin kinase and the beta-adrenergic receptor kinase. In order to investigate the nature of the phosphatases which might be involved in controlling the state of receptor phosphorylation we studied the ability of four highly purified well characterized protein phosphatases to dephosphorylate preparations of rhodopsin or beta 2-adrenergic receptor which had been highly phosphorylated by beta-adrenergic receptor kinase. These included: type 1 phosphatase, calcineurin phosphatase, type 2A phosphatase, and the high molecular weight latent phosphatase 2. Under conditions in which all the phosphatases could dephosphorylate such common substrates as (/sup 32/P)phosphorylase a and (/sup 32/P)myelin basic protein at similar rates only the latent phosphatase 2 was active on the phosphorylated receptors. Moreover, a latent phosphatase activity was found predominantly in a sequestered membrane fraction of frog erythrocytes. This parallels the distribution of a beta-adrenergic receptor phosphatase activity recently described in these cells. These data suggest a potential role for the latent phosphatase 2 as a specific receptor phosphatase.

  13. Analysis of hydrophobic interactions of antagonists with the beta2-adrenergic receptor.

    PubMed

    Novoseletsky, V N; Pyrkov, T V; Efremov, R G

    2010-01-01

    The adrenergic receptors mediate a wide variety of physiological responses, including vasodilatation and vasoconstriction, heart rate modulation, and others. Beta-adrenergic antagonists ('beta-blockers') thus constitute a widely used class of drugs in cardiovascular medicine as well as in management of anxiety, migraine, and glaucoma. The importance of the hydrophobic effect has been evidenced for a wide range of beta-blocker properties. To better understand the role of the hydrophobic effect in recognition of beta-blockers by their receptor, we carried out a molecular docking study combined with an original approach to estimate receptor-ligand hydrophobic interactions. The proposed method is based on automatic detection of molecular fragments in ligands and the analysis of their interactions with receptors separately. A series of beta-blockers, based on phenylethanolamines and phenoxypropanolamines, were docked to the beta2-adrenoceptor binding site in the crystal structure. Hydrophobic complementarity between the ligand and the receptor was calculated using the PLATINUM web-server (http://model.nmr.ru/platinum). Based on the analysis of the hydrophobic match for molecular fragments of beta-blockers, we have developed a new scoring function which efficiently predicts dissociation constant (pKd) with strong correlations (r(2) approximately 0.8) with experimental data. PMID:20373213

  14. Propafenone interacts stereoselectively with beta 1- and beta 2-adrenergic receptors

    SciTech Connect

    Burnett, D.M.; Gal, J.; Zahniser, N.R.; Nies, A.S.

    1988-01-01

    In order to determine whether the new antiarrhythmic agent propafenone interacts stereoselectively with beta-adrenergic receptors, the potencies of both the (-) and (+) isomers were determined using in vitro binding assays. (-)-Propafenone was the more potent isomer and competed with /sup 125/I-pindolol in a simple manner in both rat cerebral cortical and cerebellar membranes with Ki values of 32 +/- 1.7 and 77 +/- 5.8 nM, respectively. In contrast, competition curves for (+)-propafenone in the same tissues were more complex and revealed two binding sites with affinities 10- to 75-fold less potent than those for (-)-propafenone. Moreover, the (+)-propafenone was found by high performance liquid chromatography (HPLC) analysis to be contaminated with 3% of the more potent (-)-isomer; this contamination accounted for most of the apparent activity of the (+)-propafenone. These data suggest that interactions of propafenone with both beta 1- and beta 2-receptors are markedly stereoselective for the (-) isomer. It is possible that beta-adrenergic receptor blockade by the (-) isomer may be responsible for some of the adverse clinical effects that have been reported with propafenone therapy.

  15. Adrenergic activation of electrogenic K+ secretion in guinea pig distal colonic epithelium: involvement of beta1- and beta2-adrenergic receptors.

    PubMed

    Zhang, Jin; Halm, Susan T; Halm, Dan R

    2009-08-01

    Adrenergic stimulation of electrogenic K+ secretion in isolated mucosa from guinea pig distal colon required activation of two beta-adrenergic receptor subtypes (beta-AdrR). Addition of epinephrine (epi) or norepinephrine (norepi) to the bathing solution of mucosae in Ussing chambers increased short-circuit current (Isc) and transepithelial conductance (Gt), consistent with this cation secretion. A beta-adrenergic classification was supported by propranolol antagonism of this secretory response and the lack of effect by the alpha-AdrR antagonists BE2254 (alpha1-AdrR) and yohimbine (alpha2-AdrR). Subtype-selective antagonists CGP20712A (beta1-AdrR), ICI-118551 (beta2-AdrR), and SR59320A (beta3-AdrR) were relatively ineffective at inhibiting the epi-stimulated Isc response. In combination, CGP20712A and ICI-118551 inhibited the response, which supported a synergistic action by beta1-AdrR and beta2-AdrR. Expression of mRNA for both beta1-AdrR and beta2-AdrR was indicated by RT-PCR of RNA from colonic epithelial cells. Protein expression was indicated by immunoblot showing bands at molecular weights consistent with monomers and oligomers. Immunoreactivity (ir) for beta1-AdrR and beta2-AdrR was prominent in basolateral membranes of columnar epithelial cells in the crypts of Lieberkühn as well as intercrypt surface epithelium. Cells in the pericryptal sheath also had beta1-AdrR(ir) but did not have discernable beta2-AdrR(ir). The adrenergic sensitivity of K+ secretion measured by Isc and Gt was relatively low as indicated by EC(50)s of 41 +/- 7 nM for epi and 50 +/- 14 nM for norepi. Adrenergic activation of electrogenic K+ secretion required the involvement of both beta1-AdrR and beta2-AdrR, occurring with an agonist sensitivity reduced compared with reported values for either receptor subtype. PMID:19460844

  16. Beta2-adrenergic activity modulates vascular tone regulation in lecithin:cholesterol acyltransferase knockout mice

    PubMed Central

    Manzini, S.; Pinna, C.; Busnelli, M.; Cinquanta, P.; Rigamonti, E.; Ganzetti, G.S.; Dellera, F.; Sala, A.; Calabresi, L.; Franceschini, G.; Parolini, C.; Chiesa, G.

    2015-01-01

    Lecithin:cholesterol acyltransferase (LCAT) deficiency is associated with hypoalphalipoproteinemia, generally a predisposing factor for premature coronary heart disease. The evidence of accelerated atherosclerosis in LCAT-deficient subjects is however controversial. In this study, the effect of LCAT deficiency on vascular tone and endothelial function was investigated in LCAT knockout mice, which reproduce the human lipoprotein phenotype. Aortas from wild-type (Lcatwt) and LCAT knockout (LcatKO) mice exposed to noradrenaline showed reduced contractility in LcatKO mice (P < 0.005), whereas acetylcholine exposure showed a lower NO-dependent relaxation in LcatKO mice (P < 0.05). Quantitative PCR and Western blotting analyses suggested an adequate eNOS expression in LcatKO mouse aortas. Real-time PCR analysis indicated increased expression of β2-adrenergic receptors vs wild-type mice. Aorta stimulation with noradrenaline in the presence of propranolol, to abolish the β-mediated relaxation, showed the same contractile response in the two mouse lines. Furthermore, propranolol pretreatment of mouse aortas exposed to L-NAME prevented the difference in responses between Lcatwt and LcatKO mice. The results indicate that LCAT deficiency leads to increased β2-adrenergic relaxation and to a consequently decreased NO-mediated vasodilation that can be reversed to guarantee a correct vascular tone. The present study suggests that LCAT deficiency is not associated with an impaired vascular reactivity. PMID:26254103

  17. Beta2-adrenergic activity modulates vascular tone regulation in lecithin:cholesterol acyltransferase knockout mice.

    PubMed

    Manzini, S; Pinna, C; Busnelli, M; Cinquanta, P; Rigamonti, E; Ganzetti, G S; Dellera, F; Sala, A; Calabresi, L; Franceschini, G; Parolini, C; Chiesa, G

    2015-11-01

    Lecithin:cholesterol acyltransferase (LCAT) deficiency is associated with hypoalphalipoproteinemia, generally a predisposing factor for premature coronary heart disease. The evidence of accelerated atherosclerosis in LCAT-deficient subjects is however controversial. In this study, the effect of LCAT deficiency on vascular tone and endothelial function was investigated in LCAT knockout mice, which reproduce the human lipoprotein phenotype. Aortas from wild-type (Lcat(wt)) and LCAT knockout (Lcat(KO)) mice exposed to noradrenaline showed reduced contractility in Lcat(KO) mice (P<0.005), whereas acetylcholine exposure showed a lower NO-dependent relaxation in Lcat(KO) mice (P<0.05). Quantitative PCR and Western blotting analyses suggested an adequate eNOS expression in Lcat(KO) mouse aortas. Real-time PCR analysis indicated increased expression of β2-adrenergic receptors vs wild-type mice. Aorta stimulation with noradrenaline in the presence of propranolol, to abolish the β-mediated relaxation, showed the same contractile response in the two mouse lines. Furthermore, propranolol pretreatment of mouse aortas exposed to L-NAME prevented the difference in responses between Lcat(wt) and Lcat(KO) mice. The results indicate that LCAT deficiency leads to increased β2-adrenergic relaxation and to a consequently decreased NO-mediated vasodilation that can be reversed to guarantee a correct vascular tone. The present study suggests that LCAT deficiency is not associated with an impaired vascular reactivity. PMID:26254103

  18. Molecular Characterization and Expression Analysis of Adrenergic Receptor Beta 2 (ADRB2) Gene before and after Exercise in the Horse

    PubMed Central

    Cho, Hyun-Woo; Shin, Sangsu; Song, Ki-Duk; Park, Jeong-Woong; Choi, Jae-Young; Lee, Hak-Kyo; Cho, Byung-Wook

    2015-01-01

    The adrenergic receptor beta 2 (ADRB2) plays a role in various physiological responses of the muscle to exercise, such as contraction and relaxation. Given its important role in muscle function, we investigated the structure of the horse ADRB2 gene and its expression pattern after exercise to determine if it can serve as a putative biomarker for recovery. Evolutionary analyses using synonymous and non-synonymous mutation ratios, were compared with other species (human, chimpanzee, mouse, rat, cow, pig, chicken, dog, and cat), and revealed the occurrence of positive selection in the horse ADRB2 gene. In addition, expression analyses by quantitative polymerase chain reaction exhibited ubiquitous distribution of horse ADRB2 in various tissues including lung, skeletal muscle, kidney, thyroid, appendix, colon, spinal cord and heart, with the highest expression observed in the lung. The expression of ADRB2 in skeletal muscle was significantly up-regulated about four folds 30 minutes post-exercise compared to pre-exercise. The expression level of ADRB2 in leukocytes, which could be collected with convenience compared with other tissues in horse, increased until 60 min after exercise but decreased afterward until 120 min, suggesting the ADRB2 expression levels in leukocytes could be a useful biomarker to check the early recovery status of horse after exercise. In conclusion, we identified horse ADRB2 gene and analyzed expression profiles in various tissues. Additionally, analysis of ADBR2 gene expression in leukocytes could be a useful biomarker useful for evaluation of early recovery status after exercise in racing horses. PMID:25924960

  19. Molecular Characterization and Expression Analysis of Adrenergic Receptor Beta 2 (ADRB2) Gene before and after Exercise in the Horse.

    PubMed

    Cho, Hyun-Woo; Shin, Sangsu; Song, Ki-Duk; Park, Jeong-Woong; Choi, Jae-Young; Lee, Hak-Kyo; Cho, Byung-Wook

    2015-05-01

    The adrenergic receptor beta 2 (ADRB2) plays a role in various physiological responses of the muscle to exercise, such as contraction and relaxation. Given its important role in muscle function, we investigated the structure of the horse ADRB2 gene and its expression pattern after exercise to determine if it can serve as a putative biomarker for recovery. Evolutionary analyses using synonymous and non-synonymous mutation ratios, were compared with other species (human, chimpanzee, mouse, rat, cow, pig, chicken, dog, and cat), and revealed the occurrence of positive selection in the horse ADRB2 gene. In addition, expression analyses by quantitative polymerase chain reaction exhibited ubiquitous distribution of horse ADRB2 in various tissues including lung, skeletal muscle, kidney, thyroid, appendix, colon, spinal cord and heart, with the highest expression observed in the lung. The expression of ADRB2 in skeletal muscle was significantly up-regulated about four folds 30 minutes post-exercise compared to pre-exercise. The expression level of ADRB2 in leukocytes, which could be collected with convenience compared with other tissues in horse, increased until 60 min after exercise but decreased afterward until 120 min, suggesting the ADRB2 expression levels in leukocytes could be a useful biomarker to check the early recovery status of horse after exercise. In conclusion, we identified horse ADRB2 gene and analyzed expression profiles in various tissues. Additionally, analysis of ADBR2 gene expression in leukocytes could be a useful biomarker useful for evaluation of early recovery status after exercise in racing horses. PMID:25924960

  20. Structural basis for receptor subtype-specific regulation revealed by a chimeric beta 3/beta 2-adrenergic receptor.

    PubMed Central

    Liggett, S B; Freedman, N J; Schwinn, D A; Lefkowitz, R J

    1993-01-01

    The physiological significance of multiple G-protein-coupled receptor subtypes, such as the beta-adrenergic receptors (beta ARs), remains obscure, since in many cases several subtypes activate the same effector and utilize the same physiological agonists. We inspected the deduced amino acid sequences of the beta AR subtypes for variations in the determinants for agonist regulation as a potential basis for subtype differentiation. Whereas the beta 2AR has a C terminus containing 11 serine and threonine residues representing potential sites for beta AR kinase phosphorylation, which mediates rapid agonist-promoted desensitization, only 3 serines are present in the comparable region of the beta 3AR, and they are in a nonfavorable context. The beta 3AR also lacks sequence homology in regions which are important for agonist-mediated sequestration and down-regulation of the beta 2AR, although such determinants are less well defined. We therefore tested the idea that the agonist-induced regulatory properties of the two receptors might differ by expressing both subtypes in CHW cells and exposing them to the agonist isoproterenol. The beta 3AR did not display short-term agonist-promoted functional desensitization or sequestration, or long-term down-regulation. To assign a structural basis for these subtype-specific differences in agonist regulation, we constructed a chimeric beta 3/beta 2AR which comprised the beta 3AR up to proline-365 of the cytoplasmic tail and the C terminus of the beta 2AR. When cells expressing this chimeric beta 3/beta 2AR were exposed to isoproterenol, functional desensitization was observed. Whole-cell phosphorylation studies showed that the beta 2AR displayed agonist-dependent phosphorylation, but no such phosphorylation could be demonstrated with the beta 3AR, even when beta AR kinase was overexpressed. In contrast, the chimeric beta 3/beta 2AR did display agonist-dependent phosphorylation, consistent with its functional desensitization. In

  1. Beta(2)-adrenergic receptor regulates cardiac fibroblast autophagy and collagen degradation.

    PubMed

    Aránguiz-Urroz, Pablo; Canales, Jimena; Copaja, Miguel; Troncoso, Rodrigo; Vicencio, Jose Miguel; Carrillo, Constanza; Lara, Hernán; Lavandero, Sergio; Díaz-Araya, Guillermo

    2011-01-01

    Autophagy is a physiological degradative process key to cell survival during nutrient deprivation, cell differentiation and development. It plays a major role in the turnover of damaged macromolecules and organelles, and it has been involved in the pathogenesis of different cardiovascular diseases. Activation of the adrenergic system is commonly associated with cardiac fibrosis and remodeling, and cardiac fibroblasts are key players in these processes. Whether adrenergic stimulation modulates cardiac fibroblast autophagy remains unexplored. In the present study, we aimed at this question and evaluated the effects of b(2)-adrenergic stimulation upon autophagy. Cultured adult rat cardiac fibroblasts were treated with agonists or antagonists of beta-adrenergic receptors (b-AR), and autophagy was assessed by electron microscopy, GFP-LC3 subcellular distribution, and immunowesternblot of endogenous LC3. The predominant expression of b(2)-ARs was determined and characterized by radioligand binding assays using [(3)H]dihydroalprenolol. Both, isoproterenol and norepinephrine (non-selective b-AR agonists), as well as salbutamol (selective b(2)-AR agonist) increased autophagic flux, and these effects were blocked by propanolol (b-AR antagonist), ICI-118,551 (selective b(2)-AR antagonist), 3-methyladenine but not by atenolol (selective b(1)-AR antagonist). The increase in autophagy was correlated with an enhanced degradation of collagen, and this effect was abrogated by the inhibition of autophagic flux. Overall, our data suggest that b(2)-adrenergic stimulation triggers autophagy in cardiac fibroblasts, and that this response could contribute to reduce the deleterious effects of high adrenergic stimulation upon cardiac fibrosis. PMID:20637865

  2. Preliminary study on association of beta2-adrenergic receptor polymorphism with hypertension in hypertensive subjects attending Balok Health Centre, Kuantan.

    PubMed

    Atia, A E; Norsidah, K; Nor Zamzila, A; Rafidah Hanim, M; Samsul, D; Aznan, M A M; Rashidah, A R; Norlelawati, A T

    2012-02-01

    Polymorphisms within the beta2-adrenergic receptor (ADRB2) gene have been repeatedly linked to hypertension. Among the ADRB2 polymorphisms detected, Arg16Gly and Gln27Glu codons are considered the two most important variations. The amino acid substitution at these codons may lead to abnormal regulation of ADRB2 activity. The aim of the present study was to assess the association between ADRB2 polymorphisms and hypertension. This case-control study consisted of 100 unrelated subjects (50 hypertensive and 50 matched normal controls). Arg16Gly and the Gln27Glu polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism assay. There were no significant evidence of association in allelic and genotypes distribution of Arg16Gly and Glu27Gln with blood pressure and hypertension. These findings suggest that the variation within codon 16 and 27 of ADRB2 gene were unlikely to confer genetic susceptibility for hypertension in our population samples. PMID:22582545

  3. A functional SNP upstream of the beta-2 adrenergic receptor gene (ADRB2) is associated with obesity in Oceanic populations

    PubMed Central

    Naka, I; Hikami, K; Nakayama, K; Koga, M; Nishida, N; Kimura, R; Furusawa, T; Natsuhara, K; Yamauchi, T; Nakazawa, M; Ataka, Y; Ishida, T; Inaoka, T; Iwamoto, S; Matsumura, Y; Ohtsuka, R; Tsuchiya, N; Ohashi, J

    2013-01-01

    OBJECTIVE: Obesity is a growing health concern in the Oceanic populations. To investigate the genetic factors associated with adult obesity in the Oceanic populations, the association of single nucleotide polymorphisms (SNPs) of the beta-2 adrenergic receptor (ADRB2) gene with obesity was examined in 694 adults living in Tonga and Solomon Islands. RESULTS: A screening for variation in 16 Oceanic subjects detected 17 SNPs in the entire region of ADRB2, of which nine SNPs including two non-synonymous ones, rs1042713 (Arg16Gly) and rs1042714 (Gln27Glu), were further genotyped for all subjects. The rs34623097-A allele, at a SNP located upstream of ADRB2, showed the strongest association with risk for obesity in a logistic regression analysis adjusted for age, sex, and population (P=5.6 × 10−4, odds ratio [OR]=2.5, 95% confidence interval [CI]=1.5–4.2). The 27Glu was also significantly associated with obesity in the single-point association analysis (P=0.013, OR=2.0, 95%CI=1.2–3.4); however, this association was no longer significant after adjustment for rs34623097 since these SNPs were in linkage disequilibrium with each other. A copy of the obesity-risk allele, rs34623097-A, led to a 1.6 kg/m2 increase in body mass index (BMI; defined as weight in kilograms divided by height in meters squared) (P=0.0019). A luciferase reporter assay indicated that rs34623097-A reduced the transcriptional activity of the luciferase reporter gene by approximately 10% compared with rs34623097-G. An electrophoretic mobility shift assay demonstrated that rs34623097 modulated the binding affinity with nuclear factors. An evolutionary analysis implies that a G>A mutation at rs34623097 occurred in the Neandertal genome and then the rs34623097-A allele flowed into the ancestors of present-day humans. CONCLUSION: The present results suggest that rs34623097-A, which would lead to lower expression of ADRB2, contributes to the onset of obesity in the Oceanic populations. PMID:23229733

  4. Can Specific Protein-Lipid Interactions Stabilize an Active State of the Beta 2 Adrenergic Receptor?

    PubMed

    Neale, Chris; Herce, Henry D; Pomès, Régis; García, Angel E

    2015-10-20

    G-protein-coupled receptors are eukaryotic membrane proteins with broad biological and pharmacological relevance. Like all membrane-embedded proteins, their location and orientation are influenced by lipids, which can also impact protein function via specific interactions. Extensive simulations totaling 0.25 ms reveal a process in which phospholipids from the membrane's cytosolic leaflet enter the empty G-protein binding site of an activated β2 adrenergic receptor and form salt-bridge interactions that inhibit ionic lock formation and prolong active-state residency. Simulations of the receptor embedded in an anionic membrane show increased lipid binding, providing a molecular mechanism for the experimental observation that anionic lipids can enhance receptor activity. Conservation of the arginine component of the ionic lock among Rhodopsin-like G-protein-coupled receptors suggests that intracellular lipid ingression between receptor helices H6 and H7 may be a general mechanism for active-state stabilization. PMID:26488656

  5. Caveolin-3 regulates compartmentation of cardiomyocyte beta2-adrenergic receptor-mediated cAMP signaling.

    PubMed

    Wright, Peter T; Nikolaev, Viacheslav O; O'Hara, Thomas; Diakonov, Ivan; Bhargava, Anamika; Tokar, Sergiy; Schobesberger, Sophie; Shevchuk, Andrew I; Sikkel, Markus B; Wilkinson, Ross; Trayanova, Natalia A; Lyon, Alexander R; Harding, Sian E; Gorelik, Julia

    2014-02-01

    The purpose of this study was to investigate whether caveolin-3 (Cav3) regulates localization of β2-adrenergic receptor (β2AR) and its cAMP signaling in healthy or failing cardiomyocytes. We co-expressed wildtype Cav3 or its dominant-negative mutant (Cav3DN) together with the Förster resonance energy transfer (FRET)-based cAMP sensor Epac2-camps in adult rat ventricular myocytes (ARVMs). FRET and scanning ion conductance microscopy were used to locally stimulate β2AR and to measure cytosolic cAMP. Cav3 overexpression increased the number of caveolae and decreased the magnitude of β2AR-cAMP signal. Conversely, Cav3DN expression resulted in an increased β2AR-cAMP response without altering the whole-cell L-type calcium current. Following local stimulation of Cav3DN-expressing ARVMs, β2AR response could only be generated in T-tubules. However, the normally compartmentalized β2AR-cAMP signal became diffuse, similar to the situation observed in heart failure. Finally, overexpression of Cav3 in failing myocytes led to partial β2AR redistribution back into the T-tubules. In conclusion, Cav3 plays a crucial role for the localization of β2AR and compartmentation of β2AR-cAMP signaling to the T-tubules of healthy ARVMs, and overexpression of Cav3 in failing myocytes can partially restore the disrupted localization of these receptors. PMID:24345421

  6. Caveolin-3 regulates compartmentation of cardiomyocyte beta2-adrenergic receptor-mediated cAMP signaling

    PubMed Central

    Wright, Peter T.; Nikolaev, Viacheslav O.; O’Hara, Thomas; Diakonov, Ivan; Bhargava, Anamika; Tokar, Sergiy; Schobesberger, Sophie; Shevchuk, Andrew I.; Sikkel, Markus B.; Wilkinson, Ross; Trayanova, Natalia A.; Lyon, Alexander R.; Harding, Sian E.; Gorelik, Julia

    2014-01-01

    The purpose of this study was to investigate whether caveolin-3 (Cav3) regulates localization of β2-adrenergic receptor (β2AR) and its cAMP signaling in healthy or failing cardiomyocytes. We co-expressed wildtype Cav3 or its dominant-negative mutant (Cav3DN) together with the Förster resonance energy transfer (FRET)-based cAMP sensor Epac2-camps in adult rat ventricular myocytes (ARVMs). FRET and scanning ion conductance microscopy were used to locally stimulate β2AR and to measure cytosolic cAMP. Cav3 overexpression increased the number of caveolae and decreased the magnitude of β2AR-cAMP signal. Conversely, Cav3DN expression resulted in an increased β2AR-cAMP response without altering the whole-cell L-type calcium current. Following local stimulation of Cav3DN-expressing ARVMs, β2AR response could only be generated in T-tubules. However, the normally compartmentalized β2AR-cAMP signal became diffuse, similar to the situation observed in heart failure. Finally, overexpression of Cav3 in failing myocytes led to partial β2AR redistribution back into the T-tubules. In conclusion, Cav3 plays a crucial role for the localization of β2AR and compartmentation of β2AR-cAMP signaling to the T-tubules of healthy ARVMs, and overexpression of Cav3 in failing myocytes can partially restore the disrupted localization of these receptors. PMID:24345421

  7. Repeated beta-2 adrenergic receptor agonist therapy attenuates the response to rescue bronchodilation in a hyperoxic newborn mouse model

    PubMed Central

    Raffay, Thomas; Kc, Prabha; Reynolds, James; Di Fiore, Juliann; MacFarlane, Peter; Martin, Richard

    2014-01-01

    Background Preterm infants with neonatal lung injury are prone to wheezing and are often treated with beta-2 adrenergic receptor (β-AR) agonists although any benefits of β-AR agonists may be lost with chronic use. Objective To investigate if repeated β-AR agonist exposures would down-regulate β-ARs in the immature lung resulting in a decreased response to bronchodilator rescue and whether hyperoxic exposure would aggravate this response. Methods Newborn mice were raised for 21 days in 60% or 21% oxygen and received daily aerosols of formoterol or saline. Respiratory system resistance (Rrs) and compliance (Crs) were measured in response to methacholine challenge and rescue bronchodilation with levalbuterol. Western blot analysis quantified the relative amount of lung β-ARs. Results Hyperoxia increased airway reactivity to methacholine. Animals raised in hyperoxia that received daily formoterol were most sensitive to methacholine and exhibited a blunted response to levalbuterol bronchodilation. Hyperoxia exposed animals receiving daily formoterol vs saline showed a significant decrease in the relative amount of lung β-ARs. Conclusions In this hyperoxia exposed neonatal mouse model, repeated β-AR agonist treatments increased airway reactivity and attenuated the response to a rescue bronchodilator. The blunted bronchodilator response could be explained by a reduced quantity of lung β-ARs. Our findings may account for a time-dependent decrease in therapeutic benefit of β-AR agonists in preterm infants with neonatal lung injury, which may have clinical consequences for patients already prone to airway hyperreactivity. PMID:24969536

  8. The interaction of signal transduction pathways in FRTL5 thyroid follicular cells: Studies with stable expression of beta 2-adrenergic receptors

    SciTech Connect

    Tsuzaki, S.; Cone, R.D.; Frazier, A.L.; Moses, A.C. )

    1991-03-01

    Multiple signal transduction pathways interact in FRTL5 cells to promote thyroid follicular cell differentiated function and cell proliferation. In these cells, TSH is a tissue-specific mitogen that promotes DNA synthesis primarily through activation of adenylate cyclase. To further test the role of adenylate cyclase in regulating cell growth and differentiated function we have introduced into FRTL5 the human beta 2-adrenergic receptor (BAR) complementary DNA and have studied the ability of isoproterenol, alone and in combination with insulin-like growth factor I (IGF-I), to stimulate cAMP accumulation, iodide transport, (3H)thymidine incorporation into DNA, and cell growth. Wild-type FRTL5 were infected with a PLJ retroviral construct containing the BAR in either a sense (FRTL BAR) or antisense (FRTL RBAR) orientation, and cell populations were selected on the basis of resistance to the antibiotic geneticin. FRTL BAR expressed approximately 1.3 x 10(5) high affinity binding sites per cell for the beta 2-specific ligand, CGP-12177, while neither FRTL5 wild-type nor RBAR cells demonstrated any specific binding. FRTL BAR had significantly higher levels of intracellular cAMP, (3H)thymidine incorporation, and iodide uptake in the absence of added isoproterenol than FRTL RBAR or wild-type cells. In FRTL BAR, but not RBAR cells, isoproterenol stimulated a dose-dependent accumulation of cAMP, iodide uptake, (3H)thymidine incorporation, and cell growth. FRTL BAR and RBAR cells were equally responsive to TSH and to IGF-I. Isoproterenol enhanced the ability of IGF-I to stimulate (3H)thymidine incorporation in BAR but not RBAR cells. Isoproterenol partially inhibited the ability of TSH to stimulate cAMP generation and DNA synthesis.

  9. Molecular dynamics of a biophysical model for beta2-adrenergic and G protein-coupled receptor activation.

    PubMed

    Rubenstein, Lester A; Zauhar, Randy J; Lanzara, Richard G

    2006-12-01

    This study analyzes 16 molecular dynamic simulations of a biophysical model for beta(2)-adrenergic (B2AR) and G protein-coupled receptor (GPCR) activation. In this model, a highly conserved cysteine residue, C106 (C3.25 or CysIII:01), provides a free sulfhydryl or thiol group in an acid-base equilibrium between uncharged (RSH) and charged (RS(-)) states that functions as an electrostatic molecular switch for receptor activation. The transition of C106 in the B2AR between acid and base states significantly changes the helical/transmembrane (TM) domain interactions and the electrostatic interaction energy differences (DeltaDeltaE(EL)). The DeltaDeltaE(EL) changes correlate well with the experimentally observed ligand efficacies. The TM interaction energies display patterns compatible with those previously recognized as responsible for GPCR activation. Key differences between the agonist, epinephrine, and the antagonist, pindolol, are seen for the TM3 x 6, TM3 x 4, TM6 x 7 and TM1 x 7 interaction energies. Pindolol also produces a weaker DeltaDeltaE(EL) interaction and less TM interaction energy changes, which are important differences between the agonist and antagonist ligands. The D115E mutant with pindolol displays a greater DeltaDeltaE(EL) and TM interactions than for the wild-type B2AR with pindolol. This explains the higher activity of pindolol in the D115E mutant. The constitutively active D130A mutant displays TM interaction patterns similar to those for the activating ligands implying a common pattern for receptor activation. These findings support the broad concept of protean agonism and demonstrate the potential for allosteric modulation. They also demonstrate that this two-state model agrees with many previous experimental and theoretical observations of GPCRs. PMID:16574446

  10. Influence of polymorphisms of the beta-2 adrenergic receptor on the presence of exercise-induced bronchospasm in adolescents✰

    PubMed Central

    Consentino, Cássio Leandro Mühe; Furtado-Alle, Lupe; da Silva, Larissa Rosa; Lopes, Wendell Arthur; Tureck, Luciane Viater; Milano, Gerusa Einsfeld; Lazarotto, Leilane; Cavaglieri, Cláudia Regina; Leite, Neiva

    2016-01-01

    Abstract Objective: To determine the influence of polymorphisms of the beta-2 adrenergic receptor (ADRB2) in triggering exercise-induced bronchospasm (EIB) in adolescents. Methods: The subjects were divided into two groups: present EIB (EIB+) (n=45) and absent EIB (EIB−) (n=115). The bronchial provocation test with exercise was performed with a protocol that consisted of walking/running for at least eight minutes at high intensity, i.e., >85% of maximum heart rate, considering EIB+ as a 10% decrease in forced expiratory volume in one second (FEV1). The genotyping of the ADRB2 gene was performed by the Taqman method, using the Step One Plus system. Independent t-test, Mann–Whitney and Chi-square tests, as well as Spearman's correlation coefficient were used for the statistical analysis. Results: Age, body weight, height, FEV1, FVC and FEV1/FVC ratio were lower in the EIB+ group when compared to EIB− (p<0.05). There were no significant differences in the proportion of the allele at position 27 and Arg16Gly and Gln27Glu genotypes between the EIB+ and EIB− groups (p=0.26; p=0.97 and p=0.43, respectively). However, there was a trend toward statistical significance regarding the greater proportion of the Gly16 allele for the EIB+ when compared to the EIB− group (p=0.08). Conclusions: The presence of polymorphisms associated with the Glu27 allele and Arg16Gly and Gln27Glu genotypes had no influence on EIB. However, the statistical trend toward greater frequency of the Gly16 allele in individuals with EIB+ can be considered evidence of the influence of polymorphisms of the ADBR2 gene on EIB in adolescents. PMID:26684442

  11. Beta 1- and beta 2-adrenergic /sup 125/I-pindolol binding sites in the interpeduncular nucleus of the rat: Normal distribution and the effects of deafferentation

    SciTech Connect

    Battisti, W.P.; Artymyshyn, R.P.; Murray, M.

    1989-07-01

    The plasticity of the beta 1- and beta 2-adrenergic receptor subtypes was examined in the interpeduncular nucleus (IPN) of the adult rat. The beta-adrenergic receptor antagonist 125I-pindolol (125I-PIN) was used in conjunction with the selective subtype antagonists ICI 118,551 and ICI 89,406 to determine the subnuclear distribution of beta 1- and beta 2-adrenergic receptors in this nucleus and to correlate the receptor distribution with the distribution of both noradrenergic afferents from the locus coeruleus (LC) and non-noradrenergic afferents from the fasiculus retroflexus (FR). The density of these binding sites was examined following lesions that decreased (LC lesions) or increased (FR lesions) the density of the noradrenergic projection in the IPN. Quantitative radioautography indicated that beta 1-labeled binding sites account for the larger percentage of binding sites in the IPN. The beta 1-binding sites are densest in those subnuclei that receive a noradrenergic projection from the LC: the central, rostral, and intermediate subnuclei. beta 1-binding sites are algo homogeneously distributed throughout the lateral subnuclei, where there is no detectable noradrenergic innervation. beta 2-binding sites have a more restricted distribution. They are concentrated in the ventral half of the lateral subnuclei, where they account for 70% of total 125I-PIN binding sites. beta 2-binding sites are also present along the ventral border of the IPN. Some of this labeling extends into the central and intermediate subnuclei. Bilateral lesions of the LC, which selectively remove noradrenergic innervation to the IPN, result in an increase in the beta 1-binding sites. Bilateral lesions of the FR, which remove the major cholinergic and peptidergic input from the IPN, elicit an increase in noradrenergic projections and a decrease in beta 1-binding sites.

  12. beta2 Adrenergic receptor activation induces microglial NADPH oxidase activation and dopaminergic neurotoxicity through an ERK-dependent/protein kinase A-independent pathway.

    PubMed

    Qian, Li; Hu, Xiaoming; Zhang, Dan; Snyder, Amanda; Wu, Hung-Ming; Li, Yachen; Wilson, Belinda; Lu, Ru-Band; Hong, Jau-Shyong; Flood, Patrick M

    2009-11-15

    Activation of the beta2 adrenergic receptor (beta2AR) on immune cells has been reported to possess anti-inflammatory properties, however, the pro-inflammatory properties of beta2AR activation remain unclear. In this study, using rat primary mesencephalic neuron-glia cultures, we report that salmeterol, a long-acting beta2AR agonist, selectively induces dopaminergic (DA) neurotoxicity through its ability to activate microglia. Salmeterol selectively increased the production of reactive oxygen species (ROS) by NADPH oxidase (PHOX), the major superoxide-producing enzyme in microglia. A key role of PHOX in mediating salmeterol-induced neurotoxicity was demonstrated by the inhibition of DA neurotoxicity in cultures pretreated with diphenylene-iodonium (DPI), an inhibitor of PHOX activity. Mechanistic studies revealed the activation of microglia by salmeterol results in the selective phosphorylation of ERK, a signaling pathway required for the translocation of the PHOX cytosolic subunit p47(phox) to the cell membrane. Furthermore, we found ERK inhibition, but not protein kinase A (PKA) inhibition, significantly abolished salmeterol-induced superoxide production, p47(phox) translocation, and its ability to mediate neurotoxicity. Together, these findings indicate that beta2AR activation induces microglial PHOX activation and DA neurotoxicity through an ERK-dependent/PKA-independent pathway. PMID:19330844

  13. Asthma: Gln27Glu and Arg16Gly polymorphisms of the beta2-adrenergic receptor gene as risk factors

    PubMed Central

    2014-01-01

    Background Asthma is caused by both environmental and genetic factors. The ADRB2 gene, which encodes the beta 2-adrenergic receptor, is one of the most extensively studied genes with respect to asthma prevalence and severity. The Arg16Gly (+46A > G) and Gln27Glu (+79C > G) polymorphisms in the ADRB2 gene cause changes in the amino acids flanking the receptor ligand site, altering the response to bronchodilators and the risk of asthma through complex pathways. The ADRB2 polymorphisms affect beta-adrenergic bronchodilator action and are a tool to identify at-risk populations. Objective To determine the frequency of these two polymorphisms in allergic asthma patients and healthy subjects and to correlate these data with the occurrence and severity of asthma. Methods Eighty-eight allergic asthma patients and 141 healthy subjects were included in this study. The ADRB2 polymorphisms were analyzed using the amplification-refractory mutation system – polymerase chain reaction (ARMS-PCR) technique. The statistical analysis was performed with the SPSS 21.0 software using the Fisher’s Exact and χ2 tests. Results The ADRB2 polymorphisms were associated with asthma occurrence. The Arg16Arg, Gln27Gln and Gln27Glu genotypes were risk factors; the odds ratios were 6.782 (CI = 3.07 to 16.03), 2.120 (CI = 1.22 to 3.71) and 8.096 (CI = 3.90 to 17.77), respectively. For the Gly16Gly and Glu27Glu genotypes, the odds ratios were 0.312 (CI = 0.17 to 0.56) and 0.084 (CI = 0.04 to 0.17), respectively. The haplotype analysis showed that there were associations between the following groups: Arg16Arg-Gln27Gln (OR = 5.108, CI = 1.82 to 16.37), Gly16Gly-Glu27Glu (OR = 2.816, CI = 1.25 to 6.54), Arg16Gly-Gln27Glu (OR = 0.048, CI = 0.01 to 0.14) and Gly16Gly-Gln27Glu (OR = 0.1036, CI = 0.02 to 0.39). The polymorphism Gln27Glu was associated with asthma severity, as the Gln27Gln genotype was a risk factor for severe asthma (OR

  14. Correlation of Beta-2 Adrenergic Receptor Expression in Tumor-Free Surgical Margin and at the Invasive Front of Oral Squamous Cell Carcinoma.

    PubMed

    Oliveira, Denise Tostes; Bravo-Calderón, Diego Mauricio; Lauand, Gustavo Amaral; Assao, Agnes; Suárez-Peñaranda, José-Manuel; Pérez-Sayáns, Mario; García-García, Abel; Marana, Aparecido Nilceu; Nonogaki, Suely; Lauris, José Roberto Pereira; Kowalski, Luiz Paulo

    2016-01-01

    Background. The beta-2 adrenergic receptor is expressed by neoplastic cells and is correlated with a wide spectrum of tumor cell mechanisms including proliferation, apoptosis, angiogenesis, migration, and metastasis. Objectives. The present study aimed to analyze the expression of the beta-2 adrenergic receptor (β2-AR) in tumor-free surgical margins of oral squamous cell carcinomas (OSCC) and at the invasive front. Sixty-two patients diagnosed with OSCC, confirmed by biopsy, were selected for the study. The clinicopathological data and clinical follow-up were obtained from medical records and their association with β2-AR expression was verified by the chi-square test or Fischer's exact test. To verify the correlation of β2-AR expression in tumor-free surgical margins and at the invasive front of OSCCs, Pearson's correlation coefficient test was applied. Results. The expression of β2-AR presented a statistically significant correlation between the tumor-free surgical margins and the invasive front of OSCC (r = 0.383; p = 0.002). The immunohistochemical distribution of β2-AR at the invasive front of OSCC was also statistically significant associated with alcohol (p = 0.038), simultaneous alcohol and tobacco consumption (p = 0.010), and T stage (p = 0.014). Conclusions. The correlation of β2-AR expression in OSCC and tumor-free surgical margins suggests a role of this receptor in tumor progression and its expression in normal oral epithelium seems to be constitutive. PMID:27042179

  15. Correlation of Beta-2 Adrenergic Receptor Expression in Tumor-Free Surgical Margin and at the Invasive Front of Oral Squamous Cell Carcinoma

    PubMed Central

    Bravo-Calderón, Diego Mauricio; Lauand, Gustavo Amaral; Assao, Agnes; Suárez-Peñaranda, José-Manuel; Pérez-Sayáns, Mario; García-García, Abel; Marana, Aparecido Nilceu; Nonogaki, Suely; Lauris, José Roberto Pereira; Kowalski, Luiz Paulo

    2016-01-01

    Background. The beta-2 adrenergic receptor is expressed by neoplastic cells and is correlated with a wide spectrum of tumor cell mechanisms including proliferation, apoptosis, angiogenesis, migration, and metastasis. Objectives. The present study aimed to analyze the expression of the beta-2 adrenergic receptor (β2-AR) in tumor-free surgical margins of oral squamous cell carcinomas (OSCC) and at the invasive front. Sixty-two patients diagnosed with OSCC, confirmed by biopsy, were selected for the study. The clinicopathological data and clinical follow-up were obtained from medical records and their association with β2-AR expression was verified by the chi-square test or Fischer's exact test. To verify the correlation of β2-AR expression in tumor-free surgical margins and at the invasive front of OSCCs, Pearson's correlation coefficient test was applied. Results. The expression of β2-AR presented a statistically significant correlation between the tumor-free surgical margins and the invasive front of OSCC (r = 0.383; p = 0.002). The immunohistochemical distribution of β2-AR at the invasive front of OSCC was also statistically significant associated with alcohol (p = 0.038), simultaneous alcohol and tobacco consumption (p = 0.010), and T stage (p = 0.014). Conclusions. The correlation of β2-AR expression in OSCC and tumor-free surgical margins suggests a role of this receptor in tumor progression and its expression in normal oral epithelium seems to be constitutive. PMID:27042179

  16. Genetic polymorphisms of the beta 2-adrenergic receptor in nocturnal and nonnocturnal asthma. Evidence that Gly16 correlates with the nocturnal phenotype.

    PubMed Central

    Turki, J; Pak, J; Green, S A; Martin, R J; Liggett, S B

    1995-01-01

    Nocturnal asthma represents a unique subset of patients with asthma who experience worsening symptoms and airflow obstruction at night. The basis for this phenotype of asthma is not known, but beta 2-adrenergic receptors (beta 2AR) are known to downregulate overnight in nocturnal asthmatics but not normal subjects or nonnocturnal asthmatics. We have recently delineated three polymorphic loci within the coding block of the beta 2AR which alter amino acids at positions 16, 27, and 164 and impart specific biochemical and pharmacologic phenotypes to the receptor. In site-directed mutagenesis/recombinant expression studies we have found that glycine at position 16 (Gly16) imparts an accelerated agonist-promoted downregulation of beta 2AR as compared to arginine at this position (Arg16). We hypothesized that Gly16 might be overrepresented in nocturnal asthmatics and thus determined the beta 2AR genotypes of two well-defined asthmatic cohorts: 23 nocturnal asthmatics with 34 +/- 2% nocturnal depression of peak expiratory flow rates, and 22 nonnocturnal asthmatics with virtually no such depression (2.3 +/- 0.8%). The frequency of the Gly16 allele was 80.4% in the nocturnal group as compared to 52.2% in the nonnocturnal group, while the Arg16 allele was present in 19.6 and 47.8%, respectively. This overrepresentation of the Gly16 allele in nocturnal asthma was significant at P = 0.007 with an odds ratio of having nocturnal asthma and the Gly16 polymorphism being 3.8. Comparisons of the two cohorts as to homozygosity for Gly16, homozygosity for Arg16, or heterozygosity were also consistent with segregation of Gly16 with nocturnal asthma. There was no difference in the frequency of polymorphisms at loci 27 (Gln27 or Glu27) and 164 (Thr164 or Ile164) between the two groups. Thus the Gly16 polymorphism of the beta 2AR, which imparts an enhanced downregulation of receptor number, is overrepresented in nocturnal asthma and appears to be an important genetic factor in the

  17. Beta 2-adrenergic receptor gene association with overweight and asthma in children and adolescents and its relationship with physical fitness

    PubMed Central

    Leite, Neiva; Lazarotto, Leilane; Milano, Gerusa Eisfeld; Titski, Ana Claudia Kapp; Consentino, Cássio Leandro Mühe; de Mattos, Fernanda; de Andrade, Fabiana Antunes; Furtado-Alle, Lupe

    2015-01-01

    Objective: To investigate the association of Arg16Gly and Gln27Glu polymorphisms of β2-adrenergic receptor gene (ADRB2) with the occurrence of asthma and overweight and the gene's influence on anthropometric, clinic, biochemical and physical fitness variables in children and adolescents. Methods: Subjects were evaluated for allelic frequencies of the β2-adrenergic receptor gene, height, weight, body mass index (BMI), BMI Z-score, waist circumference (WC), pubertal stage, resting heart rate (HRres), blood pressure (BP), total cholesterol (TC), glucose, insulin, high density lipoprotein (HDL-C), low density lipoprotein (LDL-C), triglyceride (TG), Homeostasis Metabolic Assessment (HOMA2-IR), Quantitative Insulin Sensitivity Check Index (QUICKI) and maximal oxygen uptake (VO2max). The participants were divided in four groups: overweight asthmatic (n=39), overweight non-asthmatic (n=115), normal weight asthmatic (n=12), and normal weight non-asthmatic (n=40). Results: Regarding the Gln27Glu polymorphism, higher total cholesterol was observed in usual genotype individuals than in genetic variant carriers (p=0.04). No evidence was found that the evaluated polymorphisms are influencing the physical fitness. The Arg16 allele was found more frequently among the normal weight asthmatic group when compared to the normal weight non-asthmatic group (p=0.02), and the Glu27 allele was more frequently found in the overweight asthmatics group when compared to the normal weight non-asthmatic group (p=0.03). Conclusions: The association of Arg16 allele with the occurrence of asthma and of the Glu27 allele with overweight asthmatic adolescents evidenced the contribution of the β2-adrenergic receptor gene to the development of obesity and asthma. PMID:26409918

  18. Indirect immunofluorescence localization of beta-adrenergic receptors and G-proteins in human A431 cells.

    PubMed Central

    Wang, H Y; Berrios, M; Malbon, C C

    1989-01-01

    Polyclonal antibodies directed against (i) rodent lung beta 2-adrenergic receptor, (ii) a synthetic fragment of an extracellular domain of the receptor, and (iii) human placenta G-protein beta-subunits, were used to localize these antigens in situ in intact and permeabilized human epidermoid carcinoma A431 cells. Antibodies directed against beta 2-adrenergic receptors showed a punctate immunofluorescence staining throughout the cell surface of fixed intact cells. Punctate staining was also observed in clones of Chinese hamster ovary cells transfected with an expression vector harbouring the gene for the hamster beta 2-adrenergic receptor. The immunofluorescence observed with anti-receptor antibodies paralleled the level of receptor expression. In contrast, the beta-subunits common to G-proteins were not stained in fixed intact cells, presumably reflecting their intracellular localization. In detergent-permeabilized fixed cells, strong punctate staining of G beta-subunits was observed throughout the cytoplasm. This is the first indirect immunofluorescence localization of beta-adrenergic receptors and G-proteins. Punctate immunofluorescence staining suggests that both antigens are distributed in clusters. Images Fig. 1. Fig. 2. Fig. 3. Fig. 4. Fig. 5. Fig. 6. Fig. 7. p528-a Fig. 9. Fig. 10. PMID:2556996

  19. Adrenergic receptors in human fetal liver membranes

    SciTech Connect

    Falkay, G.; Kovacs, L. )

    1990-01-01

    The adrenergic receptor binding capacities in human fetal and adult livers were measured to investigate the mechanism of the reduced alpha-1 adrenoreceptor response of the liver associated with a reciprocal increase in beta-adrenoreceptor activity in a number of conditions. Alpha-1 and beta-adrenoreceptor density were determined using {sup 3}H-prazosin and {sup 3}H-dihydroalprenolol, respectively, as radioligand. Heterogeneous populations of beta-adrenoreceptors were found in fetal liver contrast to adult. Decreased alpha-1 and increased beta-receptor density were found which may relate to a decreased level in cellular differentiation. These findings may be important for the investigation of perinatal hypoglycemia of newborns after treatment of premature labor with beta-mimetics. This is the first demonstration of differences in the ratio of alpha-1 and beta-adrenoceptors in human fetal liver.

  20. Evidence for the presence of beta 3-adrenergic receptor mRNA in the human brain.

    PubMed

    Rodriguez, M; Carillon, C; Coquerel, A; Le Fur, G; Ferrara, P; Caput, D; Shire, D

    1995-04-01

    The beta 3-adrenergic receptor (AR) is widely distributed in peripheral tissues, but up to now it has not been detected in the central nervous system. By using the polymerase chain reaction (PCR) technique, we found the beta 3-AR mRNA to be present in all the regions of the human brain we investigated. The quantities found were very low compared to those of the beta 1-AR and beta 2-AR mRNAs, being hardly detectable in adult brain. In contrast, the brain of very young infants contained about 100 times more beta 3-AR mRNA than the adult brain, whereas the amounts of beta 1-AR and beta 2-AR transcripts were essentially the same. In addition, using PCR we have cloned a central beta 3-AR coding region from a human frontal cortex cDNA library and have found it to be identical to the corresponding peripheral sequence. PMID:7609625

  1. Environmental factors and beta2-adrenergic receptor polymorphism: influence on the energy expenditure and nutritional status of obese women.

    PubMed

    Rosado, Eliane Lopes; Bressan, Josefina; Martínez, J Alfredo

    2015-05-01

    Our aim was to evaluate the influence of the Gln27Glu polymorphism of the β2-adrenergic receptor (ADRβ2) gene, fat intake and physical activity on the energy expenditure (EE) and nutritional status of obese women. Sixty obese women (30-46 years) participated in the study and were assigned to three groups depending on the genotypes: Gln27Gln, Gln27Glu and Glu27Glu. At baseline and after nutritional intervention, the anthropometric and body composition (bioelectrical impedance), dietary, EE (indirect calorimetry) and biochemical variables were measured. All women received a high-fat test meal to determine the postprandial EE (short-term) and an energy-restricted diet for 10 weeks (long term). The frequencies of Gln27Gln, Gln27Glu and Glu27Glu were 36.67, 40.0 and 23.33 %, respectively. Anthropometric and biochemical variables and EE did not differ between groups, although women who had no polymorphism demonstrated decreased carbohydrate oxidation. On the other hand, the Glu27Glu genotype showed a positive relation with EE in physical activity and fat oxidation. The environmental factors and Gln27Glu polymorphism did not influence the nutritional status and EE of obese women, but physical activity in obese women with the polymorphism in the ADRβ2 gene can promote fat oxidation. The results suggest that encouraging the practice of physical exercise is important considering the high frequency of this polymorphism in obese subjects. PMID:25893811

  2. Conformational entropic maps of functional coupling domains in GPCR activation: A case study with beta2 adrenergic receptor

    NASA Astrophysics Data System (ADS)

    Liu, Fan; Abrol, Ravinder; Goddard, William, III; Dougherty, Dennis

    2014-03-01

    Entropic effect in GPCR activation is poorly understood. Based on the recent solved structures, researchers in the GPCR structural biology field have proposed several ``local activating switches'' that consisted of a few number of conserved residues, but have long ignored the collective dynamical effect (conformational entropy) of a domain comprised of an ensemble of residues. A new paradigm has been proposed recently that a GPCR can be viewed as a composition of several functional coupling domains, each of which undergoes order-to-disorder or disorder-to-order transitions upon activation. Here we identified and studied these functional coupling domains by comparing the local entropy changes of each residue between the inactive and active states of the β2 adrenergic receptor from computational simulation. We found that agonist and G-protein binding increases the heterogeneity of the entropy distribution in the receptor. This new activation paradigm and computational entropy analysis scheme provides novel ways to design functionally modified mutant and identify new allosteric sites for GPCRs. The authors thank NIH and Sanofi for funding this project.

  3. Opposite action of beta1- and beta2-adrenergic receptors on Ca(V)1 L-channel current in rat adrenal chromaffin cells.

    PubMed

    Cesetti, T; Hernández-Guijo, J M; Baldelli, P; Carabelli, V; Carbone, E

    2003-01-01

    Voltage-gated Ca(2+) channels of chromaffin cells are modulated by locally released neurotransmitters through autoreceptor-activated G-proteins. Clear evidence exists in favor of a Ca(2+) channel gating inhibition mediated by purinergic, opioidergic, and alpha-adrenergic autoreceptors. Few and contradictory data suggest also a role of beta-adrenergic autoreceptors (beta-ARs), the action of which, however, remains obscure. Here, using patch-perforated recordings, we show that rat chromaffin cells respond to the beta-AR agonist isoprenaline (ISO) by either upmodulating or downmodulating the amplitude of Ca(2+) currents through two distinct modulatory pathways. ISO (1 microm) could cause either fast inhibition (approximately 25%) or slow potentiation (approximately 25%), or a combination of the two actions. Both effects were completely prevented by propranolol. Slow potentiation was more evident in cells pretreated with pertussis toxin (PTX) or when beta(1)-ARs were selectively stimulated with ISO + ICI118,551. Potentiation was absent when the beta(2)-AR-selective agonist zinterol (1 microm), the protein kinase A (PKA) inhibitor H89, or nifedipine was applied, suggesting that potentiation is associated with a PKA-mediated phosphorylation of L-channels (approximately 40% L-current increase) through beta(1)-ARs. The ISO-induced inhibition was fast and reversible, preserved in cell treated with H89, and mimicked by zinterol. The action of zinterol was mostly on L-channels (38% inhibition). Zinterol action preserved the channel activation kinetics, the voltage-dependence of the I-V characteristic, and was removed by PTX, suggesting that beta(2)AR-mediated channel inhibition was mainly voltage independent and coupled to G(i)/G(o)-proteins. Sequential application of zinterol and ISO mimicked the dual action (inhibition/potentiation) of ISO alone. The two kinetically and pharmacologically distinct beta-ARs signaling uncover alternative pathways, which may serve the autocrine

  4. The effect of the beta-2-adrenergic agonist clenbuterol or implantation with oestradiol plus trenbolone acetate on protein metabolism in wether lambs.

    PubMed

    Bohorov, O; Buttery, P J; Correia, J H; Soar, J B

    1987-01-01

    The effects of Revalor (trenbolone acetate plus oestradiol) implantation or the inclusion of clenbuterol (a beta-2-adrenergic agonist) in the diet of wether lambs was studied. Using continuous intravenous infusion of [3H]tyrosine the fractional synthetic rate of mixed protein from three separate muscles was measured. Clenbuterol slightly increased growth rate but had a significant (P less than 0.02) effect on food conversion efficiency. The weight and protein content of the longissimus dorsi and vastus lateralis muscles were increased but no such changes were observed for the vastus intermedius. For the longissimus dorsi at least the increase was probably achieved by a reduction in fractional degradation rate of the muscle protein. Revalor significantly increased the growth rate and food conversion efficiency of the animals. This increase was not specific for muscle. Estimated degradation rates of muscle protein were lower in the treated animals. The possible mode of action of these materials was discussed. The results obtained again highlight the importance of protein degradation in controlling growth. PMID:3801388

  5. Structural modifications of human beta 2 microglobulin treated with oxygen-derived radicals.

    PubMed Central

    Capeillere-Blandin, C; Delaveau, T; Descamps-Latscha, B

    1991-01-01

    Treatment of human beta 2 microglobulin (beta 2m) with defined oxygen-derived species generated by treatment with gamma-radiation was studied. As assessed by SDS/PAGE, the hydroxyl radicals (.OH) caused the disappearance of the protein band at 12 kDa that represents beta 2m, and cross-linked the protein into protein bands stable to both SDS and reducing conditions. However, when .OH was generated under oxygen in equimolar combination with the superoxide anion radical (O2.-), the high-molecular-mass protein products were less represented, and fragmented derivatives were not obviously detectable. Exposure to .OH alone, or to .OH + O2.- in the presence of O2, induced the formation of beta 2m protein derivatives with a more acidic net electrical charge than the parent molecule. In contrast, O2.- alone had virtually no effect on molecular mass or pI. Changes in u.v. fluorescence during .OH attack indicated changes in conformation, as confirmed by c.d. spectrometry. A high concentration of radicals caused the disappearance of the beta-pleated sheet structure and the formation of a random coil structure. Loss of tryptophan and significant production of dityrosine (2,2'-biphenol type) were noted, exhibiting a clear dose-dependence with .OH alone or with .OH + O2.-. The combination of .OH + O2.- induced a pattern of changes similar to that with .OH alone, but more extensive for c.d. and tryptophan oxidation (2 Trp/beta 2m molecule), and more limited for dityrosine formation. Lower levels of these oxidative agents caused the reproducible formation of species at 18 and 25 kDa which were recognized by antibodies against native beta 2m. These findings provide a model for the protein pattern observed in beta 2m amyloidosis described in the literature. Images Fig. 4. Fig. 5. PMID:1649598

  6. High affinity binding of beta 2-glycoprotein I to human endothelial cells is mediated by annexin II.

    PubMed

    Ma, K; Simantov, R; Zhang, J C; Silverstein, R; Hajjar, K A; McCrae, K R

    2000-05-19

    Beta(2)-glycoprotein I (beta(2)GPI) is an abundant plasma phospholipid-binding protein and an autoantigen in the antiphospholipid antibody syndrome. Binding of beta(2)GPI to endothelial cells targets them for activation by anti-beta(2)GPI antibodies, which circulate and are associated with thrombosis in patients with the antiphospholipid antibody syndrome. However, the binding of beta(2)GPI to endothelial cells has not been characterized and is assumed to result from association of beta(2)GPI with membrane phospholipid. Here, we characterize the binding of beta(2)GPI to endothelial cells and identify the beta(2)GPI binding site. (125)I-beta(2)GPI bound with high affinity (K(d) approximately 18 nm) to human umbilical vein endothelial cells (HUVECs). Using affinity purification, we isolated beta(2)GPI-binding proteins of approximately 78 and approximately 36 kDa from HUVECs and EAHY.926 cells. Amino acid sequences of tryptic peptides from each of these were identical to sequences within annexin II. A role for annexin II in binding of beta(2)GPI to cells was confirmed by the observations that annexin II-transfected HEK 293 cells bound approximately 10-fold more (125)I-beta(2)GPI than control cells and that anti-annexin II antibodies inhibited the binding of (125)I-beta(2)GPI to HUVECs by approximately 90%. Finally, surface plasmon resonance studies revealed high affinity binding between annexin II and beta(2)GPI. These results demonstrate that annexin II mediates the binding of beta(2)GPI to endothelial cells. PMID:10809787

  7. Muscle protein waste in tumor-bearing rats is effectively antagonized by a beta 2-adrenergic agonist (clenbuterol). Role of the ATP-ubiquitin-dependent proteolytic pathway.

    PubMed Central

    Costelli, P; García-Martínez, C; Llovera, M; Carbó, N; López-Soriano, F J; Agell, N; Tessitore, L; Baccino, F M; Argilés, J M

    1995-01-01

    Tissue protein hypercatabolism (TPH) is a most important feature in cancer cachexia, particularly with regard to the skeletal muscle. The rat ascites hepatoma Yoshida AH-130 is a very suitable model system for studying the mechanisms involved in the processes that lead to tissue depletion, since it induces in the host a rapid and progressive muscle waste mainly due to TPH (Tessitore, L., G. Bonelli, and F. M. Baccino. 1987. Biochem. J. 241:153-159). Detectable plasma levels of tumor necrosis factor-alpha associated with marked perturbations in the hormonal homeostasis have been shown to concur in forcing metabolism into a catabolic setting (Tessitore, L., P. Costelli, and F. M. Baccino. 1993. Br. J. Cancer. 67:15-23). The present study was directed to investigate if beta 2-adrenergic agonists, which are known to favor skeletal muscle hypertrophy, could effectively antagonize the enhanced muscle protein breakdown in this cancer cachexia model. One such agent, i.e., clenbuterol, indeed largely prevented skeletal muscle waste in AH-130-bearing rats by restoring protein degradative rates close to control values. This normalization of protein breakdown rates was achieved through a decrease of the hyperactivation of the ATP-ubiquitin-dependent proteolytic pathway, as previously demonstrated in our laboratory (Llovera, M., C. García-Martínez, N. Agell, M. Marzábal, F. J. López-Soriano, and J. M. Argilés. 1994. FEBS (Fed. Eur. Biochem. Soc.) Lett. 338:311-318). By contrast, the drug did not exert any measurable effect on various parenchymal organs, nor did it modify the plasma level of corticosterone and insulin, which were increased and decreased, respectively, in the tumor hosts. The present data give new insights into the mechanisms by which clenbuterol exerts its preventive effect on muscle protein waste and seem to warrant the implementation of experimental protocols involving the use of clenbuterol or alike drugs in the treatment of pathological states involving

  8. Mechanosensitivity of human osteosarcoma cells and phospholipase C {beta}2 expression

    SciTech Connect

    Hoberg, M. . E-mail: Maik.Hoberg@med.uni-tuebingen.de; Gratz, H.-H.; Noll, M.; Jones, D.B.

    2005-07-22

    Bone adapts to mechanical load by osteosynthesis, suggesting that osteoblasts might respond to mechanical stimuli. We therefore investigated cell proliferation and phospholipase C (PLC) expression in osteoblasts. One Hertz uniaxial stretching at 4000 {mu}strains significantly increased the proliferation rates of human osteoblast-like osteosarcoma cell line MG-63 and primary human osteoblasts. However, U-2/OS, SaOS-2, OST, and MNNG/HOS cells showed no significant changes in proliferation rate. We investigated the expression pattern of different isoforms of PLC in these cell lines. We were able to detect PLC {beta}1, {beta}3, {gamma}1, {gamma}2, and {delta}1 in all cells, but PLC {beta}2 was only detectable in the mechanosensitive cells. We therefore investigated the possible role of PLC {beta}2 in mechanotransduction. Inducible antisense expression for 24 h inhibited the translation of PLC {beta}1 in U-2/OS cells by 35% and PLC {beta}2 in MG-63 by 29%. Fluid shear flow experiments with MG-63 lacking PLC {beta}2 revealed a significantly higher level of cells losing attachment to coverslips and a significantly lower number of cells increasing intracellular free calcium.

  9. Characterization of the Human Platelet α-Adrenergic Receptor

    PubMed Central

    Alexander, R. Wayne; Cooper, Barry; Handin, Robert I.

    1978-01-01

    Human platelets aggregate and undergo a release reaction when incubated with catecholamines. Indirect evidence indicates that these events are mediated through α-adrenergic receptors. We used [3H]dihydroergocryptine, an α-adrenergic antagonist, to identify binding sites on platelets that have the characteristics of α-adrenergic receptors. Catecholamines compete for the binding sites in a stereo-specific manner with the potency series of (−) epinephrine > (−) norepinephrine > (±) phenylephrine > (−) isoproterenol. The dissociation constant (Kd) of (−) epinephrine is 0.34 μM. Binding is saturable using a platelet particulate fraction but not with intact platelets. There are 0.130 pmol binding sites per milligram protein in fresh platelet membranes. This number represents approximately 100 binding sites per platelet. The Kd for [3H]-dihydroergocryptine was 0.003−0.01 μM. The α-adrenergic antagonist phentolamine (Kd = 0.0069 μM) was much more potent than the β-adrenergic antagonist (±) propranolol (Kd = 27 μM) in competing for the binding sites. The binding data were correlated with catecholamine-induced platelet aggregation and inhibition of basal and prostaglandin E1-stimulated adenylate cyclase. (−) Epinephrine was more potent than (−) norepinephrine in producing aggregation whereas (−) isoproterenol was ineffective. The threshold dose for inducing aggregation by (−) epinephrine was 0.46 μM. Phentolamine and dihydroergocyrptine blocked this response, whereas (±) propranolol had no effect. (−) Epinephrine and (−) norepinephrine inhibited basal and prostaglandin E1-stimulated adenylate cyclase in a dose-related manner. The concentration of (−) epinephrine inhibiting adenylate cyclase 50% was 0.7 μM. This inhibition was also blocked by phentolamine and dihydroergocryptine but not by (±) propranolol. The specificity of binding and the close correlation with α-adrenergic receptor-mediated biochemical and physiological responses

  10. Lentivirus vector-mediated Rho guanine nucleotide dissociation inhibitor 2 induces beta-2 adrenergic receptor desensitization in β2AR desensitization mice model

    PubMed Central

    Ni, Songshi; Zhao, Jing; Fu, Zhenxue

    2014-01-01

    Background It is well-known that chronic administration of β2AR agonists can induce β2AR desensitization. Our previous study showed that Rho guanine nucleotide dissociation inhibitor 2 (RhoGDI2) overexpression induced beta-2 adrenergic receptor (β2AR) desensitization in airway smooth muscle cells. The purpose of this study was to further study the function of RhoGDI2 in β2AR desensitization by β2AR desensitization mouse model. Methods Studies were performed using a β2AR desensitization mice model induced by salbutamol. The mice were randomly divided into five groups (n=45): RhoGDI2 overexpression group (n=10); RhoGDI2 siRNA group (n=10); empty viral vector group (n=10); experimental control group (n=10); blank control group—without any drug treatment (n=5). The first four groups were used the same methods and the same dose to establish β2AR desensitization mice model by salbutamol. The first three groups that salbutamol-treated were used for intratracheal delivery of lentiviral vectors. Airway hyperreactivity was measured through a whole-body plethysmograph system. RhoGDI2, β2AR, GRK2 mRNA and protein expression levels were then detected by RT-PCR and western blot analyses in fresh lung tissues. As well as the activity of GRK was assessed by light-dependent phosphorylation of rhodopsin. Results We successfully constructed β2AR desensitization mouse model. As expected, airway responsiveness after inhaling acetylcholine chloride (Ach) was markedly increased in the RhoGDI2 overexpression group compared to experimental control group and blank control group when concentrations of Ach was 45 mg/mL (all P<0.05), while, it was markedly decreased in the RhoGDI2 siRNA group compared to experimental control group (P<0.05). RhoGDI2, GRK2 expressions and GRK enzymatic activity were significantly increased in RhoGDI2 overexpression group compared to experimental control group and blank control group (all P<0.05). RhoGDI2, GRK2 expressions and GRK enzymatic activity

  11. Crystal Structure of the Central Coiled-Coil Domain from Human Liprin-[beta]2

    SciTech Connect

    Stafford, Ryan L.; Tang, Ming-Yun; Sawaya, Michael R.; Phillips, Martin L.; Bowie, James U.

    2012-02-07

    Liprins are a conserved family of scaffolding proteins important for the proper regulation and development of neuronal synapses. Humans have four liprin-{alpha}s and two liprin-{beta}s which all contain long coiled-coil domains followed by three tandem SAM domains. Complex interactions between the coiled-coil and SAM domains are thought to create liprin scaffolds, but the structural and biochemical properties of these domains remain largely uncharacterized. In this study we find that the human liprin-{beta}2 coiled-coil forms an extended dimer. Several protease-resistant subdomains within the liprin-{beta}1 and liprin-{beta}2 coiled-coils were also identified. A 2.0 {angstrom} crystal structure of the central, protease-resistant core of the liprin-{beta}2 coiled-coil reveals a parallel helix orientation. These studies represent an initial step toward determining the overall architecture of liprin scaffolds and understanding the molecular basis for their synaptic functions.

  12. Human myometrial adrenergic receptors during pregnancy: identification of the alpha-adrenergic receptor by (/sup 3/H) dihydroergocryptine binding

    SciTech Connect

    Jacobs, M.M.; Hayashida, D.; Roberts, J.M.

    1985-07-15

    The radioactive alpha-adrenergic antagonist (/sup 3/H) dihydroergocryptine binds to particulate preparations of term pregnant human myometrium in a manner compatible with binding to the alpha-adrenergic receptor (alpha-receptor). (/sup 3/H) Dihydroergocryptine binds with high affinity (KD = 2 nmol/L and low capacity (receptor concentration = 100 fmol/mg of protein). Adrenergic agonists compete for (/sup 3/H) dihydroergocryptine binding sites stereo-selectively ((-)-norepinephrine is 100 times as potent as (+)-norepinephrine) and in a manner compatible with alpha-adrenergic potencies (epinephrine approximately equal to norepinephrine much greater than isoproterenol). Studies in which prazosin, an alpha 1-antagonist, and yohimbine, and alpha 2-antagonist, competed for (/sup 3/H) dihydroergocryptine binding sites in human myometrium indicated that approximately 70% are alpha 2-receptors and that 30% are alpha 1-receptors. (/sup 3/H) dihydroergocryptine binding to human myometrial membrane particulate provides an important tool with which to study the molecular mechanisms of uterine alpha-adrenergic response.

  13. Expression of transforming growth factors beta-1, beta 2 and beta 3 in human bladder carcinomas.

    PubMed Central

    Eder, I. E.; Stenzl, A.; Hobisch, A.; Cronauer, M. V.; Bartsch, G.; Klocker, H.

    1997-01-01

    We previously detected elevated transforming growth factor beta-1 (TGF-beta1) serum levels in patients with invasive bladder carcinomas. In this study, we therefore investigated whether elevated serum levels correlate with enhanced TGF-beta expression in human bladder tumours. mRNA levels of TGF-beta1, -beta2 and -beta3 were reduced in bladder tumour tissue to 86%, 68% and 56%, respectively, of the levels in normal urothelium. On the other hand, TGF-beta1 protein levels were found to be higher in superficial tumours (Ta-T1) (mean level of 0.153 ng mg(-1)) and in invasive T2/T3 tumours (mean level of 0.104 ng mg(-1)) compared with normal urothelium (mean level of 0.065 ng mg(-1)). Invasive T4 tumours, however, contained only low amounts of TGF-beta1 (mean level of 0.02 ng mg(-1)). Neither in mean nor in individual patients were serum and tissue TGF-beta levels correlated with each other. Cell culture experiments on primary bladder cells revealed a 57% decrease in TGF-beta1 mRNA levels in tumour compared with normal epithelial cells. Tumour epithelial cells contained about two times higher levels of TGF-beta2 and TGF-beta3 mRNA than normal epithelial cells. Fibroblasts expressed about the same amount of TGF-beta1 or TGF-beta2 as epithelial cells. Yet, fibroblasts released only 19% and 13% of the amount secreted by tumour epithelial cells into the supernatant. TGF-beta3, on the other hand, was expressed by fibroblasts with higher levels than by epithelial cells. TGF-beta1 was the predominent isoform in bladder tissue and cells at protein as well as on mRNA levels indicating that TGFs-beta2 and -beta3 are of minor importance in bladder cancer. In summary, there is a lack of correlation between TGF-beta serum levels and TGF-beta expression in tumour tissue in bladder cancer. Images Figure 1 PMID:9192977

  14. The selectivity of beta-adrenoceptor antagonists at the human beta1, beta2 and beta3 adrenoceptors.

    PubMed

    Baker, Jillian G

    2005-02-01

    Beta-adrenoceptor antagonists ("beta-blockers") are one of the most widely used classes of drugs in cardiovascular medicine (hypertension, ischaemic heart disease and increasingly in heart failure) as well as in the management of anxiety, migraine and glaucoma. Where known, the mode of action in cardiovascular disease is from antagonism of endogenous catecholamine responses in the heart (mainly at beta1-adrenoceptors), while the worrisome side effects of bronchospasm result from airway beta2-adrenoceptor blockade. The aim of this study was to determine the selectivity of beta-antagonists for the human beta-adrenoceptor subtypes. (3)H-CGP 12177 whole cell-binding studies were undertaken in CHO cell lines stably expressing either the human beta1-, beta2- or the beta3-adrenoceptor in order to determine the affinity of ligands for each receptor subtype in the same cell background. In this study, the selectivity of well-known subtype-selective ligands was clearly demonstrated: thus, the selective beta1 antagonist CGP 20712A was 501-fold selective over beta2 and 4169-fold selective over beta3; the beta2-selective antagonist ICI 118551 was 550- and 661-fold selective over beta1 and beta3, respectively, and the selective beta3 compound CL 316243 was 10-fold selective over beta2 and more than 129-fold selective over beta1. Those beta2-adrenoceptor agonists used clinically for the treatment of asthma and COPD were beta2 selective: 29-, 61- and 2818-fold for salbutamol, terbutaline and salmeterol over beta1, respectively. There was little difference in the affinity of these ligands between beta1 and beta3 adrenoceptors. The clinically used beta-antagonists studied ranged from bisoprolol (14-fold beta1-selective) to timolol (26-fold beta2-selective). However, the majority showed little selectivity for the beta1- over the beta2-adrenoceptor, with many actually being more beta2-selective. This study shows that the beta1/beta2 selectivity of most clinically used beta-blockers is

  15. Development of beta 1 and beta 2 adrenergic receptors in baboon brain: an autoradiographic study using (/sup 125/I)iodocyanopindolol

    SciTech Connect

    Slesinger, P.A.; Lowenstein, P.R.; Singer, H.S.; Walker, L.C.; Casanova, M.F.; Price, D.L.; Coyle, J.T.

    1988-07-15

    (125I)iodocyanopindolol (ICYP) autoradiography was used to investigate the temporal development and distribution of beta 1 and beta 2 receptors in brains of baboons at ages embryonic day 100 (E100), full-term gestation (El80), and 3 years. In all brain regions examined, with the exception of the hippocampus, binding to beta 1 receptors exceeded that to beta 2 receptors. The highest densities of beta 1 receptors were found in the caudate nucleus, putamen, globus pallidus, substantia nigra, and cerebral cortex; intermediate receptor densities were observed in most nuclei of thalamus, and the lowest concentrations were in the hippocampus. At E100, beta receptors were identified in the striatum, globus pallidus, and thalamus. During maturation, the number of beta 1 receptors declined in cortical areas but increased in the head of the caudate and putamen. Significant differences in the developmental distribution of beta receptors during development were also detected: at E100 and E180 beta 1 receptors appeared as patches in the caudate and putamen, but by 3 years of age they were more homogeneously distributed in both regions; changes also occurred in the distribution of binding within cortical layers. Autoradiograms of (125I)ICYP and (3H)mazindol binding show overlapping patches of labeling in the E180 striatum, suggesting a possible developmental association between beta receptors and dopamine high-affinity uptake carrier sites. This study demonstrates that noradrenergic receptors in the primate forebrain undergo significant developmental reorganization with regional variations.

  16. Selective elution of HLA antigens and beta 2-microglobulin from human platelets by chloroquine diphosphate

    SciTech Connect

    Kao, K.J.

    1988-01-01

    To determine whether chloroquine can specifically elute HLA antigens and beta 2-microglobulin (beta 2-M) from the platelet surface, quantitative immunofluorescence flow cytometry and monoclonal antibodies were used to show that HLA antigens and beta 2-M were proportionally eluted from the platelet surface without affecting the membrane glycoproteins IIb and IIIa. Second, an autoradiogram of electrophoresed I-125-labeled platelets showed that only beta 2-M but not other I-125-labeled membrane proteins could be eluted. Although HLA antigens were poorly labeled by I-125 and could not be detected on the autoradiogram, the eluted HLA antigens could be detected by anti-HLA monoclonal antibody and immunoblotting techniques. No loss of plasma membrane integrity was observed by transmission electron microscopy after chloroquine treatment of platelets. The results indicate that chloroquine selectively elutes HLA antigens and their noncovalently associated beta 2-M without affecting other integral platelet membrane proteins.

  17. Interactions between human serum proteins and oral streptococci reveal occurrence of receptors for aggregated beta 2-microglobulin.

    PubMed Central

    Ericson, D; Bratthall, D; Björck, L; Myhre, E; Kronvall, G

    1979-01-01

    A total of 31 strains of oral streptococci representing Streptococcus mutans, Streptococcus sanguis, Streptococcus mitior, Streptococcus salivarius, and Streptococcus milleri were tested for possible binding of human immunoglobulins G, G1, G2, G3, G4, A1, A2, M1, and M2 and haptoglobin, hemoglobin, fibrinogen, and aggregated beta 2-microglobulin. Radiolabeled beta 2-microglobulin in aggregated form showed affinity for 20 of the 31 strains tested. Binding activity for the protein was found in strains belonging to all five species. The bacterial receptor was resistant to trypsin. Monomeric, unlabeled beta 2-microglobulin did not interfere with the binding of the aggregated form. Of the other proteins tested, only the immunoglobulin A1 protein showed positive binding, and that was only with a single strain of S. milleri. beta 2-Microglobulin is present on all nucleated cell membranes in vivo. The reaction between aggregated beta 2-microglobulin and oral streptococci is a new type of human-bacterium interaction which should be considered in studies of bacterial adherence. PMID:90015

  18. Cloning and expression of a human kidney cDNA for an /alpha//sub 2/-adrenergic receptor subtype

    SciTech Connect

    Regan, J.W.; Kobilka, T.S.; Yang-Feng, T.L.; Caron, M.G.; Lefkowitz, R.J.; Kobilka, B.K.

    1988-09-01

    An /alpha//sub 2/-adrenergic receptor subtype has been cloned from a human kidney cDNA library using the gene for the human platelet /alpha//sub 2/-adrenergic receptor as a probe. The deduced amino acid sequence resembles the human platelet /alpha//sub 2/-adrenergic receptor and is consistent with the structure of other members of he family of guanine nucleotide-binding protein-coupled receptors. The cDNA was expressed in a mammalian cell line (COS-7), and the /alpha//sub 2/-adrenergic ligand (/sup 3/H)rauwolscine was bound. Competition curve analysis with a variety of adrenergic ligands suggests that this cDNA clone represents the /alpha//sub 2/B-adrenergic receptor. The gene for this receptor is on human chromosome 4, whereas the gene for the human platelet /alpha//sub 2/-adrenergic receptor (/alpha//sub 2/A) lies on chromosome 10. This ability to express the receptor in mammalian cells, free of other adrenergic receptor subtypes, should help in developing more selective /alpha/-adrenergic ligands.

  19. Expression of two human beta-adrenergic receptors in Escherichia coli: functional interaction with two forms of the stimulatory G protein.

    PubMed Central

    Freissmuth, M; Selzer, E; Marullo, S; Schütz, W; Strosberg, A D

    1991-01-01

    When expressed in Escherichia coli, the human beta 1- and beta 2-adrenergic receptors retain their ligand binding specificity. Their functional integrity was investigated by analyzing receptor-guanine nucleotide-binding regulatory (G) protein coupling by using two splice variants of the alpha subunit of the stimulatory G protein Gs synthesized in E. coli (rGs alpha-S and rGs alpha-L) and the beta gamma subunits of G protein purified from bovine brain. In competition binding experiments with (-)-[125I]iodocyanopindolol and (-)-isoproterenol, rGs alpha-S.beta gamma and rGs alpha-L.beta gamma reconstituted guanine nucleotide-sensitive high-affinity agonist binding with comparable affinities, whereas rGs alpha PT, a mutant of rGs alpha-L with an altered carboxyl terminus, and a recombinant subtype of the alpha subunit of the inhibitory G protein, rGi alpha-1, were approximately 20- and approximately 200-fold less potent, respectively. A comparison of the beta 1- and beta 2-adrenergic receptor expressed in E. coli with the beta 2-receptor in S49 murine lymphoma cyc- cell membranes revealed a similar affinity of rGs alpha-S and rGs alpha-L for the recombinant and native receptors. After stable incorporation of rGs alpha-S.beta gamma into E. coli membranes, receptor-G protein coupling was also verified by determining the isoproterenol-mediated acceleration of the rate for guanine 5'-[gamma-[35S]thio]triphosphate binding. These results show that (i) receptor-G protein coupling can be reconstituted in E. coli using recombinant components and that (ii) such an approach may be more generally used to evaluate coupling preferences between defined molecular species of receptors and G-protein subunits. PMID:1656450

  20. Transforming growth factor beta 1 and beta 2 induce down-modulation of thrombomodulin in human umbilical vein endothelial cells.

    PubMed

    Ohji, T; Urano, H; Shirahata, A; Yamagishi, M; Higashi, K; Gotoh, S; Karasaki, Y

    1995-05-01

    To investigate the effects of transforming growth factor-betas (TGF-betas) on endothelial anticoagulant activity, we assayed thrombomodulin (TM) activity and antigen levels of human umbilical vein endothelial cells (HUVECs) incubated with TGF-betas in vitro. TGF-beta 1 suppressed surface TM activity and surface TM antigen levels maximally 12 h after incubation in dose-dependent manners. TGF-beta 2 was almost equipotent with TGF-beta 1 for the suppression of them. Both TGF-betas suppressed total TM antigen level in HUVECs, and the time course of the suppression was similar to that of the cell surface TM antigen level. The maximal reductions of TM mRNA levels by TGF-betas were observed at several hours ahead of those observed in both surface and total TM antigens levels, suggesting that the TGF-beta-mediated suppression of TM antigen of HUVECs is primarily regulated at the TM mRNA level. Our present work suggests that the down-modulation of TM level induced by TGF-betas in HUVECs contributes in vivo to promoting the thrombogenesis either at the sites of injury of vessel walls, such as atherosclerotic lesions where TGF-beta 1 is released from platelets, smooth muscle cells and monocytes, or at neovascular walls in tumors secreting TGF-beta 2. PMID:7482408

  1. Protein phosphorylation in isolated human adipocytes - Adrenergic control of the phosphorylation of hormone-sensitive lipase

    SciTech Connect

    Smiley, R.M. Columbia Univ College of Physicians and Surgeons, New York, NY ); Paul, S.; Browning, M.D.; Leibel, R.L.; Hirsch, J. )

    1990-01-01

    The effect of adrenergic agents on protein phosphorylation in human adipocytes was examined. Freshly isolated human fat cells were incubated with {sup 32}PO{sub 4} in order to label intracellular ATP, then treated with a variety of adrenergic and other pharmacologic agents. Treatment with the {beta}-adrenergic agonist isoproterenol led to a significant increase in phosphate content of at least five protein bands (M{sub r} 52, 53, 63, 67, 84 kDa). The increase in phosphorylation was partially inhibited by the {alpha}-2 agonist clonidine. Epinephrine, a combined {alpha} and {beta} agonist, was less effective at increasing phosphate content of the proteins than was isoproterenol. Neither insulin nor the {alpha}-1 agonist phenylephrine had any discernible effect on the pattern of protein phosphorylation. The 84 kDa phosphorylated peptide band appears to contain hormone-sensitive lipase, a key enzyme in the lipolytic pathway which is activated by phosphorylation. These results are somewhat different than previously reported results for rat adipocytes, and represent the first report of overall pattern and adrenergic modulation of protein phosphorylation in human adipocytes.

  2. Alpha-1 adrenergic receptor: Binding and phosphoinositide breakdown in human myometrium

    SciTech Connect

    Breuiller-Fouche, M.; Doualla-Bell Kotto Maka, F.; Geny, B.; Ferre, F. )

    1991-07-01

    Alpha-1 adrenergic receptors were examined in both inner and outer layers of human pregnant myometrium using radioligand binding of (3H)prazosin. (3H)prazosin bound rapidly and reversibly to a single class of high affinity binding sites in myometrial membrane preparations. Scatchard analysis gave similar values of equilibrium dissociation constants in both myometrial layers. In contrast, more alpha-1 adrenergic receptors were detected in the outer layer than in the inner layer. Antagonist inhibited (3H)prazosin binding with an order of potency of prazosin greater than phentolamine greater than idazoxan. Competition experiments have also revealed that a stable guanine nucleotide decreases the apparent affinity of norepinephrine for myometrial (3H)prazosin binding sites. The functional status of these alpha-1 adrenergic receptors was also assessed by measuring the norepinephrine-induced accumulation of inositol phosphates in myometrial tissue. Norepinephrine produced a concentration-dependent accumulation of inositol phosphates in both myometrial layers. However, norepinephrine-induced increases in inositol 1,4,5-triphosphate were only observed in the outer layer. These results indicate that alpha-1 adrenergic receptors in human myometrium at the end of pregnancy are linked to phosphoinositide hydrolysis and that this response occurs mainly in the outer layer.

  3. Antibodies to beta 1 and beta 2 adrenoreceptors in Chagas' disease.

    PubMed Central

    Sterin-Borda, L; Perez Leiros, C; Wald, M; Cremaschi, G; Borda, E

    1988-01-01

    Evidence accumulated over the last decade concerning human and experimental models suggests that an immunopathological mechanism may be involved in the pathogenesis of chronic Chagas' disease. In this paper we demonstrate the existence of two different circulating IgG in chagasic patients which bind with myocardial beta 1 and spleen cell beta 2 adrenoceptors, acting as non-competitive inhibitors. Both chagasic IgG against beta 1 and beta 2 adrenoceptor increased intracellular levels of cAMP that could be blocked by specific beta 1 and beta 2 adrenoceptor antagonists. The specificity for beta 1 and beta 2 adrenoceptors and the independence of other tissue reactive antibodies was demonstrated by IgG absorption with turkey red blood cell (TRBC), human lymphocytes (HL) or guinea pig red blood cells (GPRBC). The F(ab')2 fraction acted similarly. This supports the specificity of beta 1 and beta 2 adrenoceptors to the chagasic IgG and the independence of the other tissue reactive antibodies, such as EVI system. The probable pathogenic role of both beta 1 and beta 2 adrenergic chagasic antibody is discussed. PMID:2853016

  4. The occurrence of cpb2-toxigenic Clostridium perfringens and the possible role of the beta2-toxin in enteric disease of domestic animals, wild animals and humans.

    PubMed

    van Asten, Alphons J A M; Nikolaou, Georgios N; Gröne, Andrea

    2010-02-01

    The virulence of Clostridium perfringens, a bacterium causing enteritis and enterotoxaemia in domestic and wild animals and humans, results largely from its ability to produce toxins. In 1997, an unknown toxin of C. perfringens, the beta2-toxin, and its encoding gene cpb2 were described. Since that time numerous studies have been published dealing with a possible association of cpb2-harbouring strains of C. perfringens and the occurrence of enteric disease in domestic and wild animals and humans. This article offers an overview of the current literature on the spread and pathological significance of cpb2-harbouring C. perfringens. Unambiguous conclusions on the prevalence of cpb2 and the contribution of beta2-toxin to the disease cannot be drawn from existing studies but in some animal species a strong correlation between the presence of cpb2-harbouring C. perfringens, the beta2-toxin and enteric disease has been reported. PMID:19101180

  5. β2 Adrenergic receptors mediate important electrophysiological effects in human ventricular myocardium

    PubMed Central

    Lowe, M; Rowland, E; Brown, M; Grace, A

    2001-01-01

    OBJECTIVE—To define the effects of β2 adrenergic receptor stimulation on ventricular repolarisation in vivo.
DESIGN—Prospective study.
SETTING—Tertiary referral centre.
PATIENTS—85 patients with coronary artery disease and 22 normal controls.
INTERVENTIONS—Intravenous and intracoronary salbutamol (a β2 adrenergic receptor selective agonist; 10-30 µg/min and 1-10 µg/min), and intravenous isoprenaline (a mixed β1/β2 adrenergic receptor agonist; 1-5 µg/min), infused during fixed atrial pacing.
MAIN OUTCOME MEASURES—QT intervals, QT dispersion, monophasic action potential duration.
RESULTS—In patients with coronary artery disease, salbutamol decreased QTonset and QTpeak but increased QTend duration; QTonset-QTpeak and QTpeak-QTend intervals increased, resulting in T wave prolongation (mean (SEM): 201 (2) ms to 233 (2) ms; p < 0.01). There was a large increase in dispersion of QTonset, QTpeak, and QTend which was more pronounced in patients with coronary artery disease—for example, QTend dispersion: 50 (2) ms baseline v 98 (4) ms salbutamol (controls), and 70 (1) ms baseline v 108 (3) ms salbutamol (coronary artery disease); p < 0.001. Similar responses were obtained with isoprenaline. Monophasic action potential duration at 90% repolarisation shortened during intracoronary infusion of salbutamol, from 278 (4.1) ms to 257 (3.8) ms (p < 0.05).
CONCLUSIONS—β2 adrenergic receptors mediate important electrophysiological effects in human ventricular myocardium. The increase in dispersion of repolarisation provides a mechanism whereby catecholamines acting through this receptor subtype may trigger ventricular arrhythmias.


Keywords: β2 adrenergic receptors; ventricular repolarisation; QT dispersion; salbutamol; isoprenaline PMID:11410561

  6. Homology modeling of human alpha 1 beta 2 gamma 2 and house fly beta 3 GABA receptor channels and Surflex-docking of fipronil.

    PubMed

    Cheng, Jin; Ju, Xiu-Lian; Chen, Xiang-Yang; Liu, Gen-Yan

    2009-09-01

    To further explore the mechanism of selective binding of the representative gamma-aminobutyric acid receptors (GABARs) noncompetitive antagonist (NCA) fipronil to insect over mammalian GABARs, three-dimensional models of human alpha 1 beta 2 gamma 2 and house fly beta 3 GABAR were generated by homology modeling, using the cryo-electron microscopy structure of the nicotinic acetylcholine receptor (nAChR) of Torpedo marmorata as a template. Fipronil was docked into the putative binding site of the human alpha 1 beta 2 gamma 2 and house fly beta 3 receptors by Surflex-docking, and the calculated docking energies are in agreement with experimental results. The GABA receptor antagonist fipronil exhibited higher potency with house fly beta 3 GABAR than with human alpha 1 beta 2 gamma 2 GABAR. Furthermore, analyses of Surflex-docking suggest that the H-bond interaction of fipronil with Ala2 and Thr6 in the second transmembrane segment (TM2) of these GABARs plays a relatively important role in ligand selective binding. The different subunit assemblies of human alpha 1 beta 2 gamma 2 and house fly beta 3 GABARs may result in differential selectivity for fipronil. PMID:19238461

  7. Muscarinic cholinergic and alpha 2-adrenergic receptors in the epithelium and muscularis of the human ileum

    SciTech Connect

    Lepor, H.; Rigaud, G.; Shapiro, E.; Baumann, M.; Kodner, I.J.; Fleshman, J.W. )

    1990-04-01

    The aim of this study was to characterize the binding and functional properties of muscarinic cholinergic (MCh) and alpha 2-adrenergic receptors in the human ileum to provide insight into pharmacologic strategies for managing urinary and fecal incontinence after bladder and rectal replacement with intestinal segments. MCh and alpha 2-adrenergic binding sites were characterized in the epithelium and muscularis of eight human ileal segments with 3H-N-methylscopolamine and 3H-rauwolscine, respectively. The dissociation constant for 3H-N-methylscopolamine in the epithelium and muscularis was 0.32 +/- 0.07 nmol/L and 0.45 +/- 0.10 nmol/L, respectively (p = 0.32). The MCh receptor content was approximately eightfold greater in the muscularis compared with the epithelium (p = 0.008). The dissociation constant for 3H-rauwolscine in the muscularis and epithelium was 2.55 +/- 0.42 nmol/L and 2.03 +/- 0.19 nmol/L, respectively (p = 0.29). The alpha 2-adrenoceptor density was twofold greater in the epithelium compared with the muscularis (p = 0.05). Noncumulative concentration-response experiments were performed with carbachol, an MCh agonist, and UK-14304, a selective alpha 2-adrenergic agonist. The epithelium did not contract in the presence of high concentrations of carbachol and UK-14304. The muscularis preparations were responsive only to carbachol. The muscularis contains primarily MCh receptors mediating smooth muscle contraction. The alpha 2-adrenoceptors are localized primarily to the epithelium and may regulate water secretion in the intestine. The distribution and functional properties of ileal MCh and alpha 2-adrenergic receptors provide a theoretic basis for the treatment of incontinence after bladder and rectal replacement with intestinal segments.

  8. Contribution of beta 1- and beta 2-adrenoceptors of human atrium and ventricle to the effects of noradrenaline and adrenaline as assessed with (-)-atenolol.

    PubMed Central

    Lemoine, H.; Schönell, H.; Kaumann, A. J.

    1988-01-01

    1. (-)-Atenolol was used as a tool to assess the function of beta 1- and beta 2-adrenoceptors in human heart. Right atrial and left ventricular preparations from patients undergoing open heart surgery were set up to contract isometrically. Membrane particles were prepared for beta-adrenoceptor labelling with [3H]-(-)-bupranolol and adenylate cyclase assays. 2. The positive inotropic effects of (-)-noradrenaline were antagonized to a similar extent by (-)-atenolol in atrial and ventricular preparations. (-)-Atenolol consistently antagonized the effects of (-)-adrenaline to a lesser extent than those of (-)-noradrenaline in atrial preparations. In ventricular preparations (-)-atenolol antagonized the effects of low concentrations of (-)-adrenaline to a lesser extent than those of high concentrations. 3. pKB values (M) of (-)-atenolol, estimated with non-linear analysis from the blockade of the positive inotropic effects of the catecholamines, were 7.4 for beta 1-adrenoceptors and 6.0 for beta 2-adrenoceptors. 4. (-)-Atenolol inhibited the binding of [3H]-(-)-bupranolol to ventricular beta 1-adrenoceptors with a pKD (M) of 5.9 and to ventricular beta 2-adrenoceptors with a pKD of 4.6. 5. (-)-Atenolol inhibited the catecholamine-induced adenylate cyclase stimulation in the atrium and ventricle with pKB values of 5.8-6.4 for beta 1- and pKB values of 4.7-5.7 for beta 2-adrenoceptors. The binding and cyclase assays suggest a partial affinity loss for (-)-atenolol inherent to membrane preparations. 6. beta 1-Adrenoceptors mediate the maximum positive inotropic effects of (-)-noradrenaline in both the atrium and ventricle of man. beta 2-Adrenoceptors appear to be capable of mediating maximal positive inotropic effects of (-)-adrenaline in atrium. In contrast, ventricular beta 2-adrenoceptors mediated only submaximal effects of (-)-adrenaline. PMID:2851354

  9. Contribution of β-adrenergic receptors to exercise-induced bronchodilatation in healthy humans.

    PubMed

    Antonelli, Andrea; Torchio, Roberto; Bertolaccini, Luca; Terzi, Alberto; Rolfo, Fabrizio; Agostoni, Piergiuseppe; Gulotta, Carlo; Brusasco, Vito; Pellegrino, Riccardo

    2012-10-15

    Exercise in healthy subjects is usually associated with progressive bronchodilatation. Though the decrease in vagal tone is deemed to be the main underlying mechanism, activation of bronchial β(2)-receptors may constitute an additional cause. To examine the contribution of β(2)-adrenergic receptors to bronchodilatation during exercise in healthy humans, we studied 15 healthy male volunteers during maximum exercise test at control conditions and after a non-selective β-adrenergic blocker (carvedilol 12.5mg twice a day until heart rate decreased at least by 10beats/min) and inhaled β(2)-agonist (albuterol 400μg). Airway caliber was estimated from the partial flow at 40% of control forced vital capacity (V˙(part40)) and its changes during exercise from the slope of linear regression analysis of V˙(part40) values against the corresponding minute ventilation during maximal exercise until exhaustion. At control, V˙(part40) increased progressively and significantly with exercise. After albuterol, resting V˙(part40) was significantly larger than at control increased but did not further increase during exercise. After carvedilol, V˙(part40) was similar to control but its increase with exercise was significantly attenuated. These findings suggest that β(2)-adrenergic system plays a major role in exercise-induced bronchodilation in healthy subjects. PMID:22842007

  10. Effects of halothane on the human beta-adrenergic receptor of lymphocyte membranes

    SciTech Connect

    Marty, J.; Nivoche, Y.; Nimier, M.; Rocchiccioli, C.; Luscombe, F.; Henzel, D.; Loiseau, A.; Desmonts, J.M.

    1987-12-01

    The effects of halothane on beta-adrenergic receptor antagonist interaction were studied using the membranes of human lymphocytes as a model. Membrane preparations of lymphocytes were obtained from blood samples withdrawn from seven healthy young volunteers. Beta-receptor studies were performed using (-)/sup 125/I iodocyanopindolol (/sup 125/ICP) binding. Non-specific binding was determined in the presence of (-)isoproterenol. Beta-receptor density (Bmax) and the dissociation constant (KD) for /sup 125/ICP were determined from saturation curves. Beta-receptor affinity for agonists evaluated by the IC50 (the concentration of isoproterenol required to inhibit 50% of specific /sup 125/ICP binding) and the dissociation constant (KL) for isoproterenol was established from competition curves. The effect of halothane 1%, in an air oxygen mixture (oxygen fraction: 0.3) administered by tonometry during ligand membrane incubation, on beta-adrenergic receptor, was compared to that of control experiments not exposed to halothane. Halothane produced a moderate but significant decrease of Bmax (-10%) and a significant increase in non-specific binding (+30%), while KD, IC50, and KL were unchanged. The authors conclude that halothane, in vitro, decreases beta-adrenergic receptor density. This effect could be mediated by an alteration of the receptor in the membrane due to action of halothane on the lipid phase of the membrane.

  11. beta-2 Microglobulin values among human immunodeficiency virus (HIV)-negative, HIV-positive asymptomatic, and HIV-positive symptomatic Ugandans.

    PubMed Central

    Piwowar, E M; Tugume, S B; Grant, R M; Lutalo, T; Pattishall, K; Katongole-Mbidde, E

    1995-01-01

    Mean serum beta-2 microglobulin levels among healthy human immunodeficiency virus-seronegative and asymptomatic and symptomatic human immunodeficiency virus-seropositive Ugandans were found to be 2.35, 3.75, and 5.06 mg/liter, respectively (P < 0.001). The upper limit of the normal range (3.5 mg/liter) is higher in this African population than that reported elsewhere. PMID:7697536

  12. The immunomodulatory activity of human amniotic fluid can be correlated with transforming growth factor-beta 1 (TGF-beta 1) and beta 2 activity.

    PubMed Central

    Lang, A K; Searle, R F

    1994-01-01

    The role of alphafetoprotein (AFP) in the immunomodulatory activity of amniotic fluids (AF) from normally progressing human pregnancy (weeks 14-16) was investigated. A panel of 42 AF (25% v/v) reduced significantly phytohaemagglutinin (PHA)-induced peripheral blood mononuclear cell (PBMC) proliferation in serum-free cultures with a mean per cent inhibition of 68.4 +/- 5.5%. In contrast, AFP preparations, with one exception (U.AFP), failed to display inhibitory activity. Pretreatment of AF with anti-TGF-beta 1 and beta 2 antibodies used alone resulted in the mean per cent loss of inhibition of 33.1 +/- 3.9% and 52.3 +/- 7.5%, respectively. A summative loss of AF-mediated inhibition was detected when anti-TGF-beta 1 and beta 2 antibodies were used in combination, but immunomodulation was rarely abolished 100% by this treatment. Anti-TGF-beta 2 antibody treatment, unlike anti-TGF-beta 1 antibody treatment, reversed the inhibitory activity of U.AFP. The amount of TGF-beta 1 and beta 2 contained in human AF was studied by growth inhibition of Mv1 Lu cells. The mean levels of TGF-beta 1 and beta 2 in AF were 11 +/- 0.9 U/ml and 2.3 +/- 0.4 U/ml, respectively, which corresponds with a mean per cent inhibition of 49 +/- 4.7%. U.AFP also significantly inhibited Mv1 Lu cell growth. To investigate the mechanism of AF-mediated inhibition, the effect of AF and AFP on IL-2 production by concanavalin A (Con A)-stimulated PBMC blasts was determined by the CTLL-2 cell bioassay. IL-2 production was reduced 55.5% in AF-treated blasts and 61% in U.AFP-treated blasts compared with controls. Our findings indicate that the immunomodulatory activity of human AF can be correlated with TGF-beta 1 and beta 2 and not with AFP, the inhibitory activity of U.AFP preparation reflecting copurifying TGF-beta 2 activity. PMID:7518368

  13. Heterogeneous responses of human limbs to infused adrenergic agonists: a gravitational effect?

    NASA Technical Reports Server (NTRS)

    Pawelczyk, James A.; Levine, Benjamin D.

    2002-01-01

    Unlike quadrupeds, the legs of humans are regularly exposed to elevated pressures relative to the arms. We hypothesized that this "dependent hypertension" would be associated with altered adrenergic responsiveness. Isoproterenol (0.75-24 ng x 100 ml limb volume-1 x min-1) and phenylephrine (0.025-0.8 microg x 100 ml limb volume-1 x min-1) were infused incrementally in the brachial and femoral arteries of 12 normal volunteers; changes in limb blood flow were quantified by using strain-gauge plethysmography. Compared with the forearm, baseline calf vascular resistance was greater (38.8 +/- 2.5 vs. 26.9 +/- 2.0 mmHg x 100 ml x min x ml-1; P < 0.001) and maximal conductance was lower (46.1 +/- 11.9 vs. 59.4 +/- 13.4 ml x ml-1 x min-1 x mmHg-1; P < 0.03). Vascular conductance did not differ between the two limbs during isoproterenol infusions, whereas decreases in vascular conductance were greater in the calf than the forearm during phenylephrine infusions (P < 0.001). With responses normalized to maximal conductance, the half-maximal response for phenylephrine was significantly less for the calf than the forearm (P < 0.001), whereas the half-maximal response for isoproterenol did not differ between limbs. We conclude that alpha1- but not beta-adrenergic-receptor responsiveness in human limbs is nonuniform. The relatively greater response to alpha1-adrenergic-receptor stimulation in the calf may represent an adaptive mechanism that limits blood pooling and capillary filtration in the legs during standing.

  14. Allosteric interactions between the antagonist prazosin and amiloride analogs at the human alpha(1A)-adrenergic receptor.

    PubMed

    Leppik, R A; Mynett, A; Lazareno, S; Birdsall, N J

    2000-03-01

    It has been demonstrated previously that amilorides can interact with a well defined allosteric site on the human alpha(2A)-adrenergic receptor. In this study, the question was explored as to whether the human alpha(1A)-adrenergic receptor also possesses an equivalent allosteric site. The six amilorides examined strongly increased the dissociation rate of the antagonist [(3)H]prazosin from the alpha(1A)-adrenergic receptor in a concentration-dependent manner. With the parent amiloride, the dissociation data were well fitted by an equation derived from the ternary complex allosteric model, compatible with amiloride acting at a defined allosteric site on the alpha(1A)-adrenergic receptor. In contrast, the dissociation data for [(3)H]prazosin in the presence of the amiloride analogs were not compatible with the equation derived from a one-allosteric-site model, but could be fitted well by an equation derived from a two-allosteric-site model. However, certain individual parameters could not be resolved. The observed dissociation rate constants increased steeply with increasing amiloride analog concentration, and in some cases the data could be fitted with a logistic equation. The slope factors calculated from such fits were 1.2 to 2.1. It is concluded that the structure-binding relationships of the amilorides at the alpha(1A)- and alpha(2A)-adrenergic receptors are different. The interactions of the five amiloride analogs, but not the parent amiloride, with the alpha(1A)-adrenergic receptor are compatible with the presence of two (but not one) allosteric sites, and is thus more complex than that found for the alpha(2A)-adrenergic receptor. PMID:10692482

  15. Translational activity and functional stability of human fibroblast beta 1 and beta 2 interferon mRNAs lacking 3'-terminal RNA sequences.

    PubMed Central

    Soreq, H; Sagar, A D; Sehgal, P B

    1981-01-01

    Polyadenylylated mRNA was purified from poly(I).poly(C)- and cycloheximide-superinduced human fibroblast (FS-4) cultures. The mRNA was subjected to electrophoresis through an agarose/CH3HgOH gel, and human fibroblast beta 1 and beta 2 interferon mRNAs were isolated. Each mRNA preparation was phosphorolyzed at 0 degrees C for 20 min by using a molar excess of polynucleotide phosphorylase to produce RNAs lacking poly(A) and then incubated at 37 degrees C for varying lengths of time to allow the phosphorylase to further digest the deadenylylated RNA from the 3' end in a processive and synchronous manner. Removal of the poly(A) (less than or equal to 100 residues) and approximately 100 adjacent residues from human fibroblast beta 1 interferon mRNA (native length, 900 residues, including a 3'-noncoding region of 203 residues) did not alter the translational activity or the functional stability of this mRNA in Xenopus oocytes, whereas deletion of the poly(A) and approximately 200 adjacent residues decreased its translational efficiency. On the other hand, removal of the poly(A) (approximately 200 residues) and approximately 200 adjacent residues from human fibroblast beta 2 interferon mRNA (native length, 1300 residues) did not alter the translational activity or the functional stability of this molecule in oocytes. Thus, neither the poly(A) nor large segments of the 3'-noncoding region (which includes the hexanucleotide A-A-U-A-A-A sequence, at least in the case of beta 1 mRNA) are required for the maintenance of the functional stability of human beta 1 and beta 2 interferon mRNAs in Xenopus oocytes. Images PMID:6165016

  16. Role of arachidonic acid metabolites in the action of a beta adrenergic agonist on human monocyte phagocytosis.

    PubMed

    Borda, E S; Tenenbaum, A; Sales, M E; Rumi, L; Sterin-Borda, L

    1998-02-01

    The mechanisms by which beta adrenergic stimulation regulates phagocytosis of Candida albicans by human peripheral monocytes (HPM) are characterized. Isoproterenol (ISO) inhibits phagocytosis in a concentration-dependent manner. This effect was blunted by propranolol, inhibitors of phospholipase A2 (PLA2), cyclooxygenase and verapamil, pointing to a participation of arachidonic acid (AA) metabolites and calcium in the phenomenon. Prostaglandin E2 (PGE2) and dibutyryl cyclic AMP (db-cAMP) also exerted the same inhibitory effect on phagocytosis. ISO interacts with beta adrenergic receptors of HPM increasing PGE2 and cAMP. We conclude that the mechanisms by which beta adrenergic stimulation regulates phagocytosis of Candida albicans by HPM appear to be secondary to beta adrenoceptor-mediated hydrolysis of AA accompanied by an increase in PGE2 generation and cAMP production. Both PGE2 and cAMP could act as mediators of the inhibitory action of beta agonists on the HPM-phagocytosis process. PMID:9578144

  17. Identification of alpha 2-adrenergic receptor sites in human retinoblastoma (Y-79) and neuroblastoma (SH-SY5Y) cells

    SciTech Connect

    Kazmi, S.M.; Mishra, R.K.

    1989-02-15

    The existence of specific alpha 2-adrenergic receptor sites has been shown in human retinoblastoma (Y-79) and neuroblastoma (SH-SH5Y) cells using direct radioligand binding. (/sup 3/H)Rauwolscine, a selective alpha 2-adrenergic receptor antagonist, exhibited high affinity, saturable binding to both Y-79 and SH-SY5Y cell membranes. The binding of alpha 1 specific antagonist, (/sup 3/H)Prazocine, was not detectable in either cell type. Competition studies with antagonists yielded pharmacological characteristics typical of alpha 2-adrenergic receptors: rauwolscine greater than yohimbine greater than phentolamine greater than prazocine. Based on the affinity constants of prazocine and oxymetazoline, it appears that Y-79 cells contain alpha 2A receptor, whereas SH-SY5Y cells probably represent a mixture of alpha 2A and alpha 2B receptors. alpha 2-agonists clonidine and (-)epinephrine inhibition curves yielded high and low affinity states of the receptor in SH-SY5Y cells. Gpp(NH)p and sodium ions reduced the proportion of high affinity sites of alpha 2 receptors. These two neuronal cell lines of human origin would prove useful in elucidating the action and regulation of human alpha 2-adrenergic receptors and their interaction with other receptor systems.

  18. Characterization and distribution of alpha 2-adrenergic receptors in the human intestinal mucosa.

    PubMed Central

    Valet, P; Senard, J M; Devedjian, J C; Planat, V; Salomon, R; Voisin, T; Drean, G; Couvineau, A; Daviaud, D; Denis, C

    1993-01-01

    The subtype and the expression of the alpha 2-adrenergic receptor were investigated in the normal mucosa from human intestine by means of radioligand binding, RNase mapping, and measurement of adenylate cyclase activity. The study of the binding of the alpha 2-adrenergic antagonist, [3H]RX821002, to epithelial cell membranes indicated the existence of a single class of noninteracting sites displaying a high affinity for the radioligand (Kd = 1.1 +/- 0.5 nM). The rank order of potency of antagonists to inhibit [3H]RX821002 binding (RX821002 > yohimbine = rauwolscine > phentolamine approximately idazoxan >> chlorpromazine > prazosin) suggested that the receptor is of the alpha 2A subtype. A conclusion which is confirmed by the fact that only alpha 2C10 transcripts were found in the human intestine mucosa. Competition curves with (-)-norepinephrine demonstrated that 60% of the receptor population exhibited high affinity for agonists. This high-affinity state was abolished by the addition of GTP plus Na+ or by prior treatment of the membranes with pertussis toxin indicating it corresponded to G protein-coupled receptors. [32P]ADP-ribosylation and immunoblotting experiments identified two pertussis toxin-sensitive G proteins corresponding to Gi2 and Gi3. The study of the distribution of the receptor indicated that (a) the proximal colon is the intestine segment exhibiting the highest receptor density and (b) the receptor is predominantly expressed in crypts and is preferentially located in the basolateral membrane of the polarized cell. The distribution of the receptor along the crypt-surface axis of the colon mucosa can be correlated with a higher level of alpha 2C10-specific mRNA and a higher efficiency of UK14304 to inhibit adenylate cyclase in crypt cells. Images PMID:8098045

  19. Targeting ß2 adrenergic receptors regulate human T cell function directly and indirectly.

    PubMed

    Zalli, A; Bosch, J A; Goodyear, O; Riddell, N; McGettrick, H M; Moss, P; Wallace, G R

    2015-03-01

    It is well-established that central nervous system activation affects peripheral blood mononuclear cell (PBMCs) function through the release of the catecholamines (Epi) and norepinephrine (NE), which act on ß2-adrenergic receptors (ß2AR). However, most studies have used non-specific stimulation of cells rather than antigen-specific responses. Likewise, few studies have parsed out the direct effects of ß2AR stimulation on T cells versus indirect effects via adrenergic stimulation of antigen presenting cells (APC). Here we report the effect of salmeterol (Sal), a selective ß2AR agonist, on IFN-γ(+) CD4 and IFN-γ(+) CD8 T cells following stimulation with Cytomegalovirus lysate (CMVL-strain AD169) or individual peptides spanning the entire region of the HCMV pp65 protein (pp65). Cells were also stimulated with Staphylococcal enterotoxin B. Additionally, we investigated the effect of Epi and Sal on cytotoxic cell killing of transfected target cells at the single cell level using the CD107a assay. The results show that Sal reduced the percentage of IFN-γ(+) CD4 and IFN-γ(+) CD8 T cells both when applied directly to isolated T cells, and indirectly via treatment of APC. These inhibitory effects were mediated via a ß2 adrenergic-dependent pathway and were stronger for CD8 as compared to CD4 T cells. Similarly, the results show that Sal suppressed cytotoxicity of both CD8 T and NK cells in vitro following stimulation with Chinese hamster ovary cell line transfected with MICA(*009) (T-CHO) and the human erythromyeloblastoid leukemic (K562) cell line. The inhibitory effect on cytotoxicity following stimulation with T-CHO was stronger in NK cells compared with CD8 T cells. Thus, targeting the ß2AR on lymphocytes and on APC leads to inhibition of inflammatory cytokine production and target cell killing. Moreover, there is a hierarchy of responses, with CD8 T cells and NK cells inhibited more effectively than CD4 T cells. PMID:25526818

  20. Risk versus benefit considerations for the beta(2)-agonists.

    PubMed

    Kelly, H William

    2006-09-01

    Short-acting beta(2)-agonists are the mainstay of therapy for acute bronchospasm associated with asthma and chronic obstructive pulmonary disease, whereas long-acting beta(2)-agonists are used in maintaining disease control in these respiratory disorders. This review describes and compares the pharmacology of the beta(2)-agonists and explains how these differences translate into differences in efficacy and beta(2)-adrenergic-mediated adverse effects. Questions commonly asked by clinicians regarding the efficacy and safety of short- and long-acting beta(2)-agonists include issues about cardiovascular effects, tolerance to their bronchodilator and bronchoprotective effects, blunting of albuterol response by long-acting beta(2)-agonists, potential masking of worsening asthma control, and the role of long-acting beta(2)-agonists as adjunctive therapy with inhaled corticosteroids in maintaining asthma control. Pharmacogenetics may play a role in determining which patients may be at risk for a reduced response to a beta(2)-agonist. The continued use of racemic albuterol, which contains a mixture of R-albuterol and S-albuterol, has been questioned because of data from preclinical and clinical studies suggesting that S-albuterol causes proinflammatory effects and may increase bronchial hyperreactivity. The preclinical and clinical effects of these two stereoisomers are reviewed. Data describing the efficacy and safety of levalbuterol (R-albuterol) and racemic albuterol are presented. PMID:16945063

  1. Modeling and simulation studies of human β3 adrenergic receptor and its interactions with agonists.

    PubMed

    Sahi, Shakti; Tewatia, Parul; Malik, Balwant K

    2012-12-01

    β3 adrenergic receptor (β3AR) is known to mediate various pharmacological and physiological effects such as thermogenesis in brown adipocytes, lipolysis in white adipocytes, glucose homeostasis and intestinal smooth muscle relaxation. Several efforts have been made in this field to understand their function and regulation in different human tissues and they have emerged as potential attractive targets in drug discovery for the treatment of diabetes, depression, obesity etc. Although the crystal structures of Bovine Rhodopsin and β2 adrenergic receptor have been resolved, to date there is no three dimensional structural information on β3AR. Our aim in this study was to model 3D structure of β3AR by various molecular modeling and simulation techniques. In this paper, we describe a refined predicted model of β3AR using different algorithms for structure prediction. The structural refinement and minimization of the generated 3D model of β3AR were done by Schrodinger suite 9.1. Docking studies of β3AR model with the known agonists enabled us to identify specific residues, viz, Asp 117, Ser 208, Ser 209, Ser 212, Arg 315, Asn 332, within the β3AR binding pocket, which might play an important role in ligand binding. Receptor ligand interaction studies clearly indicated that these five residues showed strong hydrogen bonding interactions with the ligands. The results have been correlated with the experimental data available. The predicted ligand binding interactions and the simulation studies validate the methods used to predict the 3D-structure. PMID:22242799

  2. Beta Adrenergic Receptors in Keratinocytes

    PubMed Central

    Sivamani, Raja K.; Lam, Susanne T.; Isseroff, R. Rivkah

    2007-01-01

    Synopsis Beta2 adrenergic receptors were identified in keratinocytes more than 30 years ago, but their function in the epidermis continues to be elucidated. Abnormalities in their expression, signaling pathway, or in the generation of endogenous catecholamine agonists by keratinocytes have been implicated in the pathogenesis of cutaneous diseases such as atopic dermatitis, vitiligo and psoriasis. New studies also indicate that the beta2AR also modulates keratinocyte migration, and thus can function to regulate wound re-epithelialization. This review focuses on the function of these receptors in keratinocytes and their contribution to cutaneous physiology and disease. PMID:17903623

  3. Browning of Subcutaneous White Adipose Tissue in Humans after Severe Adrenergic Stress.

    PubMed

    Sidossis, Labros S; Porter, Craig; Saraf, Manish K; Børsheim, Elisabet; Radhakrishnan, Ravi S; Chao, Tony; Ali, Arham; Chondronikola, Maria; Mlcak, Ronald; Finnerty, Celeste C; Hawkins, Hal K; Toliver-Kinsky, Tracy; Herndon, David N

    2015-08-01

    Since the presence of brown adipose tissue (BAT) was confirmed in adult humans, BAT has become a therapeutic target for obesity and insulin resistance. We examined whether human subcutaneous white adipose tissue (sWAT) can adopt a BAT-like phenotype using a clinical model of prolonged and severe adrenergic stress. sWAT samples were collected from severely burned and healthy individuals. A subset of burn victims were prospectively followed during their acute hospitalization. Browning of sWAT was determined by the presence of multilocular adipocytes, uncoupling protein 1 (UCP1), and increased mitochondrial density and respiratory capacity. Multilocular UCP1-positive adipocytes were found in sWAT samples from burn patients. UCP1 mRNA, mitochondrial density, and leak respiratory capacity in sWAT increased after burn trauma. Our data demonstrate that human sWAT can transform from an energy-storing to an energy-dissipating tissue, which opens new research avenues in our quest to prevent and treat obesity and its metabolic complications. PMID:26244931

  4. Effect of β2‐adrenergic receptor polymorphisms on epinephrine and exercise‐stimulated lipolysis in humans

    PubMed Central

    Du, Shichun; Joyner, Michael J.; Curry, Timothy B.; Eisenach, John H.; Johnson, Christopher P.; Schrage, William G.; Jensen, Michael D.

    2014-01-01

    Abstract The β2‐adrenergic system is an important regulator of human adipose tissue lipolysis. Polymorphisms that result in amino acid substitutions in the β2‐adrenergic receptor have been reported to alter lipolysis. We hypothesized that variations in the amino acid at position 16 of the β2‐adrenergic receptor would result in different lipolytic responses to intravenous epinephrine and exercise. 17 volunteers homozygous for glycine at position 16 (Gly/Gly, nine female) and 16 volunteers homozygous for arginine at position 16 (Arg/Arg, eight female) of the β2‐adrenergic receptor participated in this study. On one study day participants received infusions of epinephrine at submaximal (5 ng kg−1 min−1) and maximal (40 ng kg−1 min−1) lipolytic doses. The other study day volunteers bicycled for 90 min at 50–60% of maximum oxygen consumption (VO2max). [9,10‐3H] Palmitate was infused both days to measure free fatty acid – palmitate kinetics. Oxygen consumption was measured using indirect calorimetry. Palmitate release rates in response to epinephrine and exercise were not different in the Gly/Gly and Arg/Arg participants. The only statistically significant difference we observed was a lesser ΔVO2 in Arg/Arg volunteers in response to the submaximal epinephrine infusion. The polymorphisms resulting in Arg/Arg and Gly/Gly at position 16 of the β2‐adrenergic receptor do not result in clinically meaningful differences in lipolysis responses to epinephrine or submaximal exercise. PMID:24844639

  5. Discovery of novel acetanilide derivatives as potent and selective beta3-adrenergic receptor agonists.

    PubMed

    Maruyama, Tatsuya; Onda, Kenichi; Hayakawa, Masahiko; Matsui, Tetsuo; Takasu, Toshiyuki; Ohta, Mitsuaki

    2009-06-01

    In the search for potent and selective human beta3-adrenergic receptor (AR) agonists as potential drugs for the treatment of obesity and noninsulin-dependent (type II) diabetes, a novel series of acetanilide-based analogues were prepared and their biological activities were evaluated at the human beta3-, beta2-, and beta1-ARs. Among these compounds, 2-pyridylacetanilide (2f), pyrimidin-2-ylacetanilide (2u), and pyrazin-2-ylacetanilide (2v) derivatives exhibited potent agonistic activity at the beta3-AR with functional selectivity over the beta1- and beta2-ARs. In particular, compound 2u was found to be the most potent and selective beta3-AR agonist with an EC(50) value of 0.11 microM and no agonistic activity for either the beta1- or beta2-AR. In addition, 2f, 2u, and 2v showed significant hypoglycemic activity in a rodent diabetic model. PMID:19232786

  6. Activation of Human Brown Adipose Tissue by a β3-Adrenergic Receptor Agonist

    PubMed Central

    Cypess, Aaron M.; Weiner, Lauren S.; Roberts-Toler, Carla; Elía, Elisa Franquet; Kessler, Skyler H.; Kahn, Peter A.; English, Jeffrey; Chatman, Kelly; Trauger, Sunia A.; Doria, Alessandro; Kolodny, Gerald M.

    2015-01-01

    SUMMARY Increasing energy expenditure through activation of endogenous brown adipose tissue (BAT) is a potential approach to treat obesity and diabetes. The class of β3-adrenergic receptor (AR) agonists stimulates rodent BAT, but this activity has never been demonstrated in humans. Here we determined the ability of 200 mg oral mirabegron (Myrbetriq, Astellas Pharma, Inc.), a β3-AR agonist currently approved to treat overactive bladder, to stimulate BAT as compared to placebo. Mirabegron led to higher BAT metabolic activity as measured via 18F-fluorodeoxyglucose (18F-FDG) using positron emission tomography (PET) combined with computed tomography (CT) in all twelve healthy male subjects (p = 0.001), and it increased resting metabolic rate (RMR) by 203 ± 40 kcal/day (+13%; p = 0.001). BAT metabolic activity was also a significant predictor of the changes in RMR (p = 0.006). Therefore, a β3-AR agonist can stimulate human BAT thermogenesis and may be a promising treatment for metabolic disease. PMID:25565203

  7. Terbutaline-induced desensitization of human lymphocyte beta 2-adrenoceptors. Accelerated restoration of beta-adrenoceptor responsiveness by prednisone and ketotifen.

    PubMed Central

    Brodde, O E; Brinkmann, M; Schemuth, R; O'Hara, N; Daul, A

    1985-01-01

    We investigated, in 36 healthy volunteers, the effects of prednisone and ketotifen on recovery of lymphocyte beta 2-adrenoceptor density (determined by (-)-125iodocyanopindolol binding) and responsiveness (assessed by lymphocyte cyclic AMP [cAMP] responses to 10 microM (-)-isoprenaline) after desensitization by the beta 2-agonist terbutaline. Terbutaline (3 X 5 mg/d) decreased lymphocyte beta 2-adrenoceptor density by approximately 40-50%; concomitantly, lymphocyte cAMP responses to 10 microM (-)-isoprenaline were significantly reduced. After withdrawal of terbutaline beta 2-adrenoceptor, density and responsiveness gradually increased, reaching predrug levels after 4 d. Prednisone (1 X 100 mg orally) accelerated beta 2-adrenoceptor recovery; only 8-10 h after administration of the steroid beta 2-adrenoceptor density and cAMP responses to (-)-isoprenaline had reached values not significantly different from pretreatment levels. Similar effects were obtained with ketotifen (2 mg; thereafter 2 X 1 mg/d for 4 d): 24 h after application of the drug beta 2-adrenoceptor density and cAMP responses to (-)-isoprenaline had reached pretreatment levels. Furthermore, ketotifen simultaneously applied with terbutaline completely prevented terbutaline-induced decrease in lymphocyte beta 2-adrenoceptor density and responsiveness. Prednisone (1 X 100 mg orally) or ketotifen (2 mg; thereafter 2 X 1 mg/d for 2 d) had no significant influence on lymphocyte beta 2-adrenoceptor density in healthy volunteers not pretreated with terbutaline, but shifted the ratio high-to-low affinity state of the lymphocyte beta 2-adrenoceptor toward high affinity state. We conclude that glucocorticoids as well as ketotifen can accelerate recovery of density and responsiveness of lymphocyte beta 2-adrenoceptors desensitized by long-term treatment with beta 2-agonists. Such an effect may have clinical implications for preventing tachyphylaxis of asthmatic patients against therapy with beta 2-agonists. PMID

  8. Beta-2 Microglobulin Tumor Marker

    MedlinePlus

    ... limited. Home Visit Global Sites Search Help? Beta-2 Microglobulin Tumor Marker Share this page: Was this page helpful? Also known as: B2M; B 2 M; β2-Microglobulin; Thymotaxin Formal name: Beta 2 ...

  9. Alpha 2 adrenergic receptors in hyperplastic human prostate: identification and characterization using (/sup 3/H) rauwolscine

    SciTech Connect

    Shapiro, E.; Lepor, H.

    1986-05-01

    (/sup 3/H)Rauwolscine ((/sup 3/H)Ra), a selective ligand for the alpha 2 adrenergic receptor, was used to identify and characterize alpha 2 adrenergic receptors in prostate glands of men with benign prostatic hyperplasia. Specific binding of (/sup 3/H)Ra to prostatic tissue homogenates was rapid and readily reversible by addition of excess unlabelled phentolamine. Scatchard analysis of saturation experiments demonstrates a single, saturable class of high affinity binding sites (Bmax = 0.31 +/- 0.04 fmol./microgram. DNA, Kd = 0.9 +/- 0.11 nM.). The relative potency of alpha adrenergic drugs (clonidine, alpha-methylnorepinephrine and prazosin) in competing for (/sup 3/H)Ra binding sites was consistent with the order predicted for an alpha 2 subtype. The role of alpha 2 adrenergic receptors in normal prostatic function and in men with bladder outlet obstruction secondary to BPH requires further investigation.

  10. Alpha-1-Adrenergic Receptor Subtypes in Non-Failing and Failing Human Myocardium

    PubMed Central

    Jensen, Brian C.; Swigart, Philip M; DeMarco, Teresa; Hoopes, Charles; Simpson, Paul C.

    2009-01-01

    Background Alpha-1-adrenergic receptors (α1-ARs) play adaptive roles in the heart and protect against the development of heart failure (HF). The three α1-AR subtypes,α1A, α1B, and α1D, have distinct physiological roles in mouse heart, but very little is known about α1-subtypes in human heart. Here we test the hypothesis that the α1A and α1B subtypes are present in human myocardium, similar to the mouse, and are not down-regulated in heart failure. Methods and Results Hearts from transplant recipients and unused donors were failing (n = 12; mean EF 24%) or non-failing (n = 9; mean EF 59%), and similar in age (~44 years) and sex (~70% male). We measured the α1-AR subtypes in multiple regions of both ventricles by quantitative real-time reverse transcription PCR and radioligand binding. All three α1-AR subtype mRNAs were present, and α1A mRNA was most abundant (~65% of total α1-AR mRNA). However, only α1A and α1B binding were present, and the α1B was most abundant (60% of total). In failing hearts, α1A and α1B binding were not down-regulated, in contrast with β1-ARs. Conclusions Our data show for the first time that the α1A and α1B subtypes are both present in human myocardium, but α1D binding is not, and that the α1-subtypes are not down-regulated in HF. Since α1-subtypes in the human heart are similar to mouse, where adaptive and protective effects of α1-subtypes are most convincing, it might become feasible to treat HF with a drug targeting the α1A and/or α1B. PMID:19919991

  11. [Beta-adrenergic receptor blocker poisoning].

    PubMed

    Reingardiene, Dagmara

    2007-01-01

    Beta-adrenergic receptor blocking drugs are used in the treatment of hypertension, angina, myocardial infarction, cardiac dysrhythmia, cardiomyopathy, migraine headache, thyrotoxicosis, and glaucoma. beta-adrenergic receptor blocking agents are competitive antagonist at beta(1), beta(2), or both types of adrenergic receptors. Overdoses of beta-adrenergic receptor blockers are uncommon, but are associated with significant morbidity and mortality. This review article discusses the properties of beta-adrenergic receptor blockers, presents the doses of these drugs causing toxicity and doses, after ingestion of which, referral to an emergency department is recommended. Clinical presentation of overdose (the cardiovascular, neurologic manifestations, pulmonary and other complications), diagnosis, and treatment (gastrointestinal decontamination; the usage of atropine, phosphodiesterase inhibitors, glucagon, insulin; indications for cardiac pacing, extracorporeal procedures of drug removal, etc.) are analyzed. In addition, this article focuses on clinical course and prognosis of beta-blocker overdose. PMID:17768375

  12. Evidence that the human cutaneous venoarteriolar response is not mediated by adrenergic mechanisms

    NASA Technical Reports Server (NTRS)

    Crandall, C. G.; Shibasaki, M.; Yen, T. C.

    2002-01-01

    The venoarteriolar response causes vasoconstriction to skin and muscle via local mechanisms secondary to venous congestion. The purpose of this project was to investigate whether this response occurs through alpha-adrenergic mechanisms. In supine individuals, forearm skin blood flow was monitored via laser-Doppler flowmetry over sites following local administration of terazosin (alpha(1)-antagonist), yohimbine (alpha(2)-antagonist), phentolamine (non-selective alpha-antagonist) and bretylium tosylate (inhibits neurotransmission of adrenergic nerves) via intradermal microdialysis or intradermal injection. In addition, skin blood flow was monitored over an area of forearm skin that was locally anaesthetized via application of EMLA (2.5 % lidocaine (lignocaine) and 2.5 % prilocaine) cream. Skin blood flow was also monitored over adjacent sites that received the vehicle for the specified drug. Each trial was performed on a minimum of seven subjects and on separate days. The venoarteriolar response was engaged by lowering the subject's arm from heart level such that the sites of skin blood flow measurement were 34 +/- 1 cm below the heart. The arm remained in this position for 2 min. Selective and non-selective alpha-adrenoceptor antagonism and presynaptic inhibition of adrenergic neurotransmission did not abolish the venoarteriolar response. However, local anaesthesia blocked the venoarteriolar response without altering alpha-adrenergic mediated vasoconstriction. These data suggest that the venoarteriolar response does not occur through adrenergic mechanisms as previously reported. Rather, the venoarteriolar response may due to myogenic mechanisms associated with changes in vascular pressure or is mediated by a non-adrenergic, but neurally mediated, local mechanism.

  13. Effect of intracellular loop 3 on intrinsic dynamics of human β2-adrenergic receptor

    PubMed Central

    2013-01-01

    Background To understand the effect of the long intracellular loop 3 (ICL3) on the intrinsic dynamics of human β2-adrenergic receptor, molecular dynamics (MD) simulations were performed on two different models, both of which were based on the inactive crystal structure in complex with carazolol (after removal of carazolol and T4-lysozyme). In the so-called loop model, the ICL3 region that is missing in available crystal structures was modeled as an unstructured loop of 32-residues length, whereas in the clipped model, the two open ends were covalently bonded to each other. The latter model without ICL3 was taken as a reference, which has also been commonly used in recent computational studies. Each model was embedded into POPC bilayer membrane with explicit water and subjected to a 1 μs molecular dynamics (MD) simulation at 310 K. Results After around 600 ns, the loop model started a transition to a “very inactive” conformation, which is characterized by a further movement of the intracellular half of transmembrane helix 6 (TM6) towards the receptor core, and a close packing of ICL3 underneath the membrane completely blocking the G-protein’s binding site. Concurrently, the binding site at the extracellular part of the receptor expanded slightly with the Ser207-Asp113 distance increasing to 18 Å from 11 Å, which was further elaborated by docking studies. Conclusions The essential dynamics analysis indicated a strong coupling between the extracellular and intracellular parts of the intact receptor, implicating a functional relevance for allosteric regulation. In contrast, no such transition to the “very inactive” state, nor any structural correlation, was observed in the clipped model without ICL3. Furthermore, elastic network analysis using different conformers for the loop model indicated a consistent picture on the specific ICL3 conformational change being driven by global modes. PMID:24206668

  14. Interaction of selected vasodilating beta-blockers with adrenergic receptors in human cardiovascular tissues

    SciTech Connect

    Monopoli, A.; Forlani, A.; Bevilacqua, M.; Vago, T.; Norbiato, G.; Bertora, P.; Biglioli, P.; Alamanni, F.; Ongini, E.

    1989-07-01

    beta- And alpha 1-adrenoceptor antagonist properties of bufuralol, carvedilol, celiprolol, dilevalol, labetalol, and pindolol were investigated in human myocardium and mammary artery using binding techniques and functional studies. In myocardial membranes, beta-adrenoceptor antagonists showed monophasic competition isotherms for (125I)pindolol binding with high affinity (Ki from 1-100 nM), except for celiprolol which displayed a biphasic competition isotherm (pKi = 6.4 +/- 0.06 for beta 1- and 4.8 +/- 0.07 for beta 2-adrenoceptors). Drug interactions with alpha 1-adrenoceptors were evaluated in human mammary artery by (3H)prazosin binding and by measuring contractile responses to norepinephrine (NE). Labetalol and carvedilol showed a moderate affinity for alpha 1-adrenoceptors (pKi = 6.2 +/- 0.01 and 6.1 +/- 0.06, respectively), and inhibited NE-induced contractions (pA2 = 6.93 +/- 0.23 and 8.64 +/- 0.24, respectively). Dilevalol, bufuralol, and pindolol displayed weak effect both in binding (Ki in micromolar range) and functional experiments (pA2 = 5.98, 5.54, and 6.23, respectively). Celiprolol did not show antagonist properties up to 100 microM in functional studies, but displayed a slight affinity for alpha 1-adrenoceptors in binding studies. The data indicate that the vasodilating activity of these beta-adrenoceptor antagonists is caused in some instances by an alpha 1-adrenoceptor antagonism (labetalol, carvedilol), whereas for the others alternative mechanisms should be considered.

  15. Norepinephrine increases NADPH oxidase-derived superoxide in human peripheral blood mononuclear cells via α-adrenergic receptors

    PubMed Central

    Deo, Shekhar H.; Jenkins, Nathan T.; Padilla, Jaume; Parrish, Alan R.

    2013-01-01

    Many diseases associated with sympathoexcitation also exhibit elevated reactive oxygen species (ROS). A recent animal study indicated that exogenous administration of the sympathetic neurotransmitter norepinephrine (NE) increased systemic ROS via circulating leukocytes. The mechanisms contributing to this effect of NE and whether these findings can be translated to humans is unknown. Thus we tested the hypothesis that NE increases superoxide production in human peripheral blood mononuclear cells (PBMCs) via NADPH oxidase. Primary human PBMCs were freshly isolated from healthy young men and placed in culture. After NE (50 pg/ml, 50 ng/ml, and 50 μg/ml concentrations) or control treatments, NADPH oxidase mRNA expression (gp91phox, p22phox, and p67phox) was assessed using real-time RT-PCR, and intracellular superoxide production was measured using dihydroethidium fluorescence. PBMCs were also treated with selective adrenergic agonists-antagonists to determine the receptor population involved. In addition, CD14+ monocyte-endothelial cell adhesion was determined using a fluorescent-based assay. NE significantly increased NADPH oxidase gene expression and intracellular superoxide production in a time-dependent manner (superoxide: 0.9 ± 0.2 fold, 6 h vs. 3.0 ± 0.3 fold, 36 h; NE, 50 μg/ml; P < 0.05). The sustained increase in NE-induced superoxide production was primarily mediated via α-adrenergic receptors, preferentially α2-receptors. The NADPH oxidase blocker diphenylene iodonium and protein kinase C inhibitor Staurosporine significantly attenuated NE-induced increases in superoxide production. Importantly, NE treatment increased CD14+ monocyte-endothelial cell adhesion. These findings indicate for the first time that NE increases superoxide production in freshly isolated primary human PBMCs via NADPH oxidase through α-adrenergic receptors, an effect facilitating monocyte adhesion to the endothelium. PMID:24068047

  16. Beta 2 (CD18) and beta 1 (CD29) integrin mechanisms in migration of human polymorphonuclear leucocytes and monocytes through lung fibroblast barriers: shared and distinct mechanisms.

    PubMed Central

    Shang, X Z; Issekutz, A C

    1997-01-01

    Accumulation of leucocytes in inflamed lung tissue and alveolar space involves their migration through vascular endothelium and then lung connective tissue. As a model of this process, we investigated human polymorphonuclear leucocyte (PMNL) and monocyte migration through a biological barrier of human lung fibroblasts (HLF) grown on polycarbonate filters. Very few PMNL (1-2%) or monocytes (3-8%) migrated through the HLF barriers spontaneously. Migration increased to 48-53% of added PMNL and 17-24% of added monocytes, when a C5a chemotactic gradient was present. The monocyte migration induced by C5a was not inhibited by monoclonal antibodies (mAb) to CD18 (beta 2 integrins). This CD18-independent migration was partially inhibited (35%) by mAb to gamma 5 of VLA-5 and completely inhibited by the combination of mAb to gamma 4 of VLA-4 with mAb to VLA-5, in the presence of mAb to CD18. In contrast, PMNL migration across HLF induced by C5a was partially inhibited by mAb to CD18 alone, but even with the addition of mAb to VLA-4, VLA-5 beta 1 and VLA-6, the greatest degree of inhibition was only 60%. Blocking the function of CD18 was not required to observe the inhibition by mAb to VLA-4, although the inhibitory effect of mAb to VLA-5 and VLA-6 alone or in combination was only observed when CD18 mechanisms were also blocked with anti-CD18 mAb. These results demonstrate that (a) both monocytes and PMNL can use either CD11/CD18 (beta 2 integrin) or beta 1 (CD49/CD29) integrins to migrate through HLF barriers; (b) in the case of monocytes, the VLA-4 and VLA-5 integrins account for essentially all the CD11/CD18-independent migration mechanisms; and (c) in contrast to monocytes, PMNL CD18-independent migration is mediated not only by VLA-4 and VLA-5, but also by VLA-6, and up to 40% of the migration appears to be via yet to be defined PMNL surface molecules. PMID:9497495

  17. Polymorphonuclear leucocyte migration through human dermal fibroblast monolayers is dependent on both beta 2-integrin (CD11/CD18) and beta 1-integrin (CD29) mechanisms.

    PubMed Central

    Gao, J X; Issekutz, A C

    1995-01-01

    Accumulation of leucocytes in inflammation involves their migration through vascular endothelium and then in the connective tissue. We investigated human polymorphonuclear leucocyte (PMNL) migration through a biological barrier of human dermal fibroblasts grown on microporous filters, as a model of PMNL migration in the connective tissue. PMNL did not migrate through a fibroblast monolayer unless a chemotactic factor, e.g. C5a, interleukin-8 (IL-8) or zymosan-activated plasma (ZAP; C5adesArg), was added. This migration was partially inhibited (35-70%, depending on the stimulus) by treatment of PMNL with monoclonal antibody (mAb) to CD18 (beta 2-integrins). Most of the CD18-independent migration was inhibited by mAb to beta 1-integrins (CD29). Inhibition by mAb to beta 1 was observed when the PMNL, but not the fibroblasts, were treated with mAb. The role of beta 1-integrins in PMNL transfibroblast migration was detectable only when the function of the CD11-CD18 complex was blocked, because mAb to beta 1-integrin alone had no significant effect on PMNL migration. Migration induced by C5a was more CD18-independent compared to IL-8 or C5adesArg. The CD18-independent migration was also inhibited by mAb to the beta 1-integrin subunits alpha 5 (of very late antigens-5; VLA-5) and alpha 6 (of VLA-6). Treatment of the fibroblasts (4 hr) with tumour necrosis factor-alpha (TNF-alpha) or IL-1 alpha enhanced C5a-induced PMNL transfibroblast migration and increased the proportion of migration utilizing the CD11-CD18 mechanism. However, TNF-alpha treatment had no effect on the degree of beta 1-integrin-dependent migration. These findings suggest that in response to the chemotactic factors C5a, IL-8 and C5adesArg, PMNL migration in the connective tissue is mediated by both CD11-CD18 (beta 2) and beta 1-integrins on the PMNL. The VLA-5 and VLA-6 members of beta 1-integrins are involved in this process. This is in contrast to PMNL migration across endothelium in this system, which

  18. A Novel Dimeric Inhibitor Targeting Beta2GPI in Beta2GPI/Antibody Complexes Implicated in Antiphospholipid Syndrome

    SciTech Connect

    A Kolyada; C Lee; A De Biasio; N Beglova

    2011-12-31

    {beta}2GPI is a major antigen for autoantibodies associated with antiphospholipid syndrome (APS), an autoimmune disease characterized by thrombosis and recurrent pregnancy loss. Only the dimeric form of {beta}2GPI generated by anti-{beta}2GPI antibodies is pathologically important, in contrast to monomeric {beta}2GPI which is abundant in plasma. We created a dimeric inhibitor, A1-A1, to selectively target {beta}2GPI in {beta}2GPI/antibody complexes. To make this inhibitor, we isolated the first ligand-binding module from ApoER2 (A1) and connected two A1 modules with a flexible linker. A1-A1 interferes with two pathologically important interactions in APS, the binding of {beta}2GPI/antibody complexes with anionic phospholipids and ApoER2. We compared the efficiency of A1-A1 to monomeric A1 for inhibition of the binding of {beta}2GPI/antibody complexes to anionic phospholipids. We tested the inhibition of {beta}2GPI present in human serum, {beta}2GPI purified from human plasma and the individual domain V of {beta}2GPI. We demonstrated that when {beta}2GPI/antibody complexes are formed, A1-A1 is much more effective than A1 in inhibition of the binding of {beta}2GPI to cardiolipin, regardless of the source of {beta}2GPI. Similarly, A1-A1 strongly inhibits the binding of dimerized domain V of {beta}2GPI to cardiolipin compared to the monomeric A1 inhibitor. In the absence of anti-{beta}2GPI antibodies, both A1-A1 and A1 only weakly inhibit the binding of pathologically inactive monomeric {beta}2GPI to cardiolipin. Our results suggest that the approach of using a dimeric inhibitor to block {beta}2GPI in the pathological multivalent {beta}2GPI/antibody complexes holds significant promise. The novel inhibitor A1-A1 may be a starting point in the development of an effective therapeutic for antiphospholipid syndrome.

  19. Inhibition of α-adrenergic vasoconstriction in exercising human thigh muscles

    PubMed Central

    Wray, D Walter; Fadel, Paul J; Smith, Michael L; Raven, Peter; Sander, Mikael

    2004-01-01

    The mechanisms underlying metabolic inhibition of sympathetic responses within exercising skeletal muscle remain incompletely understood. The aim of the present study was to test whether α2-adrenoreceptor-mediated vasoconstriction was more sensitive to metabolic inhibition than α1-vasoconstriction during dynamic knee-extensor exercise. We studied healthy volunteers using two protocols: (1) wide dose ranges of the α-adrenoreceptor agonists phenylephrine (PE, α1 selective) and BHT-933 (BHT, α2 selective) were administered intra-arterially at rest and during 27 W knee-extensor exercise (n = 13); (2) flow-adjusted doses of PE (0.3 μg kg−1 l−1) and BHT (15 μg kg−1 l−1) were administered at rest and during ramped exercise (7 W to 37 W; n= 10). Ultrasound Doppler and thermodilution techniques provided direct measurements of femoral blood flow (FBF). PE (0.8 μg kg−1) and BHT (40 μg kg−1) produced comparable maximal reductions in FBF at rest (−58 ± 6 versus−64 ± 4%). Despite increasing the doses, PE (1.6 μg kg−1 min−1) and BHT (80 μg kg−1 min−1) caused significantly smaller changes in FBF during 27 W exercise (−13 ± 4 versus−3 ± 5%). During ramped exercise, significant vasoconstriction at lower intensities (7 and 17 W) was seen following PE (−16 ± 5 and −16 ± 4%), but not BHT (−2 ± 4 and −4 ± 5%). At the highest intensity (37 W), FBF was not significantly changed by either drug. Collectively, these data demonstrate metabolic inhibition of α-adrenergic vasoconstriction in large postural muscles of healthy humans. Both α1- and α2-adrenoreceptor agonists produce comparable vasoconstriction in the resting leg, and dynamic thigh exercise attenuates α1- and α2-mediated vasoconstriction similarly. However, α2-mediated vasoconstriction appears more sensitive to metabolic inhibition, because α2 is completely inhibited even at low workloads, whereas α1 becomes progressively inhibited with increasing workloads. PMID

  20. Identification of the origin of adrenergic and cholinergic nerve fibers within the superior hypogastric plexus of the human fetus

    PubMed Central

    Zaitouna, Mazen; Alsaid, Bayan; Diallo, Djibril; Benoit, Gérard; Bessede, Thomas

    2013-01-01

    Nerve fibers contributing to the superior hypogastric plexus (SHP) and the hypogastric nerves (HN) are currently considered to comprise an adrenergic part of the autonomic nervous system located between vertebrae (T1 and L2), with cholinergic aspects originating from the second to fourth sacral spinal segments (S2, S3 and S4). The aim of this study was to identify the origin and the nature of the nerve fibers within the SHP and the HN, especially the cholinergic fibers, using computer-assisted anatomic dissection (CAAD). Serial histological sections were performed at the level of the lumbar spine and pelvis in five human fetuses between 14 and 30 weeks of gestation. Sections were treated with histological staining [hematoxylin-eosin (HE) and Masson's trichrome (TriM)] and with immunohistochemical methods to detect nerve fibers (anti-S100), adrenergic fibers (anti-TH), cholinergic fibers (anti-VAChT) and nitrergic fibers (anti-nNOS). The sections were then digitalized using a high-resolution scanner and the 3D images were reconstructed using winsurf software. These experiments revealed the coexistence of adrenergic and cholinergic fibers within the SHP and the HNs. One-third of these cholinergic fibers were nitrergic fibers [anti-VACHT (+)/anti-NOS (+)] and potentially pro-erectile, while the others were non-nitrergic [anti-VACHT (+)/anti-NOS (−)]. We found these cholinergic fibers arose from the lumbar nerve roots. This study described the nature of the SHP nerve fibers which gives a better understanding of the urinary and sexual dysfunctions after surgical injuries. PMID:23668336

  1. [Serum beta 2 microglobulin (beta 2M) following renal transplantation].

    PubMed

    Pacheco-Silva, A; Nishida, S K; Silva, M S; Ramos, O L; Azjen, H; Pereira, A B

    1994-01-01

    Although there was an important improvement in graft and patient survival the last 10 years, graft rejection continues to be a major barrier to the success of renal transplantation. Identification of a laboratory test that could help to diagnose graft rejection would facilitate the management of renal transplanted patients. PURPOSE--To evaluate the utility of monitoring serum beta 2M in recently transplanted patients. METHODS--We daily determined serum beta 2M levels in 20 receptors of renal grafts (10 from living related and 10 from cadaveric donors) and compared them to their clinical and laboratory evolution. RESULTS--Eight patients who presented immediate good renal function following grafting and did not have rejection had a mean serum beta 2M of 3.7 mg/L on the 4th day post transplant. The sensitivity of the test for the diagnosis of acute rejection was 87.5%, but the specificity was only 46%. Patients who presented acute tubular necrosis (ATN) without rejection had a progressive decrease in their serum levels of beta 2M, while their serum creatinine changed as they were dialyzed. In contrast, patients with ATN and concomitance of acute rejection or CSA nephrotoxicity presented elevated beta 2M and creatinine serum levels. CONCLUSION--Daily monitoring of serum beta 2M does not improve the ability to diagnose acute rejection in patients with good renal function. However, serum beta 2M levels seemed to be useful in diagnosing acute rejection or CSA nephrotoxicity in patients with ATN. PMID:7787867

  2. α₁-Adrenergic receptors contribute to the acute effects of 3,4-methylenedioxymethamphetamine in humans.

    PubMed

    Hysek, Cédric M; Fink, Anja E; Simmler, Linda D; Donzelli, Massimiliano; Grouzmann, Eric; Liechti, Matthias E

    2013-10-01

    Preclinical studies implicate a role for α₁-noradrenergic receptors in the effects of psychostimulants, including 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy"). The present study evaluated the effects of the α₁-noradrenergic receptor antagonist doxazosin on the acute pharmacodynamic and pharmacokinetic response to MDMA in 16 healthy subjects. Doxazosin (8 mg/d) or placebo was administered for 3 days before MDMA (125 mg) or placebo using a randomized, double-blind, placebo-controlled, 4-session, crossover design. Doxazosin reduced MDMA-induced elevations in blood pressure, body temperature, and moderately attenuated positive mood but enhanced tachycardia associated with MDMA. The results indicate that α₁-adrenergic receptors contribute to the acute cardiostimulant and to a minor extent possibly also to the thermogenic and euphoric effects of MDMA in humans. PMID:23857311

  3. Additive competitive interaction of verapamil and quinidine at alpha-adrenergic receptors of isolated cardiac guinea pig myocytes and human platelets

    SciTech Connect

    Mueller, A.; Noack, E.

    1988-01-01

    Recent clinical work has questioned the safety of a combined therapy of oral quinidine and intravenenous verapamil, because some patients were reported to react with severe hypotension probably due to drug interactions with vascular alpha-adrenergic receptors. In order to obtain further quantitative information on the underlying mechanism, the authors used the radioligands (/sup 3/H)-prazosin and (/sup 3/H)-yohimbine to perform binding studies on intact cells, with predominantly alpha-1 (isolated myocytes) or alpha-2 subtypes (human platelets) of adrenergic receptors. Their studies confirm that both verapamil and quinidine possess a distinct alpha-adrenergic receptor blocking activity and do not discriminate between the alpha-1 and alpha-2 subtype. Their interaction was competitive and in the presence of both drugs inhibition of radioligand binding was additive. The alpha-adrenergic blockade by verapamil was stereospecific as D-verapamil increased the dissociation constant of the radioligand to a much lesser degree than L-verapamil. The calcium channel blocker nitrendipine, a 1,4-dihydropyridine derivative, did not show any competition up to concentrations of 10 ..mu..mol/l. 26 references, 5 figures, 1 table.

  4. Construction of bioactive chimeric MHC class I tetramer by expression and purification of human-murine chimeric MHC heavy chain and beta(2)m as a fusion protein in Escherichia coli.

    PubMed

    Ren, Ding; Wang, Fang; He, Xiaowen; Jiang, Lei; Li, Dean; Ying, He; Sun, Shuhan

    2006-12-01

    Major histocompatibility (MHC) class I tetramers are used in the quantitative analysis of epitope peptide-specific CD8+ T-cells. An MHC class I tetramer was composed of 4 MHC class I complexes and a fluorescently labeled streptavidin (SA) molecule. Each MHC class I complex consists of an MHC heavy chain, a beta(2)-microglobulin (beta(2)m) molecule and a synthetic epitope peptide. In most previous studies, an MHC class I complex was formed in the refolding buffer with an expressed MHC heavy chain molecule and beta(2)m, respectively. This procedure inevitably resulted in the disadvantages of forming unwanted multimers and self-refolding products, and the purification of each kind of monomer was time-consuming. In the present study, the genes of a human/murine chimeric MHC heavy chain (HLA-A2 alpha1, HLA-A2 alpha2 and MHC-H2D alpha3) and beta(2)m were tandem-cloned into plasmid pET17b and expressed as a fusion protein. The recombinant fusion protein was refolded with each of the three HLA-A2 restricted peptides (HBc18-27 FLPSDFFPSI, HBx52-60 HLSLRGLPV, and HBx92-100 VLHKRTLGL) and thus three chimeric MHC class I complexes were obtained. Biotinylation was performed, and its level of efficiency was observed via a band-shift assay in non-reducing polyacrylamide gel electrophoresis (PAGE). Such chimeric MHC class I tetramers showed a sensitive binding activity in monitoring HLA/A2 restrictive cytotoxic T lymphocytes (CTLs) in immunized HLA/A*0201 transgenic mice. PMID:17046278

  5. In situ assessment of the role of the beta 1-, beta 2- and beta 3-adrenoceptors in the control of lipolysis and nutritive blood flow in human subcutaneous adipose tissue.

    PubMed Central

    Barbe, P.; Millet, L.; Galitzky, J.; Lafontan, M.; Berlan, M.

    1996-01-01

    1. The involvement of beta 1-, beta 2- and beta 3-adrenoceptors in the control of lipolysis and nutritive blood flow was investigated in abdominal subcutaneous adipose tissue of healthy young adults by use of an in situ microdialysis technique. 2. Dialysis probes were infused either with isoprenaline (non-selective beta-adrenoceptor agonist), CGP 12,177 (selective beta 3-adrenoceptor agonist having beta 1-/beta 2-antagonist properties), dobutamine (selective beta 1-adrenoceptor agonist) or terbutaline (selective beta 2-adrenoceptor agonist). The recovery of each probe used for perfusion was calculated by an in vivo calibration method. The local blood flow was estimated through the measurement of the escape of ethanol infused simultaneously with the drugs included in the probe. 3. Isoprenaline infusion at 0.01 microM had a weak effect while higher concentrations of isoprenaline (0.1 and 1 microM) caused a rapid, sustained and concentration-dependent increase of glycerol outflow; the maximum increase was 306 +/- 34% with 1 microM. Isoprenaline also increased the nutritive blood flow in adipose tissue; a significant effect appeared at 0.1 microM isoprenaline and was greater at 1 microM. 4. CGP 12,177 (10 and 100 microM) increased the glycerol concentration in the dialysate (128 +/- 8 and 149 +/- 12%, respectively) and nutritive blood flow. Terbutaline and dobutamine (100 microM) both provoked rapid and similar increases in glycerol outflow (252 +/- 18 and 249 +/- 18%, respectively). Both, terbutaline and dobutamine increased nutritive blood flow. 5. It is concluded that beta 1- and beta 2-adrenoceptor subtypes are both mainly involved in the mobilization of lipids and in the control of nutritive blood flow. beta 3-Adrenoceptors play a weaker role in the control of lipolysis and nutritive blood flow in human subcutaneous abdominal adipose tissue. PMID:8851509

  6. The Alpha-1D Is the Predominant Alpha-1-Adrenergic Receptor Subtype in Human Epicardial Coronary Arteries

    PubMed Central

    Jensen, Brian C.; Swigart, Philip M.; Laden, Marie-Eve; DeMarco, Teresa; Hoopes, Charles; Simpson, Paul C.

    2009-01-01

    Objectives The goal was to identify alpha-1-adrenergic receptor (α1-AR) subtypes in human coronary arteries. Background The α1-ARs regulate human coronary blood flow. α1-ARs exist as three molecular subtypes, α1A, α1B, and α1D, and the α1D subtype mediates coronary vasoconstriction in the mouse. However, the α1A is thought to be the only subtype in human coronary arteries. Methods We obtained human epicardial coronary arteries and left ventricular (LV) myocardium from 19 transplant recipients and 6 unused donors (age 19–70 years; 68% male; 32% with coronary artery disease). We cultured coronary rings and human coronary smooth muscle cells. We assayed α1- and β-AR subtype mRNAs by quantitative real-time reverse transcription PCR; and subtype proteins, by radioligand binding and ERK activation. Results The α1D subtype was 85% of total coronary α1-AR mRNA and 75% of total α1-AR protein, and α1D stimulation activated ERK. In contrast, the α1D was low in LV myocardium. Total coronary α1-AR levels were one-third of β-ARs, which were 99% the β2 subtype. Conclusions The α1D subtype is predominant and functional in human epicardial coronary arteries, whereas the α1A and α1B are present at very low levels. This distribution is similar to the mouse, where myocardial α1A and α1B-ARs mediate beneficial functional responses, and coronary α1Ds mediate vasoconstriction. Thus, α1D-selective antagonists might mediate coronary vasodilation, without the negative cardiac effects of non-selective α1-AR antagonists in current use. Furthermore, it could be possible to selectively activate beneficial myocardial α1A and/or α1B-AR signaling without causing coronary vasoconstriction. PMID:19761933

  7. A Myocardial Slice Culture Model Reveals Alpha-1A-Adrenergic Receptor Signaling in the Human Heart

    PubMed Central

    Thomas, R. Croft; Singh, Abhishek; Cowley, Patrick; Myagmar, Bat-Erdene; Montgomery, Megan D.; Swigart, Philip M.; De Marco, Teresa; Baker, Anthony J.; Simpson, Paul C.

    2016-01-01

    Background Translation of preclinical findings could benefit from a simple, reproducible, high throughput human model to study myocardial signaling. Alpha-1A-adrenergic receptors (ARs) are expressed at very low levels in the human heart, and it is unknown if they function. Objectives To develop a high throughput human myocardial slice culture model, and to test the hypothesis that alpha-1A- ARs are functional in the human heart. Methods Cores of LV free wall 8 mm diameter were taken from 52 hearts (18 failing and 34 nonfailing). Slices 250 μm thick were cut with a Krumdieck apparatus and cultured using a rotating incubation unit. Results About 60 slices were cut from each LV core, and a typical study could use 96 slices. Myocyte morphology was maintained, and diffusion into the slice center was rapid. Slice viability was stable for at least 3 days in culture by ATP and MTT assays. The beta-AR agonist isoproterenol stimulated phospholamban phosphorylation, and the alpha-1A-AR agonist A61603 stimulated ERK phosphorylation, with nanomolar EC50 values in slices from both failing and nonfailing hearts. Strips cut from the slices were used to quantify activation of contraction by isoproterenol, A61603, and phenylephrine. The slices supported transduction by adenovirus. Conclusions We have developed a simple, high throughput LV myocardial slice culture model to study signaling in the human heart. This model can be useful for translational studies, and we show for the first time that the alpha-1A-AR is functional in signaling and contraction in the human heart. PMID:27453955

  8. Regulation of subtypes of beta-adrenergic receptors in rat brain following treatment with 6-hydroxydopamine

    SciTech Connect

    Johnson, E.W.; Wolfe, B.B.; Molinoff, P.B.

    1989-07-01

    The technique of quantitative autoradiography has been used to localize changes in the densities of subtypes of beta-adrenergic receptors in rat brain following treatment with 6-hydroxydopamine. Previously reported increases in the density of beta 1-adrenergic receptors in the cerebral cortex were confirmed. The anatomical resolution of autoradiography made it possible to detect changes in the density of beta 2-adrenergic receptors in the cortex and in a number of other brain regions. The density of beta 1-adrenergic receptors increased from 30 to 50% depending on the region of the cortex being examined. The increase in the somatomotor cortex was greater than that in the frontal or occipital cortex. The increase in the density of beta 2-adrenergic receptors in the cortex was not as widespread as that of beta 1-adrenergic receptors and occurred primarily in frontal cortex, where the density of receptors increased by 40%. The densities of both beta 1- and beta 2-adrenergic receptors increased in a number of forebrain, thalamic, and midbrain structures. Selective changes in the density of beta 1-adrenergic receptors were observed in the superficial gray layer of the superior colliculus and in the amygdala. The density of beta 2-adrenergic receptors increased in the caudate-putamen, the substantia nigra, and the lateral and central nuclei of the thalamus, whereas the density of beta 1-adrenergic receptors did not change in these regions. The densities of both subtypes of beta-adrenergic receptors increased in the hippocampus, the cerebellum, the lateral posterior nucleus of the thalamus, and the dorsal lateral geniculate.

  9. Adrenergic stimulation alters the expression of inflammasome components and interleukins in primary human monocytes

    PubMed Central

    HORSTMANN, JOHANN-PHILIPP; MARZI, INGO; RELJA, BORNA

    2016-01-01

    Prior to their release, interleukin (IL)-1β and IL-18 are cleaved to their bioactive forms by a multiprotein complex known as an inflammasome, which is comprised of a number of elements that are subject to nuclear factor-κB-dependent transcription. Catecholamines have been indicated to exert an enhancing effect on the IL-1β release. The aim of the present study was to determine whether alterations in inflammasome gene expression may be responsible for the modified IL-1β and IL-18 secretion following lipopolysaccharide (LPS) and catecholamine co-stimulation. Monocytes were isolated from the peripheral blood of 21 healthy volunteers using CD14+ microbeads. Following stimulation with LPS (2 µg/ml) and/or phenylephrine (PE; 10 µM) for 24 h, the supernatants were subjected to ELISA to evaluate the ex vivo protein expression levels of IL-1β and IL-18. In addition, the gene expression levels of inflammasome components associated with the cleavage of IL-1β and IL-18, including NLRP1, NLRP3, caspase-1 and PYCARD were determined using polymerase chain reaction. The results indicated that LPS significantly increased IL-1β expression compared with the unstimulated control samples. Co-stimulation with LPS + PE significantly enhanced IL-1β expression compared with LPS alone. Furthermore, IL-18 expression was significantly reduced by LPS and LPS + PE co-stimulation. The gene expression levels of IL-18, NLRP1, caspase-1 and PYCARD were comparable in the LPS- and LPS + PE-stimulated cells. LPS significantly induced the expression levels of IL-1β and NLRP3, and to a lesser degree, the expression of NLRP1, compared with the control. By contrast, PE markedly induced the expression levels of IL-18 and NLRP1, while LPS reduced the gene expression of IL-18. In conclusion, adrenergic stimulation suppressed NLRP3 expression and enhanced NLRP1 expression, indicating that NLRP3 may regulate IL-1β secretion and NLRP1 may regulate the release of IL-18. PMID:26889257

  10. Molecular Insights into the Dynamics of Pharmacogenetically Important N-Terminal Variants of the Human β2-Adrenergic Receptor

    PubMed Central

    Sengupta, Durba; Joshi, Manali

    2014-01-01

    The human β2-adrenergic receptor (β2AR), a member of the G-protein coupled receptor (GPCR) family, is expressed in bronchial smooth muscle cells. Upon activation by agonists, β2AR causes bronchodilation and relief in asthma patients. The N-terminal polymorphism of β2AR at the 16th position, Arg16Gly, has warranted a lot of attention since it is linked to variations in response to albuterol (agonist) treatment. Although the β2AR is one of the well-studied GPCRs, the N-terminus which harbors this mutation, is absent in all available experimental structures. The goal of this work was to study the molecular level differences between the N-terminal variants using structural modeling and atomistic molecular dynamics simulations. Our simulations reveal that the N-terminal region of the Arg variant shows greater dynamics than the Gly variant, leading to differential placement. Further, the position and dynamics of the N-terminal region, further, affects the ligand binding-site accessibility. Interestingly, long-range effects are also seen at the ligand binding site, which is marginally larger in the Gly as compared to the Arg variant resulting in the preferential docking of albuterol to the Gly variant. This study thus reveals key differences between the variants providing a molecular framework towards understanding the variable drug response in asthma patients. PMID:25501358

  11. α1-adrenergic receptors positively regulate Toll-like receptor cytokine production from human monocytes and macrophages.

    PubMed

    Grisanti, Laurel A; Woster, Andrew P; Dahlman, Julie; Sauter, Edward R; Combs, Colin K; Porter, James E

    2011-08-01

    Catecholamines released from the sympathetic nervous system in response to stress or injury affect expression of inflammatory cytokines generated by immune cells. α(1)-Adrenergic receptors (ARs) are expressed on innate immune cell populations, but their subtype expression patterns and signaling characteristics are not well characterized. Primary human monocytes, a human monocytic cell line, and monocyte-derived macrophage cells were used to measure expression of the proinflammatory mediator interleukin (IL)-1β responding to lipopolysaccharide (LPS) in the presence or absence of α(1)-AR activation. Based on our previous findings, we hypothesized that α(1)-AR stimulation on innate immune cells positively regulates LPS-initiated IL-1β production. IL-1β production in response to LPS was synergistically higher for both monocytes and macrophages in the presence of the selective α(1)-AR agonist (R)-(-)-phenylephrine hydrochloride (PE). This synergistic IL-1β response could be blocked with a selective α(1)-AR antagonist as well as inhibitors of protein kinase C (PKC). Radioligand binding studies characterized a homogenous α(1B)-AR subtype population on monocytes, which changed to a heterogeneous receptor subtype expression pattern when differentiated to macrophages. Furthermore, increased p38 mitogen-activated protein kinase (MAPK) activation was observed only with concurrent PE and LPS stimulation, peaking after 120 and 30 min in monocytes and macrophages, respectively. Blocking the PKC/p38 MAPK signaling pathway in both innate immune cell types inhibited the synergistic IL-1β increase observed with concurrent PE and LPS treatments. This study characterizes α(1)-AR subtype expression on both human monocyte and macrophage cells and illustrates a mechanism by which increased IL-1β production can be modulated by α(1)-AR input. PMID:21571945

  12. Distribution of beta-adrenergic receptors in failing human myocardium. Implications for mechanisms of down-regulation

    SciTech Connect

    Murphree, S.S.; Saffitz, J.E.

    1989-06-01

    The density of beta-adrenergic receptors is reduced in crude membranes prepared from failing human myocardium. We used quantitative autoradiography of radioligand binding sites in intact tissue slices to determine whether the total tissue content of receptors is reduced and to characterize the transmural distribution of receptors in cardiac myocytes and the coronary vasculature in hearts obtained from nine cardiac transplant patients with severe congestive failure. Binding of (125Iodo)cyanopindolol to transmural slices of human myocardium was rapid, saturable, stereoselective, and displaceable by agonists and antagonists with an appropriate rank order of potency. Binding isotherms in four normal and nine failing ventricles showed a significant reduction in the total tissue content of beta-receptors in failing myocardium (38.3 +/- 2.0 fmol/mg protein) compared with normal tissue (52.4 +/- 1.7 fmol/mg protein, p = 0.038). In the normal ventricles, the greatest receptor density was observed autoradiographically in myocytic regions of the subendocardium. Receptor density of the coronary arterioles was approximately 70% of that in adjacent myocytic regions. The density of binding sites in both myocytic regions and arterioles was diminished in all regions of the failing ventricles, but down-regulation was due primarily to a selective reduction of beta-receptors of subendocardial myocytes (63 +/- 5% of subepicardial receptor density vs. 115 +/- 6% in controls, p less than 0.0001). These observations indicate that down-regulation occurs nonuniformly in the transmural distribution and thus is likely not related simply to elevated circulating catecholamine levels.

  13. Agonist binding to β-adrenergic receptors on human airway epithelial cells inhibits migration and wound repair.

    PubMed

    Peitzman, Elizabeth R; Zaidman, Nathan A; Maniak, Peter J; O'Grady, Scott M

    2015-12-15

    Human airway epithelial cells express β-adrenergic receptors (β-ARs), which regulate mucociliary clearance by stimulating transepithelial anion transport and ciliary beat frequency. Previous studies using airway epithelial cells showed that stimulation with isoproterenol increased cell migration and wound repair by a cAMP-dependent mechanism. In the present study, impedance-sensing arrays were used to measure cell migration and epithelial restitution following wounding of confluent normal human bronchial epithelial (NHBE) and Calu-3 cells by electroporation. Stimulation with epinephrine or the β2-AR-selective agonist salbutamol significantly delayed wound closure and reduced the mean surface area of lamellipodia protruding into the wound. Treatment with the β-AR bias agonist carvedilol or isoetharine also produced a delay in epithelial restitution similar in magnitude to epinephrine and salbutamol. Measurements of extracellular signal-regulated kinase phosphorylation following salbutamol or carvedilol stimulation showed no significant change in the level of phosphorylation compared with untreated control cells. However, inhibition of protein phosphatase 2A activity completely blocked the delay in wound closure produced by β-AR agonists. In Calu-3 cells, where CFTR expression was inhibited by RNAi, salbutamol did not inhibit wound repair, suggesting that β-AR agonist stimulation and loss of CFTR function share a common pathway leading to inhibition of epithelial repair. Confocal images of the basal membrane of Calu-3 cells labeled with anti-β1-integrin (clone HUTS-4) antibody showed that treatment with epinephrine or carvedilol reduced the level of activated integrin in the membrane. These findings suggest that treatment with β-AR agonists delays airway epithelial repair by a G protein- and cAMP-independent mechanism involving protein phosphatase 2A and a reduction in β1-integrin activation in the basal membrane. PMID:26491049

  14. Coexistence of adrenergic and cholinergic nerves in the inferior hypogastric plexus: anatomical and immunohistochemical study with 3D reconstruction in human male fetus

    PubMed Central

    Alsaid, Bayan; Bessede, Thomas; Karam, Ibrahim; Abd-Alsamad, Issam; Uhl, Jean-Francois; Benoît, Gérard; Droupy, Stéphane; Delmas, Vincent

    2009-01-01

    Classic anatomical methods have failed to determine the precise location, origin and nature of nerve fibres in the inferior hypogastric plexus (IHP). The purpose of this study was to identify the location and nature (adrenergic and/or cholinergic) of IHP nerve fibres and to provide a three-dimensional (3D) representation of pelvic nerves and their relationship to other anatomical structures. Serial transverse sections of the pelvic portion of two human male fetuses (16 and 17 weeks’ gestation) were studied histologically and immunohistochemically, digitized and reconstructed three-dimensionally. 3D reconstruction allowed a ‘computer-assisted dissection’, identifying the precise location and distribution of the pelvic nerve elements. Proximal (supra-levator) and distal (infra-levator) communications between the pudendal nerve and IHP were observed. By determining the nature of the nerve fibres using immunostaining, we were able to demonstrate that the hypogastric nerves and pelvic splanchnic nerves, which are classically considered purely sympathetic and parasympathetic, respectively, contain both adrenergic and cholinergic nerve fibres. The pelvic autonomic nervous system is more complex than previously thought, as adrenergic and cholinergic fibres were found to co-exist in both ‘sympathetic’ and ‘parasympathetic’ nerves. This study is the first step to a 3D cartography of neurotransmitter distribution which could help in the selection of molecules to be used in the treatment of incontinence, erectile dysfunction and ejaculatory disorders. PMID:19438760

  15. Characterization of human plasma apolipoprotein E-containing lipoproteins in the high density lipoprotein size range: focus on pre-beta1-LpE, pre-beta2-LpE, and alpha-LpE.

    PubMed

    Krimbou, L; Tremblay, M; Davignon, J; Cohn, J S

    1997-01-01

    We have used two-dimensional gel electrophoresis to separate and characterize human plasma apolipoprotein (apo) E-containing lipoproteins in the high density lipoprotein (HDL) size range. Lipoproteins were separated from whole plasma by electrophoresis (according to charge) in a 0.75% agarose gel, and then in the second dimension (according to size) in a 2-15% non-denaturing polyacrylamide gradient gel. ApoE-containing lipoproteins were detected by radiography after electrotransfer of lipoproteins to nitrocellulose membranes and incubation with 125I-labeled affinity-purified polyclonal apoE antibody. ApoE-containing lipoproteins in the HDL size range had a particle size ranging from 9 to 18.5 nm in diameter and could be characterized as having either gamma, pre-beta1-, pre-beta2- or alpha-electrophoretic mobility (designated gamma-LpE, pre-beta1-LpE, pre-beta2LpE, and alpha-LpE respectively). gamma-LpE and a substantial proportion of pre-beta1- and pre-beta2-LpE did not co-migrate with apoA-I, apoA-II, apoC-III, or apoB-100. Subsequent experiments focused on the pre-beta1-LpE, pre-beta2LpE, and alpha-LpE subfractions, which represented > 95% of apoE in HDL-sized lipoproteins. Storage of plasma at 4 degrees C or in vitro incubation of plasma at 37 degrees C caused a relative decrease in pre-beta1-LpE and increase in alpha-LpE. Normolipidemic patients with an apoE 2/2 phenotype tended to have increased levels of alpha-LpE, whereas apoE 4/4 subjects tended to have a greater proportion of HDL-apoE as pre-beta1-LpE. Decrease in plasma HDL apoE concentration after an oral fat load was associated with a reduction in the plasma concentration of all HDL-apoE subfractions. These results demonstrate that: 1) apoE-containing HDL are heterogeneous in size and charge; 2) pre-beta1-LpE is a relatively labile HDL subfraction; 3) HDL-apoE subfraction distribution is dependent on apoE phenotype; and 4) all apoE-containing HDL subfractions participate in the plasma transfer of apo

  16. Activity of the Adrenergic Nerve System in the Airways Permeability of Healthy Persons

    PubMed Central

    Gashi, Njazi; Islami, Pëllumb; Mustafa, Lirim; Maloku, Halit; Veseli, Arta; Islami, Hilmi

    2013-01-01

    Objective: In this work, role of the adrenergic nerve system (alpha1 and beta2) in adjustment of the bronchomotor tonus in healthy people was researched. Methods: Parameters of the lung function are determined by Body plethysmography. Raw and ITGV were registered and SRaw was calculated as well. Aerosolization is done with standard aerosolizing machines – Asema. Results: Results gained shows that following the blockade of beta-2 adrenergic receptor with Propranolol (20 mg–aerosol), stimulation of alpha adrenergic receptor with Oxedrine (120 mg-aerosol) and blockage of these receptors with Tolazoline (20 mg-aerosol), does not change significantly the bronchomotor tonus of the tracheobronchial tree (p > 0.1). Meanwhile, stimulation of the beta-2 adrenergic receptor with Hexoprenaline (2 inh × 0.2 mg) is associated with a significant increase of the peripheral resistance of the airways (p < 0.01). Conclusion: This suggests that the activity of the alpha1-adrenergic receptor, unlike the activity of the beta2-adrenergic receptor in the healthy people smooth musculature, is not significant and as such is insufficient to oppose to the tonic activities of the cholinergic system. PMID:24554803

  17. Binding of dopamine and 3-methoxytyramine as l-DOPA metabolites to human alpha(2)-adrenergic and dopaminergic receptors.

    PubMed

    Alachkar, Amal; Brotchie, Jonathan M; Jones, Owen T

    2010-07-01

    The ability of l-3,4-dihydroxyphenylalanine (l-DOPA), l-DOPA-methyl ester and their major metabolites, dopamine, dihydroxyphenylacetic acid (DOPAC), homovanillic (HVA), 3-O-methyldopa and 3-methoxytyramine (3-MT) to bind to alpha(2) adrenergic and D1 and D2 dopamine receptors was assessed by radioligand binding to cloned human receptors expressed in cell lines. As anticipated, dopamine bound with high affinity to D1 (IC(50) 1.1 + or - 0.16 microM) and D2 (IC(50) 0.7 + or - 0.3 microM) dopamine receptors. However, dopamine also bound with high affinity to alpha(2A) (IC(50) was 2.6 + or - 0.5 microM), alpha(2C) (IC(50) 3.2 + or - 0.7 microM). 3-MT bound to alpha(2A) with high affinity (IC(50), 3.6 + or - 0.2 microM) though moderate affinity to alpha(2)c, D1 and D2 receptors (values of IC(50) were 55 + or - 14, 121 + or - 43, 36 + or - 14 microM, respectively). l-DOPA-methyl ester bound with high affinity to alpha(2) (IC(50) 17-36 microM) but not dopamine receptors (IC(50) 0.9-2.5 mM). l-DOPA, 3-O-methyldopa and DOPAC had no observable effect on binding to any of the receptors tested. These data suggest that the effects of l-DOPA in Parkinson's disease may result from actions of its metabolites dopamine and 3-MT on both dopaminergic and non-dopaminergic receptors. These findings may provide explanations for the differences between l-DOPA and dopamine receptor agonists in mediating anti-parkinsonian effects and propensity to be associated with dyskinesia and motor complications such as wearing-off and on-off. PMID:20302892

  18. Purification and characterization of the human platelet. cap alpha. /sub 2/-adrenergic receptor

    SciTech Connect

    Shreeve, S.M.; Kerlavage, A.R.; Fraser, C.M.; Mariani, A.P.; Venter, J.C.

    1986-05-01

    The ..cap alpha../sub 2/-receptor (..cap alpha../sub 2/-R) from human platelets has been purified to homogeneity using a four step process. An affinity column was prepared by coupling p-aminoclonidine to CH-Sepharose 4B via the p-NH/sub 2/ group. Digitonin solubilized ..cap alpha../sub 2/-R bound to the affinity matrix were eluted with 100 ..mu..M phentolamine and directly applied to a DEAE-Sepharose column. Bound receptors were eluted with a linear gradient of 0-500 mM NaCl, pooled and chromatographed on HPLC size exclusion columns. Three peaks of ..cap alpha../sub 2/-R binding were eluted from HPLC columns (t = 33, 42, 47 min). Radioiodination of HPLC eluates and analysis by SDS-PAGE indicated that ..cap alpha../sub 2/-R binding was associated with a 75-85 kDa protein. These data suggest that the ..cap alpha../sub 2/-R may exist in monomeric and oligomeric forms in the purified state and support previous target size data which indicate that the ..cap alpha../sub 2/-R exists as a dimer in the native membrane. The pure radioiodinated ..cap alpha../sub 2/-R (77-85 kDa) is a glycoprotein with terminal sialic acid or N-acetylglucosamine residues and has a pI of 4.1 on column isoelectric focusing. These data are consistent with those previously reported on the partially purified ..cap alpha../sub 2/-R. Electron micrographs confirm the oligomeric nature and size of the pure ..cap alpha../sub 2/-R.

  19. Sympathetic neural signaling via the β2-adrenergic receptor suppresses T-cell receptor-mediated human and mouse CD8(+) T-cell effector function.

    PubMed

    Estrada, Leonardo D; Ağaç, Didem; Farrar, J David

    2016-08-01

    Postganglionic sympathetic neurons innervate secondary lymphoid organs and secrete norepinephrine (NE) as the primary neurotransmitter. NE binds and signals through five distinct members of the adrenergic receptor family. In this study, we show elevated expression of the β2-adrenergic receptor (ADRB2) on primary human CD8(+) effector memory T cells. Treatment of both human and murine CD8(+) T cells with NE decreased IFN-γ and TNF-α secretion and suppressed their cytolytic capacity in response to T-cell receptor (TCR) activation. The effects of NE were specifically reversed by β2-specific antagonists. Adrb2(-/-) CD8(+) T cells were completely resistant to the effects of NE. Further, the ADRB2-specific pharmacological ligand, albuterol, significantly suppressed effector functions in both human and mouse CD8(+) T cells. While both TCR activation and stimulation with IL-12 + IL-18 were able to induce inflammatory cytokine secretion, NE failed to suppress IFN-γ secretion in response to IL-12 + IL18. Finally, the long-acting ADRB2-specific agonist, salmeterol, markedly reduced the cytokine secretion capacity of CD8(+) T cells in response to infection with vesicular stomatitis virus. This study reveals a novel intrinsic role for ADRB2 signaling in CD8(+) T-cell function and underscores the novel role this pathway plays in adaptive T-cell responses to infection. PMID:27222010

  20. Interactive effect of beta-adrenergic stimulation and mechanical stretch on low-frequency oscillations of ventricular action potential duration in humans.

    PubMed

    Pueyo, Esther; Orini, Michele; Rodríguez, José F; Taggart, Peter

    2016-08-01

    Ventricular repolarization dynamics are crucial to arrhythmogenesis. Low-frequency oscillations of repolarization have recently been reported in humans and the magnitude of these oscillations proposed to be a strong predictor of sudden cardiac death. Available evidence suggests a role of the sympathetic nervous system. We have used biophysically detailed models integrating ventricular electrophysiology, calcium dynamics, mechanics and β-adrenergic signaling to investigate the underlying mechanisms. The main results were: (1) Phasic beta-adrenergic stimulation (β-AS) at a Mayer wave frequency between 0.03 and 0.15Hz resulted in a gradual decrease of action potential (AP) duration (APD) with concomitant small APD oscillations. (2) After 3-4minutes of phasic β-AS, the mean APD adapted and oscillations of APD became apparent. (3) Phasic changes in haemodynamic loading at the same Mayer wave frequency (a known accompaniment of enhanced sympathetic nerve activity), simulated as variations in the sarcomere length, also induced APD oscillations. (4) The effect of phasic β-AS and haemodynamic loading on the magnitude of APD oscillations was synergistic. (5) The presence of calcium overload and reduced repolarization reserve further enhanced the magnitude of APD oscillations and was accompanied by afterdepolarizations and/or spontaneous APs. In conclusion, low-frequency oscillations of repolarization recently reported in humans were induced by phasic β-AS and phasic mechanical loading, which acted synergistically, and were greatly enhanced by disease-associated conditions, leading to arrhythmogenic events. PMID:27178727

  1. 3D Structure Prediction of Human β1-Adrenergic Receptor via Threading-Based Homology Modeling for Implications in Structure-Based Drug Designing

    PubMed Central

    Ul-Haq, Zaheer; Saeed, Maria; Halim, Sobia Ahsan; Khan, Waqasuddin

    2015-01-01

    Dilated cardiomyopathy is a disease of left ventricular dysfunction accompanied by impairment of the β1-adrenergic receptor (β1-AR) signal cascade. The disturbed β1-AR function may be based on an elevated sympathetic tone observed in patients with heart failure. Prolonged adrenergic stimulation may induce metabolic and electrophysiological disturbances in the myocardium, resulting in tachyarrhythmia that leads to the development of heart failure in human and sudden death. Hence, β1-AR is considered as a promising drug target but attempts to develop effective and specific drug against this tempting pharmaceutical target is slowed down due to the lack of 3D structure of Homo sapiens β1-AR (hsβADR1). This study encompasses elucidation of 3D structural and physicochemical properties of hsβADR1 via threading-based homology modeling. Furthermore, the docking performance of several docking programs including Surflex-Dock, FRED, and GOLD were validated by re-docking and cross-docking experiments. GOLD and Surflex-Dock performed best in re-docking and cross docking experiments, respectively. Consequently, Surflex-Dock was used to predict the binding modes of four hsβADR1 agonists. This study provides clear understanding of hsβADR1 structure and its binding mechanism, thus help in providing the remedial solutions of cardiovascular, effective treatment of asthma and other diseases caused by malfunctioning of the target protein. PMID:25860348

  2. 3D structure prediction of human β1-adrenergic receptor via threading-based homology modeling for implications in structure-based drug designing.

    PubMed

    Ul-Haq, Zaheer; Saeed, Maria; Halim, Sobia Ahsan; Khan, Waqasuddin

    2015-01-01

    Dilated cardiomyopathy is a disease of left ventricular dysfunction accompanied by impairment of the β1-adrenergic receptor (β1-AR) signal cascade. The disturbed β1-AR function may be based on an elevated sympathetic tone observed in patients with heart failure. Prolonged adrenergic stimulation may induce metabolic and electrophysiological disturbances in the myocardium, resulting in tachyarrhythmia that leads to the development of heart failure in human and sudden death. Hence, β1-AR is considered as a promising drug target but attempts to develop effective and specific drug against this tempting pharmaceutical target is slowed down due to the lack of 3D structure of Homo sapiens β1-AR (hsβADR1). This study encompasses elucidation of 3D structural and physicochemical properties of hsβADR1 via threading-based homology modeling. Furthermore, the docking performance of several docking programs including Surflex-Dock, FRED, and GOLD were validated by re-docking and cross-docking experiments. GOLD and Surflex-Dock performed best in re-docking and cross docking experiments, respectively. Consequently, Surflex-Dock was used to predict the binding modes of four hsβADR1 agonists. This study provides clear understanding of hsβADR1 structure and its binding mechanism, thus help in providing the remedial solutions of cardiovascular, effective treatment of asthma and other diseases caused by malfunctioning of the target protein. PMID:25860348

  3. A Specific Cholesterol Binding Site Is Established by the 2.8 Å Structure of the Human [beta][subscript 2]-Adrenergic Receptor

    SciTech Connect

    Hanson, Michael A.; Cherezov, Vadim; Griffith, Mark T.; Roth, Christopher B.; Jaakola, Veli-Pekka; Chien, Ellen Y.T.; Velasquez, Jeffrey; Kuhn, Peter; Stevens, Raymond C.

    2008-07-08

    The role of cholesterol in eukaryotic membrane protein function has been attributed primarily to an influence on membrane fluidity and curvature. We present the 2.8 {angstrom} resolution crystal structure of a thermally stabilized human {beta}{sub 2}-adrenergic receptor bound to cholesterol and the partial inverse agonist timolol. The receptors pack as monomers in an antiparallel association with two distinct cholesterol molecules bound per receptor, but not in the packing interface, thereby indicating a structurally relevant cholesterol-binding site between helices I, II, III, and IV. Thermal stability analysis using isothermal denaturation confirms that a cholesterol analog significantly enhances the stability of the receptor. A consensus motif is defined that predicts cholesterol binding for 44% of human class A receptors, suggesting that specific sterol binding is important to the structure and stability of other G protein-coupled receptors, and that this site may provide a target for therapeutic discovery.

  4. 21 CFR 866.5440 - Beta-2-glycoprotein III immunological test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Beta-2-glycoprotein III immunological test system. 866.5440 Section 866.5440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... the beta-2-glycoprotein III (a serum protein) in serum and other body fluids. Measurement of...

  5. 21 CFR 866.5430 - Beta-2-glycoprotein I immunological test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Beta-2-glycoprotein I immunological test system. 866.5430 Section 866.5430 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... the beta-2-glycoprotein I (a serum protein) in serum and other body fluids. Measurement of...

  6. 21 CFR 866.5630 - Beta-2-microglobulin immunological test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Beta-2-microglobulin immunological test system. 866.5630 Section 866.5630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... beta-2-microglobulin (a protein molecule) in serum, urine, and other body fluids. Measurement of...

  7. 21 CFR 866.5440 - Beta-2-glycoprotein III immunological test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Beta-2-glycoprotein III immunological test system. 866.5440 Section 866.5440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... the beta-2-glycoprotein III (a serum protein) in serum and other body fluids. Measurement of...

  8. 21 CFR 866.5430 - Beta-2-glycoprotein I immunological test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Beta-2-glycoprotein I immunological test system. 866.5430 Section 866.5430 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... the beta-2-glycoprotein I (a serum protein) in serum and other body fluids. Measurement of...

  9. 21 CFR 866.5440 - Beta-2-glycoprotein III immunological test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Beta-2-glycoprotein III immunological test system. 866.5440 Section 866.5440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... the beta-2-glycoprotein III (a serum protein) in serum and other body fluids. Measurement of...

  10. 21 CFR 866.5630 - Beta-2-microglobulin immunological test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Beta-2-microglobulin immunological test system. 866.5630 Section 866.5630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... beta-2-microglobulin (a protein molecule) in serum, urine, and other body fluids. Measurement of...

  11. 21 CFR 866.5430 - Beta-2-glycoprotein I immunological test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Beta-2-glycoprotein I immunological test system. 866.5430 Section 866.5430 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... the beta-2-glycoprotein I (a serum protein) in serum and other body fluids. Measurement of...

  12. 21 CFR 866.5430 - Beta-2-glycoprotein I immunological test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Beta-2-glycoprotein I immunological test system. 866.5430 Section 866.5430 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... the beta-2-glycoprotein I (a serum protein) in serum and other body fluids. Measurement of...

  13. 21 CFR 866.5440 - Beta-2-glycoprotein III immunological test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Beta-2-glycoprotein III immunological test system. 866.5440 Section 866.5440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... the beta-2-glycoprotein III (a serum protein) in serum and other body fluids. Measurement of...

  14. 21 CFR 866.5630 - Beta-2-microglobulin immunological test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Beta-2-microglobulin immunological test system. 866.5630 Section 866.5630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... beta-2-microglobulin (a protein molecule) in serum, urine, and other body fluids. Measurement of...

  15. 21 CFR 866.5630 - Beta-2-microglobulin immunological test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Beta-2-microglobulin immunological test system. 866.5630 Section 866.5630 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... beta-2-microglobulin (a protein molecule) in serum, urine, and other body fluids. Measurement of...

  16. Species differences in the localization and number of CNS beta adrenergic receptors: Rat versus guinea pig

    SciTech Connect

    Booze, R.M.; Crisostomo, E.A.; Davis, J.N.

    1989-06-01

    The localization and number of beta adrenergic receptors were directly compared in the brains of rats and guinea pigs. The time course of association and saturability of (125I)cyanopindolol (CYP) binding to slide-mounted tissue sections was similar in rats (Kd = 17 pM) and guinea pigs (Kd = 20 pM). The beta-1 and beta-2 receptor subtypes were examined through the use of highly selective unlabeled receptor antagonists, ICI 118,551 (50 nM) and ICI 89,406 (70 nM). Dramatic species differences between rats and guinea pigs were observed in the neuroanatomical regional localization of the beta adrenergic receptor subtypes. For example, in the thalamus prominent beta-1 and beta-2 receptor populations were identified in the rat; however, the entire thalamus of the guinea pig had few, if any, beta adrenergic receptors of either subtype. Hippocampal area CA1 had high levels of beta-2 adrenergic receptors in both rats and guinea pigs but was accompanied by a widespread distribution of beta-2 adrenergic receptors only in rats. Quantitative autoradiographic analyses of 25 selected neuroanatomical regions (1) confirmed the qualitative differences in CNS beta adrenergic receptor localization, (2) determined that guinea pigs had significantly lower levels of beta adrenergic receptors than rats and (3) indicated a differential pattern of receptor subtypes between the two species. Knowledge of species differences in receptor patterns may be useful in designing effective experiments as well as in exploring the relationships between receptor and innervation patterns. Collectively, these data suggest caution be used in extrapolation of the relationships of neurotransmitters and receptors from studies of a single species.

  17. Effect of PDE5 inhibition on the modulation of sympathetic α-adrenergic vasoconstriction in contracting skeletal muscle of young and older recreationally active humans.

    PubMed

    Nyberg, Michael; Piil, Peter; Egelund, Jon; Sprague, Randy S; Mortensen, Stefan P; Hellsten, Ylva

    2015-12-01

    Aging is associated with an altered regulation of blood flow to contracting skeletal muscle; however, the precise mechanisms remain unclear. We recently demonstrated that inhibition of cGMP-binding phosphodiesterase 5 (PDE5) increased blood flow to contracting skeletal muscle of older but not young human subjects. Here we examined whether this effect of PDE5 inhibition was related to an improved ability to blunt α-adrenergic vasoconstriction (functional sympatholysis) and/or improved efficacy of local vasodilator pathways. A group of young (23 ± 1 yr) and a group of older (72 ± 1 yr) male subjects performed knee-extensor exercise in a control setting and following intake of the highly selective PDE5 inhibitor sildenafil. During both conditions, exercise was performed without and with arterial tyramine infusion to evoke endogenous norepinephrine release and consequently stimulation of α1- and α2-adrenergic receptors. The level of the sympatholytic compound ATP was measured in venous plasma by use of the microdialysis technique. Sildenafil increased (P < 0.05) vascular conductance during exercise in the older group, but tyramine infusion reduced (P < 0.05) this effect by 38 ± 9%. Similarly, tyramine reduced (P < 0.05) the vasodilation induced by arterial infusion of a nitric oxide (NO) donor by 54 ± 9% in the older group, and this effect was not altered by sildenafil. Venous plasma [ATP] did not change with PDE5 inhibition in the older subjects during exercise. Collectively, PDE5 inhibition in older humans was not associated with an improved ability for functional sympatholysis. An improved efficacy of the NO system may be one mechanism underlying the effect of PDE5 inhibition on exercise hyperemia in aging. PMID:26432842

  18. [The role of beta-2 stimulators in cardiac insufficiency].

    PubMed

    Mettauer, B; Rouleau, J L; Tremblay, G

    1984-01-01

    Beta-2 adrenergic stimulators, a class of drugs which has been used for a long time in the treatment of bronchial asthma and in tocolysis, have recently become part of the therapeutic arsenal for congestive heart failure. Their action seems to be essentially vasodilator, although they do have a mild positive inotropic effect. In the short term, they improve the cardiac output and they decrease the peripheral vascular resistance. Their long term haemodynamic effects are still controversial. However, their are some arguments in favour of the persistence of the beneficial effects observed in the short term. They have a contradictory action on the capacity for exercise; one study states that they improve exercise capacity and another study finds that they do not. Their action on the length of survival is still unknown. Some reports suggest that they may aggravate ventricular arrhythmias. At the moment, then, this class of drugs is only used experimentally in congestive heart failure. We need to wait for the results of larger studies on the long-term benefits, the exercise capacity and the survival. Possible side effects also need to be studied in more detail. PMID:6147114

  19. beta2-Agonists at the Olympic Games.

    PubMed

    Fitch, Kenneth D

    2006-01-01

    The different approaches that the International Olympic Committee (IOC) had adopted to beta2-agonists and the implications for athletes are reviewed by a former Olympic team physician who later became a member of the Medical Commission of the IOC (IOC-MC). Steadily increasing knowledge of the effects of inhaled beta2-agonists on health, is concerned with the fact that oral beta2-agonists may be anabolic, and rapid increased use of inhaled beta2-agonists by elite athletes has contributed to the changes to the IOC rules. Since 2001, the necessity for athletes to meet IOC criteria (i.e., that they have asthma and/or exercise-induced asthma [EIA]) has resulted in improved management of athletes. The prevalence of beta2-agonist use by athletes mirrors the known prevalence of asthma symptoms in each country, although athletes in endurance events have the highest prevalence. The age-of-onset of asthma/EIA in elite winter athletes may be atypical. Of the 193 athletes at the 2006 Winter Olympics who met th IOC's criteria, only 32.1% had childhood asthma and 48.7% of athletes reported onset at age 20 yr or older. These findings lead to speculation that years of intense endurance training may be a causative factor in bronchial hyperreactivity. The distinction between oral (prohibited in sports) and inhaled salbutamol is possible, but athletes must be warned that excessive use of inhaled salbutamol can lead to urinary concentrations similar to those observed after oral administration. This article provides justification that athletes should provide evidence of asthma or EIA before being permitted to use inhaled beta2-agonists. PMID:17085798

  20. Characterization of beta-adrenergic receptors in dispersed rat testicular interstitial cells

    SciTech Connect

    Poyet, P.; Labrie, F.

    1987-01-01

    Recent studies have shown that beta-adrenergic agents stimulate steroidogenesis and cyclic AMP formation in mouse Leydig cells in culture. To obtain information about the possible presence and the characteristics of a beta-adrenergic receptor in rat testicular interstitial cells, the potent beta-adrenergic antagonist (/sup 125/I)cyanopindolol (CYP) was used as ligand. Interstitial cells prepared by collagenase dispersion from rat testis were incubated with the ligand for 2 h at room temperature. (/sup 125/I)cyanopindolol binds to a single class of high affinity sites at an apparent KD value of 15 pM. A number of sites of 6,600 sites/cell is measured when 0.1 microM (-) propranolol is used to determine non-specific binding. The order of potency of a series of agonists competing for (/sup 125/I)cyanopindolol binding is consistent with the interaction of a beta 2-subtype receptor: zinterol greater than (-) isoproterenol greater than (-) epinephrine = salbutamol much greater than (-) norepinephrine. In addition, it was observed that the potency of a large series of specific beta 1 and beta 2 synthetic compounds for displacing (/sup 125/I)cyanopindolol in rat interstitial cells is similar to the potency observed for these compounds in a typical beta 2-adrenergic tissue, the rat lung. For example, the potency of zinterol, a specific beta 2-adrenergic agonist, is 10 times higher in interstitial cells and lung than in rat heart, a typical beta 1-adrenergic tissue. Inversely, practolol, a typical beta 1-antagonist, is about 50 times more potent in rat heart than in interstitial cells and lung.

  1. Contracting human skeletal muscle maintains the ability to blunt α1-adrenergic vasoconstriction during KIR channel and Na+/K+-ATPase inhibition

    PubMed Central

    Crecelius, Anne R; Kirby, Brett S; Hearon, Christopher M; Luckasen, Gary J; Larson, Dennis G; Dinenno, Frank A

    2015-01-01

    Sympathetic vasoconstriction in contracting skeletal muscle is blunted relative to that which occurs in resting tissue; however, the mechanisms underlying this ‘functional sympatholysis’ remain unclear in humans. We tested the hypothesis that α1-adrenergic vasoconstriction is augmented during exercise following inhibition of inwardly rectifying potassium (KIR) channels and Na+/K+-ATPase (BaCl2 + ouabain). In young healthy humans, we measured forearm blood flow (Doppler ultrasound) and calculated forearm vascular conductance (FVC) at rest, during steady-state stimulus conditions (pre-phenylephrine), and after 2 min of phenylephrine (PE; an α1-adrenoceptor agonist) infusion via brachial artery catheter in response to two different stimuli: moderate (15% maximal voluntary contraction) rhythmic handgrip exercise or adenosine infusion. In Protocol 1 (n = 11 subjects) a total of six trials were performed in three conditions: control (saline), combined enzymatic inhibition of nitric oxide (NO) and prostaglandin (PG) synthesis (l-NMMA + ketorolac) and combined inhibition of NO, PGs, KIR channels and Na+/K+-ATPase (l-NMMA + ketorolac + BaCl2 + ouabain). In Protocol 2 (n = 6) a total of four trials were performed in two conditions: control (saline), and combined KIR channel and Na+/K+-ATPase inhibition. All trials occurred after local β-adrenoceptor blockade (propranolol). PE-mediated vasoconstriction was calculated (%ΔFVC) in each condition. Contrary to our hypothesis, despite attenuated exercise hyperaemia of ∼30%, inhibition of KIR channels and Na+/K+-ATPase, combined with inhibition of NO and PGs (Protocol 1) or alone (Protocol 2) did not enhance α1-mediated vasoconstriction during exercise (Protocol 1: −27 ± 3%; P = 0.2 vs. control, P = 0.4 vs.l-NMMA + ketorolac; Protocol 2: −21 ± 7%; P = 0.9 vs. control). Thus, contracting human skeletal muscle maintains the ability to blunt α1-adrenergic vasoconstriction during

  2. The effects of beta2 adrenoceptor gene polymorphisms on pressor response during laryngoscopy and tracheal intubation.

    PubMed

    Kim, N-S; Lee, I-O; Lee, M-K; Lim, S-H; Choi, Y-S; Kong, M-H

    2002-03-01

    We investigated whether human beta2 adrenoceptor (beta2AR) gene polymorphisms are associated with the pressor response to laryngoscopy and tracheal intubation. Ninety-two patients undergoing elective surgery under general anaesthesia were enrolled into this study. Arterial systolic pressure, heart rate and rate pressure product were measured before induction of anaesthesia and 1 min following laryngoscopy and tracheal intubation. Genomic DNA was then used to identify the beta2AR-16 and beta2AR-27 genes using an allele-specific polymerase chain reaction method. Using multiple linear regression models, controlling for age, sex, weight, baseline blood pressure, heart rate and rate pressure product, we found that patients who possessed the glutamic acid homozygote of beta2AR-27 produced significantly greater changes in mean arterial pressure and rate pressure products than patients with the glutamine homozygote of beta2AR-27 (beta coefficient for mean blood pressure = 11.81, beta coefficient for pulse-pressure product = 8.76, both p-values = 0.023). These findings suggest that genetic variability in the human beta2AR gene polymorphisms may be associated with the pressor response to laryngoscopy and tracheal intubation. PMID:11879211

  3. Glucocorticoids down-regulate beta 1-adrenergic-receptor expression by suppressing transcription of the receptor gene.

    PubMed Central

    Kiely, J; Hadcock, J R; Bahouth, S W; Malbon, C C

    1994-01-01

    The expression of beta 2-adrenergic receptors is up-regulated by glucocorticoids. In contrast, beta 1-adrenergic receptors display glucocorticoid-induced down-regulation. In rat C6 glioma cells, which express both of these subtypes of beta-adrenergic receptors, the synthetic glucocorticoid dexamethasone stimulates no change in the total beta-adrenergic receptor content, but rather shifts the beta 1:beta 2 ratio from 80:20 to 50:50. Radioligand binding and immunoblotting demonstrate a sharp decline in beta 1-adrenergic receptor expression. Metabolic labelling of cells with [35S]-methionine in tandem with immunoprecipitation by beta 1-adrenergic-receptor-specific antibodies reveals a sharp decline in the synthesis of the receptor within 48 h for cells challenged with glucocorticoid. Steady-state levels of beta 1-adrenergic-receptor mRNA declined from 0.47 to 0.26 amol/microgram of total cellular RNA within 2 h of dexamethasone challenge, as measured by DNA-excess solution hybridization. The stability of receptor mRNA was not influenced by glucocorticoid; the half-lives of the beta 1- and beta 2-subtype mRNAs were 1.7 and 1.5 h respectively. Nuclear run-on assays revealed the basis for the down-regulation of receptor expression, i.e. a sharp decline in the relative rate of transcription for the beta 1-adrenergic-receptor gene in nuclei from dexamethasone-treated as compared with vehicle-treated cells. These data demonstrate transcriptional suppression as a molecular explanation for glucocorticoid-induced down-regulation of beta 1-adrenergic receptors. Images Figure 1 Figure 2 Figure 6 PMID:8092990

  4. Evaluation of tocolytic efficacy of selective beta2 adrenoceptor agonists on buffalo uterus.

    PubMed

    Garg, Satish K; Garg, K M; Sabir, M

    2004-09-01

    Present study was conducted on prostaglandin F2alpha (PGF2alpha), oxytocin, (OT), potassium chloride (KCI) and barium chloride (BaCl2) pre-contracted perimetrial uterine strips of dioestrus and pregnant buffaloes to evaluate the tocolytic efficacy of selective beta2 adrenoceptor agonists-albuterol (salbutamol) and terbutaline. Cumulative concentration-response curves of both the beta2 adrenoceptor agonists were constructed and the mean effective concentration (EC50) values determined and compared statistically. Based on the comparative EC50 values in relaxing the pre-contracted uterine strips with different spasmogens, the rank order potency of albuterol was found to be--PGF2alpha > BaCl2 > OT > KCl on uterine strips from dioestrus animals, while OT> BaCl2> PGF2alpha >KCl on the uterine strips of pregnant buffaloes. The rank order potency of terbutaline on uterine strips from dioestrus stage animals was- BaCl2 > OT > KCl > PGF2alpha, while BaCl2 > PGF2alpha > KCl > OT on uterine tissues of pregnant animals. Thus, irrespective of the state of uterus, whether gravid or non-gravid, KCl-depolarized uterine tissues required comparatively higher concentrations of albuterol or terbutaline to produce tocolytic effect. High concentrations of K+ in biophase may have interfered with the beta2 adrenoceptor agonists-induced outward K+ current and hyperpolarization. From the results of present study, it was evident that selective beta2 adrenergic agonists had good tocolytic efficacy on the uterus of buffaloes. Further, indirectly the possibility of existence and activation of K(Ca) channels by selective beta2 adrenoceptor agonists in mediating tocolysis of buffalo myometrium can not be ruled out, however, detailed studies using specific K(Ca) channel blockers are required for characterizing the nature of such channels in buffalo uterus. PMID:15462186

  5. A systematic study on the influence of the main ingredients of an ivy leaves dry extract on the β2-adrenergic responsiveness of human airway smooth muscle cells.

    PubMed

    Greunke, Christian; Hage-Hülsmann, Anne; Sorkalla, Thomas; Keksel, Nelli; Häberlein, Felix; Häberlein, Hanns

    2015-04-01

    The bronchospasmolytic and secretolytic effects of ivy leaves dry extracts can be explained by an increased β2-adrenergic responsiveness of the bronchi. Recently, it was shown that α-hederin inhibits the internalization of β2-adrenergic receptors (ß2AR) under stimulating conditions. α-Hederin pretreated alveolar type II cells and human airway smooth muscle cells revealed an increased ß2AR binding and an elevated intracellular cAMP level, respectively. In order to identify whether additional compounds also mediate an increased β2-adrenergic responsiveness, we examined the ingredients of an ivy leaves dry extract (EA 575) protocatechuic acid, neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, rutin, kaempferol-3-O-rutinoside, 3,4-, 3,5- and 4,5-dicaffeoylquinic acid, hederacoside B, and β-hederin. Within all the tested substances, only β-hederin inhibited the internalization of GFP-tagged ß2AR in stably transfected HEK293 cells. Using fluorescence correlation spectroscopy β-hederin (1 μM, 24 h) pretreated HASM cells showed a statistically significant increase in the ß2AR binding from 33.0 ± 8.9% to 44.1 ± 11.5% which was distributed with 36.0 ± 9.5% for τbound1 and 8.1 ± 2.6% for τbound2, respectively (n = 8, p < 0.05). The increased binding was selectively found for the receptor-ligand complex with unrestricted lateral mobility (τbound1 of 0.9 ± 0.1 ms, D1 = 9.1 ± 0.2 μm(2)/s, n = 8), whereas the binding of ß2AR with hindered lateral mobility (τbound2 of 64.2 ± 47.6 ms, D2 = 0.15 ± 0.02 μm(2)/s, n = 8) was not affected. Compared to control cells, a statistically significant increase of 17.5 ± 6.4% (n = 4, p < 0.05) and 24.2 ± 5.8% (n = 4, p < 0.001) in the cAMP formation was found for β-hederin pretreated HASM cells after stimulation with 10 μM of terbutaline and simultaneous stimulation with 10 μM terbutaline and 10 μM forskolin, respectively. Within this systematic study

  6. Physiological and Clinical Implications of Adrenergic Pathways at High Altitude.

    PubMed

    Richalet, Jean-Paul

    2016-01-01

    The adrenergic system is part of a full array of mechanisms allowing the human body to adapt to the hypoxic environment. Triggered by the stimulation of peripheral chemoreceptors, the adrenergic centers in the medulla are activated in acute hypoxia and augment the adrenergic drive to the organs, especially to the heart, leading to tachycardia. With prolonged exposure to altitude hypoxia, the adrenergic drive persists, as witnessed by elevated blood concentrations of catecholamines and nerve activity in adrenergic fibers. In response to this persistent stimulation, the pathways leading to the activation of adenylate cyclase are modified. A downregulation of β-adrenergic and adenosinergic receptors is observed, while muscarinic receptors are upregulated. The expression and activity of Gi and Gs proteins are modified, leading to a decreased response of adenylate cyclase activity to adrenergic stimulation. The clinical consequences of these cellular and molecular changes are of importance, especially for exercise performance and protection of heart function. The decrease in maximal exercise heart rate in prolonged hypoxia is fully accounted for the observed changes in adrenergic and muscarinic pathways. The decreased heart rate response to isoproterenol infusion is another marker of the desensitization of adrenergic pathways. These changes can be considered as mechanisms protecting the heart from a too high oxygen consumption in conditions where the oxygen availability is severely reduced. Similarly, intermittent exposure to hypoxia has been shown to protect the heart from an ischemic insult with similar mechanisms involving G proteins and downregulation of β receptors. Other pathways with G proteins are concerned in adaptation to hypoxia, such as lactate release by the muscles and renal handling of calcium. Altogether, the activation of the adrenergic system is useful for the acute physiological response to hypoxia. With prolonged exposure to hypoxia, the autonomous

  7. Chromosome mapping of the human arrestin (SAG), {beta}-arrestin 2 (ARRB2), and {beta}-adrenergic receptor kinase 2 (ADRBK2) genes

    SciTech Connect

    Calabrese, G.; Sallese, M.; Stornaiuolo, A.

    1994-09-01

    Two types of proteins play a major role in determining homologous desensitization of G-coupled receptors: {beta}-adrenergic receptor kinase ({beta}ARK), which phosphorylates the agonist-occupied receptor and its functional cofactor, {beta}-arrestin. Both {beta}ARK and {beta}-arrestin are members of multigene families. The family of G-protein-coupled receptor kinases includes rhodopsin kinase, {beta}ARK1, {beta}ARK2, IT11-A (GRK4), GRK5, and GRK6. The arrestin/{beta}-arrestin gene family includes arrestin (also known as S-antigen), {beta}-arrestin 1, and {beta}-arrestin 2. Here we report the chromosome mapping of the human genes for arrestin (SAG), {beta}arrestin 2 (ARRB2), and {beta}ARK2 (ADRBK2) by fluorescence in situ hybridization (FISH). FISH results confirmed the assignment of the gene coding for arrestin (SAG) to chromosome 2 and allowed us to refine its localization to band q37. The gene coding for {beta}-arrestin 2 (ARRB2) was mapped to chromosome 17p13 and that coding for {beta}ARK2 (ADRBK2) to chromosome 22q11. 17 refs., 1 fig.

  8. TGF-{beta}2 inhibits AKT activation and FGF-2-induced corneal endothelial cell proliferation

    SciTech Connect

    Lu Jiawei; Lu Zhenyu; Reinach, Peter

    2006-11-01

    The corneal endothelial cells form a boundary layer between anterior chamber and cornea. This single cell layer is important to maintain cornea transparency by eliciting net fluid transport into the anterior chamber. Injuries of the corneal endothelial layer in humans lead to corneal swelling and translucence. This hindrance is thought to be due to limited proliferative capacity of the endothelial layer. Fibroblast growth factor 2 (FGF-2) and transforming growth factor-beta 2 (TGF-{beta}2) are both found in aqueous humor, and these two cytokines promote and inhibit cell growth, respectively. The intracellular signaling mechanisms by which TGF-{beta}2 suppresses the mitogenic response to FGF-2, however, remain unclear. We have addressed this question by investigating potential crosstalk between FGF-2-induced and TGF-{beta}2-regulated intracellular signaling events in cultured bovine corneal endothelial (BCE) cells. We found that TGF-{beta}2 and FGF-2 oppositely affect BCE cell proliferation and TGF-{beta}2 can override the stimulating effects of FGF-2 by increasing COX-2 expression in these cells. Consistent with these findings, overexpression of COX-2 significantly reduced FGF-2-induced cell proliferation whereas a COX-2 specific inhibitor NS398 reversed the effect of TGF-{beta}2 on FGF-2-induced cell proliferation. The COX-2 product prostaglandin E2 (PGE-2) blocks FGF-2-induced cell proliferation. Whereas FGF-2 stimulates cell proliferation by activating the AKT pathway, TGF-{beta}2 and PGE-2 both inhibit this pathway. In accordance with the effect of PGE-2, cAMP also inhibits FGF-2-induced AKT activation. These findings suggest that the mitogenic response to FGF-2 in vivo in the corneal endothelial layer may be inhibited by TGF-{beta}2-induced suppression of the PI3-kinase/AKT signaling pathway.

  9. Impact of the Tamsulosin in Alpha Adrenergic Receptor of Airways at Patients with Increased Bronchial Reactibility

    PubMed Central

    Mustafa, Lirim; Ilazi, Ali; Dauti, Arta; Islami, Pellumb; Kastrati, Bashkim; Islami, Hilmi

    2015-01-01

    Objective: In this work, effect of tamsulosin as antagonist of alpha1A and alpha1B adrenergic receptor and effect of agonists of beta2 adrenergic receptor–salbutamol in patients with increased bronchial reactibility was studied. Methods: Parameters of the lung function are determined with Body plethysmography six (6) hours after administration of tamsulosin. Raw and ITGV were registered and specific resistance (SRaw) was calculated as well. Tamsulosin was administered in per os manner as a preparation in the shape of the capsules with a brand name of “Prolosin”, produced by Niche Generics Limited, Hitchin, Herts. Results: After six (6) hours of administration of tamsulosin, results gained indicate that blockage of alpha1A and alpha1B-adrenergic receptor (0.8 mg per os) has not changed significantly (p > 0.1) the bronchomotor tonus of tracheobronchial tree in comparison to the check-up that has inhaled salbutamol agonist of adrenergic beta2 receptor (2 inh. x 0.2 mg), (p < 0.05). Blood pressure suffered no significant decrease following administration of the 0.8 mg dose of tamsulosin. Conclusion: This suggests that even after six hours of administration of tamsulosin, and determining of lung function parameters, the activity of alpha1A and alpha1B-adrenergic receptor in the smooth bronchial musculature has not changed in patients with increased bronchial reactibility. PMID:26543414

  10. Beta-Adrenergic Agonists

    PubMed Central

    Barisione, Giovanni; Baroffio, Michele; Crimi, Emanuele; Brusasco, Vito

    2010-01-01

    Inhaled β2-adrenoceptor (β2-AR) agonists are considered essential bronchodilator drugs in the treatment of bronchial asthma, both as symptoms-relievers and, in combination with inhaled corticosteroids, as disease-controllers. In this article, we first review the basic mechanisms by which the β2-adrenergic system contributes to the control of airway smooth muscle tone. Then, we go on describing the structural characteristics of β2-AR and the molecular basis of G-protein-coupled receptor signaling and mechanisms of its desensitization/ dysfunction. In particular, phosphorylation mediated by protein kinase A and β-adrenergic receptor kinase are examined in detail. Finally, we discuss the pivotal role of inhaled β2-AR agonists in the treatment of asthma and the concerns about their safety that have been recently raised.

  11. ADRENERGIC RECEPTOR GENOTYPE INFLUENCES THE EFFECTS OF STRENGTH TRAINING ON MID-THIGH INTER-MUSCULAR FAT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is little information regarding the effects of strength training (ST) on intermuscular fat (IMF), which can have adverse effects on health status in the elderly. Regional fat alterations resulting from exercise interventions may be influenced by adrenergic receptor (ADR) Beta2 Gln27Glu and AD...

  12. The adrenergic receptor subtypes present in frog (Rana esculenta) skin.

    PubMed

    Bellantuono, Vito; Cassano, Giuseppe; Lippe, Claudio

    2008-08-01

    Frog skin transports ions and water under hormonal control. In spite of the fundamental role played by adrenergic stimulation in maintaining the water balance of the organism, the receptor subtype(s) present in the skin have not been identified yet. We measured the increase in short-circuit current (ISC, an estimate of ion transport) induced by cirazoline, clonidine, xamoterol, formoterol, or BRL 37344, in order to verify the presence of alpha1, alpha2, beta1, beta2, or beta3 receptor subtypes, respectively. Only after treatment with formoterol, BRL 37344 and, to a lesser extent, cirazoline was measured a significant increase in ISC (57%, 33.2%, and 4.7%, respectively). The formoterol and BRL 37344 concentrations producing half-maximal effect (EC50) were 1.12 and 70.1 nM, respectively. Moreover, the formoterol effect was inhibited by treatment with ICI 118551 (antagonist of beta2 receptors) while SR 59230A (antagonist of beta3 receptors) had no effect; opposite findings were obtained when the BRL 37344 stimulation was investigated. Finally, by measuring the transepithelial fluxes of 22Na+ and 36Cl-, we demonstrated that Na+ absorption is increased by activation of beta2 and beta3 and is cAMP-sensitive, whereas the Cl- secretion is only increased by activation of beta2 receptors and is cAMP- and calmodulin-sensitive. PMID:18544474

  13. The role of beta-adrenergic receptors in the cutaneous water evaporation mechanism in the heat-acclimated pigeon (Columba livia).

    PubMed

    Ophir, E; Arieli, Y; Raber, P; Marder, J

    2000-01-01

    The effects of selective and non-selective beta-adrenergic agents on cutaneous water evaporation (CWE) were studied in hand-reared rock pigeons (Columba livia). CWE was measured by the vapor diffusive resistance method, using a transient porometer. Intramuscular and subcutaneous injections of a non-selective beta-adrenergic antagonist (propranolol) or a selective beta(2)-adrenergic antagonist (ICI-118551) to heat-acclimated (HAc) pigeons at ambient temperature (T(a)) of 24 degrees C resulted in intensive CWE. The CWE values that were triggered by propranolol and ICI-118551 (18.59+/-0.73 and 16.48+/-0.70 mg cm(-2) h(-1), respectively) were close to those induced by heat exposure (17.62+/-1.40 mg cm(-2) h(-1)). Subcutaneous administration of propranolol produced local response. Intramuscular injection of salbutamol (selective beta(2)-adrenergic agonist) to HAc pigeons drastically diminished CWE induced by either propranolol, metoprolol or heat exposure. Such manipulations also enhanced panting at relatively low T(a)s (42 degrees C). The inhibition of beta(1)-adrenergic receptors by metoprolol increased CWE, while inhibition by atenolol produced no change from basal values. This difference may be attributed to their distinctive nature in penetrating the blood-brain barrier. Our findings indicate a regulatory pathway for CWE consisting of both beta(1)- and beta(2)-adrenergic receptors. We suggest that the beta(1)-adrenergic effect is restricted mainly to the CNS, while the beta(2)-adrenergic effect takes place at the effector level. We postulate this level to be either the cutaneous microvasculature or the epidermal layer. PMID:10779732

  14. Electron microscopic localization of receptors for aggregated beta 2-microglobulin on the surface of beta-hemolytic streptococci.

    PubMed Central

    Wagner, M; Wagner, B; Kronvall, G; Björck, L

    1983-01-01

    The presence and location of receptors for aggregated human beta 2-microglobulin (beta 2m) on the surface of group A, C, and G streptococci were studied by electron microscopic techniques. Ferritin-conjugated aggregates of human beta 2m were used in direct binding experiments. Ferritin-conjugated antibodies against beta 2m were employed in a two-step indirect binding assay where the streptococci were incubated with unlabeled beta 2m aggregates before the addition of antibodies. Similar results were obtained with these two methods. Among tested group C and G strains, some showed binding of beta 2m, whereas others were negative. In group A streptococci, beta 2m binding was localized to filamentous structures typical of M protein. In two M protein-negative group A strains, the reactivity was heterogeneous, revealing a majority of unlabeled, but also some heavily labeled streptococci. Morphologically, these beta 2m-binding bacteria exhibited M protein-like projections in contrast to the smooth surfaces of unlabeled cells. Images PMID:6352498

  15. Dissociations in the Effects of β2-Adrenergic Receptor Agonists on cAMP Formation and Superoxide Production in Human Neutrophils: Support for the Concept of Functional Selectivity

    PubMed Central

    Brunskole Hummel, Irena; Reinartz, Michael T.; Kälble, Solveig; Burhenne, Heike; Schwede, Frank; Buschauer, Armin; Seifert, Roland

    2013-01-01

    In neutrophils, activation of the β2-adrenergic receptor (β2AR), a Gs-coupled receptor, inhibits inflammatory responses, which could be therapeutically exploited. The aim of this study was to evaluate the effects of various β2AR ligands on adenosine-3′,5′-cyclic monophosphate (cAMP) accumulation and N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP)-induced superoxide anion (O2•−) production in human neutrophils and to probe the concept of ligand-specific receptor conformations (also referred to as functional selectivity or biased signaling) in a native cell system. This is an important question because so far, evidence for functional selectivity has been predominantly obtained with recombinant systems, due to the inherent difficulties to genetically manipulate human native cells. cAMP concentration was determined by HPLC/tandem mass spectrometry, and O2•− formation was assessed by superoxide dismutase-inhibitable reduction of ferricytochrome c. β2AR agonists were generally more potent in inhibiting fMLP-induced O2•− production than in stimulating cAMP accumulation. (−)-Ephedrine and dichloroisoproterenol were devoid of any agonistic activity in the cAMP assay, but partially inhibited fMLP-induced O2•− production. Moreover, (−)-adrenaline was equi-efficacious in both assays whereas the efficacy of salbutamol was more than two-fold higher in the O2•− assay. Functional selectivity was visualized by deviations of ligand potencies and efficacies from linear correlations for various parameters. We obtained no evidence for involvement of protein kinase A in the inhibition of fMLP-induced O2•− production after β2AR-stimulation although cAMP-increasing substances inhibited O2•− production. Taken together, our data corroborate the concept of ligand-specific receptor conformations with unique signaling capabilities in native human cells and suggest that the β2AR inhibits O2•− production in a cAMP-independent manner. PMID

  16. Alpha-1-Adrenergic Receptors: Targets for Agonist Drugs to Treat Heart Failure

    PubMed Central

    Jensen, Brian C.; O'Connell, Timothy D.; Simpson, Paul C.

    2011-01-01

    Evidence from cell, animal, and human studies demonstrates that α1-adrenergic receptors mediate adaptive and protective effects in the heart. These effects may be particularly important in chronic heart failure, when catecholamine levels are elevated and β-adrenergic receptors are down regulated and dysfunctional. This review summarizes these data and proposes that selectively activating α1-adrenergic receptors in the heart may represent a novel and effective way to treat heart failure. PMID:21118696

  17. Adrenergic vasomotor responses in nasal mucosa of hooded seals.

    PubMed

    Folkow, L P

    1992-12-01

    In seals respiratory heat and water losses are restricted through nasal heat exchange. The heat exchange efficiency is apparently controlled through adjustments in the nasal mucosal blood flow rate and/or pattern. In this study the adrenergic mechanisms involved in regulation of mucosal blood flow were investigated. The nasal mucosal vasculature of 14 newly killed hooded seal (Cystophora cristata) pups was perfused by a constant-flow peristaltic pump with 37 degrees C oxygenated modified Krebs solution via the sphenopalatine arteries. The effects of single-dose injections of various drugs on resistance to flow were monitored with a pressure transducer. Epinephrine, norepinephrine, alpha 1-adrenoceptor agonist phenylephrine, alpha 2-agonist clonidine, beta 1-agonist dobutamine, and beta 2-agonist terbutaline caused transient pressure increases that were blocked by alpha-adrenoceptor antagonists. Papaverine and vasoactive intestinal polypeptide induced vasodilatation, showing that some basal vascular tone was present. Nevertheless, the beta 1- and beta 2-agonist isoproterenol had no effect on resistance, and none of the beta-agonists attenuated the pressor responses to alpha-agonists. In conclusion, adrenergic control of nasal mucosal blood flow in seals is essentially exerted through alpha-adrenoceptor-mediated arteriolar constriction, whereas beta-adrenoceptor-mediated dilatation seems to be of little importance. It is suggested that such sympathoadrenergic vascular mechanisms contribute to control nasal heat exchange efficiency in seals. PMID:1481941

  18. Binding potencies of 3 new beta 2 specific blockers to beta receptors in the ciliary processes and the possible relevance of these drugs to intraocular pressure control.

    PubMed Central

    Trope, G E; Clark, B

    1984-01-01

    The binding potencies of 3 new beta 2 blocking drugs to beta receptors in the ciliary processes were studied by means of radioligand techniques. The drugs studied were IPS339, ICI118,551, and Sandoz L1 32-468. The order of potency of these drugs was IPS339 greater than Sandoz L1 32-468 greater than ICI118,551. The beta 2 dissociation constants (KDs) for these drugs were 0.90 nM, 6.60 nM, and 55 nM respectively. These results are compared with those for other adrenergic agents, including timolol. The potential role of topical beta 2 blockers in glaucoma is discussed. PMID:6142724

  19. β-Adrenergic blockers.

    PubMed

    Frishman, William H; Saunders, Elijah

    2011-09-01

    KEY POINTS AND PRACTICAL RECOMMENDATIONS: •  β-Blockers are appropriate treatment for patients with hypertension and those who have concomitant ischemic heart disease, heart failure, obstructive cardiomyopathy, or certain arrhythmias. •  β-Blockers can be used in combination with other antihypertensive drugs to achieve maximal blood pressure control. Labetalol can be used in hypertensive emergencies and urgencies. •  β-Blockers may be useful in patients having hyperkinetic circulation (palpitations, tachycardia, hypertension, and anxiety), migraine headache, and essential tremor. •  β-Blockers are highly heterogeneous with respect to various pharmacologic effects: degree of intrinsic sympathomimetic activity, membrane-stabilizing activity, β(1) selectivity, α(1) -adrenergic-blocking effect, tissue solubility, routes of systemic elimination, potencies and duration of action, and specific effects may be important in the selection of a drug for clinical use. •  β-Blocker usage to reduce perioperative ischemia and cardiovascular complications may not benefit as many patients as was once hoped and may actually cause harm in some individuals. Currently the best evidence supports β-blocker use in two patient groups: patients undergoing vascular surgery with known ischemic heart disease or multiple risk factors for it and for patients already receiving β-blockers for known cardiovascular conditions. PMID:21896144

  20. Inhaled adrenergic bronchodilators: historical development and clinical application.

    PubMed

    Rau, J L

    2000-07-01

    The adrenergic bronchodilators that have been developed for oral inhalation represent successive refinement in terms of receptor specificity and duration of action. Beta agonist bronchodilators have durations of 4-6 hours, or, in the case of salmeterol, of up to 12 hours, offering convenient dosing. Inhalation of the aerosol formulations targets the lung directly. The release of levalbuterol now provides an agent with a single isomer active on beta-2 receptors. The currently available agents offer clinicians and patients with reversible obstructive lung disease a choice of sophisticated drugs for airway smooth muscle relaxation. Although improvements in the drugs have reduced adverse effects and beta agonists are considered safe, concerns persist about the effect of beta agonists in asthma. An improved understanding of asthma pathophysiology may lead to more appropriate use of beta agonists in asthma. PMID:10926383

  1. The effect of alpha2-adrenergic receptors on cutaneous water evaporation in the rock pigeon (Columba livia).

    PubMed

    Ophir, Eshel; Arieli, Yehuda; Marder, Jacob

    2004-12-01

    The role of beta-adrenergic receptors in regulating cutaneous water evaporation (CWE) in the rock pigeon (Columba livia) is well documented. Here, we studied the involvement of the alpha2-adrenergic receptors in this cooling mechanism of the heat-acclimated (HAc) pigeon. Systemic alpha2-adrenergic activation [clonidine, 50 microg kg(-1), intramuscular (i.m.)] was found to increase CWE in heat-acclimated pigeons at an ambient temperature (T(a)) of 25 degrees C. Subcutaneous administration of the drug had no significant effect. Preinjection of an alpha2-adrenergic antagonist (yohimbine, 10 mg kg(-1), i.m.) completely prevented clonidine-induced CWE and attenuated propranolol-induced CWE by 53%. Pretreatment with a beta-adrenergic agonist (isoproterenol, 4 mg kg(-1), i.m.) abolished the effect of clonidine. None of the above treatments was found to elicit significant CWE in nonacclimated (NAc) pigeons. These findings, in addition to previously reported data, indicate a complex regulatory pathway of CWE in the heat-acclimated pigeon consisting of alpha2- and beta2-adrenergic receptors. The possible hierarchical pattern of these receptors is discussed. PMID:15596385

  2. Labeled ALPHA4BETA2 ligands and methods therefor

    DOEpatents

    Mukherjee, Jogeshwar; Pichika, Ramaiah; Potkin, Steven; Leslie, Frances; Chattopadhyay, Sankha

    2013-02-19

    Contemplated compositions and methods are employed to bind in vitro and in vivo to an .alpha.4.beta.2 nicotinic acetylcholine receptor in a highly selective manner. Where such compounds are labeled, compositions and methods employing such compounds can be used for PET and SPECT analysis. Alternatively, and/or additionally contemplated compounds can be used as antagonists, partial agonists or agonists in the treatment of diseases or conditions associated with .alpha.4.beta..beta.2 dysfunction.

  3. Response of the Adrenergic System After Provoked Bronchoconstriction in Patients with Bronchial Asthma

    PubMed Central

    Islami, Hilmi; Ilazi, Ali; Gashi, Nijazi; Mustafa, Lirim; Maloku, Halit; Jashanica, Adelina

    2014-01-01

    Objective: In this paper, effect of the Tolazoline as antagonist of the alpha-2 adrenergic receptors in patients with bronchial asthma and chronic obstructive bronchitis was studied, and also the effect of stimulation with Hexoprenaline of beta-2 adrenergic receptor after bronchi-constriction caused with Propranolol, and Acetylcholine. Methods: Lung function parameters are determined with Body plethysmography. In patients with bronchial asthma and chronic obstructive bronchitis was registered resistance (Raw), was determined the amount of intrathoracic gas volume (ITGV), and specific resistance was calculated as well (SRaw). Aerosolization was done with standard aerosolizing machine-Asema. Results: The study included a total of 21 patients. Two hours after the inhalation of Propranolol, in experimental group, it was applied the blocker of alpha-2 adrenergic receptors (Tolazoline 20 mg / ml with inhalator ways), which did not cause changes in bronchomotor tonus of tracheobronchial system (p > 1.0). Meanwhile, at the same patient, stimulation of beta-2 adrenergic receptor with Hexoprenaline (2 inh x 0.2 mg) is associated with a significant decrease of the specific resistance of airways (SRaw, p < 0.01). Control group results show that after bronchi-constriction caused by Propranolol-aerosol (20 mg / ml) in patients with bronchial asthma and chronic obstructive bronchitis, an increase of specific resistance in airways was caused (SRaw, p < 0.01), which confirms the presence of hyper-reactive bronco-constrictor effects intermediated by vagal ways. Two hours after Propranolol, inhaled Hexorenaline has blocked the action of Propranolol, but not entirely. Furthermore, two hours after acetylcholine-aerosol (1 mg /ml) was applied, inhaled Ipratropium (2 inh x 1 mg) has fully blocked the action of chemical bronchoconstrictor mediators, causing a decline of specific resistance in the airways (SRaw; p < 0.01). Conclusion: This suggests that primary mechanism, which would cause

  4. Adrenergic regulation of innate immunity: a review

    PubMed Central

    Scanzano, Angela; Cosentino, Marco

    2015-01-01

    The sympathetic nervous system has a major role in the brain-immune cross-talk, but few information exist on the sympathoadrenergic regulation of innate immune system. The aim of this review is to summarize available knowledge regarding the sympathetic modulation of the innate immune response, providing a rational background for the possible repurposing of adrenergic drugs as immunomodulating agents. The cells of immune system express adrenoceptors (AR), which represent the target for noradrenaline and adrenaline. In human neutrophils, adrenaline and noradrenaline inhibit migration, CD11b/CD18 expression, and oxidative metabolism, possibly through β-AR, although the role of α1- and α2-AR requires further investigation. Natural Killer express β-AR, which are usually inhibitory. Monocytes express β-AR and their activation is usually antiinflammatory. On murine Dentritic cells (DC), β-AR mediate sympathetic influence on DC-T cells interactions. In human DC β2-AR may affect Th1/2 differentiation of CD4+ T cells. In microglia and in astrocytes, β2-AR dysregulation may contribute to neuroinflammation in autoimmune and neurodegenerative disease. In conclusion, extensive evidence supports a critical role for adrenergic mechanisms in the regulation of innate immunity, in peripheral tissues as well as in the CNS. Sympathoadrenergic pathways in the innate immune system may represent novel antiinflammatory and immunomodulating targets with significant therapeutic potential. PMID:26321956

  5. The emerging pharmacogenomics of the beta-adrenergic receptors.

    PubMed

    Taylor, Matthew R G; Bristow, Michael R

    2004-01-01

    Beta-adrenergic signaling mechanisms are of central importance to cardiovascular health and disease. Modulation of these pathways represents an important pharmacologic approach to the treatment of heart failure and hypertension. Advances in molecular genetics have identified genetic polymorphisms in the human beta-adrenergic receptor genes; some of this variation predicts changes in protein sequence/structure, and potentially changes in function, of the b-adrenergic receptors. This article reviews the current state of knowledge and understanding of the genetic variation present in the three human beta-adrenergic receptor genes. Already, variation in these genes has been associated with observed differences in several cardiovascular phenotypes. This work has led to the demonstration of functional differences in activity between receptors with certain known polymorphisms and "wild-type" receptors. An understanding of these polymorphisms is key to the development of studies of how differences in drug response/effects may be mediated by these polymorphisms. Such studies are anticipated to provide a foundation for the development of novel pharmacologic approaches where selection of and dosing of cardiovascular therapy is tailored to individuals on the basis of each patient's specific genetic makeup. PMID:15591842

  6. Understanding the links among neuromedin U gene, beta2-adrenoceptor gene and bone health: an observational study in European children.

    PubMed

    Gianfagna, Francesco; Cugino, Daniela; Ahrens, Wolfgang; Bailey, Mark E S; Bammann, Karin; Herrmann, Diana; Koni, Anna C; Kourides, Yiannis; Marild, Staffan; Molnár, Dénes; Moreno, Luis A; Pitsiladis, Yannis P; Russo, Paola; Siani, Alfonso; Sieri, Sabina; Sioen, Isabelle; Veidebaum, Toomas; Iacoviello, Licia

    2013-01-01

    Neuromedin U, encoded by the NMU gene, is a hypothalamic neuropeptide that regulates both energy metabolism and bone mass. The beta-2 adrenergic receptor, encoded by the ADRB2 gene, mediates several effects of catecholamine hormones and neurotransmitters in bone. We investigated whether NMU single nucleotide polymorphisms (SNPs) and haplotypes, as well as functional ADRB2 SNPs, are associated with bone stiffness in children from the IDEFICS cohort, also evaluating whether NMU and ADRB2 interact to affect this trait. A sample of 2,274 subjects (52.5% boys, age 6.2 ± 1.8 years) from eight European countries, having data on calcaneus bone stiffness index (SI, mean of both feet) and genotyping (NMU gene: rs6827359, rs12500837, rs9999653; ADRB2 gene: rs1042713, rs1042714), was studied. After false discovery rate adjustment, SI was significantly associated with all NMU SNPs. rs6827359 CC homozygotes showed the strongest association (recessive model, Δ= -1.8, p=0.006). Among the five retrieved haplotypes with frequencies higher than 1% (range 2.0-43.9%), the CCT haplotype (frequency=39.7%) was associated with lower SI values (dominant model, Δ= -1.0, p=0.04) as compared to the most prevalent haplotype. A non-significant decrease in SI was observed in in ADRB2 rs1042713 GG homozygotes, while subjects carrying SI-lowering genotypes at both SNPs (frequency = 8.4%) showed much lower SI than non-carriers (Δ= -3.9, p<0.0001; p for interaction=0.025). The association was more evident in preschool girls, in whom SI showed a curvilinear trend across ages. In subgroup analyses, rs9999653 CC NMU or both GG ADRB2 genotypes were associated with either lower serum calcium or β-CrossLaps levels (p=0.01). This study in European children shows, for the first time in humans, a role for NMU gene through interaction with ADRB2 gene in bone strength regulation, more evident in preschool girls. PMID:23936460

  7. Understanding the Links among neuromedin U Gene, beta2-adrenoceptor Gene and Bone Health: An Observational Study in European Children

    PubMed Central

    Gianfagna, Francesco; Cugino, Daniela; Ahrens, Wolfgang; Bailey, Mark E. S.; Bammann, Karin; Herrmann, Diana; Koni, Anna C.; Kourides, Yiannis; Marild, Staffan; Molnár, Dénes; Moreno, Luis A.; Pitsiladis, Yannis P.; Russo, Paola; Siani, Alfonso; Sieri, Sabina; Sioen, Isabelle; Veidebaum, Toomas; Iacoviello, Licia

    2013-01-01

    Neuromedin U, encoded by the NMU gene, is a hypothalamic neuropeptide that regulates both energy metabolism and bone mass. The beta-2 adrenergic receptor, encoded by the ADRB2 gene, mediates several effects of catecholamine hormones and neurotransmitters in bone. We investigated whether NMU single nucleotide polymorphisms (SNPs) and haplotypes, as well as functional ADRB2 SNPs, are associated with bone stiffness in children from the IDEFICS cohort, also evaluating whether NMU and ADRB2 interact to affect this trait. A sample of 2,274 subjects (52.5% boys, age 6.2±1.8 years) from eight European countries, having data on calcaneus bone stiffness index (SI, mean of both feet) and genotyping (NMU gene: rs6827359, rs12500837, rs9999653; ADRB2 gene: rs1042713, rs1042714), was studied. After false discovery rate adjustment, SI was significantly associated with all NMU SNPs. rs6827359 CC homozygotes showed the strongest association (recessive model, Δ = −1.8, p = 0.006). Among the five retrieved haplotypes with frequencies higher than 1% (range 2.0–43.9%), the CCT haplotype (frequency = 39.7%) was associated with lower SI values (dominant model, Δ = −1.0, p = 0.04) as compared to the most prevalent haplotype. A non-significant decrease in SI was observed in in ADRB2 rs1042713 GG homozygotes, while subjects carrying SI-lowering genotypes at both SNPs (frequency = 8.4%) showed much lower SI than non-carriers (Δ = −3.9, p<0.0001; p for interaction = 0.025). The association was more evident in preschool girls, in whom SI showed a curvilinear trend across ages. In subgroup analyses, rs9999653 CC NMU or both GG ADRB2 genotypes were associated with either lower serum calcium or β-CrossLaps levels (p = 0.01). This study in European children shows, for the first time in humans, a role for NMU gene through interaction with ADRB2 gene in bone strength regulation, more evident in preschool girls. PMID:23936460

  8. Exercise induced changes in lymphocyte beta adrenergic receptors correlate with peak exercise heart rates in healthy trained and sedentary human subjects

    SciTech Connect

    Eisinger, M.; Engelmeier, R.; Glisson, S.; Scanlon, P.

    1986-03-05

    Lymphocyte beta adrenergic receptors (lymph BAR) increase after maximal multistage treadmill exercise (TME) presumably by externalization from intracellular vesicles. Nine healthy subjects underwent symptom limited TME by the Bruce protocol. Heart rate was measured at the end of each 3 minute stage. Plasma norepinephrine (NE), plasma epinephrine (EPI) and lymph BAR were measured at rest and at peak exercise. Catecholamines were determined by high performance liquid chromatography. Lymph BAR were measured by separating cells from 25cc of whole blood across a Ficoll-Hypaque density gradient and incubating membrane preparations with 7 dilutions of I/sup 125/ cyanopindolol in the presence or absence of 1..mu..M(-) propranolol in a total assay volume of 450 ..mu..l. BAR was standardized to Lowry-Peterson protein at rest and exercise. The relationship of maximum heart rate versus peak plasma NE, EPI and lymph BAR was analyzed by linear regression. The following conclusions were reached: (1) there is a significant correlation between exercise induced changes in lymph BAR and peak heart rate; (2) this relationship does not exist between peak plasma NE or EPI and peak heart rate.

  9. cap alpha. -2 adrenergic receptor: a radiohistochemical study

    SciTech Connect

    Unnerstall, J.R.

    1984-01-01

    ..cap alpha..-2 adrenergic agents have been shown to influence blood pressure, heart rate and other physiological and behavioral functions through interactions with adrenergic pathways within the central nervous system. Pharmacologically relevant ..cap alpha..-1 adrenergic receptors were biochemically characterized and radiohistochemically analyzed in intact tissue sections of the rat and human central nervous system. The anatomical distribution of the ..cap alpha..-2 receptors, labeled with the agonist (/sup 3/H)para-aminoclonidine, verified the concept that ..cap alpha..-2 receptors are closely associated with adrenergic nerve terminals and that ..cap alpha..-2 agents can influence autonomic and endocrine function through an action in the central nervous system. Since ..cap alpha..-2 agonists can influence sympathetic outflow, ..cap alpha..-2 binding sites were closely analyzed in the intermediolateral cell column of the thoracic spinal cord. The transport of putative presynaptic ..cap alpha..-2 binding sites in the rat sciatic nerve was analyzed by light microscopic radiohistochemical techniques. Finally, in intact tissue section of the rat central nervous system, the biochemical characteristics of (/sup 3/H)rauwolscine binding were analyzed. Data were also shown which indicates that the synthetic ..cap alpha..-2 antagonist (/sup 3/H)RX781094 also binds to ..cap alpha..-2 receptors with high-affinity. Further, the distribution of (/sup 3/H)RX781094 binding sites in the rat central nervous system was identical to the distribution seen when using (/sup 3/H)para-aminoclonidine.

  10. [The beta-adrenergic receptor].

    PubMed

    Bicho, M P; Manso, C F

    1992-12-01

    The Authors review the constitution and mechanism of action of the beta adrenergic receptor. It is part of a large family which includes visual pigments, muscarinic, serotonergic, olfactive and substance K receptors. Catecholamines given an electron to the receptor. It goes then successively to the alpha submit of Gs protein ant to adenylyl cyclase. The process of activation consists in a successive transfer of one electron. PMID:1337834

  11. 21 CFR 866.5430 - Beta-2-glycoprotein I immunological test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Beta-2-glycoprotein I immunological test system....5430 Beta-2-glycoprotein I immunological test system. (a) Identification. A beta-2-glycoprotein I... the beta-2-glycoprotein I (a serum protein) in serum and other body fluids. Measurement of...

  12. 21 CFR 866.5630 - Beta-2-microglobulin immunological test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Beta-2-microglobulin immunological test system....5630 Beta-2-microglobulin immunological test system. (a) Identification. A beta-2-microglobulin... beta-2-microglobulin (a protein molecule) in serum, urine, and other body fluids. Measurement of...

  13. Differential inhibition of mitogenic responsiveness by monoclonal antibodies to beta 2-microglobulin.

    PubMed

    Tam, P E; Messner, R P

    1991-03-01

    A panel of 10 monoclonal antibodies (MoAbs) to human beta 2-microglobulin (beta 2m) was used to evaluate the modulation of lymphocyte activation induced by different mitogenic stimuli. All 10 MoAbs inhibited proliferative responses of peripheral blood mononuclear cells (PBMC) to phytohemagglutinin (PHA), concanavalin A (Con A), pokeweed mitogen (PWM), and allogeneic cells in mixed lymphocyte culture (MLC), although some MoAbs were inhibitory at much lower concentrations than others. No enhancement or direct mitogenicity was observed, but at low MoAb concentrations a delayed peak response sometimes occurred. Differentiation of B cells in PWM-stimulated PBMC cultures was also inhibited as measured by reduced accumulation of supernatant IgM and IgG. Anti-beta 2m MoAb did not interfere with the binding of PHA or PWM to PBMC, and membrane mobility as judged by subsequent capping of these lectins also appeared to be normal. Furthermore, anti-beta 2m was inhibitory when added 24 hr prior to peak responsiveness, and proliferative responses to the phorbol ester PMA in combination with ionomycin were also inhibited by MoAb, indicating that membrane-mediated events were not the target of inhibition. A comparison of the inhibitory effects of anti-beta 2m MoAb on activation by different stimuli revealed that PWM and MLC responses were much more sensitive to inhibition followed by, in order of decreasing inhibition, Con A, PHA, ionomycin alone, and PMA/ionomycin. A MoAb to a monomorphic determinant of HLA-A, B, C exhibited the same inhibitory trend, suggesting that the mechanism of inhibition was the same as for anti-beta 2m MoAbs. No inhibition was observed when PBMC were stimulated by PMA alone, suggesting that the MoAbs have little effect on activation mediated by protein kinase C but may preferentially affect the calcium-dependent pathway of activation. Thus, this differential inhibition observed with different stimuli may reflect the relative contribution of class I

  14. Adenoviral delivery of the beta2-adrenoceptor gene in sepsis: a subcutaneous approach in rat for kidney protection.

    PubMed

    Nakamura, Akio; Imaizumi, Akira; Niimi, Ryo; Yanagawa, Yukishige; Kohsaka, Takao; Johns, Edward J

    2005-12-01

    Successful gene therapy requires gene delivery that is efficient, has an optimal route of administration and has biosafety. The aims of the present study were to evaluate the safety and applicability of the subcutaneous delivery route for adenoviral transgenes containing the human beta(2)-adrenoceptor (adeno-beta(2)-AR) and to investigate whether this approach prevented renal dysfunction in a rat model of endotoxaemic shock induced by LPS (lipopolysaccharide). Subcutaneous administration of adeno-beta(2)-AR (a total of 10(10) viral particles) significantly increased beta-AR density in the kidney, lung and liver, but was without effect on physiological and plasma biochemical parameters. Moreover, this dose of virus did not cause any of the potential toxic responses of viral administration, such as inflammation and tissue TNF (tumour necrosis factor)-alpha expression. Although the LPS challenge caused a decrease in glomerular filtration rate, fractional excretion of sodium and renal beta-AR density in all groups, the reduction in renal function was significantly less in the rats given adeno-beta(2)-AR compared with non-treated rats. Thus, although further evaluation will be required, this initial study demonstrated that the subcutaneous injection of adeno-beta(2)-AR was efficient, comparatively non-pathogenic and potentially therapeutic to deal with acute renal failure associated with sepsis. PMID:16076286

  15. Receptors for fibrinogen and aggregated beta 2-microglobulin detected in strains of group B streptococci.

    PubMed Central

    Schönbeck, C; Björck, L; Kronvall, G

    1981-01-01

    Binding of radiolabeled human fibrinogen and aggregated beta-microglobulin was measured in 60 strains of beta-hemolytic group B streptococci. Positive fibrinogen binding was detected in seven of the strains. Six of the group B strains showed an uptake of aggregated beta 2-microglobulin. Four individual strains carried both receptors, indicating a positive correlation between their occurrence. Inhibition studies showed that fibrinogen competed sterically with beta 2-microglobulin binding. Receptors for both proteins were trypsin sensitive. The presence of receptors did not correlate with the serological type of the 49 group B strains tested. However, all seven type II strains were negative. No uptake of fibrinogen was noted in any of 40 group D strains tested. Binding structures for fibrinogen and aggregated beta 2-microglobulin detected in group B streptococci were similar to receptors for the same proteins in group A, C, and G streptococci in terms of mutual correlation and steric interference of binding. The occasional occurrence of these receptors also in group B strains might reflect a common origin of some types of surface proteins in gram-positive cocci. PMID:6164650

  16. Genetic suppression of β2-adrenergic receptors ameliorates tau pathology in a mouse model of tauopathies

    PubMed Central

    Wisely, Elena V.; Xiang, Yang K.; Oddo, Salvatore

    2014-01-01

    Accumulation of the microtubule-binding protein tau is a key event in several neurodegenerative disorders referred to as tauopathies, which include Alzheimer's disease, frontotemporal lobar degeneration, Pick's disease, progressive supranuclear palsy and corticobasal degeneration. Thus, understanding the molecular pathways leading to tau accumulation will have a major impact across multiple neurodegenerative disorders. To elucidate the pathways involved in tau pathology, we removed the gene encoding the beta-2 adrenergic receptors (β2ARs) from a mouse model overexpressing mutant human tau. Notably, the number of β2ARs is increased in brains of AD patients and epidemiological studies show that the use of beta-blockers decreases the incidence of AD. The mechanisms underlying these observations, however, are not clear. We show that the tau transgenic mice lacking the β2AR gene had a reduced mortality rate compared with the parental tau transgenic mice. Removing the gene encoding the β2ARs from the tau transgenic mice also significantly improved motor deficits. Neuropathologically, the improvement in lifespan and motor function was associated with a reduction in brain tau immunoreactivity and phosphorylation. Mechanistically, we provide compelling evidence that the β2AR-mediated changes in tau were linked to a reduction in the activity of GSK3β and CDK5, two of the major tau kinases. These studies provide a mechanistic link between β2ARs and tau and suggest the molecular basis linking the use of beta-blockers to a reduced incidence of AD. Furthermore, these data suggest that a detailed pharmacological modulation of β2ARs could be exploited to develop better therapeutic strategies for AD and other tauopathies. PMID:24626633

  17. alpha4beta2 nicotinic acetylcholine receptors on dopaminergic neurons mediate nicotine reward and anxiety relief

    PubMed Central

    McGranahan, Tresa M.; Patzlaff, Natalie E.; Grady, Sharon R.; Heinemann, Stephen F.; Booker, T.K.

    2012-01-01

    Nicotine is the primary psychoactive substance in tobacco and it exerts its effects by interaction with various subtypes of nicotinic acetylcholine receptors (nAChRs) in the brain. One of the major subtypes expressed in brain, the alpha4beta2-nAChR, endogenously modulates neuronal excitability and thereby, modifies certain normal, as well as nicotine-induced, behaviors. Although alpha4-containing nAChRs are widely expressed across the brain, a major focus has been on their roles within midbrain dopaminergic regions involved in drug addition, mental illness and movement control in humans. We developed a unique model system to examine the role of alpha4-nAChRs within dopaminergic neurons by a targeted genetic deletion of the alpha4 subunit from dopaminergic neurons in mice. The loss alpha4 mRNA and alpha4beta2-nAChRs from dopaminergic neurons was confirmed, as well as selective loss of alpha4beta2-nAChR function from dopaminergic but not GABAergic neurons. Two behaviors central to nicotine dependence, reward and anxiety relief, were examined. Alpha4-nAChRs specifically on dopaminergic neurons were demonstrated to be necessary for nicotine reward as measured by nicotine place preference, but not for another drug of addiction, cocaine. Alpha4-nAChRs are necessary for the anxiolytic effects of nicotine in the elevated plus maze and elimination of alpha4-beta2-nAChRs specifically from dopaminergic neurons decreased sensitivity to the anxiolytic effects of nicotine. Deletion of alpha4-nAChRs specifically from dopaminergic neurons also increased sensitivity to nicotine-induced locomotor depression, however nicotine-induced hypothermia was unaffected. This is the first work to develop a dopaminergic specific deletion of a nAChR subunit and examine resulting changes in nicotine behaviors. PMID:21795541

  18. Adrenergic and non-adrenergic control of active skeletal muscle blood flow: implications for blood pressure regulation during exercise.

    PubMed

    Holwerda, Seth W; Restaino, Robert M; Fadel, Paul J

    2015-03-01

    Blood flow to active skeletal muscle increases markedly during dynamic exercise. However, despite the massive capacity of skeletal muscle vasculature to dilate, arterial blood pressure is well maintained. Sympathetic nerve activity is elevated with increased intensity of dynamic exercise, and is essential for redistribution of cardiac output to active skeletal muscle and maintenance of arterial blood pressure. In addition, aside from the sympathetic nervous system, evidence from human studies is now emerging that supports roles for non-adrenergic vasoconstrictor pathways that become active during exercise and contribute to vasoconstriction in active skeletal muscle. Neuropeptide Y and adenosine triphosphate are neurotransmitters that are co-released with norepinephrine from sympathetic nerve terminals capable of producing vasoconstriction. Likewise, plasma concentrations of arginine vasopressin, angiotensin II (Ang II) and endothelin-1 (ET-1) increase during dynamic exercise, particularly at higher intensities. Ang II and ET-1 have both been shown to be important vasoconstrictor pathways for restraint of blood flow in active skeletal muscle and the maintenance of arterial blood pressure during exercise. Indeed, although both adrenergic and non-adrenergic vasoconstriction can be attenuated in exercising muscle with greater intensity of exercise, with the higher volume of blood flow, the active skeletal muscle vasculature remains capable of contributing importantly to the maintenance of blood pressure. In this brief review we provide an update on skeletal muscle blood flow regulation during exercise with an emphasis on adrenergic and non-adrenergic vasoconstrictor pathways and their potential capacity to offset vasodilation and aid in the regulation of blood pressure. PMID:25467222

  19. Systemic administration of transforming growth factor-beta 2 prevents the impaired bone formation and osteopenia induced by unloading in rats.

    PubMed Central

    Machwate, M; Zerath, E; Holy, X; Hott, M; Godet, D; Lomri, A; Marie, P J

    1995-01-01

    We investigated the effect of recombinant human transforming growth factor beta 2 (rhTGF-beta 2) administration on trabecular bone loss induced by unloading in rats. Hind limb suspension for 14 d inhibited bone formation and induced osteopenia as shown by decreased bone volume, calcium and protein contents in long bone metaphysis. Systemic infusion of rhTFG-beta 2 (2 micrograms/kg per day) maintained normal bone formation rate, and prevented the decrease in bone volume, bone mineral content, trabecular thickness and number induced by unloading. In vitro analysis of tibial marrow stromal cells showed that rhTGF-beta 2 infusion in unloaded rats increased the proliferation of osteoblast precursor cells, but did not affect alkaline phosphatase activity or osteocalcin production. Northern blot analysis of RNA extracted from the femoral metaphysis showed that rhTGF-beta 2 infusion in unloaded rats increased steady-state levels of type I collagen mRNA but not alkaline phosphatase mRNA levels. rhTGF-beta 2 infusion at the dose used had no effect on metaphyseal bone volume and formation, osteoblast proliferation or collagen expression in control rats. The results show that systemic administration of rhTGF-beta 2 enhances osteoblast precursor cell proliferation and type I collagen expression by osteoblasts, and prevents the impaired bone formation and osteopenia induced by unloading. Images PMID:7657798

  20. The mechanism of beta-adrenergic preconditioning: roles for adenosine and ROS during triggering and mediation.

    PubMed

    Salie, Ruduwaan; Moolman, Johannes A; Lochner, Amanda

    2012-09-01

    The aim of this study was to investigate the mechanism of beta-adrenergic preconditioning (BPC). The roles of adenosine and its receptor subtypes, the generation of oxygen free radicals (ROS) and activation of the K(ATP) channels as well as the phosphoinositide-3-kinase (PI(3)K)/PKB/Akt and extracellular signal-regulated kinase (ERK) signal transduction pathways during the triggering and mediation phases were evaluated. Using the isolated working rat heart, BPC was elicited by administration of denopamine (beta1 adrenergic receptor agonist, 10(-7) M), isoproterenol (beta1/beta2 adrenergic receptor agonist, 10(-7) M) or formoterol (beta2 adrenergic receptor agonist, 10(-9) M) for 5 min followed by 5 min washout. Index ischaemia was 35 min regional ischaemia and infarct size determined using the tetrazolium method. The role of adenosine was studied using adenosine deaminase and selective antagonists as well as the PI(3)K and ERK inhibitors, wortmannin and PD98,059, bracketing the triggering and mediating phases. Involvement of ROS, PKC, the mitochondrial K(ATP) channels, release of endogenous opioids and bradykinin was studied by administration of N-acetyl cysteine (NAC), bisindolylmaleimide, the K(ATP) channel blocker 5-hydroxydecanoate (5-HD), naloxone or HOE140, respectively. Activation of PKB/Akt and ERKp44/p42 during triggering and reperfusion was determined by Western blot. Preconditioning with all three beta-adrenergic receptor agonists caused a reduction in infarct size and an improvement in postischaemic function. BPC preconditioning with isoproterenol, denopamine or formoterol was abolished by the adenosine A3 receptor antagonist MRS1191 during both the triggering and mediation phases. Isoproterenol-induced preconditioning (beta1/beta2 PC) was attenuated by MRS1754, an adenosine A(2B) receptor antagonist, during the triggering phase and abolished during reperfusion. The mediation phase of beta1/beta2 PC was also abolished by ZM241385, an adenosine A(2

  1. Centaurin-alpha 1, an ADP-ribosylation factor 6 GTPase activating protein, inhibits beta 2-adrenoceptor internalization.

    PubMed

    Lawrence, Joanna; Mundell, Stuart J; Yun, Hongruo; Kelly, Eamonn; Venkateswarlu, Kanamarlapudi

    2005-06-01

    The small GTP-binding protein ADP ribosylation factor 6 (ARF6) has recently been implicated in the internalization of G protein-coupled receptors (GPCRs), although its precise molecular mechanism in this process remains unclear. We have recently identified centaurin alpha(1) as a GTPase activating protein (GAP) for ARF6. In the current study, we characterized the effects of centaurin alpha(1) on the agonist-induced internalization of the beta(2)-adrenoceptor transiently expressed in human embryonic kidney (HEK) 293 cells. Using an enzyme-linked immunosorbent assay as well as confocal imaging of cells, we found that expression of centaurin alpha(1) strongly inhibited the isoproterenol-induced internalization of beta(2)-adrenoceptor. On the other hand, expression of functionally inactive versions of centaurin alpha(1), including an R49C mutant, which has no catalytic activity, and a double pleckstrin homology (PH) mutant (DM; R148C/R273C), which has mutations in both the PH domains of centaurin alpha(1), rendering it unable to translocate to the cell membrane, were unable to inhibit beta(2)-adrenoceptor internalization. In addition, a constitutively active version of ARF6, ARF6Q67L, reversed the ability of centaurin alpha(1) to inhibit beta(2)-adrenoceptor internalization. Finally, expression of centaurin alpha(1) also inhibited the agonist-induced internalization of beta(2)-adrenoceptor endogenously expressed in HEK 293 cells, whereas the R49C and DM mutant versions of centaurin alpha(1) had no effect. Together, these data indicate that by acting as an ARF6 GAP, centaurin alpha(1) is able to switch off ARF6 and so inhibit its ability to mediate beta(2)-adrenoceptor internalization. Thus, ARF6 GAPs, such as centaurin alpha(1), are likely to play a crucial role in GPCR trafficking by modulating the activity of ARF6. PMID:15778454

  2. A novel transforming growth factor beta2 antisense transcript in mammalian lung.

    PubMed Central

    Coker, R K; Laurent, G J; Dabbagh, K; Dawson, J; McAnulty, R J

    1998-01-01

    Transforming growth factor (TGF) beta2 gene expression was examined in murine, rat and human lung by in situ hybridization with riboprobes. Hybridization signal was observed in a variety of cells with the sense probe, and Northern-blot analysis with this probe demonstrated the presence of a novel 3.5 kb transcript. This first report suggesting the existance of a natural TGFbeta2 antisense transcript raises the possibility that such a transcript may play a role in regulating TGFbeta2 production. PMID:9601055

  3. Conformationally restrained analogs of sympathomimetic catecholamines. Synthesis, conformational analysis, and adrenergic activity of isochroman derivatives.

    PubMed

    Macchia, B; Balsamo, A; Breschi, M C; Chiellini, G; Lapucci, A; Macchia, M; Manera, C; Martinelli, A; Martini, C; Scatizzi, R

    1993-10-15

    In previous papers dealing with the study of the conformations and the biopharmacological activity of conformationally restrained analogs of sympathomimetic catecholamines (NE and ISO), proposals were advanced for the three-dimensional molecular models A, B, and C; these models provided information about the steric requirements for the direct activation of alpha 1, alpha 2,beta 1, and beta 2 adrenoceptors, respectively. The 1-(aminomethyl)-6,7-dihydroxyisochromans 11 and 12 and the 1-(aminomethyl)-5,6-dihydroxyisochromans 13 and 14 (1-AMDICs) are two different types of semirigid analogs of NE and ISO. The alpha 1, alpha 2, beta 1, and beta 2 adrenergic properties of the 1-AMDICs 11-14 were evaluated in vitro, both by radioligand binding assays and by functional tests on isolated preparations, and were compared with those of their parent compounds (NE and ISO). The results of a conformational study carried out by means of both 1H NMR spectrometry and theoretical calculations indicated that, in these 1-AMDICs, the presumed active groups (aryl moiety, amine nitrogen and benzylic ethereal oxygen) are in a spatial relationship corresponding to the one found for NE and ISO in their preferred conformations, which also proved to be the pharmacophoric conformation in the models A-C. By means of a comparison of the stereostructures of the 1-AMDICs 11-14 with their biopharmacological properties, it was possible to obtain a further definition of the model B with respect to the activation of the alpha 2 adrenoceptors; the superimposition of the 1-AMDICs 11 and 12 with the molecular model C made it possible to detect an area of the beta-adrenergic receptors which might hinder the fit of adrenergic drugs that are analogs of catecholamines with these receptors. PMID:8230093

  4. Propranolol, a beta-adrenergic antagonist, retards response to MSH in skin of Anolis carolinensis.

    PubMed

    Vaughan, G L; Greenberg, N

    1987-01-01

    Lacking sympathetic innervation, the skin of A. carolinensis, an iguanid lizard, darkens within minutes in response to circulating melanocyte stimulating hormone (MSH) or beta adrenergic agonists such as epinephrine (EPI). This change is produced by dispersion of melanin from a perinculear position within dermal melanophores into superficial dendritic processes. These melanophores possess alpha-2 and beta-2 adrenergic as well as MSH receptors except in a patch of skin behind the eye, the eyespot, which lacks alpha receptors. Activation of beta or MSH receptors leads to stimulation of adenyl cyclase whereas alpha stimulation inhibits the enzyme to override the others. In a series of trials, injection of saline or propranolol was followed after 30 minutes by saline, EPI, or MSH. Propranolol inhibited chromatophore response to EPI. It also, unexpectedly, retarded the response to MSH, increasing latency to eyespot formation and body color change as well as the duration of darkening for both. Alteration of MSH response by a beta blocker could be explained by linkage of both adrenergic receptors and the MSH receptor to a common adenyl cyclase molecule to form a functional unit in the membrane of the melanophore. PMID:3671516

  5. 21 CFR 866.5440 - Beta-2-glycoprotein III immunological test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the beta-2-glycoprotein III (a serum protein) in serum and other body fluids. Measurement of beta-2-glycoprotein III aids in the diagnosis of an inherited deficiency of this serum protein and a variety of...

  6. Thyroid-beta2 and the retinoid RAR-alpha, RXR-gamma and ROR-beta2 receptor mRNAs; expression profiles in mouse retina, retinal explants and neocortex.

    PubMed

    Azadi, S; Zhang, Y; Caffé, A R; Holmqvist, B; van Veen, T

    2002-05-01

    In neonatal retinal explants cultured long-term green cones are missing. Recently it was reported that thyroid hormone beta2 receptors (TR-beta2) are essential for these green cones to differentiate. Therefore transcript level of these receptors was investigated in our mouse retinal explants. However, thyroid receptors function as heterodimers with retinoid receptors (RR); so the fate of selected RRs was similarly analyzed using semi-quantitative RT-PCR. Loss of TR-beta2 and RR (RXR-gamma and ROR-beta2) mRNAs was observed after culturing the neonatal retina for 12 days. This indicates that these proteins are involved in determination of green cone identity. In addition, levels of the selected RR transcripts are differentially affected by short- or long-term culture. In the latter case an attached retinal pigment epithelium seems to play a protective role. Furthermore, divergent diurnal peaks of RR mRNAs are present in young as well as aged mouse retina and neocortex. This data might be relevant in the context of human ageing disorders. PMID:11997680

  7. The effect of surgery on the renal excretion of beta 2-microglobulin.

    PubMed

    Walenkamp, G H; Vree, T B; Guelen, P J; Jongman-Nix, B

    1983-03-28

    Surgical trauma causes an increase in the renal excretion rate of beta 2-microglobulin whilst creatinine excretion is not influenced. The increase in the renal excretion rate of beta 2-microglobulin is probably the result of an increased release of beta 2-microglobulin by the cells which exceeds a maximum in the active tubular reabsorption of the compound by the proximal tubule cell. The renal excretion of beta 2-microglobulin is proportional to the relative clinical trauma score. PMID:6189646

  8. Data Testing for ENDF/B-VII.1beta2

    SciTech Connect

    MacFarlane, Robert

    2011-01-01

    Calculations have been performed for 390 critical assemblies from the International Handbook of Evaluated Criticality Safety Benchmark Experiments using the beta2 release of ENDF/B-VII.1. The results are compared to previous results for ENDF/B-VII. Cases that changed between the two versions are highlighted, and the results are discussed. The Cross Section Evaluation Working Group (CSEWG) is working on a new release of the ENDF/B-VII library of evaluated nuclear data, and the 'beta2' set of files was recently made available by the National Nuclear Data Center (NNDC). A set of about 850 input files for the MCNP Monte Carlo code to run critical assemblies from the International Handbook of Evaluated Criticality Safety Benchmark Experiments was available from our previous data testing work for ENDF/B-VII.0. We have now run 390 of those cases using data based on the beta2 files, and those results will be presented below. The ENDF files were downloaded from the NNDC to a Mac workstation. They were then processed using NJOY10 into ACE format files for use in the MCNP Monte Carlo code. The processing was limited to materials needed for the data testing work at this point. The existing MCNP input decks were used. No checking was done to see if any of the benchmarks had been updated since the ENDF/B-VII testing was finished. Most runs used 50 million histories in order to get Monte Carlo statistical uncertainties down the 0.01% range.

  9. Clenbuterol, a beta(2)-agonist, retards atrophy in denervated muscles

    NASA Technical Reports Server (NTRS)

    Zeman, Richard J.; Ludemann, Robert; Etlinger, Joseph D.

    1987-01-01

    The effects of a beta(2) agonist, clenbuterol, on the protein content as well as on the contractile strength and the muscle fiber cross-sectional area of various denervated muscles from rats were investigated. It was found that denervated soleus, anterior tibialis, and gastrocnemius muscles, but not the extensor digitorum longus, of rats treated for 2-3 weeks with clenbuterol contained 95-110 percent more protein than denervated controls. The twofold difference in the protein content of denervated solei was paralleled by similar changes in contractile strength and muscle fiber cross-sectional area.

  10. [beta 2-Adrenomimetics before and after extracorporeal lithotripsy].

    PubMed

    Pytel', Iu A; Rapoport, D M; Rudenko, V I; Chaban, A V

    1998-01-01

    Successful disintegration of the calculus in nephrolithiasis patients is impossible without normalization of the upper urinary tracts urodynamics in dyskinesia. We employ combined treatment with high-selective beta-2-adrenomimetic hexoprenalin (hinipral) to improve migration of the concrement fragments and therefore to prevent ureteral occlusion, acute pyelonephritis and renal colic. Hexoprenalin (hinipral) is taken 6 tablets a day or intravenously in drops (5 ml per 100 ml of saline) 3-5 days before and for 10-12 days after extracorporeal shock-wave lithotripsy. Adjuvant use of hexoprenalin in combined treatment of nephrolithiasis complicated by ureteropelvic dysfunction allows effective conduction of lithotripsy. PMID:9820034

  11. Human alpha 2-adrenergic receptor subtype distribution: widespread and subtype-selective expression of alpha 2C10, alpha 2C4, and alpha 2C2 mRNA in multiple tissues.

    PubMed

    Eason, M G; Liggett, S B

    1993-07-01

    At present, molecular cloning and pharmacological studies have delineated three human alpha 2-adrenergic receptor (alpha 2AR) subtypes, alpha 2C10, alpha 2C4, and alpha 2C2. Assignment of the alpha 2AR subtypes to specific functions has been limited by an unclear definition of tissue alpha 2AR expression outside of the central nervous system. It has been suggested that alpha 2C4 expression is confined to the brain, that alpha 2C2 expression is only in the liver and kidney, and that there is nearly ubiquitous expression of alpha 2C10. However, this is based on studies of a limited number of rat tissues or on studies using non-species-specific approaches. Therefore, to define alpha 2C10, alpha 2C4, and alpha 2C2 tissue expression, we used reverse transcription of total RNA isolated from 20 human tissues, followed by amplification of alpha 2AR cDNA using the polymerase chain reaction. This technique provided two advantages: high sensitivity and, with the use of subtype-specific oligonucleotide primers and probes, differentiation between the alpha 2AR subtypes. The tissues studied were aorta, vena cava, heart (epicardium and endocardium), lung, skeletal muscle, liver, pancreas (head and tail), fat (perinephric and subcutaneous), kidney (cortex and medulla), prostate, stomach, ileum, jejunum, colon, adrenal gland, and spleen. We found that the majority of these tissues expressed alpha 2C10, with the exceptions being the head of the pancreas, subcutaneous fat, colon, and spleen. In marked distinction to other studies, however, we found a prolific expression of the alpha 2C4 and alpha 2C2 subtypes. Expression of alpha 2C4 was found in all tissues with the exception of liver, fat, stomach, and colon, and a virtually ubiquitous expression of alpha 2C2 was found, with the exception of epicardium. Of all tissues studied, only colon and subcutaneous fat expressed a single alpha 2AR subtype, which was alpha 2C2. Thus, the alpha 2AR subtypes do not have a confined expression but

  12. A single disulfide bond differentiates aggregation pathways of beta2-microglobulin.

    PubMed

    Chen, Yiwen; Dokholyan, Nikolay V

    2005-11-25

    Deposition of wild-type beta2-microglobulin (beta2m) into amyloid fibrils is a complication in patients undergoing long-term hemodialysis. The native beta-sandwich fold of beta2m has a highly conserved disulfide bond linking Cys25 and Cys80. Oxidized beta2m forms needle-like amyloid fibrils at pH 2.5 in vitro, whereas reduced beta2m, at acid pH, in which the intra-chain disulfide bond is disrupted, cannot form typical fibrils. Instead, reduced beta2m forms thinner and more flexible filaments. To uncover the difference in molecular mechanisms underlying the aggregation of the oxidized and reduced beta2m, we performed molecular dynamics simulations of beta2m oligomerization under oxidized and reduced conditions. We show that, consistent with experimental observations, the oxidized beta2m forms domain-swapped dimer, in which the two proteins exchange their N-terminal segments complementing each other. In contrast, both dimers and trimers, formed by reduced beta2m, are comprised of parallel beta-sheets between monomers and stabilized by the hydrogen bond network along the backbone. The oligomerized monomers are in extended conformations, capable of further aggregation. We find that both reduced and oxidized dimers are thermodynamically less stable than their corresponding monomers, indicating that beta2m oligomerization is not accompanied by the formation of a thermodynamically stable dimer. Our studies suggest that the different aggregation pathways of oxidized and reduced beta2m are dictated by the formation of distinct precursor oligomeric species that are modulated by Cys25-Cys80 disulfide-bonds. We propose that the propagation of domain swapping is the aggregation mechanism for the oxidized beta2m, while "parallel stacking" of partially unfolded beta2m is the aggregation mechanism for the reduced beta2m. PMID:16242719

  13. Relationship between Human Evolution and Neurally Mediated Syncope Disclosed by the Polymorphic Sites of the Adrenergic Receptor Gene α2B-AR

    PubMed Central

    Komiyama, Tomoyoshi; Oka, Akira; Kamiguchi, Hiroshi; Nagata, Eiichiro; Sakura, Hiroshi; Otsuka, Kuniaki; Kobayashi, Hiroyuki

    2015-01-01

    The objective of this study was to clarify the effects of disease on neurally mediated syncope (NMS) during an acute stress reaction. We analyzed the mechanism of the molecular interaction and the polymorphisms of the alpha-2 adrenoreceptor (α2B-AR) gene as the potential psychiatric cause of incentive stress. We focused on the following three genotypes of the repeat polymorphism site at Glu 301–303 in the α2B-AR gene: Glu12/12, Glu12/9, and Glu9/9. On the basis of our clinical research, NMS is likely to occur in people with the Glu12/9 heterotype. To verify this, we assessed this relationship with the interaction of Gi protein and adenylate cyclase by in silico analysis of the Glu12/9 heterotype. By measuring the difference in the dissociation time of the Gi-α subunit twice, we found that the Glu12/9 heterotype suppressed the action of adenylate cyclase longer than the Glu homotypes. As this difference in the Glu repeat number effect is thought to be one of the causes of NMS, we investigated the evolutionary significance of the Glu repeat number. Glu8 was originally repeated in simians, while the Glu12 repeats occurred over time during the evolution of bipedalism in humans. Taken with the Glu12 numbers, NMS would likely become a defensive measure to prevent significant blood flow to the human brain. PMID:25860977

  14. Relationship between human evolution and neurally mediated syncope disclosed by the polymorphic sites of the adrenergic receptor gene α2B-AR.

    PubMed

    Komiyama, Tomoyoshi; Hirokawa, Takatsugu; Sato, Kyoko; Oka, Akira; Kamiguchi, Hiroshi; Nagata, Eiichiro; Sakura, Hiroshi; Otsuka, Kuniaki; Kobayashi, Hiroyuki

    2015-01-01

    The objective of this study was to clarify the effects of disease on neurally mediated syncope (NMS) during an acute stress reaction. We analyzed the mechanism of the molecular interaction and the polymorphisms of the alpha-2 adrenoreceptor (α2B-AR) gene as the potential psychiatric cause of incentive stress. We focused on the following three genotypes of the repeat polymorphism site at Glu 301-303 in the α2B-AR gene: Glu12/12, Glu12/9, and Glu9/9. On the basis of our clinical research, NMS is likely to occur in people with the Glu12/9 heterotype. To verify this, we assessed this relationship with the interaction of Gi protein and adenylate cyclase by in silico analysis of the Glu12/9 heterotype. By measuring the difference in the dissociation time of the Gi-α subunit twice, we found that the Glu12/9 heterotype suppressed the action of adenylate cyclase longer than the Glu homotypes. As this difference in the Glu repeat number effect is thought to be one of the causes of NMS, we investigated the evolutionary significance of the Glu repeat number. Glu8 was originally repeated in simians, while the Glu12 repeats occurred over time during the evolution of bipedalism in humans. Taken with the Glu12 numbers, NMS would likely become a defensive measure to prevent significant blood flow to the human brain. PMID:25860977

  15. Optimum Topical Delivery of Adrenergic Agonists to Oral Mucosa Vasculature

    PubMed Central

    Soref, Cheryl M.

    2015-01-01

    Purpose Identify an orotopical vehicle to deliver an α-adrenergic vasoconstrictor to submucosal vasculature that is readily palatable to cancer/bone marrow transplant patients that suppresses chemo-radiotherapy-associated oral mucositis. Methods A [3H] norepinephrine ligand binding assay was developed to quantify receptor binding in hamster oral mucosa. Vehicle components (alcohols, polyols, cellulose, PVP) were tested versus [3H] norepinephrine binding. Vehicle refinement was also done to mask phenylephrine bitter taste and achieve human subject acceptance. The optimized vehicle was tested with α-adrenergic active agents to suppress radiation-induced oral mucositis in mice. Results The ligand binding assay quantified dose- and time-dependent, saturable binding of [3H] norepinephrine. An ethanol:glycerol:propylene glycol:water (6:6:8:80) vehicle provided the best delivery and binding. Further vehicle modification (flavoring and sucralose) yielded a vehicle with excellent taste scores in humans. Addition of phenylephrine, norepinephrine or epinephrine to the optimized vehicle and painting into mouse mouths 20 min before 19 Gy irradiation conferred significant suppression of the weight loss (P < 0.001) observed in mice who received oral vehicle. Conclusion We identified a highly efficient vehicle for the topical delivery of phenylephrine to the oral mucosa of both hamster and human subjects. This will enable its testing to suppress oral mucositis in an upcoming human clinical trial. PMID:25079392

  16. Transforming growth factor-beta2 induces bronchial epithelial mucin expression in asthma.

    PubMed

    Chu, Hong Wei; Balzar, Silvana; Seedorf, Gregory J; Westcott, Jay Y; Trudeau, John B; Silkoff, Phil; Wenzel, Sally E

    2004-10-01

    The transforming growth factor (TGF)-beta family is important for tissue repair in pathological conditions including asthma. However, little is known about the impact of either TGF-beta1 or TGF-beta2 on asthmatic airway epithelial mucin expression. We evaluated bronchial epithelial TGF-beta1 and TGF-beta2 expression and their effects on mucin expression, and the role of TGF-beta1 or TGF-beta2 in interleukin (IL)-13-induced mucin expression. Epithelial TGF-beta1, TGF-beta2, and mucin expression were evaluated in endobronchial biopsies from asthmatics and normal subjects. The effects of TGF-beta1 or TGF-beta2 on mucin MUC5AC protein and mRNA expression, and the impact of IL-13 on epithelial TGF-beta1, TGF-beta2, and MUC5AC were determined in cultured bronchial epithelial cells from endobronchial brushings of both subject groups. In biopsy tissue, epithelial TGF-beta2 expression levels were higher than TGF-beta1 in both asthmatics and normals. TGF-beta2, but not TGF-beta1, was increased in asthmatics compared with normals, and significantly correlated with mucin expression. TGF-beta2, but not TGF-beta1, increased mucin expression in cultured epithelial cells from both subject groups. IL-13 increased the release of TGF-beta2, but not TGF-beta1, from epithelial cells. A neutralizing TGF-beta2 antibody partially inhibited IL-13-induced mucin expression. These data suggest that TGF-beta2 production by asthmatic bronchial epithelial cells may increase airway mucin expression. IL-13-induced mucin expression may occur in part through TGF-beta2 up-regulation. PMID:15466377

  17. A nuclear pathway for alpha 1-adrenergic receptor signaling in cardiac cells.

    PubMed Central

    Ardati, A; Nemer, M

    1993-01-01

    alpha 1-Adrenergic agonists and antagonists constitute an important class of therapeutic agents commonly used for the treatment of various cardiovascular diseases like hypertension, congestive heart failure and supraventricular tachycardia. At the heart level, activation of alpha 1-adrenergic receptors is associated with marked morphological and genetic changes. These include enhancement of contractility, myocardial growth (hypertrophy) and release of the heart major secretory product, atrial natriuretic factor (ANF). However, the signal transduction pathways which link extracellular activation of the receptors to cellular and genetic changes are not well understood. Using primary cardiocyte cultures from neonate rat hearts, an alpha 1-adrenergic regulatory sequence has been identified in the 5' flanking region of the ANF gene. This sequence, which is necessary and sufficient for transcriptional activation in response to the alpha 1-specific agonist phenylephrine, interacts with novel zinc-dependent proteins which are induced by alpha 1-adrenergic stimulation. Consistent with a conserved regulatory mechanism, the alpha 1 response element is highly conserved between rodent, bovine and human ANF genes, and is also present in the promoter region of other alpha 1-responsive cardiac genes. The identification of a nuclear pathway for alpha 1-receptor signaling will be useful for elucidating the intracellular effectors of alpha 1-adrenergic receptors. Images PMID:8262057

  18. β-Adrenergic Regulation of Cardiac Progenitor Cell Death Versus Survival and Proliferation

    PubMed Central

    Khan, Mohsin; Mohsin, Sadia; Avitabile, Daniele; Siddiqi, Sailay; Nguyen, Jonathan; Wallach, Kathleen; Quijada, Pearl; McGregor, Michael; Gude, Natalie; Alvarez, Roberto; Tilley, Douglas G.; Koch, Walter J.; Sussman, Mark A.

    2013-01-01

    Rationale Short-term β-adrenergic stimulation promotes contractility in response to stress but is ultimately detrimental in the failing heart because of accrual of cardiomyocyte death. Endogenous cardiac progenitor cell (CPC) activation may partially offset cardiomyocyte losses, but consequences of long-term β-adrenergic drive on CPC survival and proliferation are unknown. Objective We sought to determine the relationship between β-adrenergic activity and regulation of CPC function. Methods and Results Mouse and human CPCs express only β2 adrenergic receptor (β2-AR) in conjunction with stem cell marker c-kit. Activation of β2-AR signaling promotes proliferation associated with increased AKT, extracellular signal-regulated kinase 1/2, and endothelial NO synthase phosphorylation, upregulation of cyclin D1, and decreased levels of G protein–coupled receptor kinase 2. Conversely, silencing of β2-AR expression or treatment with β2-antagonist ICI 118, 551 impairs CPC proliferation and survival. β1-AR expression in CPC is induced by differentiation stimuli, sensitizing CPC to isoproterenol-induced cell death that is abrogated by metoprolol. Efficacy of β1-AR blockade by metoprolol to increase CPC survival and proliferation was confirmed in vivo by adoptive transfer of CPC into failing mouse myocardium. Conclusions β-adrenergic stimulation promotes expansion and survival of CPCs through β2-AR, but acquisition of β1-AR on commitment to the myocyte lineage results in loss of CPCs and early myocyte precursors. PMID:23243208

  19. Targeting of Beta Adrenergic Receptors Results in Therapeutic Efficacy against Models of Hemangioendothelioma and Angiosarcoma

    PubMed Central

    Stiles, Jessica M.; Amaya, Clarissa; Rains, Steven; Diaz, Dolores; Pham, Robert; Battiste, James; Modiano, Jaime F.; Kokta, Victor; Boucheron, Laura E.; Mitchell, Dianne C.; Bryan, Brad A.

    2013-01-01

    Therapeutic targeting of the beta-adrenergic receptors has recently shown remarkable efficacy in the treatment of benign vascular tumors such as infantile hemangiomas. As infantile hemangiomas are reported to express high levels of beta adrenergic receptors, we examined the expression of these receptors on more aggressive vascular tumors such as hemangioendotheliomas and angiosarcomas, revealing beta 1, 2, and 3 receptors were indeed present and therefore aggressive vascular tumors may similarly show increased susceptibility to the inhibitory effects of beta blockade. Using a panel of hemangioendothelioma and angiosarcoma cell lines, we demonstrate that beta adrenergic inhibition blocks cell proliferation and induces apoptosis in a dose dependent manner. Beta blockade is selective for vascular tumor cells over normal endothelial cells and synergistically effective when combined with standard chemotherapeutic or cytotoxic agents. We demonstrate that inhibition of beta adrenergic signaling induces large scale changes in the global gene expression patterns of vascular tumors, including alterations in the expression of established cell cycle and apoptotic regulators. Using in vivo tumor models we demonstrate that beta blockade shows remarkable efficacy as a single agent in reducing the growth of angiosarcoma tumors. In summary, these experiments demonstrate the selective cytotoxicity and tumor suppressive ability of beta adrenergic inhibition on malignant vascular tumors and have laid the groundwork for a promising treatment of angiosarcomas in humans. PMID:23555867

  20. [The Regulatory Proteins of β-Adrenergic Receptor and Their Functions].

    PubMed

    Tian, Ai-ju; Li, Zi-jian

    2015-04-01

    Vascular diseases has become a top killer of human health, and cardiovascular receptors are pivotal in the occurrence, development, prevention and treatment of cardiovascular diseases. As for the important member of G protein-coupled receptor, β-adrenergic receptor is undoubtedly a most important target of cardiovascular drugs. Being the hot spot in the cardiovascular research and application, β- adrenergic receptor blocker has been considered as the greatest breakthrough for the prevention and cure of cardiovascular disease after digitalis. The 2012 Nobel Prize in chemistry was awarded again to the researchers on β-adrenergic receptors. Extensive researchs show that β-adrenergic receptors are precisely regulated by different regulatory proteins in cells in the transduction of different physiological and pathological signaling pathways. Based on these findings, function-selective ligands recently arise in the receptor research and will be the new chance of drug discovery. In this article we reviewed the related signal pathways and functions of β-adrenergic receptor regulatory proteins. PMID:26201103

  1. The ins and outs of adrenergic signaling.

    PubMed

    Lohse, Martin J

    2015-09-01

    Adrenergic signaling, in particular signaling in the sympathetic nervous system, is a prime example of the control of an essential physiological system. It has served as a model system both for the control of mediator release and for receptor signaling and regulation. This review covers the historical development of the field and then addresses issues that represent key fields of ongoing research: the mechanisms and kinetics of receptor activation, temporal patterns of downstream signaling and signal bias, receptor mobility and aggregation, and signal compartmentation and specificity. The available evidence suggests that adrenergic signaling may involve complex spatiotemporal patterns, which give texture to the signaling process and may contain additional biological information. PMID:26199112

  2. Beta 2-microglobulin amyloidosis presenting as esophageal perforation in a hemodialysis patient.

    PubMed

    Khan, G A; Lewis, F I; Dasgupta, M

    1997-01-01

    A 45-year-old male with hypertensive end-stage renal disease and on maintenance hemodialysis for 13 years is reported. He presented with life-threatening hematemesis, secondary to esophageal rupture. Immunohistological staining and electron microscopy examination of the esophageal perforation showed depositions of beta 2-microglobulin (beta 2-M) amyoloid. The unique aspect presented here is the localized esophageal involvement with beta 2-M amyloidosis. This is the first reported patient with esophageal perforation, due to the deposition and infiltration of the lower esophagus with beta 2-M which predisposed to its rupture. PMID:9426849

  3. Glucocorticoids and beta-adrenergic-receptor agonists: their combined effect on fetal rabbit lung surfactant.

    PubMed

    Ekelund, L; Enhorning, G

    1985-08-15

    In a previous study on pregnant rabbits (Am J Obstet Gynecol 1983; 147:437) we found that a prolonged infusion of the beta 2-adrenergic-receptor agonist terbutaline would first cause a release of fetal pulmonary surfactant, so that more was available in the airways. However, the airway fluid then contained less surfactant, indicating a depletion of stores. Since terbutaline is often used in high doses as a tocolytic agent, surfactant depletion could be a serious side effect. With further studies on rabbits, we wanted to test the hypothesis that with an accelerated surfactant synthesis, achieved with glucocorticoids, the increased release, evoked with the terbutaline, would never cause a depletion of the surfactant stores. Our results supported this hypothesis. Betamethasone, administered to the pregnant doe on the twenty-sixth and twenty-seventh days of gestation, 0.1 mg/kg, increased compliance of the fetal lungs, and more phospholipid phosphorus could be lavaged from the airways. These effects were further increased when, following steroid administration, the doe was infused with terbutaline. Depletion of the surfactant stores was never seen when betamethasone was given prior to the beta-adrenergic-receptor agonist. PMID:3839627

  4. 4,4'-Di-isothiocyanatostilbene-2,2'-disulphonic acid ('DIDS') activates protein kinase C and Na+/H+ exchange in human platelets via alpha 2A-adrenergic receptors.

    PubMed Central

    Nieuwland, R; Van Willigen, G; Akkerman, J W

    1993-01-01

    Most agonists stimulate platelets by inducing Ca2+ mobilization, Ca2+ influx and protein kinase C (PKC) activation leading to Na+/H+ exchange, exposure of fibrinogen-binding sites and aggregation. In contrast, previous studies showed that adrenaline induces exposure of fibrinogen-binding sites and aggregation without appreciable changes in cystolic Ca2+ content or PKC activity. In the present study we investigated platelet responses mediated via alpha 2A-adrenergic receptors, using 4,4'-di-isothiocyanatostilbene-2,2'-disulphonic acid (DIDS), which is known to bind to this type of receptor. Addition of DIDS (2-20 microM) induced (i) a rise in cytosolic pH of 0.23 +/- 0.05 pH unit (n = 5) as detected by BCECF fluorescence, due to activation of the Na+/H+ exchanger, (ii) a 3.5-4-fold increase in the phosphorylation of the 47 kDa protein, a major substrate of PKC, (iii) exposure of 81,072 +/- 7293 (n = 3) binding sites for 125I-fibrinogen per platelet, and (iv) irreversible aggregation. These responses occurred without changes in cytosolic [Ca2+], secretion of dense-granule contents and enhanced phosphoinositide metabolism, and were not affected by inhibition of thromboxane A2 generation (30 microM indomethacin). The alpha 2A-adrenergic-receptor antagonists oxymetazoline (500 microM) and yohimbine (1 mM) completely abolished DIDS-induced responses. Inhibition of PKC (1 microM staurosporine) prevented phosphorylation of the 47 kDa protein, the increase in Na+/H+ exchange and exposure of fibrinogen-binding sites. Thus our present data suggest that activation of PKC is an early event in DIDS-induced platelet activation via the alpha 2A-adrenergic receptor, which precedes any of the other known signal-transducing sequences. PMID:8393664

  5. Nicotine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone induce cyclooxygenase-2 activity in human gastric cancer cells: Involvement of nicotinic acetylcholine receptor (nAChR) and {beta}-adrenergic receptor signaling pathways

    SciTech Connect

    Shin, Vivian Yvonne; Jin, H.C.; Ng, Enders K.O.; Yu Jun; Leung, W.K.; Cho, C.H.; Sung, J.J.Y.

    2008-12-01

    Induction of cyclooxygenase-2 (COX-2) associates with cigarette smoke exposure in many malignancies. Nicotine and its derivative, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), are the two important components in cigarette smoke that contributes to cancer development. However, the molecular mechanism(s) by which nicotine or NNK promotes gastric carcinogenesis remains largely unknown. We found that nicotine and NNK significantly enhanced cell proliferation in AGS cells that expressed both alpha7 nicotinic acetylcholine receptor ({alpha}7 nAChR) and {beta}-adrenergic receptors. Treatment of cells with {alpha}-bungarotoxin ({alpha}-BTX, {alpha}7nAChR antagonist) or propranolol ({beta}-adrenergic receptor antagonist) blocked NNK-induced COX-2/PGE{sub 2} and cell proliferation, while nicotine-mediated cell growth and COX-2/PGE{sub 2} induction can only be suppressed by propranolol, but not {alpha}-BTX. Moreover, in contrast to the dependence of growth promoting effect of nicotine on Erk activation, inhibitor of p38 mitogen-activated protein kinase (MAPK) repressed NNK-induced COX-2 upregulation and resulted in suppression of cell growth. In addition, nicotine and NNK mediated COX-2 induction via different receptors to modulate several G1/S transition regulatory proteins and promote gastric cancer cell growth. Selective COX-2 inhibitor (SC-236) caused G1 arrest and abrogated nicotine/NNK-induced cell proliferation. Aberrant expression of cyclin D1 and other G1 regulatory proteins are reversed by blockade of COX-2. These results pointed to the importance of adrenergic and nicotinic receptors in gastric tumor growth through MAPK/COX-2 activation, which may perhaps provide a chemoprevention strategy for cigarette smoke-related gastric carcinogenesis.

  6. Effects of Adrenergic Receptor Activation and Blockade on the Systolic Preejection Period, Heart Rate, and Arterial Pressure in Man

    PubMed Central

    Harris, Willard S.; Schoenfeld, Clyde D.; Weissler, Arnold M.

    1967-01-01

    We have investigated the possibility that alterations in the duration of the systolic preejection period can be used to estimate adrenergic influences on the human left ventricle. The preejection period was determined from high speed, simultaneous recordings of the phonocardiogram, carotid pulse tracing, and electrocardiogram. The preejection period was shortened by isoproterenol, epinephrine, and moderate doses of norepinephrine—all of which activate beta adrenergic receptors—and by cedilanid-D. It was unaltered by changes in heart rate induced by atropine and right atrial electrical pacing. Beta adrenergic receptor blockade by propranolol abolished the shortening effects of the three catecholamines but did not inhibit that due to cedilanid-D. Vasoconstriction, both alpha adrenergic (epinephrine and norepinephrine after propranolol) and nonadrenergic (angiotensin), prolonged the preejection period. Most of the shortening of the preejection period by beta adrenergic receptor activating agents and cedilanid-D and all of the prolongation accompanying pharmacologic vasoconstriction occurred after the onset of the first heart sound, thereby excluding changes in electrical-mechanical delay as a major factor in the observed preejection period responses. Shortening of the preejection period by beta adrenergic activity induced with isoproterenol was dose-related. Increasing doses of propranolol produced parallel shifts to the right in the isoproterenol dose-response curve. In 37 normal resting subjects intravenous propranolol (10 mg) prolonged the preejection period an average of 10 (SE ± 1) msec. In six patients with psychogenic sinus tachycardia and a patient with a pheochromocytoma the presence of excessive beta adrenergic influences on the left ventricle was demonstrated by the finding of an initially short preejection period which responded with an abnormally great prolongation to beta adrenergic receptor blockade. Images PMID:4294053

  7. Identification and characterization of alpha 1 adrenergic receptors in the canine prostate using (/sup 125/I)-Heat

    SciTech Connect

    Lepor, H.; Baumann, M.; Shapiro, E.

    1987-11-01

    We have recently utilized radioligand receptor binding methods to characterize muscarinic cholinergic and alpha adrenergic receptors in human prostate adenomas. The primary advantages of radioligand receptor binding methods are that neurotransmitter receptor density is quantitated, the affinity of unlabelled drugs for receptor sites is determined, and receptors can be localized using autoradiography on slide-mounted tissue sections. Recently, (/sup 125/I)-Heat, a selective and high affinity ligand with high specific activity (2200 Ci/mmole) has been used to characterize alpha 1 adrenergic receptors in the brain. In this study alpha 1 adrenergic receptors in the dog prostate were characterized using (/sup 125/I)-Heat. The Scatchard plots were linear indicating homogeneity of (/sup 125/I)-Heat binding sites. The mean alpha 1 adrenergic receptor density determined from these Scatchard plots was 0.61 +/- 0.07 fmol/mg. wet wt. +/- S.E.M. The binding of (/sup 125/I)-Heat to canine prostate alpha 1 adrenergic binding sites was of high affinity (Kd = 86 +/- 19 pM). Steady state conditions were reached following an incubation interval of 30 minutes and specific binding and tissue concentration were linear within the range of tissue concentrations assayed. The specificity of (/sup 125/I)-Heat for alpha 1 adrenergic binding sites was confirmed by competitive displacement assays using unlabelled clonidine and prazosin. Retrospective analysis of the saturation experiments demonstrated that Bmax can be accurately calculated by determining specific (/sup 125/I)-Heat binding at a single ligand concentration. (/sup 125/I)-Heat is an ideal ligand for studying alpha 1 adrenergic receptors in the prostate and its favorable properties should facilitate the autoradiographic localization of alpha 1 adrenergic receptors in the prostate.

  8. Catechol-O-methyltransferase Inhibition Increases Pain Sensitivity through Activation of Both β2 and β3 Adrenergic Receptors

    PubMed Central

    Nackley-Neely, Andrea Gail; Tan, Kai Soo; Fecho, Karamarie; Flood, Patrick; Diatchenko, Luda; Maixner, William

    2007-01-01

    Catechol-O-methyltransferase (COMT), an enzyme that metabolizes catecholamines, has recently been implicated in the modulation of pain. Our group demonstrated that human genetic variants of COMT are predictive for the development of Temporomandibular Joint Disorder (TMJD) and are associated with heightened experimental pain sensitivity (Diatchenko et al. 2005). Variants associated with heightened pain sensitivity produce lower COMT activity. Here we report the mechanisms underlying COMT-dependent pain sensitivity. To characterize the means whereby elevated catecholamine levels, resulting from reduced COMT activity, modulate heightened pain sensitivity, we administered a COMT inhibitor to rats and measured behavioral responsiveness to mechanical and thermal stimuli. We show that depressed COMT activity results in enhanced mechanical and thermal pain sensitivity. This phenomenon is completely blocked by the nonselective β-adrenergic antagonist propranolol or by the combined administration of selective β2- and β3-adrenergic antagonists, while administration of β1-adrenergic, α-adrenergic, or dopaminergic receptor antagonists fail to alter COMT-dependent pain sensitivity. These data provide the first direct evidence that low COMT activity leads to increased pain sensitivity via a β2/3-adrenergic mechanism. These findings are of considerable clinical importance, suggesting that pain conditions resulting from low COMT activity and/or elevated catecholamine levels can be treated with pharmacological agents that block both β2- and β3-adrenergic receptors. PMID:17084978

  9. Cloning and expression of a rat brain. alpha. sub 2B -adrenergic receptor

    SciTech Connect

    Flordellis, C.S.; Handy, D.E.; Bresnahan, M.R.; Zannis, V.I.; Gavras, H. )

    1991-02-01

    The authors isolated a cDNA clone (RB{alpha}{sub 2B}) and its homologous gene (GR{alpha}{sub 2B}) encoding an {alpha}{sub 2B}-adrenergic receptor subtype by screening a rat brain cDNA and a rat genomic library. Nucleotide sequence analysis showed that both clones code for a protein of 458 amino acids, which is 87% homologous to the human kidney glycosylated adrenergic receptor ({alpha}{sub 2}-C4) and divergent from the rat kidney nonglycosylated {alpha}{sub 2B} subtype (RNG{alpha}{sub 2}). Transient expression of RB{alpha}{sub 2B} in COS-7 cells resulted in high-affinity saturable binding for ({sup 3}H)rauwolscine and a high receptor number in the membranes of transfected COS-7 cells. Pharmacological analysis demonstrated that the expressed receptor bound adrenergic ligands with the following order of potency: rauwolscine {gt} yohimbine {gt} prazosin {gt} oxymetazoline, with a prazosin-to-oxymetazoline K{sub i} ratio of 0.34. This profile is characteristic of the {alpha}{sub 2B}-adrenergic receptor subtype. Blotting analysis of rat brain mRNA gave one major and two minor mRNA species, and hybridization with strand-specific probes showed that both DNA strands of GR{alpha}{sub 2B} may be transcriptionally active. These findings show that rat brain expresses an {alpha}{sub 2B}-adrenergic receptor subtype that is structurally different from the rat kidney nonglycosylated {alpha}{sub 2B} subtype. Thus the rat expresses at least two divergent {alpha}{sub 2B}-adrenergic receptors.

  10. A missense mutation in the beta-2 integrin gene (ITGB2) causes canine leukocyte adhesion deficiency.

    PubMed

    Kijas, J M; Bauer, T R; Gäfvert, S; Marklund, S; Trowald-Wigh, G; Johannisson, A; Hedhammar, A; Binns, M; Juneja, R K; Hickstein, D D; Andersson, L

    1999-10-01

    Canine leukocyte adhesion deficiency (CLAD) is a fatal immunodeficiency disease found in Irish setters. The clinical manifestations of CLAD are very similar to LAD in humans and BLAD in cattle, which are both caused by mutations in ITGB2 encoding the leukocyte integrin beta-2 subunit (CD18). Sequence analysis of the ITGB2 coding sequence from a CLAD dog and a healthy control revealed a single missense mutation, Cys36Ser. This cysteine residue is conserved among all beta integrins, and the mutation most likely disrupts a disulfide bond. The mutation showed a complete association with CLAD in Irish setters and was not found in a sample of dogs from other breeds. The causative nature of this mutation was confirmed by transduction experiments using retroviral vectors and human LAD EBV B-cells. The normal canine CD18 formed heterodimers with the human CD11 subunit, whereas gene transfer of the mutant CD18 resulted in very low levels of CD11/CD18 expression. The identification of the causative mutation for CLAD now makes it possible to identify carrier animals with a simple diagnostic DNA test, and it forms the basis for using CLAD as a large animal model for the development and evaluation of clinical treatments for human LAD. PMID:10512685

  11. Beta-2-linked glucans secreted by fast-growing species of Rhizobium

    SciTech Connect

    York, W.S.; McNeil, M.; Darvill, A.G.; Albersheim, P.

    1980-04-01

    Fast-growing species of Rhizobium were found to secrete low-molecular-weight ..beta..-2-linked glucans when cultured in synthetic liquid medium. These glucans are quite similar to ..beta..-2-linked glucans produced by species of Agrobacterium. No reducing terminus was detected in these glucans.

  12. Beta-2-linked glucans secreted by fast-growing species of Rhizobium.

    PubMed Central

    York, W S; McNeil, M; Darvill, A G; Albersheim, P

    1980-01-01

    Fast-growing species of Rhizobium were found to secrete low-molecular-weight beta-2-linked glucans when cultured in synthetic liquid medium. These glucans are quite similar to beta-2-linked glucans produced by species of Agrobacterium. No reducing terminus was detected in these glucans. PMID:7372570

  13. Agonist-dependent single channel current and gating in alpha4beta2delta and alpha1beta2gamma2S GABAA receptors.

    PubMed

    Keramidas, Angelo; Harrison, Neil L

    2008-02-01

    The family of gamma-aminobutyric acid type A receptors (GABA(A)Rs) mediates two types of inhibition in the mammalian brain. Phasic inhibition is mediated by synaptic GABA(A)Rs that are mainly comprised of alpha(1), beta(2), and gamma(2) subunits, whereas tonic inhibition is mediated by extrasynaptic GABA(A)Rs comprised of alpha(4/6), beta(2), and delta subunits. We investigated the activation properties of recombinant alpha(4)beta(2)delta and alpha(1)beta(2)gamma(2S) GABA(A)Rs in response to GABA and 4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3(2H)-one (THIP) using electrophysiological recordings from outside-out membrane patches. Rapid agonist application experiments indicated that THIP produced faster opening rates at alpha(4)beta(2)delta GABA(A)Rs (beta approximately 1600 s(-1)) than at alpha(1)beta(2)gamma(2S) GABA(A)Rs (beta approximately 460 s(-1)), whereas GABA activated alpha(1)beta(2)gamma(2S) GABA(A)Rs more rapidly (beta approximately 1800 s(-1)) than alpha(4)beta(2)delta GABA(A)Rs (beta < 440 s(-1)). Single channel recordings of alpha(1)beta(2)gamma(2S) and alpha(4)beta(2)delta GABA(A)Rs showed that both channels open to a main conductance state of approximately 25 pS at -70 mV when activated by GABA and low concentrations of THIP, whereas saturating concentrations of THIP elicited approximately 36 pS openings at both channels. Saturating concentrations of GABA elicited brief (<10 ms) openings with low intraburst open probability (P(O) approximately 0.3) at alpha(4)beta(2)delta GABA(A)Rs and at least two "modes" of single channel bursting activity, lasting approximately 100 ms at alpha(1)beta(2)gamma(2S) GABA(A)Rs. The most prevalent bursting mode had a P(O) of approximately 0.7 and was described by a reaction scheme with three open and three shut states, whereas the "high" P(O) mode ( approximately 0.9) was characterized by two shut and three open states. Single channel activity elicited by THIP in alpha(4)beta(2)delta and alpha(1)beta(2)gamma(2S) GABA

  14. Beta-aminopeptidase-catalyzed biotransformations of beta(2)-dipeptides: kinetic resolution and enzymatic coupling.

    PubMed

    Heck, Tobias; Reimer, Artur; Seebach, Dieter; Gardiner, James; Deniau, Gildas; Lukaszuk, Aneta; Kohler, Hans-Peter E; Geueke, Birgit

    2010-05-17

    We have previously shown that the beta-aminopeptidases BapA from Sphingosinicella xenopeptidilytica and DmpA from Ochrobactrum anthropi can catalyze reactions with non-natural beta(3)-peptides and beta(3)-amino acid amides. Here we report that these exceptional enzymes are also able to utilize synthetic dipeptides with N-terminal beta(2)-amino acid residues as substrates under aqueous conditions. The suitability of a beta(2)-peptide as a substrate for BapA or DmpA was strongly dependent on the size of the C(alpha) substituent of the N-terminal beta(2)-amino acid. BapA was shown to convert a diastereomeric mixture of the beta(2)-peptide H-beta(2)hPhe-beta(2)hAla-OH, but did not act on diastereomerically pure beta(2),beta(3)-dipeptides containing an N-terminal beta(2)-homoalanine. In contrast, DmpA was only active with the latter dipeptides as substrates. BapA-catalyzed transformation of the diastereomeric mixture of H-beta(2)hPhe-beta(2)hAla-OH proceeded along two highly S-enantioselective reaction routes, one leading to substrate hydrolysis and the other to the synthesis of coupling products. The synthetic route predominated even at neutral pH. A rise in pH of three log units shifted the synthesis-to-hydrolysis ratio (v(S)/v(H)) further towards peptide formation. Because the equilibrium of the reaction lies on the side of hydrolysis, prolonged incubation resulted in the cleavage of all peptides that carried an N-terminal beta-amino acid of S configuration. After completion of the enzymatic reaction, only the S enantiomer of beta(2)-homophenylalanine was detected (ee>99 % for H-(S)-beta(2)-hPhe-OH, E>500); this confirmed the high enantioselectivity of the reaction. Our findings suggest interesting new applications of the enzymes BapA and DmpA for the production of enantiopure beta(2)-amino acids and the enantioselective coupling of N-terminal beta(2)-amino acids to peptides. PMID:20340152

  15. Mass spectrometric characterization of conformational preludes to [beta]2-microglobulin aggregation

    NASA Astrophysics Data System (ADS)

    Jørgensen, Thomas J. D.; Cheng, Lei; Heegaard, Niels H. H.

    2007-12-01

    Characterization of protein folding and unfolding is an important issue for basic biological science, for understanding the devastating amyloid diseases, and for the manufacture and use of biological therapeutics. Unlike nuclear magnetic resonance spectroscopy, the use of mass spectrometry to monitor amide hydrogen (1H/2H) exchange kinetics (HX-MS) allows characterization of structural dynamics even when only limited amounts of protein is available. As an adjunct technique, requiring even less material and very well suited for serial monitoring of folding phenomena in a single solution under native conditions capillary electrophoresis may also be very informative. These approaches are here used to examine the small (99 amino acid residues) protein [beta]2-microglobulin ([beta]2m) which is prone to amyloidogenic unfolding especially after cleavage at its lysine-58 residue. The propensity for unfolding of native, non-cleaved [beta]2m and lysine-58 cleaved [beta]2m variants as well as the effect of acetonitrile on the conformational equilibria could be addressed by these approaches. At physiological conditions, intact [beta]2m and the lysine-58 cleaved variants undergo a transient unfolding that exhibit an EX1 type hydrogen exchange behaviour. We have measured the unfolding rate constants for the cleaved variant where Lys-58 is removed ([Delta]K58-[beta]2m) and the cleaved variant where this residue is preserved (cK58-[beta]2m) at various temperatures. Below 37 °C, the variant devoid of Lys-58 ([Delta]K58-[beta]2m) has a higher unfolding rate than cK58-[beta]2m and this correlates with the observation that [Delta]K58-[beta]2m has a higher propensity to aggregate. The results of our studies provide valuable insight into the early conformational perturbations involved in rendering this protein insoluble and amyloidogenic. The approaches used in this study should be useful also for the characterization of other conformationally unstable proteins.

  16. Clearance and synthesis rates of beta 2-microglobulin in patients undergoing hemodialysis and in normal subjects

    SciTech Connect

    Floege, J.; Bartsch, A.; Schulze, M.; Shaldon, S.; Koch, K.M.; Smeby, L.C. )

    1991-08-01

    Retention of {beta} 2-microglobulin in patients undergoing hemodialysis is associated with a {beta} 2-microglobulin-derived amyloidosis. Removal of {beta} 2-microglobulin by renal replacement therapy has been proposed for the prevention of this amyloidosis. Currently, however, data on the {beta} 2-microglobulin synthesis rate in patients undergoing hemodialysis are scarce, and consequently it remains speculative how much removal would be necessary to counterbalance synthesis. The plasma kinetics of iodine 131-labeled {beta} 2-microglobulin were therefore examined in 11 patients with anuria who were undergoing long-term hemodialysis. Five healthy persons served as controls. Kinetic modeling of the plasma curves showed that the data fitted a two-pool model (r2 greater than 0.96) consisting of a rapid 2 to 4 hour distribution phase followed by a less steep curve, described by the plasma (metabolic) clearance (Clp). Synthetic rates were calculated from Clp and the {beta} 2-microglobulin steady state plasma concentration (plus {beta} 2-microglobulin removal during hemodialysis in the case of high flux hemodialysis). The results showed a significantly higher Clp in normal controls as compared with patients undergoing hemodialysis (65.5 {plus minus} 12.8 ml/min (mean {plus minus} SD) versus 3.4 {plus minus} 0.7 ml/min). In contrast, the {beta} 2-microglobulin synthesis rate in the patient group (3.10 {plus minus} 0.79 mg/kg/day) was not significantly different from that of normal controls (2.40 {plus minus} 0.67 mg/kg/day), which was due to markedly elevated {beta} 2-microglobulin plasma concentrations in the patients (37.6 {plus minus} 14.1 mg/L vs 1.92 {plus minus} 0.27 mg/L). These findings suggest that the presence of end-stage renal disease does not have a significant impact on the beta 2-microglobulin generation rate.

  17. Comparison of the β-Adrenergic Receptor Antagonists Landiolol and Esmolol: Receptor Selectivity, Partial Agonism, and Pharmacochaperoning Actions.

    PubMed

    Nasrollahi-Shirazi, Shahrooz; Sucic, Sonja; Yang, Qiong; Freissmuth, Michael; Nanoff, Christian

    2016-10-01

    Blockage of β1-adrenergic receptors is one of the most effective treatments in cardiovascular medicine. Esmolol was introduced some three decades ago as a short-acting β1-selective antagonist. Landiolol is a more recent addition. Here we compared the two compounds for their selectivity for β1-adrenergic receptors over β2-adrenergic receptors, partial agonistic activity, signaling bias, and pharmacochaperoning action by using human embryonic kidney (HEK)293 cell lines, which heterologously express each human receptor subtype. The affinity of landiolol for β1-adrenergic receptors and β2-adrenergic receptors was higher and lower than that of esmolol, respectively, resulting in an improved selectivity (216-fold versus 30-fold). The principal metabolite of landiolol (M1) was also β1-selective, but its affinity was very low. Both landiolol and esmolol caused a very modest rise in cAMP levels but a robust increase in the phosphorylation of extracellular signal regulated kinases 1 and 2, indicating that the two drugs exerted partial agonist activity with a signaling bias. If cells were incubated for ≥24 hours in the presence of ≥1 μM esmolol, the levels of β1-adrenergic-but not of β2-adrenergic-receptors increased. This effect was contingent on export of the β1-receptor from endoplasmic reticulum and was not seen in the presence of landiolol. On the basis of these observations, we conclude that landiolol offers the advantage of: 1) improved selectivity and 2) the absence of pharmacochaperoning activity, which sensitizes cells to rebound effects upon drug discontinuation. PMID:27451411

  18. Long-acting beta2-agonist in addition to tiotropium versus either tiotropium or long-acting beta2-agonist alone for chronic obstructive pulmonary disease

    PubMed Central

    Karner, Charlotta; Cates, Christopher J

    2014-01-01

    Background Long-acting bronchodilators comprising long-acting beta2-agonists and the anticholinergic agent tiotropium are commonly used for managing persistent symptoms of chronic obstructive pulmonary disease. Combining these treatments, which have different mechanisms of action, may be more effective than the individual components. However, the benefits and risks of combining tiotropium and long-acting beta2-agonists for the treatment of chronic obstructive pulmonary (COPD) disease are unclear. Objectives To assess the relative effects of treatment with tiotropium in addition to long-acting beta2-agonist compared to tiotropium or long-acting beta2-agonist alone in patients with chronic obstructive pulmonary disease. Search methods We searched the Cochrane Airways Group Specialised Register of trials and clinicaltrials.gov up to January 2012. Selection criteria We included parallel group, randomised controlled trials of three months or longer comparing treatment with tiotropium in addition to long-acting beta2-agonist against tiotropium or long-acting beta2-agonist alone for patients with chronic obstructive pulmonary disease. Data collection and analysis Two review authors independently assessed trials for inclusion and then extracted data on trial quality and the outcome results. We contacted study authors for additional information. We collected information on adverse effects from the trials. Main results Five trials were included in this review, mostly recruiting participants with moderate or severe chronic obstructive pulmonary disease. All of them compared tiotropium in addition to long-acting beta2-agonist to tiotropium alone, but only one trial additionally compared a combination of the two types of bronchodilator with long-acting beta2-agonist (formoterol) alone. Two studies used the long-acting beta2-agonist indacaterol, two used formoterol and one used salmeterol. Compared to tiotropium alone (3263 patients), treatment with tiotropium plus long

  19. [INTERACTION OF THE DYE CONGO RED WITH FIBRILS OF LYSOZYME, BETA2-MICROGLOBULIN AND TRANSTHYRETIN].

    PubMed

    Antimonova, O I; Grudinina, N A; Egorov, V V; Polyakov, D S; Iljin, V V; Shavlovsky, M M

    2016-01-01

    By means of spectrophotometric assay we investigated interaction of the dye Congo red (CR) with fibrils of model proteins--hen egg white lysozyme, recombinant human beta2-microglobulin (b2M) and recombinant human transthyretin (TTR). The commercial dye sample was found to contain a significant amount of impurities. Methods for the dye purification are disclosed and CR molar extinction coefficient at 490 nm (ε490) was determined to be 3.3 x 10(4) M(-1) x cm(-1) at pH above 6.0. Formation of the CR-fibril complex results in changes in the dye visible absorption spectrum. According to the data on titration of fibril solutions with excess of the dye, CR binds to lysozyme fibrils at a ratio of about 5 molecules per protein monomer within fibril structure, to b2M fibrils--about 4 molecules per monomer, to TTR fibrils--about 4 molecules per subunit of the protein. PMID:27228663

  20. Homologous beta-adrenergic desensitization in isolated rat hepatocytes.

    PubMed Central

    García-Sáinz, J A; Michel, B

    1987-01-01

    Hepatocytes from hypothyroid rats have a marked beta-adrenergic responsiveness. Preincubation of these hepatocytes with isoprenaline induced a time-dependent and concentration-dependent desensitization of the beta-adrenergic responsiveness without altering that to glucagon (homologous desensitization). The desensitization was evidenced both in the cyclic AMP accumulation and in the stimulation of ureagenesis induced by the beta-adrenergic agonists. Under the same conditions, preincubation with glucagon induced no desensitization. Propranolol was also unable to induce desensitization, but blocked that induced by isoprenaline. Pertussis-toxin treatment did not alter the homologous beta-adrenergic desensitization induced by isoprenaline. PMID:2825633

  1. Mission and sizing analysis for the Beta 2 two-stage-to-orbit vehicle

    NASA Technical Reports Server (NTRS)

    Nadell, Shari-Beth; Baumgarten, William J.; Alexander, Stephen W.

    1992-01-01

    NASA Lewis Research Center studied a horizontal takeoff and landing, fully reusable, two-stage-to-orbit (TSTO) vehicle capable of launching and returning a 10,000 pound payload to low Earth polar orbit using low-risk technology. The vehicle, called Beta 2, was derived from the USAF/Boeing Beta vehicle, a TSTO study vehicle capable of launching a 50,000 pound payload to low Earth polar orbit. Development of the Beta 2 from the USAF/Boeing Beta vehicle occurred in a series of iterations during which the size of the vehicle was decreased to accommodate the smaller payload, the staging Mach number was decreased from 8.0 to 6.5, and the rocket propulsion system was removed from the booster. The final Beta 2 vehicle consisted of a rocket powered orbiter and an all airbreathing booster. The gross takeoff weight of the Beta 2 vehicle was approximately 1.1 million pounds. In addition to its baseline mission, the Beta 2 was capable of delivering approximately 17,500 pounds to the Space Station with the same takeoff gross weight. The mission and sizing analysis performed to arrived at the Beta 2 vehicle is discussed.

  2. Polymerization of intact beta 2-microglobulin in tissue causes amyloidosis in patients on chronic hemodialysis.

    PubMed Central

    Gorevic, P D; Munoz, P C; Casey, T T; DiRaimondo, C R; Stone, W J; Prelli, F C; Rodrigues, M M; Poulik, M D; Frangione, B

    1986-01-01

    Systemic amyloidosis with a predilection for bone and synovium may complicate the course of patients on long-term hemodialysis. This form of amyloidosis can be typed as distinct from other amyloid diseases by using small tissue samples obtained by bone biopsy and at postmortem. Immunoblot analysis of two-dimensional gels of partially solubilized amyloid fibrils established that tissue deposits are composed of monomers, dimers, and higher polymers of beta 2-microglobulin (beta 2m) and that amyloid P component was also present. Anti-beta 2m antiserum recognized fibrils, as shown by immunoelectron microscopy. Purified monomer isolated from dissociated fibrils yielded peptides corresponding to the entire known sequence of beta 2m. Virtually all serum beta 2m, as well as that present in tissue fluid bathing amyloid fibrils, was monomeric. Hemodialysis-related amyloidosis is an example of a deposition disease occurring in hemodialysis patients. We have shown conclusively that, in this amyloid disease, polymerization of an intact normal serum protein to a fibrillar configuration may occur without proteolysis. We propose the designation A beta 2m for this form of amyloid fibril subunit protein. Images PMID:3532124

  3. Characterization of beta2 (CD18) integrin phosphorylation in phorbol ester-activated T lymphocytes.

    PubMed Central

    Valmu, L; Hilden, T J; van Willigen, G; Gahmberg, C G

    1999-01-01

    Integrins are transmembrane proteins involved in cell-cell and cell-extracellular-matrix interactions. The affinity and avidity of integrins for their ligands change in response to cytoplasmic signals. This 'inside-out' activation has been reported to occur also with beta2 integrins (CD18). The beta2 integrin subunit has previously been shown to become phosphorylated in T lymphocytes on cytoplasmic serine and the functionally important threonine residues after treatment with phorbol esters or on triggering of T-cell receptors. We have now characterized the phosphorylation of beta2 integrins in T-cells in more detail. When T-cells were activated by phorbol esters the phosphorylation was mainly on Ser756. After inhibition of serine/threonine phosphatases, phosphorylation was also found in two of the threonine residues in the threonine triplet 758-760 of the beta2 cytoplasmic domain. Activation of T-cells by phorbol esters resulted in phosphorylation in only approx. 10% of the integrin molecules. Okadaic acid increased this phosphorylation to approx. 30% of the beta2 molecules, assuming three phosphorylation sites. This indicates that a strong dynamic phosphorylation exists in serine and threonine residues of the beta2 integrins. PMID:10085235

  4. Do inhaled beta(2)-agonists have an ergogenic potential in non-asthmatic competitive athletes?

    PubMed

    Kindermann, Wilfried

    2007-01-01

    The prevalence of asthma is higher in elite athletes than in the general population. The risk of developing asthmatic symptoms is the highest in endurance athletes and swimmers. Asthma seems particularly widespread in winter-sport athletes such as cross-country skiers. Asthmatic athletes commonly use inhaled beta(2)-agonists to prevent and treat asthmatic symptoms. However, beta(2)-agonists are prohibited according to the Prohibited List of the World Anti-Doping Agency. An exception can be made only for the substances formoterol, salbutamol, salmeterol and terbutaline by inhalation, as long as a therapeutic use exemption has been applied for and granted. In this context, the question arises of whether beta(2)-agonists have ergogenic benefits justifying the prohibition of these substances. In 17 of 19 randomised placebo-controlled trials in non-asthmatic competitive athletes, performance-enhancing effects of the inhaled beta(2)-agonists formoterol, salbutamol, salmeterol and terbutaline could not be proved. This is particularly true for endurance performance, anaerobic power and strength performance. In three of four studies, even supratherapeutic doses of salbutamol (800-1200 microg) had no ergogenic effect. In contrast to inhaled beta(2)-agonists, oral administration of salbutamol seems to be able to improve the muscle strength and the endurance performance. There appears to be no justification to prohibit inhaled beta(2)-agonists from the point of view of the ergogenic effects. PMID:17241101

  5. Adrenergic Modulation of Pancreatic Glucagon Secretion in Man

    PubMed Central

    Gerich, John E.; Langlois, Maurice; Noacco, Claudio; Schneider, Victor; Forsham, Peter H.

    1974-01-01

    In order to characterize the influence of the adrenergic system on pancreatic glucagon secretion in man, changes in basal glucagon secretion during infusions of pure alpha and beta adrenergic agonists and their specific antagonists were studied. During infusion of isoproterenol (3 μg/min), a beta adrenergic agonist, plasma glucagon rose from a mean (±SE) basal level of 104±10 to 171±15 pg/ml, P < 0.0002. Concomitant infusion of propranolol (80 μg/min), a beta adrenergic antagonist, prevented the effects of isoproterenol, although propranolol itself had no effect on basal glucagon secretion. During infusion of methoxamine (0.5 mg/min), an alpha adrenergic agonist, plasma glucagon declined from a mean basal level of 122±15 to 75±17 pg/ml, P < 0.001. Infusion of phentolamine (0.5 mg/min), an alpha adrenergic antagonist, caused a rise in plasma glucagon from a mean basal level of 118±16 to 175±21 pg/ml, P < 0.0001. Concomitant infusion of methoxamine with phentolamine caused a reversal of the effects of phentolamine. The present studies thus confirm that catecholamines affect glucagon secretion in man and demonstrate that the pancreatic alpha cell possesses both alpha and beta adrenergic receptors. Beta adrenergic stimulation augments basal glucagon secretion, while alpha adrenergic stimulation diminishes basal glucagon secretion. Furthermore, since infusion of phentolamine, an alpha adrenergic antagonist, resulted in an elevation of basal plasma glucagon levels, there appears to be an inhibitory alpha adrenergic tone governing basal glucagon secretion. The above findings suggest that catecholamines may influence glucose homeostasis in man through their effects on both pancreatic alpha and beta cell function. Images PMID:4825234

  6. Anti-beta-2 glycoprotein I epitope specificity: from experimental models to diagnostic tools.

    PubMed

    Meroni, P L

    2016-07-01

    Beta-2 glycoprotein I (β2GPI) is the main antigenic target for anti-phospholipid antibodies (aPL), the serological markers of anti-phospholipid syndrome (APS). Conformational changes of the molecule seem to be essential for exposing the cryptic epitope for aPL binding and to trigger pathogenic pathways. There is increasing evidence that a conformational epitope located in the Domain I (DI) of the molecule is the main epitope targeted by human autoantibodies. The pathogenic role of the DI epitope has been recently supported by in vivo models and by immuno-histopathological findings in APS patients. Antibodies targeting β2GPI-DI are more frequently detected in patients with full-blown APS compared to asymptomatic aPL carriers or patients with infectious diseases who have antibodies directed against the whole molecule. Anti-DI antibodies are positively correlated with medium to high titres of aPL, with the presence of lupus anticoagulant and thrombotic and pregnancy manifestations, enabling identification of patients at higher risk of clinical events. However, some APS patients develop antibodies reacting against β2GPI epitopes other than DI, suggesting that other anti-β2GPI antibody subsets may be clinically relevant. Although preliminary results suggest that anti-DI antibodies can be detected by different assays in a comparable manner, further prospective studies are needed to support their use in the clinical setting and their predictive value. PMID:27252268

  7. The effect of Yohimbine, an alpha2 adrenergic receptor antagonist, on the growth hormone response to apomorphine in normal subjects.

    PubMed Central

    Lal, S; Thavundayil, J X; Krishnan, B; Nair, N P; Schwartz, G; Guyda, H

    1996-01-01

    Yohimbine HCl (16 mg po) administered 30 min before clonidine (CLON) (2 ug/kg infused over 10 min) (N = 5) or apomorphine HCl (Apo) (0.5 mg sc) (N = 10) antagonized the growth hormone (GH) response to CLON but had no effect on the GH response to Apo in normal men. This finding suggests that in humans, alpha2 adrenergic mechanisms do not modulate dopaminergic function, at least not in the hypothalamic-pituitary axis, and that the GH response to Apo is not mediated via an alpha2 adrenergic link. PMID:8820174

  8. Effect of adrenergic agonists on coronary blood flow: a laboratory study in healthy volunteers.

    PubMed

    Vargas Pelaez, Alvaro F; Gao, Zhaohui; Ahmad, Tariq A; Leuenberger, Urs A; Proctor, David N; Maman, Stephan R; Muller, Matthew D

    2016-05-01

    Myocardial oxygen supply and demand mismatch is fundamental to the pathophysiology of ischemia and infarction. The sympathetic nervous system, through α-adrenergic receptors and β-adrenergic receptors, influences both myocardial oxygen supply and demand. In animal models, mechanistic studies have established that adrenergic receptors contribute to coronary vascular tone. The purpose of this laboratory study was to noninvasively quantify coronary responses to adrenergic receptor stimulation in humans. Fourteen healthy volunteers (11 men and 3 women) performed isometric handgrip exercise to fatigue followed by intravenous infusion of isoproterenol. A subset of individuals also received infusions of phenylephrine (n = 6), terbutaline (n = 10), and epinephrine (n = 4); all dosages were based on fat-free mass and were infused slowly to achieve steady-state. The left anterior descending coronary artery was visualized using Doppler echocardiography. Beat-by-beat heart rate (HR), blood pressure (BP), peak diastolic coronary velocity (CBVpeak), and coronary velocity time integral were calculated. Data are presented as M ± SD Isometric handgrip elicited significant increases in BP, HR, and CBVpeak (from 23.3 ± 5.3 to 34.5 ± 9.9 cm/sec). Isoproterenol raised HR and CBVpeak (from 22.6 ± 4.8 to 43.9 ± 12.4 cm/sec). Terbutaline and epinephrine evoked coronary hyperemia whereas phenylephrine did not significantly alter CBVpeak. Different indices of coronary hyperemia (changes in CBVpeak and velocity time integral) were significantly correlated (R = 0.803). The current data indicate that coronary hyperemia occurs in healthy humans in response to isometric handgrip exercise and low-dose, steady-state infusions of isoproterenol, terbutaline, and epinephrine. The contribution of β1 versus β2 receptors to coronary hyperemia remains to be determined. In this echocardiographic study, we demonstrate that coronary blood flow increases when β-adrenergic

  9. Phosphoinositide metabolism and adrenergic receptors in astrocytes

    SciTech Connect

    Noble, E.P.; Ritchie, T.; de Vellis, J.

    1986-03-01

    Agonist-induced phosphoinositide (PI) breakdown functions as a signal generating system. Diacylglycerol, one breakdown product of phosphotidylinositol-4,5-diphosphate hydrolysis, can stimulate protein kinase C, whereas inositol triphosphate, the other product, has been proposed to be a second messenger for Ca/sup + +/ mobilization. Using purified astrocyte cultures from neonatal rat brain, the effects of adrenergic agonists and antagonists at 10/sup -5/ M were measured on PI breakdown. Astrocytes grown in culture were prelabeled with (/sup 3/H)inositol, and basal (/sup 3/H) inositol phosphate (IP/sub 1/) accumulation was measured in the presence of Li/sup +/. Epinephrine > norepinephrine (NE) were the most active stimulants of IP/sub 1/ production. The ..cap alpha../sub 1/ adrenoreceptor blockers, phentolamine and phenoxybenzamine, added alone had no effect on IP/sub 1/ production was reduced below basal levels. Propranolol partially blocked the effects of NE. Clonidine and isoproterenol, separately added, reduced IP/sub 1/ below basal levels and when added together diminished IP/sub 1/ accumulation even further. The role of adrenergic stimulation in the production of c-AMP.

  10. beta. -Adrenergic stimulation of brown adipocyte proliferation

    SciTech Connect

    Geloeen, A.; Collet, A.J.; Guay, G.; Bukowiecki, L.J. Laboratoire de Thermoregulation et Metabolisme Energetique, Lyon )

    1988-01-01

    The mechanisms of brown adipose tissue (BAT) growth were studied by quantitative photonic radioautography using tritiated thymidine to follow mitotic activity. To identify the nature of the adrenergic pathways mediating brown adipocyte proliferation and differentiation, the effects of cold exposure (4 days at 4{degree}C) on BAT growth were compared with those induced by treating rats at 25{degree}C with norepinephrine (a mixed agonist), isoproterenol (a {beta}-agonist), and phenylephrine (an {alpha}-agonist). Norepinephrine mimicked the effects of cold exposure, not only on the mitotic activity, but also on the distribution of the labeling among the various cellular types. Isoproterenol entirely reproduced the effects of norepinephrine both on the labeling index and on the cellular type labeling frequency. These results demonstrate that norepinephrine triggers a coordinated proliferation of brown adipocytes and endothelial cells in warm-exposed rats that is similar to that observed after cold exposure. They also suggest that cold exposure stimulates BAT growth by increasing the release of norepinephrine from sympathetic nerves and that the neurohormone activates mitoses in BAT precursor cells via {beta}-adrenergic pathways.

  11. Altered hepatic vasopressin and alpha 1-adrenergic receptors after chronic endotoxin infusion

    SciTech Connect

    Roth, B.L.; Spitzer, J.A.

    1987-05-01

    Sepsis and septic shock are complicated by a number of hemodynamic and metabolic aberrations. These include catecholamine refractoriness and altered glucose metabolism. Recently, a nonshock rat model of continuous endotoxin infusion via an implanted osmotic pump was developed that reproduces some of the metabolic and cardiovascular findings of human sepsis. By using this model, we have found a decreased number of hepatic plasma membrane alpha 1-adrenergic and (Arg8)vasopressin receptors in rats continuously infused with endotoxin. There was a significant decrease in (/sup 3/H)prazosin (35 +/- 7%) and (/sup 3/H) (Arg8)vasopressin (43 +/- 8%) receptors after 30 h of continuous endotoxin infusion with no change in affinity. The ability of norepinephrine to form the high-affinity complex with alpha 1-adrenergic receptors was not altered after chronic endotoxin infusion. The results are consistent with the concept that alterations in receptor number might underlie certain of the metabolic consequences of chronic sepsis.

  12. Rat hepatic. beta. /sub 2/-adrenergic receptor: structural similarities to the rat fat cell. beta. /sub 1/-adrenergic receptor

    SciTech Connect

    Graziano, M.P.

    1984-01-01

    The mammalian ..beta../sub 2/-adrenergic receptor from rat liver has been purified by sequential cycles of affinity chromatography followed by steric-exclusion high performance liquid chromatography. Electrophoresis of highly purified receptor preparations on polyacrylamide gels in the presence of sodium dodecyl sulfate under reducing conditions reveals a single peptide M/sub r/ = 67,000, as judged by silver staining. Purified ..beta../sub 2/-adrenergic receptor migrates on steric-exclusion high performance liquid chromatography in two peaks, with M/sub r/ = 140,000 and 67,000. Specific binding of the high affinity, ..beta..-adrenergic receptor antagonists (-)(/sup 3/H)dihydroalprenolol and (-)(/sup 125/I)iodocyanopindolol to purified rat liver ..beta..-adrenergic receptor preparations displays stereoselectivity for (-)isomers of agonists and a rank order of potencies for agonists characteristics of a ..beta../sub 2/-adrenergic receptor. Radioiodinated, ..beta../sub 1/-adrenergic receptors from rat fat cells and ..beta../sub 2/-adrenergic receptors from rat liver purified in the presence of protease inhibitors comigrate in electrophoretic separations on polyacrylamide gels in the presence of sodium dodecyl sulfate as 67,000-M/sub r/ peptides. Autoradiograms of two dimensional partial proteolytic digests of the purified, radioiodinated rat liver ..beta../sub 2/-adrenergic receptor, generated with ..cap alpha..-chymotrypsin, S. aureus V8 protease and elastase reveal a pattern of peptide fragments essentially identical to those generated by partial proteolytic digests of the purified, radioiodinated ..beta../sub 1/-adrenergic receptor from rat fat cells, by these same proteases. These data indicate that a high degree of homology exists between these two pharmacologically distinct mammalian ..beta..-adrenergic receptor proteins.

  13. Identification and characterization of a novel family of Drosophila beta-adrenergic-like octopamine G-protein coupled receptors.

    PubMed

    Maqueira, Braudel; Chatwin, Heather; Evans, Peter D

    2005-07-01

    Insect octopamine receptors carry out many functional roles traditionally associated with vertebrate adrenergic receptors. These include control of carbohydrate metabolism, modulation of muscular tension, modulation of sensory inputs and modulation of memory and learning. The activation of octopamine receptors mediating many of these actions leads to increases in the levels of cyclic AMP. However, to date none of the insect octopamine receptors that have been cloned have been convincingly shown to be capable of directly mediating selective and significant increases in cyclic AMP levels. Here we report on the identification and characterization of a novel, neuronally expressed family of three Drosophila G-protein coupled receptors that are selectively coupled to increases in intracellular cyclic AMP levels by octopamine. This group of receptors, DmOct beta1R (CG6919), DmOct beta2R (CG6989) and DmOct beta3R (CG7078) shows homology to vertebrate beta-adrenergic receptors. When expressed in Chinese hamster ovary cells all three receptors show a strong preference for octopamine over tyramine for the accumulation of cyclic AMP but show unique pharmacological profiles when tested with a range of synthetic agonists and antagonists. Thus, the pharmacological profile of individual insect tissue responses to octopamine might vary with the combination and the degree of expression of the individual octopamine receptors present. PMID:15998303

  14. Epinephrine and norepinephrine act as potent agonists at the recombinant human dopamine D4 receptor.

    PubMed

    Lanau, F; Zenner, M T; Civelli, O; Hartman, D S

    1997-02-01

    The catecholamines dopamine (DA), epinephrine (EP), and norepinephrine (NE) play important roles in learning and memory, emotional states, and control of voluntary movement, as well as cardiovascular and kidney function. They activate distinct but overlapping neuronal pathways through five distinct DA receptors (D1R-D5R) and at least 10 different adrenergic receptors (alpha 1a/b/c, alpha 2a/b/c-1/c-2, and beta 1/beta 2/beta 3). The D4R, which is localized to mesolimbic areas of the brain implicated in affective and emotional behavior, has a deduced amino acid sequence with homology to both adrenergic and dopaminergic receptor subtypes. We report here that DA, EP, and NE all show binding in the nanomolar range to three isoforms of the recombinant human D4R (hD4R): D4.2, D4.4, and D4.7. Submicromolar concentrations of DA, EP, and NE were sufficient to activate hD4R isoforms in two different functional assays: agonist-induced guanosine 5'-O-(3-[35S]thiotriphosphate) binding and modulation of adenylyl cyclase activity. DA was approximately fivefold more potent than EP and NE at the D4R, whereas activation of the human D2R required at least 100-fold higher catecholamine concentrations. Functional activation of the D4R by multiple neurotransmitters may provide a novel mechanism for integration of catecholamine signaling in the brain and periphery. PMID:9003072

  15. Interaction between the renal excretion rates of beta 2-microglobulin and tobramycin in man.

    PubMed

    Vree, T B; Zweens, K; Huige, P J; Guelen, P J; Jongman-Nix, B

    1984-03-27

    The renal excretion rate of beta 2-microglobulin in man is 127 +/- 98 ng/min at alkaline urine pH (pH 7). Tobramycin, up to intravenous doses of 160 mg (2 mg/kg) does not increase the renal excretion rate of beta 2-microglobulin. Tobramycin must have less affinity than gentamicin for the tubular system for active reabsorption of amino groups containing organic compounds. Due to this reduced affinity tobramycin will be absorbed less by the proximal tubular cells, which may be one of the reasons for tobramycin being less toxic than gentamicin. beta 2-Microglobulin excretion can be used as a parameter for the relative binding affinity of aminoglycosides. PMID:6370509

  16. A beta2-frequency (20–30 Hz) oscillation in nonsynaptic networks of somatosensory cortex

    PubMed Central

    Roopun, Anita K.; Middleton, Steven J.; Cunningham, Mark O.; LeBeau, Fiona E. N.; Bibbig, Andrea; Whittington, Miles A.; Traub, Roger D.

    2006-01-01

    Beta2 frequency (20–30 Hz) oscillations appear over somatosensory and motor cortices in vivo during motor preparation and can be coherent with muscle electrical activity. We describe a beta2 frequency oscillation occurring in vitro in networks of layer V pyramidal cells, the cells of origin of the corticospinal tract. This beta2 oscillation depends on gap junctional coupling, but it survives a cut through layer 4 and, hence, does not depend on apical dendritic electrogenesis. It also survives a blockade of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors or a blockade of GABAA receptors that is sufficient to suppress gamma (30–70 Hz) oscillations in superficial cortical layers. The oscillation period is determined by the M type of K+ current. PMID:17030821

  17. Nitric oxide donor beta2-agonists: furoxan derivatives containing the fenoterol moiety and related furazans.

    PubMed

    Buonsanti, M Federica; Bertinaria, Massimo; Stilo, Antonella Di; Cena, Clara; Fruttero, Roberta; Gasco, Alberto

    2007-10-01

    The structure of fenoterol, a beta2-adrenoceptor agonist used in therapy, has been joined with furoxan NO-donor moieties to give new NO-donor beta2-agonists. The furazan analogues, devoid of the property to release NO, were also synthesized for comparison. All the compounds retained beta2-agonistic activity at micromolar or submicromolar concentration when tested on guinea pig tracheal rings precontracted with carbachol. Among the furoxan derivatives, the NO contribution to trachea relaxation was evident with product 15b at micromolar concentrations. All the new NO-donor hybrids were able to dilate rat aortic strips precontracted with phenylephrine. Both furoxan and furazan derivatives displayed antioxidant activity greater than that of fenoterol. PMID:17845020

  18. Immunization with anticardiolipin cofactor (beta-2-glycoprotein I) induces experimental antiphospholipid syndrome in naive mice.

    PubMed

    Blank, M; Faden, D; Tincani, A; Kopolovic, J; Goldberg, I; Gilburd, B; Allegri, F; Balestrieri, G; Valesini, G; Shoenfeld, Y

    1994-08-01

    Beta-2-GPI is a 50 kDa glycoprotein which is known to be a serum co-factor, with a role in determining the binding of pathogenic anticardiolipin antibodies to phospholipids. Immunization of naive mice with beta-2-GPI resulted in elevated levels of antibodies directed against negatively charged phospholipids (cardiolipin, phosphotidylserine, phosphatidylinositol). The presence of increased titres of antiphospholipid antibodies in the sera of the mice was later followed by prolonged activated partial thromboplastin time (APTT), thrombocytopenia, and when the mice were mated, by a high percentage of fetal resorptions in the uterus. These data point to the ability of beta-2-GPI to induce pathogenic anti-cardiolipin antibodies following active immunization. PMID:7980847

  19. Impaired cardiac energy metabolism in embryos lacking adrenergic stimulation.

    PubMed

    Baker, Candice N; Gidus, Sarah A; Price, George F; Peoples, Jessica N R; Ebert, Steven N

    2015-03-01

    As development proceeds from the embryonic to fetal stages, cardiac energy demands increase substantially, and oxidative phosphorylation of ADP to ATP in mitochondria becomes vital. Relatively little, however, is known about the signaling mechanisms regulating the transition from anaerobic to aerobic metabolism that occurs during the embryonic period. The main objective of this study was to test the hypothesis that adrenergic hormones provide critical stimulation of energy metabolism during embryonic/fetal development. We examined ATP and ADP concentrations in mouse embryos lacking adrenergic hormones due to targeted disruption of the essential dopamine β-hydroxylase (Dbh) gene. Embryonic ATP concentrations decreased dramatically, whereas ADP concentrations rose such that the ATP/ADP ratio in the adrenergic-deficient group was nearly 50-fold less than that found in littermate controls by embryonic day 11.5. We also found that cardiac extracellular acidification and oxygen consumption rates were significantly decreased, and mitochondria were significantly larger and more branched in adrenergic-deficient hearts. Notably, however, the mitochondria were intact with well-formed cristae, and there was no significant difference observed in mitochondrial membrane potential. Maternal administration of the adrenergic receptor agonists isoproterenol or l-phenylephrine significantly ameliorated the decreases in ATP observed in Dbh-/- embryos, suggesting that α- and β-adrenergic receptors were effective modulators of ATP concentrations in mouse embryos in vivo. These data demonstrate that adrenergic hormones stimulate cardiac energy metabolism during a critical period of embryonic development. PMID:25516547

  20. Beta 2-microglobulin associated amyloidosis: a vanishing complication of long-term hemodialysis?

    PubMed

    Schwalbe, S; Holzhauer, M; Schaeffer, J; Galanski, M; Koch, K M; Floege, J

    1997-10-01

    Beta 2-microglobulin associated amyloidosis (A beta 2m amyloidosis) is considered an inevitable complication of chronic hemodialysis, particularly in hemodialysis with cellulose based membranes. We performed a single center study to assess the prevalence of A beta 2m amyloidosis in 1988 versus 1996. Randomly selected patients, studied in 1988, were matched for time on hemodialysis (mean 71 months, range 3 to 207) and age (mean 51 years, range 22 to 80) with patients of the 1996 population. Compared to 1988 patients, the 1996 patients exhibited a lower prevalence of carpal tunnel syndrome (7 of 43 in 1988 vs. 1 of 43 in 1996; P < 0.001) and radiological evidence of A beta 2m amyloidosis (13 of 34 patients vs. 3 of 34 patients positive; P < 0.001; and 33 of 272 possible sites affected in 1988 vs. 7 of 272 sites in 1996 patients; P < 0.05). Compared to the 1988 population, the 1996 population exhibited significantly lower serum aluminum levels, lower average serum creatinine (but not urea) levels, more frequent therapy with erythropoietin, less home hemodialysis, longer hemodialysis time using high-flux synthetic dialysis membranes (mean of 13% vs. 6% of the total hemodialysis time in the 1988 group), and more frequent usage of reverse osmosis water plus bicarbonate buffer for dialysate preparation. We conclude that the prevalence and severity of A beta 2m amyloidosis unexpectedly decreased by about 80% in our center between 1988 and 1996. Given the relatively short times spent on high flux hemodialysis in both groups, increased beta 2-microglobulin removal is unlikely to account for this phenomenon. Rather, other factors, for example, dialysate composition and purity, may be involved. PMID:9328948

  1. Beta 2 toxigenic Clostridium perfringens type A colitis in a three-day-old foal.

    PubMed

    Hazlett, Murray J; Kircanski, Jasmina; Slavic, Durda; Prescott, John F

    2011-03-01

    Beta 2 (β2)-toxigenic Clostridium perfringens type A was recovered in large numbers from the intestine of a neonatal foal with colitis. The foal had been treated with gentamicin. Necropsy revealed marked distension of cecum and colon with watery, rust-colored homogeneous fluid and gastric infarction. Microscopic colonic lesions were superficial necrosis of 50% of the colonic mucosal surface and scattered 1-3-mm ulcers with subjacent neutrophilic infiltration and large Gram-positive bacilli in the necrotic mucosa. Beta-2 toxin was demonstrated in the lesions by immunohistochemical staining. PMID:21398467

  2. Elevated plasma levels of transforming growth factor (TGF)-beta1 and TGF-beta2 in patients with disseminated malignant melanoma.

    PubMed Central

    Krasagakis, K.; Thölke, D.; Farthmann, B.; Eberle, J.; Mansmann, U.; Orfanos, C. E.

    1998-01-01

    Overexpression of transforming growth factor-beta isoforms (TGF-beta1, -beta2, -beta3) has been previously reported in human melanoma cell lines and tumours. The aim of the present study was to evaluate the plasma levels of TGF-beta isoforms in melanoma patients. Significantly elevated levels of TGF-beta1 (4.2 x the controls, P = 0.0094) and of TGF-beta2 (1.5 x the controls, P = 0.012) but not of TGF-beta3 were measured in patients with disseminated but not locoregional melanoma. These results indicate systemic circulation of potentially immunosuppressive peptides of the TGF-beta family in end-stage melanoma patients. PMID:9652767

  3. Restoration of β -Adrenergic Signaling in Failing Cardiac Ventricular Myocytes via Adenoviral-Mediated Gene Transfer

    NASA Astrophysics Data System (ADS)

    Akhter, Shahab A.; Skaer, Christine A.; Kypson, Alan P.; McDonald, Patricia H.; Peppel, Karsten C.; Glower, Donald D.; Lefkowitz, Robert J.; Koch, Walter J.

    1997-10-01

    Cardiovascular gene therapy is a novel approach to the treatment of diseases such as congestive heart failure (CHF). Gene transfer to the heart would allow for the replacement of defective or missing cellular proteins that may improve cardiac performance. Our laboratory has been focusing on the feasibility of restoring β -adrenergic signaling deficiencies that are a characteristic of chronic CHF. We have now studied isolated ventricular myocytes from rabbits that have been chronically paced to produce hemodynamic failure. We document molecular β -adrenergic signaling defects including down-regulation of myocardial β -adrenergic receptors (β -ARs), functional β -AR uncoupling, and an upregulation of the β -AR kinase (β ARK1). Adenoviral-mediated gene transfer of the human β 2-AR or an inhibitor of β ARK1 to these failing myocytes led to the restoration of β -AR signaling. These results demonstrate that defects present in this critical myocardial signaling pathway can be corrected in vitro using genetic modification and raise the possibility of novel inotropic therapies for CHF including the inhibition of β ARK1 activity in the heart.

  4. Alpha-2 adrenergic stimulation triggers Achilles tenocyte hypercellularity: Comparison between two model systems

    PubMed Central

    Backman, L J; Andersson, G; Fong, G; Alfredson, H; Scott, A; Danielson, P

    2013-01-01

    The histopathology of tendons with painful tendinopathy is often tendinosis, a fibrosis-like condition of unclear pathogenesis characterized by tissue changes including hypercellularity. The primary tendon cells (tenocytes) have been shown to express adrenoreceptors (mainly alpha-2A) as well as markers of catecholamine production, particularly in tendinosis. It is known that adrenergic stimulation can induce proliferation in other cells. The present study investigated the effects of an exogenously administered alpha-2 adrenergic agonist in an established in vivo Achilles tendinosis model (rabbit) and also in an in vitro human tendon cell culture model. The catecholamine producing enzyme tyrosine hydroxylase and the alpha-2A-adrenoreceptor (α2A AR) were expressed by tenocytes, and alpha-2 adrenergic stimulation had a proliferative effect on these cells, in both models. The proliferation was inhibited by administration of an α2A AR antagonist, and the in vitro model further showed that the proliferative alpha-2A effect was mediated via a mitogenic cell signaling pathway involving phosphorylation of extracellular-signal-regulated kinases 1 and 2. The results indicate that catecholamines produced by tenocytes in tendinosis might contribute to the proliferative nature of the pathology through stimulation of the α2A AR, pointing to a novel target for future therapies. The study furthermore shows that animal models are not necessarily required for all aspects of this research. PMID:22292987

  5. The effects of spaceflight on adrenergic receptors and agonists and cell adhesion molecule expression

    NASA Technical Reports Server (NTRS)

    Mills, Paul J.; Perez, Christy J.; Adler, Karen A.; Ziegler, Michael G.; Meck, J. V. (Principal Investigator)

    2002-01-01

    Twenty-two astronauts who flew aboard 10 different US Space Shuttle flights were studied 10 days before launch, on landing day, and 2-4 days post-landing. After landing, plasma levels of norepinephrine (p<0.01) were elevated. Lymphocyte beta(2)-adrenergic receptors were desensitized 2-4 days post-landing (p<0.02). The density of CD62L on lymphocytes was unchanged but the densities of CD11a (p<0.01) and CD54 (p<0.001) were down-regulated. CD11a density was also down-regulated on monocytes (p<0.01). Neutrophils showed an up-regulation of CD11a (p<0.01) and a down-regulation of CD54 (p<0.01). CD11a density on neutrophils remained up-regulated (p<0.01) and CD54 density remained down-regulated (p<0.01) at 2-4 days post-landing. Circulating levels of soluble ICAM-1 (CD54) and soluble E-selectin (CD62E) were decreased after landing (p's<0.05). The data suggest that spaceflight leads to an environment that would support reduced leukocyte-endothelial adhesion. Sympathetic activation may contribute to this phenomenon.

  6. Influence of the beta-adrenergic receptor concentration on functional coupling to the adenylate cyclase system.

    PubMed Central

    Severne, Y; Coppens, D; Bottari, S; Riviere, M; Kram, R; Vauquelin, G

    1984-01-01

    Only part of the beta-adrenergic receptors can undergo functional coupling to the adenylate cyclase regulatory unit. This receptor subpopulation shows an increased affinity for agonists in the presence of Mg2+ and undergoes rapid "inactivation" (locking-in of the agonist) by the alkylating reagent N-ethylmaleimide in the presence of agonists. Several experimental conditions, known to modify the total receptor concentration without alteration of the other components of the adenylate cyclase system, do not affect the percentage of receptors that can undergo functional coupling: (i) homologous regulation of beta 1 receptors in rat brain by noradrenaline (through antidepressive drug or reserpine injections); (ii) up- and down-regulation of the beta 2 receptors in Friend erythroleukemia cells by, respectively, sodium butyrate and cinnarizine treatment; and (iii) dithiothreitol-mediated inactivation of receptors in turkey erythrocytes, Friend erythroleukemia cells, and rat brain. Our findings argue against a stoichiometric limitation in the number of regulatory components, genetically different receptor subpopulations, bound guanine nucleotides, or reduced accessibility of part of the receptors to the agonists as the cause for functional receptor heterogeneity. Differences in either the receptor conformation or its membrane microenvironment are more plausible explanations. PMID:6087337

  7. Targeted disruption of the mouse beta1-adrenergic receptor gene: developmental and cardiovascular effects.

    PubMed Central

    Rohrer, D K; Desai, K H; Jasper, J R; Stevens, M E; Regula, D P; Barsh, G S; Bernstein, D; Kobilka, B K

    1996-01-01

    At least three distinct beta-adrenergic receptor (beta-AR) subtypes exist in mammals. These receptors modulate a wide variety of processes, from development and behavior, to cardiac function, metabolism, and smooth muscle tone. To understand the roles that individual beta-AR subtypes play in these processes, we have used the technique of gene targeting to create homozygous beta 1-AR null mutants (beta 1-AR -/-) in mice. The majority of beta 1-AR -/- mice die prenatally, and the penetrance of lethality shows strain dependence. Beta l-AR -/- mice that do survive to adulthood appear normal, but lack the chronotropic and inotropic responses seen in wild-type mice when beta-AR agonists such as isoproterenol are administered. Moreover, this lack of responsiveness is accompanied by markedly reduced stimulation of adenylate cyclase in cardiac membranes from beta 1-AR -/- mice. These findings occur despite persistent cardiac beta 2-AR expression, demonstrating the importance of beta 1-ARs for proper mouse development and cardiac function, while highlighting functional differences between beta-AR subtypes. Images Fig. 1 Fig. 3 PMID:8693001

  8. Propranolol responsiveness in vascular tumors is not determined by qualitative differences in adrenergic receptors.

    PubMed

    Boucek, Robert J; Kirsh, Andrew L; Majesky, Mark W; Perkins, Jonathan A

    2013-11-01

    Propranolol, a beta 1 (ADBR1) and beta 2 (ADBR2) adrenergic receptor blocker, accelerates regression of proliferating infantile hemangiomas (IH-P) while not affecting non-involuting congenital hemangiomas (NICH) and nonproliferating IH (IH-NP). To determine the expression of ADBRs in vascular tumors, immunofluorescent staining and confocal microscopy were employed to determine the in situ cellular distribution of ADBRs in formalin-fixed paraffin-embedded tissue sections of IH-P, IH-NP, and NICH. In situ cellular proliferation, indexed by Ki-67 expression, distinguished IH-P (n = 3) from both IH-NP (n = 3) and NICH (n = 2). In IH-P, IH-NP, and NICH tumor sections, both ADBR1 and ADBR2 were co-localized in both endothelial cells (ECs; GLUT1(+) in IH; CD31+ in NICH) and pericytes (smooth muscle actin). We tentatively conclude that either EC and/or pericytes in IH-P could be target(s) of propranolol. Cell proliferation, but not absence of either class of ADBR, distinguished the propranolol responsive IH-P from the nonresponsive IH-NP and NICH. PMID:24009211

  9. Transforming growth factor-{beta}2 enhances differentiation of cardiac myocytes from embryonic stem cells

    SciTech Connect

    Kumar, Dinender . E-mail: Dinender.Kumar@uvm.edu; Sun, Baiming

    2005-06-24

    Stem cell therapy holds great promise for the treatment of injured myocardium, but is challenged by a limited supply of appropriate cells. Three different isoforms of transforming growth factor-{beta} (TGF-{beta}) -{beta}1, -{beta}2, and -{beta}3 exhibit distinct regulatory effects on cell growth, differentiation, and migration during embryonic development. We compared the effects of these three different isoforms on cardiomyocyte differentiation from embryonic stem (ES) cells. In contrast to TGF-{beta}1, or -{beta}3, treatment of mouse ES cells with TGF-{beta}2 isoform significantly increased embryoid body (EB) proliferation as well as the extent of the EB outgrowth that beat rhythmically. At 17 days, 49% of the EBs treated with TGF-{beta}2 exhibited spontaneous beating compared with 15% in controls. Cardiac myocyte specific protein markers sarcomeric myosin and {alpha}-actin were demonstrated in beating EBs and cells isolated from EBs. In conclusion, TGF-{beta}2 but not TGF-{beta}1, or -{beta}3 promotes cardiac myocyte differentiation from ES cells.

  10. Beta2-microglobuline plasma level and painful shoulder in haemodialysed patients.

    PubMed

    Barisić, Igor; Ljutić, Dragan; Vlak, Tonko; Bekavac, Josip; Perić, Irena; Mise, Kornelija; Klancnik, Marisa; Janković, Stipan

    2010-03-01

    Painful shoulder in patients on chronic haemodialyis is most often associated with dialysis arthropathy or accumulation of deposits containing modified fibrils of beta2- microglobuline especially in bones and joints due to insufficient elimination during the therapy. The aim of this study is to investigate whether there is connection between painful shoulder and plasma level of beta2-microglobuline and to corroborate that with morphologic parameters found in proved amyloidosis. It has to be emphasized that even other causes may contribute the development of painful shoulder. Real time sonography and conventional plain radiographs of the 108 shoulders were performed in 54 patients receiving chronic haemodialysis as a treatment of terminal renal failure (without previous history of rheumatoid arthritis), 27 symptomatic with persistent pain and stiffness in both shoulders and lasting for more than 6 weeks and restriction of movements in various degree and 27 asymptomatic. Plasma level of beta2-microglobuline, CRP and uric acid were taken periodically as routine procedure during a one year prospective trial, as well as plasma level of calcium, phosphor and alkaline phosphatase. Plasmatic level of beta2-microglobuline is strongly connected with painful shoulder in dialyzed patients, as well as CRP as sign of acute inflammation. That is proved by morphologic parameters associated with histological proved amyloidosis in patients on long term dialysis, more then 10 years. PMID:20402341

  11. Amiloride interacts with renal. cap alpha. - and. beta. -adrenergic receptors

    SciTech Connect

    Howard, M.J.; Mullen, M.D.; Insel, P.A.

    1987-07-01

    The authors have used radioligand binding techniques to assess whether amiloride and certain analogues of amiloride (ethylisopropyl amiloride and benzamil) can bind to adrenergic receptors in the kidney. They found that amiloride could compete for (/sup 3/H)rauwolscine (..cap alpha../sub 2/-adrenergic receptors), (/sup 3/H)prazosin (..cap alpha../sub 1/-adrenergic receptors), and (/sup 125/I)iodocyanopindolol (..beta..-adrenergic receptors) binding in rat renal cortical membranes with inhibitor constants of 13.6 /plus minus/ 5.7, 24.4 /plus minus/ 7.4, and 8.36 /plus minus/ 13.5 ..mu..M, respectively. Ethylisopropyl amiloride and benzamil were from 2- to 25-fold more potent than amiloride in competing for radioligand binding sites in studies with these membranes. In addition, amiloride and the two analogues competed for (/sup 3/H)prazosin sites on intact Madin-Darby canine kidney cells and amiloride blocked epinephrine-stimulated prostaglandin E/sub 2/ production in these cells. They conclude that amiloride competes for binding to several classes of renal adrenergic receptors with a rank order of potency of ..cap alpha../sub 2/ > ..cap alpha../sub 1/ > ..beta... Binding to, and antagonism of, adrenergic receptors occurs at concentrations of amiloride that are lower than previously observed nonspecific interactions of this agent.

  12. β2-Agonist clenbuterol hinders human monocyte differentiation into dendritic cells.

    PubMed

    Giordani, Luciana; Cuzziol, Noemi; Del Pinto, Tamara; Sanchez, Massimo; Maccari, Sonia; Massimi, Alessia; Pietraforte, Donatella; Viora, Marina

    2015-12-10

    Clenbuterol (CLB) is a beta2-adrenergic agonist commonly used in asthma therapy, but is also a non-steroidal anabolic drug often abused in sport doping practices. Here we evaluated the in vitro impact of CLB on the physiology and function of human monocytes and dendritic cells (DCs), instrumental in the development of immune responses. We demonstrate that CLB inhibits the differentiation of monocytes into DCs and this effect is specific and dependent on β2-adrenergic receptor (AR) activation. We found that CLB treatment reduced the percentage of CD1a(+) immature DCs, while increasing the frequency of monocytes retaining CD14 surface expression. Moreover, CLB inhibited tumor necrosis factor-alpha (TNF-alpha) enhanced IL-(interleukin)-10 and IL-6 production. In contrast, CLB did not modulate the phenotypic and functional properties of monocytes and DCs, such as the surface expression of HLA-DR, CD83, CD80 and CD86 molecules, cytokine production, immunostimulatory activity and phagocytic activity. Moreover, we found that CLB did not modulate the activation of NF-kB in DCs. Moreover, we found that the differentiation of monocytes into DCs was associated with a significant decrease of β2-ARs mRNA expression. These results provide new insights on the effect of CLB on monocyte differentiation into DCs. Considering the frequent illegal use of CLB in doping, our work suggests that this drug is potentially harmful to immune responses decreasing the supply of DCs, thus subverting immune surveillance. PMID:26524508

  13. SSR591813, a novel selective and partial alpha4beta2 nicotinic receptor agonist with potential as an aid to smoking cessation.

    PubMed

    Cohen, C; Bergis, O E; Galli, F; Lochead, A W; Jegham, S; Biton, B; Leonardon, J; Avenet, P; Sgard, F; Besnard, F; Graham, D; Coste, A; Oblin, A; Curet, O; Voltz, C; Gardes, A; Caille, D; Perrault, G; George, P; Soubrie, P; Scatton, B

    2003-07-01

    (5aS,8S,10aR)-5a,6,9,10-Tetrahydro,7H,11H-8,10a-methanopyrido[2',3':5,6]pyrano[2,3-d]azepine (SSR591813) is a novel compound that binds with high affinity to the rat and human alpha4beta2 nicotinic acetylcholine receptor (nAChR) subtypes (Ki = 107 and 36 nM, respectively) and displays selectivity for the alpha4beta2 nAChR (Ki, human alpha3beta4 > 1000, alpha3beta2 = 116; alpha1beta1deltagamma > 6000 nM and rat alpha7 > 6000 nM). Electrophysiological experiments indicate that SSR591813 is a partial agonist at the human alpha4beta2 nAChR subtype (EC50 = 1.3 micro M, IA =19% compared with the full agonist 1,1-dimethyl-4-phenyl-piperazinium). In vivo findings from microdialysis and drug discrimination studies confirm the partial intrinsic activity of SSR591813. The drug increases dopamine release in the nucleus accumbens shell (30 mg/kg i.p.) and generalizes to nicotine or amphetamine (10-20 mg/kg i.p.) in rats, with an efficacy approximately 2-fold lower than that of nicotine. Pretreatment with SSR591813 (10 mg/kg i.p.) reduces the dopamine-releasing and discriminative effects of nicotine. SSR591813 shows activity in animal models of nicotine dependence at doses devoid of unwanted side effects typically observed with nicotine (hypothermia and cardiovascular effects). The compound (10 mg/kg i.p.) also prevents withdrawal signs precipitated by mecamylamine in nicotine-dependent rats and partially blocks the discriminative cue of an acute precipitated withdrawal. SSR591813 (20 mg/kg i.p.) reduces i.v. nicotine self-administration and antagonizes nicotine-induced behavioral sensitization in rats. The present results confirm important role for alpha4beta2 nAChRs in mediating nicotine dependence and suggest that SSR591813, a partial agonist at this particular nAChR subtype, may have therapeutic potential in the clinical management of smoking cessation. PMID:12682217

  14. The role of integrin alpha D beta2 (CD11d/CD18) in monocyte/macrophage migration.

    PubMed

    Yakubenko, Valentin P; Belevych, Nataly; Mishchuk, Daria; Schurin, Aleksey; Lam, Stephen C-T; Ugarova, Tatiana P

    2008-08-15

    Integrin alpha(D)beta(2) (CD11d/CD18) is a multiligand macrophage receptor with recognition specificity identical to that of the major myeloid cell-specific integrin alpha(M)beta(2) (CD11b/CD18, Mac-1). Despite its prominent upregulation on inflammatory macrophages, the role of alpha(D)beta(2) in monocyte and macrophage migration is unknown. In this study, we have generated model and natural cell lines expressing different densities of alpha(D)beta(2) and examined their migration to various extracellular matrix proteins. When expressed at a low density, alpha(D)beta(2) on the surface of recombinant HEK293 cells and murine IC-21 macrophages cooperates with beta(1)/beta(3) integrins to support cell migration. However, its increased expression on the alpha(D)beta(2)-expressing HEK293 cells and its upregulation by PMA on the IC-21 macrophages result in increased cell adhesiveness and inhibition of cell migration. Furthermore, ligation of alpha(D)beta(2) with anti-alpha(D) blocking antibodies restores beta(1)/beta(3)-driven cell migration by removing the excess alpha(D)beta(2)-mediated adhesive bonds. Consistent with in vitro data, increased numbers of inflammatory macrophages were recovered from the inflamed peritoneum of mice after the administration of anti-alpha(D) antibody. These results demonstrate that the density of alpha(D)beta(2) is critically involved in modulating macrophage adhesiveness and their migration, and suggest that low levels of alpha(D)beta(2) contribute to monocyte migration while alpha(D)beta(2) upregulation on differentiated macrophages may facilitate their retention at sites of inflammation. PMID:18621369

  15. Mice Lacking beta2-Integrin Function Remain Glucose Tolerant in Spite of Insulin Resistance, Neutrophil Infiltration and Inflammation

    PubMed Central

    Sneddon, Claire C.; Savinko, Terhi; Uotila, Liisa; Jalicy, Susan M.; Gabriel, Jennie L.; Kang, Li; Ashford, Michael L. J.; Fagerholm, Susanna C.

    2015-01-01

    Beta2-integrins are important in leukocyte trafficking and function, and are regulated through the binding of cytoplasmic proteins, such as kindlin-3, to their intracellular domain. Here, we investigate the involvement of beta2-integrins in the regulation of metabolic disease using mice where the kindlin-3 binding site in the beta2-integrin cytoplasmic tail has been mutated (TTT/AAA-beta2-integrin knock-in (KI) mice), leading to expressed but dysfunctional beta2-integrins and significant neutrophilia in vivo. Beta2-integrin KI mice fed on a high fat diet showed normal weight gain, and normal accumulation of macrophages and lymphocytes in white adipose tissue (WAT) and liver, but increased neutrophil numbers especially in WAT. In addition, beta2-integrin KI mice fed on a high fat diet showed significantly increased peripheral insulin resistance in response to high-fat feeding. However, this was associated with improved glucose disposal following glucose load. Interestingly, beta2-integrin KI neutrophils produced more elastase in vitro, in response to stimulation. Beta2-integrin KI mice displayed variability of tissue inflammatory status, with liver and WAT exhibiting little or no difference in inflammation compared to high fat fed controls, whereas skeletal muscle demonstrated a raised inflammatory profile in association with higher elastase levels and diminished signalling through the IRS1-PKB pathway. In conclusion, although expression of dysfunctional beta2-integrins increased neutrophil production and infiltration into tissue, skeletal muscle was the most affected tissue exhibiting evidence of higher neutrophil activity and insulin resistance. Thus, beta2-integrins modulate glucose homeostasis during high fat feeding predominantly through actions on skeletal muscle to affect metabolic phenotype in vivo. PMID:26405763

  16. Mice Lacking beta2-Integrin Function Remain Glucose Tolerant in Spite of Insulin Resistance, Neutrophil Infiltration and Inflammation.

    PubMed

    Meakin, Paul J; Morrison, Vicky L; Sneddon, Claire C; Savinko, Terhi; Uotila, Liisa; Jalicy, Susan M; Gabriel, Jennie L; Kang, Li; Ashford, Michael L J; Fagerholm, Susanna C

    2015-01-01

    Beta2-integrins are important in leukocyte trafficking and function, and are regulated through the binding of cytoplasmic proteins, such as kindlin-3, to their intracellular domain. Here, we investigate the involvement of beta2-integrins in the regulation of metabolic disease using mice where the kindlin-3 binding site in the beta2-integrin cytoplasmic tail has been mutated (TTT/AAA-beta2-integrin knock-in (KI) mice), leading to expressed but dysfunctional beta2-integrins and significant neutrophilia in vivo. Beta2-integrin KI mice fed on a high fat diet showed normal weight gain, and normal accumulation of macrophages and lymphocytes in white adipose tissue (WAT) and liver, but increased neutrophil numbers especially in WAT. In addition, beta2-integrin KI mice fed on a high fat diet showed significantly increased peripheral insulin resistance in response to high-fat feeding. However, this was associated with improved glucose disposal following glucose load. Interestingly, beta2-integrin KI neutrophils produced more elastase in vitro, in response to stimulation. Beta2-integrin KI mice displayed variability of tissue inflammatory status, with liver and WAT exhibiting little or no difference in inflammation compared to high fat fed controls, whereas skeletal muscle demonstrated a raised inflammatory profile in association with higher elastase levels and diminished signalling through the IRS1-PKB pathway. In conclusion, although expression of dysfunctional beta2-integrins increased neutrophil production and infiltration into tissue, skeletal muscle was the most affected tissue exhibiting evidence of higher neutrophil activity and insulin resistance. Thus, beta2-integrins modulate glucose homeostasis during high fat feeding predominantly through actions on skeletal muscle to affect metabolic phenotype in vivo. PMID:26405763

  17. β-Adrenergic agonists mediate enhancement of β1-adrenergic receptor N-terminal cleavage and stabilization in vivo and in vitro.

    PubMed

    Hakalahti, Anna E; Khan, Hamayun; Vierimaa, Miia M; Pekkala, Emilia H; Lackman, Jarkko J; Ulvila, Johanna; Kerkelä, Risto; Petäjä-Repo, Ulla E

    2013-01-01

    The β(1)-adrenergic receptor (β(1)AR) is the predominant βAR in the heart and is the main target for β-adrenergic antagonists, widely used in the treatment of cardiovascular diseases. Previously, we have shown that the human (h) β(1)AR is cleaved in its N terminus by a metalloproteinase, both constitutively and in a receptor activation-dependent manner. In this study, we investigated the specific events involved in β(1)AR regulation, focusing on the effects of long-term treatment with β-adrenergic ligands on receptor processing in stably transfected human embryonic kidney 293(i) cells. The key findings were verified using the transiently transfected hβ(1)AR and the endogenously expressed receptor in neonatal rat cardiomyocytes. By using flow cytometry and Western blotting, we demonstrated that isoproterenol, S-propranolol, CGP-12177 [4-[3-[(1,1-dimethylethyl)amino]2-hydroxypropoxy]-1,3-dihydro-2H-benzimidazol-2-one], pindolol, and timolol, which displayed agonistic properties toward the β(1)AR in either the adenylyl cyclase or the mitogen-activated protein kinase signaling pathways, induced cleavage of the mature cell-surface receptor. In contrast, metoprolol, bisoprolol, and CGP-20712 [1-[2-((3-carbamoyl-4-hydroxy)phenoxy)ethylamino]-3-[4-(1-methyl-4-trifluoromethyl-2-imidazolyl)phenoxy]-2-propanol], which showed no agonistic activity, had only a marginal or no effect. Importantly, the agonists also stabilized intracellular receptor precursors, possibly via their pharmacological chaperone action, and they stabilized the receptor in vitro. The opposing effects on the two receptor forms thus led to an increase in the amount of cleaved receptor fragments at the plasma membrane. The results underscore the pluridimensionality of β-adrenergic ligands and extend this property from receptor activation and signaling to the regulation of β(1)AR levels. This phenomenon may contribute to the exceptional resistance of β(1)ARs to downregulation and tendency toward

  18. Conformational mobility of immobilized alpha3beta2, alpha3beta4, alpha4beta2, and alpha4beta4 nicotinic acetylcholine receptors.

    PubMed

    Moaddel, Ruin; Jozwiak, Krzysztof; Whittington, Kevin; Wainer, Irving W

    2005-02-01

    Four affinity chromatography stationary phases have been developed based upon immobilized nicotinic acetylcholine receptor (nAChR) subtypes, the alpha3beta2, alpha3beta4, alpha4beta2, and alpha4beta4 nAChRs. The stationary phases were created using membranes from cell lines expressing the subtypes and an immobilized artificial membrane stationary phase. The immobilized nAChRs were characterized using frontal chromatography with the agonist epibatidine as the marker. The observed binding affinities for the agonists epibatidine, nicotine, and cytisine were consistent with reported values, indicating that the nAChRs retained their ability to bind agonists. The noncompetitive inhibitors (NCIs) of the nAChR (R)- and (S)-mecamylamine, phencylcidine, dextromethoprphan, and levomethorphan were also chromatographed on the columns using nonlinear chromatography techniques. The studies were carried out before and after exposure of the columns to epibatidine. The NCI retention times increased after exposure to epibtatidine as did the enantioselective separation of mecamylamine and methorphan. The results indicate that the immobilized nAChRs retained their ability to undergo agonist-induced conformational change from the resting to the desensitized states. The columns provide a unique ability to study the interactions of NCIs with both of these conformational states. PMID:15679359

  19. Crystal Structures of the β2-Adrenergic Receptor

    NASA Astrophysics Data System (ADS)

    Weis, William I.; Rosenbaum, Daniel M.; Rasmussen, Søren G. F.; Choi, Hee-Jung; Thian, Foon Sun; Kobilka, Tong Sun; Yao, Xiao-Jie; Day, Peter W.; Parnot, Charles; Fung, Juan J.; Ratnala, Venkata R. P.; Kobilka, Brian K.; Cherezov, Vadim; Hanson, Michael A.; Kuhn, Peter; Stevens, Raymond C.; Edwards, Patricia C.; Schertler, Gebhard F. X.; Burghammer, Manfred; Sanishvili, Ruslan; Fischetti, Robert F.; Masood, Asna; Rohrer, Daniel K.

    G protein coupled receptors (GPCRs) constitute the largest family of membrane proteins in the human genome, and are responsible for the majority of signal transduction events involving hormones and neuro-transmitters across the cell membrane. GPCRs that bind to diffusible ligands have low natural abundance, are relatively unstable in detergents, and display basal G protein activation even in the absence of ligands. To overcome these problems two approaches were taken to obtain crystal structures of the β2-adrenergic receptor (β2AR), a well-characterized GPCR that binds cate-cholamine hormones. The receptor was bound to the partial inverse agonist carazolol and co-crystallized with a Fab made to a three-dimensional epitope formed by the third intracellular loop (ICL3), or by replacement of ICL3 with T4 lysozyme. Small crystals were obtained in lipid bicelles (β2AR-Fab) or lipidic cubic phase (β2AR-T4 lysozyme), and diffraction data were obtained using microfocus technology. The structures provide insights into the basal activity of the receptor, the structural features that enable binding of diffusible ligands, and the coupling between ligand binding and G-protein activation.

  20. Cardiac salvage by tweaking with beta-3-adrenergic receptors.

    PubMed

    Balligand, Jean-Luc

    2016-07-15

    Overstimulation of the orthosympathetic system leads to cardiovascular cell and tissue damage through prolonged activation of β-1-2 adrenergic receptors (BARs). The more recent identification of the third isotype of BAR (B3AR) in cardiac myocytes and endothelial cells with a distinctive coupling and effect on cardiac function and remodelling introduced a new facet to this paradigm. In particular, B3AR is up-regulated in cardiac disease and less prone to homologous desensitization, which may reinforce its influence on the diseased myocardium. Mice with transgenic cardiac-specific expression of the human B3AR are protected from cardiac hypertrophy and fibrosis in response to neurohormonal stimulation. B3AR has also been implicated in cardiac protection after ischaemia-reperfusion and the benefits of exercise on the heart. Many of these salvage mechanisms are mediated by B3AR coupling to nitric oxide synthase (eNOS and nNOS) and downstream cGMP/protein kinase G signalling. Notably, B3AR exerts antioxidant protective effects on these and other signalling elements, which may subserve its protective properties in the setting of chronic heart failure. Additional vasorelaxing properties and paracrine NO-mediated signalling by B3AR in endothelium, together with systemic metabolic effects on beige/brown fat complete the pleiotropic protective properties of this new therapeutic target. PMID:27001422

  1. 'Dialysis related arthropathy': a survey of 95 patients receiving chronic haemodialysis with special reference to beta 2 microglobulin related amyloidosis.

    PubMed Central

    Hurst, N P; van den Berg, R; Disney, A; Alcock, M; Albertyn, L; Green, M; Pascoe, V

    1989-01-01

    Ninety five patients receiving chronic haemodialysis (CHD) were surveyed to determine the prevalence of rheumatic disease and, where possible, its aetiology. At least three distinct rheumatic syndromes were identified--a group of patients with a syndrome consisting of large and medium joint synovial swelling, restricted hips and shoulders, tenosynovitis, carpal tunnel syndrome, and bone cysts due to deposition of beta 2 microglobulin related amyloid (AM beta 2m); a second group with erosive azotaemic osteoarthropathy; and a third group with age related degenerative disease of small, large, and axial joints. The data presented suggest that in patients receiving CHD (a) the prevalence of AM beta 2m deposition and the associated syndrome increases with duration of dialysis, but in patients who have been dialysed for more than 10 years the risk of developing AM beta 2m is related to age; (b) AM beta 2m deposition in subchondral cysts, but not synovium, causes joint destruction; also, AM beta 2m may be more prone to deposition in synovium of joints already damaged by other processes; (c) in the absence of synovial iron deposition synovial AM beta 2m is not associated with an inflammatory infiltrate; (d) hyperparathyroidism and perhaps other factors such as synovial iron deposition are probably more important than AM beta 2m as causes of peripheral joint degeneration and destructive spondyloarthropathy in patients receiving CHD. Images PMID:2658876

  2. Interactions between beta-2 adrenoceptor gene variation, cardiovascular control and dietary sodium in healthy young adults

    PubMed Central

    Eisenach, John H; Schroeder, Darrell R; Pavey, Emily S; Penheiter, Alan R; Knutson, Jean N; Turner, Stephen T; Joyner, Michael J

    2014-01-01

    Dietary sodium affects function of the beta-2 adrenoceptor (ADRB2). We tested the hypothesis that haplotype variation in the ADRB2 gene would influence the cardiovascular and regional vasodilator responses to sympathoexcitatory manoeuvres following low, normal and high sodium diets, and ADRB2-mediated forearm vasodilation in the high sodium condition. Seventy-one healthy young adults were grouped by double homozygous haplotypes: Arg16+Gln27 (n = 31), the rare Gly16+Gln27 (n = 10) and Gly16+Glu27 (n = 30). Using a randomized cross-over design, subjects were studied following 5 days of controlled low, normal and high sodium with 1 month or longer between diets (and low hormone phase of the menstrual cycle). All three visits utilized ECG and finger plethysmography for haemodynamic measures, and the high sodium visit included a brachial arterial catheter for forearm vasodilator responses to isoprenaline with plethysmography. Lymphocytes were sampled for ex vivo analysis of ADRB2 density and binding conformation. We found a main effect of haplotype on ADRB2 density (P = 0.03) with the Gly16+Glu27 haplotype having the greatest density (low, normal, high sodium: 12.9 ± 0.9, 13.5 ± 0.9 and 13.6 ± 0.8 fmol mg−1 protein, respectively) and Arg16+Gln27 having the least (9.3 ± 0.6, 10.1 ± 0.5 and 10.3 ± 0.6  fmol mg−1 protein, respectively), but there were no sodium or haplotype effects on receptor binding conformation. In the mental stress trial, there was a main effect of haplotype on cardiac output (P = 0.04), as Arg16+Gln27 had the lowest responses. Handgrip and forearm vasodilation yielded no haplotype differences, and no correlations were present for ADRB2 density and haemodynamics. Our findings support cell-based evidence that ADRB2 haplotype influences ADRB2 protein expression independent of dietary sodium, yet the haemodynamic consequences appear modest in healthy humans. PMID:25260632

  3. Nandrolone-pretreatment enhances cardiac beta(2)-adrenoceptor expression and reverses heart contractile down-regulation in the post-stress period of acute-stressed rats.

    PubMed

    Penna, Claudia; Abbadessa, Giuliana; Mancardi, Daniele; Spaccamiglio, Angela; Racca, Silvia; Pagliaro, Pasquale

    2007-10-01

    To investigate whether nandrolone decanoate (ND)-pretreatment can modulate (1) beta-adrenoceptor expression and (2) myocardial contractility in response to beta-adrenoceptors stimulation with isoproterenol (ISO), in hearts of both normal and stressed rats. Rats were treated with 15 mg/(kgday) of Deca-Durabolin (ND, 1 ml i.m.) or with vehicle (oil) for 14 days. The day after the last injection, the dose-response to ISO (1 x 10(-8), 5 x 10(-8) and 10(-7)M), was studied in isolated rat hearts harvested from unstressed animals (unstressed+vehicle (control) or unstressed+ND) or from stressed animals (stressed+vehicle or stressed+ND): acute stress protocol consisted in restrain for 1h immediately before sacrifice. ND-pretreatment increased beta(2)-adrenoceptor expression. In baseline conditions all hearts had a similar left ventricular developed pressure (LVDP) and maximum rate of increase of LVDP (dP/dt(max)). In hearts of unstressed+vehicle or unstressed+ND, ISO caused a similar increase in LVDP (+90-100%) and dP/dt(max) (+120-150%). However, hearts of stressed+vehicle animals showed a marked depression of inotropic response to ISO (i.e. for ISO 1 x 10(-8),-55% in LVDP response versus unstressed). Yet, in hearts of stressed+ND-animals the effect of stress was reversed, showing the highest response to ISO (i.e. for ISO 1 x 10(-7), +30% LVDP response versus unstressed). The ND-induced beta(2)-adrenoceptor overexpression does not affect ISO-response in unstressed animals. However, acute stress induces a down-regulation of ISO-response, which is reversed by ND-pretreatment. Since the physiological post-stress down-regulation of adrenergic-response is absent after nandrolone treatment, the heart may be exposed to a sympathetic over-stimulation. This might represent a risk for cardiovascular incidents in anabolic steroid addicts under stressing conditions. PMID:17611100

  4. Slow to fast alterations in skeletal muscle fibers caused by clenbuterol, a beta(2)-receptor agonist

    NASA Technical Reports Server (NTRS)

    Zeman, Richard J.; Ludemann, Robert; Easton, Thomas G.; Etlinger, Joseph D.

    1988-01-01

    The effects of a beta(2)-receptor agonist, clenbuterol, and a beta(2) antagonist, butoxamine, on the skeletal muscle fibers of rats were investigated. It was found that chronic treatment of rats with clenbuterol caused hypertrophy of histochemically identified fast-twitch, but not slow-twitch, fibers within the soleus, while in the extensor digitorum longus the mean areas of both fiber types were increased; in both muscles, the ratio of the number of fast-twitch to slow-twitch fibers was increased. In contrast, a treatment with butoxamine caused a reduction of the fast-twitch fiber size in both muscles, and the ratio of the fast-twitch to slow-twitch fibers was decreased.

  5. β2-adrenergic agonists modulate TNF-α induced astrocytic inflammatory gene expression and brain inflammatory cell populations

    PubMed Central

    2014-01-01

    Background The NF-κB signaling pathway orchestrates many of the intricate aspects of neuroinflammation. Astrocytic β2-adrenergic receptors have emerged as potential regulators in central nervous system inflammation and are potential targets for pharmacological modulation. The aim of this study was to elucidate the crosstalk between astrocytic β2-adrenergic receptors and the TNF-α induced inflammatory gene program. Methods Proinflammatory conditions were generated by the administration of TNF-α. Genes that are susceptible to astrocytic crosstalk between β2-adrenergic receptors (stimulated by clenbuterol) and TNF-α were identified by qPCR-macroarray-based gene expression analysis in a human 1321 N1 astrocytoma cell line. Transcriptional patterns of the identified genes in vitro were validated by RT-PCR on the 1321 N1 cell line as well as on primary rat astrocytes. In vivo expression patterns were examined by intracerebroventricular administration of clenbuterol and/or TNF-α in rats. To examine the impact on the inflammatory cell content of the brain we performed extensive FACS analysis of rat brain immune cells after intracerebroventricular clenbuterol and/or TNF-α administration. Results Parallel transcriptional patterns in vivo and in vitro confirmed the relevance of astrocytic β2-adrenergic receptors as modulators of brain inflammatory responses. Importantly, we observed pronounced effects of β2-adrenergic receptor agonists and TNF-α on IL-6, CXCL2, CXCL3, VCAM1, and ICAM1 expression, suggesting a role in inflammatory brain cell homeostasis. Extensive FACS-analysis of inflammatory cell content in the brain demonstrated that clenbuterol/TNF-α co-administration skewed the T cell population towards a double negative phenotype and induced a shift in the myeloid brain cell population towards a neutrophilic predominance. Conclusions Our results show that astrocytic β2-adrenergic receptors are potent regulators of astrocytic TNF-α-activated genes in

  6. Modulation of β-Adrenergic Receptor Signaling in Heart Failure and Longevity: Targeting Adenylyl Cyclase Type 5

    PubMed Central

    Ho, David; Yan, Lin; Iwatsubo, Kousaku; Vatner, Dorothy E.; Vatner, Stephen F.

    2011-01-01

    Despite remarkable advances in therapy, heart failure remains a leading cause of morbidity and mortality. Although enhanced β-adrenergic receptor stimulation is part of normal physiologic adaptation to either the increase in physiologic demand or decrease in cardiac function, chronic β-adrenergic stimulation has been associated with increased mortality and morbidity in both animal models and humans. For example, overexpression of cardiac Gsα or β-adrenergic receptors in transgenic mice results in enhanced cardiac function in young animals, but with prolonged overstimulation of this pathway, cardiomyopathy develops in these mice as they age. Similarly, chronic sympathomimetic amine therapy increases morbidity and mortality in patients with heart failure. Conversely, the use of β-blockade has proven to be of benefit and is currently part of the standard of care for heart failure. It is conceivable that interrupting distal mechanisms in the β-adrenergic receptor-G protein-adenylyl cyclase pathway may also provide targets for future therapeutic modalities for heart failure. Interestingly, there are two major isoforms of adenylyl cyclase (AC) in the heart (type 5 and type 6), which may exert opposite effects on the heart, i.e., cardiac overexpression of AC6 appears to be protective, whereas disruption of type 5 AC prolongs longevity and protects against cardiac stress. The goal of this review is to summarize the paradigm shift in the treatment of heart failure over the past 50 years from administering sympathomimetic amine agonists to administering β-adrenergic receptor antagonists, and to explore the basis for a novel therapy of inhibiting type 5 AC. PMID:20658186

  7. Soluble histocompatibility class I antigens and beta 2-microglobulin in pregnant females and cord blood samples.

    PubMed

    Inostroza, J; Ferrada, J; Navarrete, C; Sorensen, R U

    1997-04-15

    Pregnancy can be considered a successful transplantation of allogeneic paternal tissue to the mother. Soluble HLA class I serum levels have been found to increase during solid organ rejection episodes and during graft-versus-host disease after bone marrow transplantation. We wished to determine whether significant changes in sHLA class I and beta 2-microglobulin light chain levels occurred during pregnancy, because these may reflect adaptive changes permitting the acceptance of the fetal graft. Serum samples were obtained from women at different stages of pregnancy and in the postpartum period. Cord blood samples and serum samples from nonpregnant female and male controls living in the same geographic area in Southern Chile were also studied. The levels of sHLA class I heterodimers were determined by an ELISA sandwich technique; beta 2-microglobulin levels were measured by MEIA IMX-Abbott. There was a significant elevation of sHLA class I levels in the first 2 trimesters of pregnancy, followed by a significant drop below normal levels at the end of pregnancy, with normalization in the post-partum period. beta 2-microglobulin levels did not change significantly during pregnancy and did not correlate with sHLA class I levels. In cord blood samples, sHLA class I levels were lower and beta 2-microglobulin levels higher than those of adult controls and of mothers at the time of delivery. The variations in sHLA class I levels during pregnancy may reflect or contribute to immunoregulatory events related to the acceptance of the fetal graft. PMID:9154459

  8. Voluntary exercise-induced changes in beta2-adrenoceptor signalling in rat ventricular myocytes.

    PubMed

    Stones, Rachel; Natali, Antonio; Billeter, Rudolf; Harrison, Simon; White, Ed

    2008-09-01

    Regular exercise is beneficial to cardiovascular health. We tested whether mild voluntary exercise training modifies key myocardial parameters [ventricular mass, intracellular calcium ([Ca2+]i) handling and the response to beta-adrenoceptor (beta-AR) stimulation] in a manner distinct from that reported for beneficial, intensive training and pathological hypertrophic stimuli. Female rats performed voluntary wheel-running exercise for 6-7 weeks. The mRNA expression of target proteins was measured in left ventricular tissue using real-time reverse transcriptase-polymerase chain reaction. Simultaneous measurement of cell shortening and [Ca2+]i transients were made in single left ventricular myocytes and the inotropic response to beta1- and beta2-AR stimulation was measured. Voluntary exercise training resulted in cardiac hypertrophy, the heart weight to body weight ratio being significantly greater in trained compared with sedentary animals. However, voluntary exercise caused no significant alteration in the size or time course of myocyte shortening and [Ca2+]i transients or in the mRNA levels of key proteins that regulate Ca2+ handling. The positive inotropic response to beta1-AR stimulation and the level of beta1-AR mRNA were unaltered by voluntary exercise but both mRNA levels and inotropic response to beta2-AR stimulation were significantly reduced in trained animals. The beta2-AR inotropic response was restored by exposure to pertussis toxin. We propose that in contrast to pathological stimuli and to beneficial, intense exercise training, modulation of Ca2+ handling is not a major adaptive mechanism in the response to mild voluntary exercise. In addition, and in a reversal of the situation seen in heart failure, voluntary exercise training maintains the beta1-AR response but reduces the beta2-AR response. Therefore, although voluntary exercise induces cardiac hypertrophy, there are distinct differences between its effects on key myocardial regulatory mechanisms

  9. Verification of MCNP5-1.60 and MCNP6-Beta-2 for Criticality Safety Applications

    SciTech Connect

    Brown, Forrest B.; Kiedrowski, Brian C.; Bull, Jeffrey S.

    2012-05-01

    To verify that both MCNP5-1.60 and MCNP6-Beta-2 are performing correctly for criticality safety applications, several suites of verification/validation benchmark problems were run in early 2012. Results from these benchmark suites were compared with results from previously verified versions of MCNP5. The goals of this verification testing were: (1) Verify that MCNP5-1.60 works correctly for nuclear criticality safety applications, producing the same results as for the previous verification performed in 2010; (2) Determine the sensitivity to computer roundoff using different Fortran-90 compilers for building MCNP5 and MCNP6, to support moving to current versions of the compilers; and (3) Verify that MCNP6-Beta-2 works correctly for nuclear criticality safety applications, producing the same results as for MCNP5-1.60. This provides support for eventual migration of users and applications to MCNP6. The current production version of MCNP5 included in the RSICC release package is MCNP5-1.60. This version was first distributed by RSICC in October 2010. While there were subsequent RSICC distributions of the MCNP package in July 2011 and February 2012, no changes were made to MCNP5-1.60. The RSICC release package in February 2012 included both MCNP5-1.60 and the current beta version of MCNP6, MCNP6-Beta-2. MCNP6 is the merger of MCNP5 and MCNPX capabilities. The current release of MCNP6 available from RSICC as of February 2012 is MCNP6-Beta-2. This version includes all of the features for criticality safety calculations that are available in MCNP5-1.60, and many new features largely unrelated to nuclear criticality safety calculations. This release is a 'beta' release to allow intermediate and advanced users to begin testing the merged code in their field of expertise. It should not be used for production calculations.

  10. The expression of Clostridium perfringens consensus beta2 toxin is associated with bovine enterotoxaemia syndrome.

    PubMed

    Lebrun, M; Filée, P; Mousset, B; Desmecht, D; Galleni, M; Mainil, J G; Linden, A

    2007-02-25

    Clostridium perfringens has been implicated in a broad array of enteric infections including the fatal haemorrhagic enteritis/enterotoxaemia syndrome in cattle. The beta2 toxin (CPB2), encoded by cpb2, is suspected to be implicated in this syndrome. However, among C. perfringens isolates from cattle suspected of clostridial disease, an atypical allele was recently found to predominate at the cpb2 locus and atypical corresponding CPB2 proteins were shown to be poorly expressed, thus arguing against a biologically significant role of the beta2 toxin in clostridial diseases in cattle. This study compared genotype and phenotype of the beta2 toxin between C. perfringens isolates from a group of healthy calves (n=14, 87 isolates) and from a group of enterotoxaemic calves (n=8, 41 isolates). PCR results revealed the exclusive presence of the typical "consensus"cpb2 in the enterotoxaemic group. Western blot analysis demonstrated that the typical variant of CPB2 was often expressed in isolates from enterotoxaemic calves (43.9%) and infrequently in isolates from healthy cattle (6.9%). These data suggest that the typical variant of the CPB2 toxin may play a role in the pathogenesis of cattle enterotoxaemia. PMID:17126502

  11. The tryptophan synthase alpha 2 beta 2 complex: a comparison of the reactivity of amino groups in the alpha and beta 2 subunits and in the complex by differential labeling studies

    SciTech Connect

    Miles, E.W.; Fairwell, T.

    1984-05-01

    The interaction of the alpha and beta 2 subunits of tryptophan synthase of Escherichia coli to form an alpha 2 beta 2 complex has been probed by differential labeling studies. In the first step the separate alpha or beta 2 subunit or the alpha 2 beta 2 complex was labeled by reductive methylation with trace amounts of (/sup 3/H)HCHO in the presence of NaCNBH/sub 3/. In the second step the /sup 3/H-labeled preparation was fully labeled under denaturing conditions with (/sup 14/C)HCHO and NaCNBH/sub 3/. Peptides containing labeled monomethyl or dimethyl amino groups were isolated after thermolytic digestion or after cyanogen bromide treatment. The /sup 3/H//sup 14/C ratio of each peptide is a measure of the relative reactivity of the amino group or groups in each peptide. The most reactive amino group in the alpha subunit, lysine-109, is strongly shielded from modification in the alpha 2 beta 2 complex. The most reactive amino group in the beta 2 subunit, the amino-terminal threonine, is not shielded from modification in the alpha 2 beta 2 complex.

  12. Adrenal medullary regulation of rat renal cortical adrenergic receptors

    SciTech Connect

    Sundaresan, P.R.; Guarnaccia, M.M.; Izzo, J.L. Jr. )

    1987-11-01

    The role of the adrenal medulla in the regulation of renal cortical adrenergic receptors was investigated in renal cortical particular fractions from control rats and rats 6 wk after adrenal demedullation. The specific binding of ({sup 3}H)prazosin, ({sup 3}H)rauwolscine, and ({sup 125}I)iodocyanopindolol were used to quantitate {alpha}{sub 1}-, {alpha}{sub 2}-, and {beta}-adrenergic receptors, respectively. Adrenal demedullation increased the concentration of all three groups of renal adrenergic receptors; maximal number of binding sites (B{sub max}, per milligram membrane protein) for {alpha}{sub 1}-, and {alpha}{sub 2}-, and {beta}-adrenergic receptors were increased by 22, 18.5, and 25%, respectively. No differences were found in the equilibrium dissociation constants (K{sub D}) for any of the radioligands. Plasma corticosterone and plasma and renal norepinephrine levels were unchanged, whereas plasma epinephrine was decreased 72% by adrenal demedullation, renal cortical epinephrine was not detectable in control or demedullated animals. The results suggest that, in the physiological state, the adrenal medulla modulates the number of renal cortical adrenergic receptors, presumably through the actions of a circulating factor such as epinephrine.

  13. Adrenergic Metabolic and Hemodynamic Effects of Octopamine in the Liver

    PubMed Central

    de Oliveira, Andrea Luiza; de Paula, Mariana Nascimento; Comar, Jurandir Fernando; Vilela, Vanessa Rodrigues; Peralta, Rosane Marina; Bracht, Adelar

    2013-01-01

    The fruit extracts of Citrus aurantium (bitter orange) are traditionally used as weight-loss products and as appetite suppressants. A component of these extracts is octopamine, which is an adrenergic agent. Weight-loss and adrenergic actions are always related to metabolic changes and this work was designed to investigate a possible action of octopamine on liver metabolism. The isolated perfused rat liver was used to measure catabolic and anabolic pathways and hemodynamics. Octopamine increased glycogenolysis, glycolysis, oxygen uptake, gluconeogenesis and the portal perfusion pressure. Octopamine also accelerated the oxidation of exogenous fatty acids (octanoate and oleate), as revealed by the increase in 14CO2 production derived from 14C labeled precursors. The changes in glycogenolysis, oxygen uptake and perfusion pressure were almost completely abolished by α1-adrenergic antagonists. The same changes were partly sensitive to the β-adrenergic antagonist propranolol. It can be concluded that octopamine accelerates both catabolic and anabolic processes in the liver via adrenergic stimulation. Acceleration of oxygen uptake under substrate-free perfusion conditions also means acceleration of the oxidation of endogenous fatty acids, which are derived from lipolysis. All these effects are compatible with an overall stimulating effect of octopamine on metabolism, which is compatible with its reported weight-loss effects in experimental animals. PMID:24196353

  14. Adrenergic metabolic and hemodynamic effects of octopamine in the liver.

    PubMed

    de Oliveira, Andrea Luiza; de Paula, Mariana Nascimento; Comar, Jurandir Fernando; Vilela, Vanessa Rodrigues; Peralta, Rosane Marina; Bracht, Adelar

    2013-01-01

    The fruit extracts of Citrus aurantium (bitter orange) are traditionally used as weight-loss products and as appetite suppressants. A component of these extracts is octopamine, which is an adrenergic agent. Weight-loss and adrenergic actions are always related to metabolic changes and this work was designed to investigate a possible action of octopamine on liver metabolism. The isolated perfused rat liver was used to measure catabolic and anabolic pathways and hemodynamics. Octopamine increased glycogenolysis, glycolysis, oxygen uptake, gluconeogenesis and the portal perfusion pressure. Octopamine also accelerated the oxidation of exogenous fatty acids (octanoate and oleate), as revealed by the increase in ¹⁴CO₂ production derived from ¹⁴C labeled precursors. The changes in glycogenolysis, oxygen uptake and perfusion pressure were almost completely abolished by α₁-adrenergic antagonists. The same changes were partly sensitive to the β-adrenergic antagonist propranolol. It can be concluded that octopamine accelerates both catabolic and anabolic processes in the liver via adrenergic stimulation. Acceleration of oxygen uptake under substrate-free perfusion conditions also means acceleration of the oxidation of endogenous fatty acids, which are derived from lipolysis. All these effects are compatible with an overall stimulating effect of octopamine on metabolism, which is compatible with its reported weight-loss effects in experimental animals. PMID:24196353

  15. Bacterial induction of autoantibodies to beta2-glycoprotein-I accounts for the infectious etiology of antiphospholipid syndrome.

    PubMed

    Blank, Miri; Krause, Ilan; Fridkin, Mati; Keller, Nathan; Kopolovic, Juri; Goldberg, Iris; Tobar, Ana; Shoenfeld, Yehuda

    2002-03-01

    The antiphospholipid syndrome (APS) is characterized by the presence of pathogenic autoantibodies against beta2-glycoprotein-I (beta2GPI). The factors causing production of anti-beta2GPI remain unidentified, but an association with infectious agents has been reported. Recently, we identified a hexapeptide (TLRVYK) that is recognized specifically by a pathogenic anti-beta2GPI mAb. In the present study we evaluated the APS-related pathogenic potential of microbial pathogens carrying sequences related to this hexapeptide. Mice immunized with a panel of microbial preparations were studied for the development of anti-beta2GPI autoantibodies. IgG specific to the TLRVYK peptide were affinity purified from the immunized mice and passively infused intravenously into naive mice at day 0 of pregnancy. APS parameters were evaluated in the infused mice on day 15 of pregnancy. Following immunization, high titers of antipeptide [TLRVYK] anti-beta2GPI Ab's were observed in mice immunized with Haemophilus influenzae, Neisseria gonorrhoeae, or tetanus toxoid. The specificity of binding to the corresponding target molecules was confirmed by competition and immunoblot assays. Naive mice infused with the affinity-purified antipeptide Ab's had significant thrombocytopenia, prolonged activated partial thromboplastin time and elevated percentage of fetal loss, similar to a control group of mice immunized with a pathogenic anti-beta2GPI mAb. Our study establishes a mechanism of molecular mimicry in experimental APS, demonstrating that bacterial peptides homologous with beta2GPI induce pathogenic anti-beta2GPI Ab's along with APS manifestations. PMID:11901188

  16. β-Adrenergic Receptor Signaling in Prostate Cancer

    PubMed Central

    Braadland, Peder Rustøen; Ramberg, Håkon; Grytli, Helene Hartvedt; Taskén, Kristin Austlid

    2015-01-01

    Enhanced sympathetic signaling, often associated with obesity and chronic stress, is increasingly acknowledged as a contributor to cancer aggressiveness. In prostate cancer, intact sympathetic nerves are critical for tumor formation, and sympathectomy induces apoptosis and blocks tumor growth. Perineural invasion, involving enrichment of intra-prostatic nerves, is frequently observed in prostate cancer and is associated with poor prognosis. β2-adrenergic receptor (ADRB2), the most abundant receptor for sympathetic signals in prostate luminal cells, has been shown to regulate trans-differentiation of cancer cells to neuroendocrine-like cells and to affect apoptosis, angiogenesis, epithelial–mesenchymal transition, migration, and metastasis. Epidemiologic studies have shown that use of β-blockers, inhibiting β-adrenergic receptor activity, is associated with reduced prostate cancer-specific mortality. In this review, we aim to present an overview on how β-adrenergic receptor and its downstream signaling cascade influence the development of aggressive prostate cancer, primarily through regulating neuroendocrine differentiation. PMID:25629002

  17. Elements toward novel therapeutic targeting of the adrenergic system.

    PubMed

    Ghanemi, Abdelaziz; Hu, Xintian

    2015-02-01

    Adrenergic receptors belong to the family of the G protein coupled receptors that represent important targets in the modern pharmacotherapies. Studies on different physiological and pathophysiological properties of the adrenergic system have led to novel evidences and theories that suggest novel possible targeting of such system in a variety of pathologies and disorders, even beyond the classical known therapeutic possibilities. Herein, those advances have been illustrated with selected concepts and different examples. Furthermore, we illustrated the applications and the therapeutic implications that such findings and advances might have in the contexts of experimental pharmacology, therapeutics and clinic. We hope that the content of this work will guide researches devoted to the adrenergic aspects that combine neurosciences with pharmacology. PMID:25481798

  18. Primate gastric circulation: effects of catecholamines and adrenergic blockade.

    PubMed

    Zinner, M J; Kerr, J C; Reynolds, D G

    1976-02-01

    The effects of intra-arterial injections and infusions of epinephrine, norepinephrine, and isoproterenol on gastric blood flow were studied in anesthetized baboons. Blood flow was measured electromagnetically before and after adrenergic blockade. The results for injected epinephrine and norepinephrine indicate these agents to be pure vasoconstrictors in the primate gastric circulation, and this response is attenuated by alpha-adrenergic blockade with phenoxybenzamine. Isoproterenol is a pure vasodilator, and its response is attenuated following beta-adrenergic blockade with propranolol. Intra-arterial infusions of epinephrine and norepinephrine (.05 mug kg-1 min-1) resulted in sustained vasoconstriction with no evidence of autoregulatory escape and no postinfusion "over-shoot." This study suggests that epinephrine and norepinephrine might provide alternatives to vasopressin as a vasoconstrictor for the control of upper gastrointestinal bleeding. PMID:1259012

  19. Autoradiographic quantification of adrenergic receptors in rat kidney

    SciTech Connect

    Calianos, T. II; Muntz, K.H. )

    1990-07-01

    The adrenergic nervous system is active in kidney function, and the kidney has large numbers of adrenergic receptor subtypes. Because of the cellular complexity of the kidney, it is difficult to obtain direct assessments of adrenergic receptor binding characteristics over specific tissue compartments. Qualitative autoradiography allows the localization of adrenergic receptors over tissue types in the kidney, but quantitative autoradiography allows direct comparison of adrenergic receptor number over different cellular compartments. The purpose of this study was to obtain direct assessments of alpha 1, alpha 2, and beta adrenergic receptor numbers over different tissue compartments of the kidney using quantitative autoradiography. Sections of Sprague-Dawley rat kidney were incubated in several concentrations of 3H-dihydroalprenolol to label beta receptors, 3H-prazosin to label alpha 1 receptors and 3H-rauwolscine to label the alpha 2 receptors. Sections of rat heart incubated in 3H-dihydroalprenolol were included as standards. The sections were then prepared for receptor autoradiography. After processing, the grains were then quantified on an image analysis system, and binding curves constructed from the specific binding. In some animals, the proximal tubules were stained to localize the proximal convoluted tubules. Significant Scatchard analyses were obtained in the glomeruli with dihydroalprenolol (5.18 X 10(9) receptors/mm3) and with rauwolscine (2.48 X 10(9) receptors/mm3). Significant Scatchard analyses were obtained in the cortex with rauwolscine (9.47 X 10(9) receptors/mm3) and with prazosin (3.9 X 10(9)). In addition, specific binding was seen with rauwolscine and prazosin to the kidney arterioles.

  20. Mechanisms of alpha 1-adrenergic vascular desensitization in conscious dogs

    NASA Technical Reports Server (NTRS)

    Kiuchi, K.; Vatner, D. E.; Uemura, N.; Bigaud, M.; Hasebe, N.; Hempel, D. M.; Graham, R. M.; Vatner, S. F.

    1992-01-01

    To investigate the mechanisms of alpha 1-adrenergic vascular desensitization, osmotic minipumps containing either saline (n = 9) or amidephrine mesylate (AMD) (n = 9), a selective alpha 1-adrenergic receptor agonist, were implanted subcutaneously in dogs with chronically implanted arterial and right atrial pressure catheters and aortic flow probes. After chronic alpha 1-adrenergic receptor stimulation, significant physiological desensitization to acute AMD challenges was observed, i.e., pressor and vasoconstrictor responses to the alpha 1-adrenergic agonist were significantly depressed (p < 0.01) compared with responses in the same dogs studied in the conscious state before pump implantation. However, physiological desensitization to acute challenges of the neurotransmitter norepinephrine (NE) (0.1 micrograms/kg per minute) in the presence of beta-adrenergic receptor blockade was not observed for either mean arterial pressure (MAP) (30 +/- 7 versus 28 +/- 5 mm Hg) or total peripheral resistance (TPR) (29.8 +/- 4.9 versus 28.9 +/- 7.3 mm Hg/l per minute). In the presence of beta-adrenergic receptor plus ganglionic blockade after AMD pump implantation, physiological desensitization to NE was unmasked since the control responses to NE (0.1 micrograms/kg per minute) before the AMD pumps were now greater (p < 0.01) than after chronic AMD administration for both MAP (66 +/- 5 versus 32 +/- 2 mm Hg) and TPR (42.6 +/- 10.3 versus 23.9 +/- 4.4 mm Hg/l per minute). In the presence of beta-adrenergic receptor, ganglionic, plus NE-uptake blockade after AMD pump implantation, desensitization was even more apparent, since NE (0.1 micrograms/kg per minute) induced even greater differences in MAP (33 +/- 5 versus 109 +/- 6 mm Hg) and TPR (28.1 +/- 1.8 versus 111.8 +/- 14.7 mm Hg/l per minute). The maximal force of contraction induced by NE in the presence or absence of endothelium was significantly decreased (p < 0.05) in vitro in mesenteric artery rings from AMD pump dogs

  1. Adrenergic receptors on cerebral microvessels in control and Parkinsonian subjects

    SciTech Connect

    Cash, R.; Lasbennes, F.; Sercombe, R.; Seylaz, J.; Agid, Y.

    1985-08-12

    The binding of adrenergic ligands (/sup 3/H-prazosin, /sup 3/H-clonidine, /sup 3/H-dihydroalprenolol) was studied on a preparation of cerebral microvessels in the prefrontal cortex and putamen of control and Parkinsonian subjects. The adrenergic receptor density in microvessels of control patients was less than 0.5% and 3.3% respectively of the total binding. A significant decrease in the number of alpha-1 binding sites was observed on microvessels in the putamen of patients with Parkinson's disease. 22 references, 2 tables.

  2. Mechanisms of postspaceflight orthostatic hypotension: low alpha1-adrenergic receptor responses before flight and central autonomic dysregulation postflight.

    PubMed

    Meck, Janice V; Waters, Wendy W; Ziegler, Michael G; deBlock, Heidi F; Mills, Paul J; Robertson, David; Huang, Paul L

    2004-04-01

    Although all astronauts experience symptoms of orthostatic intolerance after short-duration spaceflight, only approximately 20% actually experience presyncope during upright posture on landing day. The presyncopal group is characterized by low vascular resistance before and after flight and low norepinephrine release during orthostatic stress on landing day. Our purpose was to determine the mechanisms of the differences between presyncopal and nonpresyncopal groups. We studied 23 astronauts 10 days before launch, on landing day, and 3 days after landing. We measured pressor responses to phenylephrine injections; norepinephrine release with tyramine injections; plasma volumes; resting plasma levels of chromogranin A (a marker of sympathetic nerve terminal release), endothelin, dihydroxyphenylglycol (DHPG, an intracellular metabolite of norepinephrine); and lymphocyte beta(2)-adrenergic receptors. We then measured hemodynamic and neurohumoral responses to upright tilt. Astronauts were separated into two groups according to their ability to complete 10 min of upright tilt on landing day. Compared with astronauts who were not presyncopal on landing day, presyncopal astronauts had 1). significantly smaller pressor responses to phenylephrine both before and after flight; 2). significantly smaller baseline norepinephrine, but significantly greater DHPG levels, on landing day; 3). significantly greater norepinephrine release with tyramine on landing day; and 4). significantly smaller norepinephrine release, but significantly greater epinephrine and arginine vasopressin release, with upright tilt on landing day. These data suggest that the etiology of orthostatic hypotension and presyncope after spaceflight includes low alpha(1)-adrenergic receptor responsiveness before flight and a remodeling of the central nervous system during spaceflight such that sympathetic responses to baroreceptor input become impaired. PMID:14670816

  3. Mechanisms of postspaceflight orthostatic hypotension: low alpha1-adrenergic receptor responses before flight and central autonomic dysregulation postflight

    NASA Technical Reports Server (NTRS)

    Meck, Janice V.; Waters, Wendy W.; Ziegler, Michael G.; deBlock, Heidi F.; Mills, Paul J.; Robertson, David; Huang, Paul L.

    2004-01-01

    Although all astronauts experience symptoms of orthostatic intolerance after short-duration spaceflight, only approximately 20% actually experience presyncope during upright posture on landing day. The presyncopal group is characterized by low vascular resistance before and after flight and low norepinephrine release during orthostatic stress on landing day. Our purpose was to determine the mechanisms of the differences between presyncopal and nonpresyncopal groups. We studied 23 astronauts 10 days before launch, on landing day, and 3 days after landing. We measured pressor responses to phenylephrine injections; norepinephrine release with tyramine injections; plasma volumes; resting plasma levels of chromogranin A (a marker of sympathetic nerve terminal release), endothelin, dihydroxyphenylglycol (DHPG, an intracellular metabolite of norepinephrine); and lymphocyte beta(2)-adrenergic receptors. We then measured hemodynamic and neurohumoral responses to upright tilt. Astronauts were separated into two groups according to their ability to complete 10 min of upright tilt on landing day. Compared with astronauts who were not presyncopal on landing day, presyncopal astronauts had 1). significantly smaller pressor responses to phenylephrine both before and after flight; 2). significantly smaller baseline norepinephrine, but significantly greater DHPG levels, on landing day; 3). significantly greater norepinephrine release with tyramine on landing day; and 4). significantly smaller norepinephrine release, but significantly greater epinephrine and arginine vasopressin release, with upright tilt on landing day. These data suggest that the etiology of orthostatic hypotension and presyncope after spaceflight includes low alpha(1)-adrenergic receptor responsiveness before flight and a remodeling of the central nervous system during spaceflight such that sympathetic responses to baroreceptor input become impaired.

  4. In vitro beta 2-microglobulin (beta 2m) secretion by normal and leukaemic B-cells: effects of recombinant cytokines and evidence for a differential response to the combined stimulus of phorbol ester and calcium ionophore.

    PubMed Central

    Jones, R. A.; Drexler, H. G.; Gignac, S. M.; Child, J. A.; Scott, C. S.

    1990-01-01

    Due to the increasing therapeutic use of immunoregulatory agents and the potential effects on cellular function, we examined the modulation of in vitro beta 2-microglobulin (beta 2m) production rates by 'normal' tonsil and leukaemic B-cells in response to a number of these agents. Tonsil B-cells responded to phorbol ester (TPA) by an increased beta 2m production rate, which was further enhanced by the combined stimuli of TPA plus the calcium ionophore A23187. In marked contrast, however, lymphocytes from a majority (8/11) of B-cell malignancies showed a suppression of the TPA-induced beta 2m production rate in response to the combined TPA/A23187 stimulus. These different responses of 'normal' and malignant B-cells were not apparent when IgM production rates were examined. The recombinant cytokines IL-1, IL-2, IFN-alpha, IFN-gamma and TNF also enhanced beta 2m production rates of both normal and leukaemic B-cells, but to a considerably lesser extent than did TPA. Bryostatin-1 increased beta 2m production to a level intermediate between that obtained by TPA and the cytokines. It is suggested that beta 2m production rates may correspond to the degree of B-cell differentiation, and/or to the degree of cellular 'activation'. The results further indicate that the in vitro measurement of beta 2m production provides a different index of the cellular response than that obtained by the conventional measurement of IgM production. PMID:2110813

  5. Ligand-dependent occupancy of the retinoic acid receptor beta 2 promoter in vivo.

    PubMed Central

    Dey, A; Minucci, S; Ozato, K

    1994-01-01

    Retinoic acid (RA) activates transcription of the RA receptor beta 2 (RAR beta 2) gene in embryonal carcinoma (EC) cells. This activation involves binding of the RAR/retinoid X receptor (RAR/RXR) heterodimer to the RA-responsive element (beta RARE). Dimethyl sulfate-based genomic footprinting was performed to examine occupancy of this promoter in P19 EC cells. No footprint was detected at the beta RARE prior to RA treatment, but a footprint was detected within the first hour of RA treatment. Concomitantly, other elements in the promoter, the cyclic AMP-responsive element and tetradecanoyl phorbol acetate-like-responsive element became footprinted. Footprints at these elements were induced by RA without requiring new protein synthesis and remained for the entire duration of RA treatment but rapidly reversed upon withdrawal of RA. A delayed protection observed at the initiator site was also reversed upon RA withdrawal. The RA-inducible footprint was not due to induction of factors that bind to these element, since in vitro assays showed that these factors are present in P19 cell extracts before RA treatment. Significantly, no RA-induced footprint was observed at any of these elements in P19 cells expressing a dominant negative RXR beta, in which RXR heterodimers are unable to bind to the beta RARE. Results indicate that binding of a liganded heterodimer receptor to the beta RARE is the initial event that allows other elements to gain access to the factors. In accordance, reporter analyses showed that a mutation in the beta RARE, but not those in other elements, abrogates RA activation of the promoter. It is likely that the RAR beta 2 promoter opens in a hierarchically ordered manner, signalled by the occupancy of liganded heterodimers. Images PMID:7969156

  6. Seeding-dependent maturation of beta2-microglobulin amyloid fibrils at neutral pH.

    PubMed

    Kihara, Miho; Chatani, Eri; Sakai, Miyo; Hasegawa, Kazuhiro; Naiki, Hironobu; Goto, Yuji

    2005-03-25

    Beta2-microglobulin (beta2-m) is a major component of amyloid fibrils deposited in patients with dialysis-related amyloidosis. Recent studies have focused on the mechanism by which amyloid fibrils are formed under physiological conditions, which had been difficult to reproduce quantitatively. Yamamoto et al. (Yamamoto, S., Hasegawa, K., Yamaguchi, I., Tsutsumi, S., Kardos, J., Goto, Y., Gejyo, F. & Naiki, H. (2004) Biochemistry 43, 11075-11082) showed that a combination of seed fibrils prepared under acidic conditions and a low concentration of sodium dodecyl sulfate below its critical micelle concentration enabled extensive fibril formation at pH 7.0. Here, we found that repeated self-seeding at pH 7.0 with fibrils formed at the same pH causes a marked acceleration of growth, indicating the maturation of fibrils. The observed maturation can be simulated by assuming the existence of two types of fibrils with different growth rates. Importantly, some mutations of beta2-m or the addition of a low concentration of urea, both destabilizing the native conformation, were not enough to extend the fibrils at pH 7.0, and a low concentration of sodium dodecyl sulfate (i.e. 0.5 mM) was essential. Thus, even though the first stage fibrils in patients are unstable and require stabilizing factors to remain at neutral pH, they can adapt to a neutral pH with repeated self-seeding, implying a mechanism of development of amyloid deposition after a long latent period in patients. PMID:15659393

  7. Chronic exposure to a beta 2-adrenoceptor agonist increases the airway response to methacholine.

    PubMed

    Witt-Enderby, P A; Yamamura, H I; Halonen, M; Palmer, J D; Bloom, J W

    1993-09-01

    Scheduled chronic administration of beta 2-adrenoceptor agonist bronchodilators in patients with asthma recently has been reported to be associated with a worsening of symptoms and an increase in bronchial responsiveness. We wanted to determine whether a 28-day in vivo exposure to albuterol (beta 2-adrenoceptor agonist) altered the response of rabbit airways to the cholinergic agonist methacholine. We found, using in vitro tissue bath techniques, that in mainstem bronchi from rabbits given a 28-day exposure to albuterol, maximum contraction to methacholine was increased in the albuterol-treated group (control group = 1.10 +/- 0.11 g vs. treated group = 1.50 +/- 0.13 g, P < 0.05). The potency (EC75) was also increased in the albuterol-treated group. The potency for the control group was 5.6 microM (95% confidence limit: 2.3-13 microM) and was 1.7 microM (95% confidence limit: 1.1-2.8 microM, P < 0.05) for the albuterol-treated group. In a subgroup of animals, maximum contraction to KCl, a receptor-independent contractile stimulus, was not significantly different between the groups (control group = 0.79 +/- 0.23 g vs. treated group = 0.82 +/- 0.20 g). The potency (EC50) for KCl-induced contractions was also not significantly different between the groups: control = 12 mM (95% confidence limit: 3.3-44 mM) vs. treated 19 mM (95% confidence limit: 18-20 mM). These data demonstrate that chronic in vivo exposure to a beta 2-adrenoceptor agonist can alter the in vitro tissue bath response of airway smooth muscle to methacholine.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7901034

  8. Antigen-specific immune responses in cattle with inherited beta2-integrin deficiency.

    PubMed

    Müller, K E; Hoek, A; Rutten, V P; Bernadina, W E; Wentink, G H

    1997-08-01

    The significance of beta2-integrins for the generation of antigen-specific immune responses in vivo was studied employing the bovine model of beta2-integrin deficiency. To that end four cattle with bovine leukocyte adhesion deficiency (BLAD) and healthy age-matched controls were immunized with tetanus toxoid (TT) and rabies virus (RV) vaccines three times in monthly intervals. In addition, two animals with BLAD and three controls received a fourth vaccination 8 months after the start of the study. Proliferative responses of peripheral blood mononuclear cells (PBMC) to the antigens TT and RV as well as specific serum immunoglobulin G (IgG) titers were determined in intervals for up to 10 months after primary vaccination. Proliferative responses of PBMC to TT and RV were substantially lower in cattle with BLAD than in controls, although PBMC from cattle with BLAD were shown to have the capacity to proliferate in the response to the mitogen concanavalin A. Occurrence of antigen-specific IgG titers was delayed and they were considerably lower in cattle with BLAD compared to controls. Finally, treatment of TT- and RV-stimulated PBMC from an immunized control with different concentrations of the anti-CD18 monoclonal antibody R15.7 resulted in a dose-dependent inhibition of lymphocyte proliferation to almost 100%. The results of the present study show that beta2-integrin deficiency leads to delayedand severely impaired immune responsiveness in vivo. The observations that antibody production, although considerably delayed and impaired, does occur and that apparently class-switching takes place in BLAD indicate T-cell reactivity in vivo. PMID:9343338

  9. Paradoxical Lung Function Response to Beta2-agonists: Radiologic Correlates and Clinical Implications

    PubMed Central

    Bhatt, Surya P.; Wells, James M.; Kim, Victor; Criner, Gerard J.; Hersh, Craig P.; Hardin, Megan; Bailey, William C.; Nath, Hrudaya; il-Kim, Young; Foreman, Marilyn G.; Stinson, Douglas S.; Wilson, Carla G.; Rennard, Stephen I.; Silverman, Edwin K.; Make, Barry J.; Dransfield, Mark T.

    2014-01-01

    Background Bronchodilator response is seen in a significant proportion of patients with chronic obstructive pulmonary disease (COPD). However, there are also reports of a paradoxical response (PR) to beta2-agonists, resulting in bronchoconstriction. Asymptomatic bronchoconstriction is likely far more common but there has been no systematic study of this phenomenon.We assessed theprevalence of PR in current and former smokers with and without COPD, and its radiologic correlates and clinical implications. Methods Subjects from a large multicenter study (COPDGene) were categorized into two groups based on PR defined as at least a 12% and 200mLreduction in FEV1 and/or FVC after administration of a short-acting beta2-agonist (180ucg albuterol). Predictors of PR and associations with respiratory morbidity and computed tomographic measures of emphysema and airway disease were assessed. Findings 9986 subjects were included. PR was seen in 4.54% and the frequency was similar in those with COPD and smokers without airflow obstruction. Compared to Caucasians, PR was twice as common in African-Americans (6.9% vs. 3.4%;p <0.001). On multivariate analyses, African- American race (adjusted OR 1.89, 95%CI 1.50 to 2.39), lesspercent emphysema (OR 0.96, 95%CI 0.92 to 0.99) and increased wall-area% of segmental airways (OR 1.04,95%CI 1.01 to 1.08) were independently associated with PR.PR was independently associated with worse dyspnea, lower six-minute-walk distance, higher BODE index, and a greater frequency of exacerbations(increased by a factor of 1.35, 95%CI 1.003 to 1.81). Interpretation Paradoxical response to beta2-agonists is associated with respiratory morbidity and is more common in African Americans. PMID:25217076

  10. Purification and high-sensitivity membrane photoaffinity labeling of mammalian beta/sub 2/-adrenergic receptor

    SciTech Connect

    Drake, F.H. III

    1986-01-01

    The Beta/sub 2/-Adrenergic receptor (BAR) from guinea pig lung has been purified to near homogeneity. The purified BAR, detected by silver staining or by total radioiodination and autoradiography, migrates on SDS-PAGE as a broad band centered at 66 kilodaltons (kD). This band can be specifically labeled with the adrenergic photoaffinity ligand, /sup 125/I-azidobenzylpindolol. The purified BAR displays the same beta/sub 2/-subtype pharmacology and mobility on SDS-PAGE as the membrane-bound BAR. Microsequenator analysis of the purified BAR suggests that the amino terminus of the receptor is blocked. Several site-specific agents were used to fragment the purified BAR; some of the fragments may be useful for obtaining amino acid sequence of the BAR. Conditions also have developed for photoaffinity labeling the BAR in membranes of mammalian tissue culture cells (human astrocytoma, 1321N1) which contain very low levels of BAR. The BAR from these cells migrates as a broad band of about 66 kD on SDS-PAGE. Endoglycosidase F, which cleaves N-linked oligosaccharides, reduces the apparent molecular weight of the BAR from these cells to 45 kD. Recovery from agonist-induced down-regulation in post-confluent cultures of 1321N1 cells in the presence of tunicamycin (an inhibitor of N-linked glycosylation) results in the appearance of a 41 kD form of the BAR. Despite the apparent absence of N-linked oligosaccharides, this 41 kD form of the BAR retains adrenergic binding activity.

  11. β-Adrenergic-mediated vasodilation in young men and women: cyclooxygenase restrains nitric oxide synthase.

    PubMed

    Limberg, Jacqueline K; Johansson, Rebecca E; Peltonen, Garrett L; Harrell, John W; Kellawan, J Mikhail; Eldridge, Marlowe W; Sebranek, Joshua J; Schrage, William G

    2016-03-15

    We tested the hypothesis that women exhibit greater vasodilator responses to β-adrenoceptor stimulation compared with men. We further hypothesized women exhibit a greater contribution of nitric oxide synthase and cyclooxygenase to β-adrenergic-mediated vasodilation compared with men. Forearm blood flow (Doppler ultrasound) was measured in young men (n = 29, 26 ± 1 yr) and women (n = 33, 25 ± 1 yr) during intra-arterial infusion of isoproterenol (β-adrenergic agonist). In subset of subjects, isoproterenol responses were examined before and after local inhibition of nitric oxide synthase [N(G)-monomethyl-l-arginine (l-NMMA); 6 male/10 female] and/or cyclooxygenase (ketorolac; 5 male/5 female). Vascular conductance (blood flow ÷ mean arterial pressure) was calculated to assess vasodilation. Vascular conductance increased with isoproterenol infusion (P < 0.01), and this effect was not different between men and women (P = 0.41). l-NMMA infusion had no effect on isoproterenol-mediated dilation in men (P > 0.99) or women (P = 0.21). In contrast, ketorolac infusion markedly increased isoproterenol-mediated responses in both men (P < 0.01) and women (P = 0.04) and this rise was lost with subsequent l-NMMA infusion (men, P < 0.01; women, P < 0.05). β-Adrenergic vasodilation is not different between men and women and sex differences in the independent contribution of nitric oxide synthase and cyclooxygenase to β-mediated vasodilation are not present. However, these data are the first to demonstrate β-adrenoceptor activation of cyclooxygenase suppresses nitric oxide synthase signaling in human forearm microcirculation and may have important implications for neurovascular control in both health and disease. PMID:26747505

  12. β-adrenergic receptor agonist, Compound 49b, inhibits TLR4 signaling pathway in diabetic retina

    PubMed Central

    Berger, Elizabeth A.; Carion, Thomas W.; Jiang, Youde; Liu, Li; Chahine, Adam; Walker, Robert Jason; Steinle, Jena J.

    2016-01-01

    Diabetic retinopathy has recently become associated with complications similar to chronic inflammatory diseases. While it is clear that tumor necrosis factor- alpha (TNF-α) is increased in diabetes, the role of innate immunity is only recently being investigated. As such, we hypothesized that diabetes would increase toll-like receptor 4 (TLR4) signaling, which could be inhibited by a β-adrenergic receptor agonist (Compound 49b) previously shown to have anti-inflammatory actions. In order to investigate β-adrenergic receptor signaling and TLR4 in the diabetic retina, streptozotocin-injected diabetic mice, as well as human primary retinal endothelial cells (REC) and rat retinal Müller cells (rMC-1) exposed to high glucose (25mM), were treated with a novel β-adrenergic receptor agonist, Compound 49b (50nM), or PBS (control). TLR4 and its downstream signaling partners (MyD88, IRAK1, TRAF6, total and phosphorylated NF-κB) were examined. In addition, we assessed high mobility box group 1 (HMGB1) protein levels. Our data showed that diabetes or high glucose culture conditions significantly increased TLR4 and downstream signaling partners. Compound 49b was able to significantly reduce TLR4 and related molecules in the diabetic animal and retinal cells. HMGB1 was significantly increased in REC and Müller cells grown in high glucose, which was subsequently reduced with Compound 49b treatment. Our findings suggest that high glucose may increase HMGB1 levels that lead to increased TLR4 signaling. Compound 49b significantly inhibited this pathway providing a potential mechanism for its protective actions. PMID:26888251

  13. Quantification of ligand bias for clinically relevant β2-adrenergic receptor ligands: implications for drug taxonomy.

    PubMed

    van der Westhuizen, Emma T; Breton, Billy; Christopoulos, Arthur; Bouvier, Michel

    2014-03-01

    The concepts of functional selectivity and ligand bias are becoming increasingly appreciated in modern drug discovery programs, necessitating more informed approaches to compound classification and, ultimately, therapeutic candidate selection. Using the β2-adrenergic receptor as a model, we present a proof of concept study that assessed the bias of 19 β-adrenergic ligands, including many clinically used compounds, across four pathways [cAMP production, extracellular signal-regulated kinase 1/2 (ERK1/2) activation, calcium mobilization, and receptor endocytosis] in the same cell background (human embryonic kidney 293S cells). Efficacy-based clustering placed the ligands into five distinct groups with respect to signaling signatures. In some cases, apparent functional selectivity originated from off-target effects on other endogenously expressed adrenergic receptors, highlighting the importance of thoroughly assessing selectivity of the responses before concluding receptor-specific ligand-biased signaling. Eliminating the nonselective compounds did not change the clustering of the 10 remaining compounds. Some ligands exhibited large differences in potency for the different pathways, suggesting that the nature of the receptor-effector complexes influences the relative affinity of the compounds for specific receptor conformations. Calculation of relative effectiveness (within pathway) and bias factors (between pathways) for each of the compounds, using an operational model of agonism, revealed a global signaling signature for all of the compounds relative to isoproterenol. Most compounds were biased toward ERK1/2 activation over the other pathways, consistent with the notion that many proximal effectors converge on this pathway. Overall, we demonstrate a higher level of ligand texture than previously anticipated, opening perspectives for the establishment of pluridimensional correlations between signaling profiles, drug classification, therapeutic efficacy, and

  14. β-Adrenergic Responsive Induction of Insulin Resistance in Liver of Aging Rats.

    PubMed

    Muscogiuri, Giovanna; Kamat, Amrita; Balas, Bogdan; Giaccari, Andrea; Defronzo, Ralph A; Musi, Nicolas; Katz, Michael S

    2011-01-01

    INTRODUCTION. We previously demonstrated increases in β-adrenergic receptor (β-AR) density in rat liver, in association with increased β-AR-mediated stimulation of glucose output in rat hepatocytes, during senescent aging. We therefore hypothesized that pharmacologic β-adrenergic stimulation might induce insulin resistance and glucose output in liver of aging rats in vivo. METHODS. In this study, pancreatic clamps were performed on young adult (4-month-old) and senescent (24-month-old) Fischer 344 male rats by infusing somatostatin (3 μg/kg/min) at time 0 to inhibit insulin secretion, and then infusing insulin (1 mU/kg/min) to replace basal insulin concentrations. At time 0 rats also received either the β-AR agonist isoproterenol (100 ng/kg/min) or saline (control). After 120 min the insulin infusion rate was increased to 4 mU/kg/min for an additional 120 min. Tritiated glucose was infused throughout the study to measure glucose turnover rates. RESULTS AND CONCLUSION. The results of the pancreatic clamp studies demonstrated that under saline control conditions hepatic glucose production (HGP) was suppressed during hyperinsulinemia in both young and old rats, with a trend toward reduced insulin sensitivity in the older animals. Isoproterenol infusion impaired insulin-induced suppression of HGP in both age groups. The results suggest that β-AR stimulation by isoproterenol increases HGP and acutely induces hepatic insulin resistance in both young and old rats. A similar role for β-adrenergic-mediated hepatic insulin resistance in aging humans would suggest a novel therapeutic target for the treatment or prevention of glucose dysregulation and diabetes developing with advancing age. PMID:21438725

  15. Beta2 oscillations (23-30 Hz) in the mouse hippocampus during novel object recognition.

    PubMed

    França, Arthur S C; do Nascimento, George C; Lopes-dos-Santos, Vítor; Muratori, Larissa; Ribeiro, Sidarta; Lobão-Soares, Bruno; Tort, Adriano B L

    2014-12-01

    The oscillatory activity of hippocampal neuronal networks is believed to play a role in memory acquisition and consolidation. Particular focus has been given to characterising theta (4-12 Hz), gamma (40-100 Hz) and ripple (150-250 Hz) oscillations. Beyond these well-described network states, few studies have investigated hippocampal beta2 (23-30 Hz) activity in vivo and its link to behaviour. A previous sudy showed that the exploration of novel environments may lead to the appearance of beta2 oscillations in the mouse hippocampus. In the present study we characterised hippocampal beta2 oscillations in mice during an object recognition task. We found prominent bursts of beta2 oscillations in the beginning of novel exploration sessions (four new objects), which could be readily observed by spectral analysis and visual inspection of local field potentials. Beta2 modulated hippocampal but not neocortical neurons and its power decreased along the session. We also found increased beta2 power in the beginning of a second exploration session performed 24 h later in a slightly modified environment (two new, two familiar objects), but to a lesser extent than in the first session. However, the increase in beta2 power in the second exploration session became similar to the first session when we pharmacologically impaired object recognition in a new set of experiments performed 1 week later. Our results suggest that hippocampal beta2 activity is associated with a dynamic network state tuned for novelty detection and which may allow new learning to occur. PMID:25288307

  16. TGF{beta}2-mediated production of hyaluronan is important for the induction of epicardial cell differentiation and invasion

    SciTech Connect

    Craig, Evisabel A.; Austin, Anita F.; Vaillancourt, Richard R.; Barnett, Joey V.; Camenisch, Todd D.

    2010-12-10

    In the developing heart, the epicardium is a major source of progenitor cells that contribute to the formation of the coronary vessel system. These epicardial progenitors give rise to the different cellular components of the coronary vasculature by undergoing a number of morphological and physiological changes collectively known as epithelial to mesenchymal transformation (EMT). However, the specific signaling mechanisms that regulate epicardial EMT are yet to be delineated. In this study we investigated the role of TGF{beta}2 and hyaluronan (HA) during epicardial EMT and how signals from these two molecules are integrated during this important process. Here we show that TGF{beta}2 induces MEKK3 activation, which in turn promotes ERK1/2 and ERK5 phosphorylation. TGF{beta}2 also increases Has2 expression and subsequent HA production. Nevertheless, inhibition of MEKK3 kinase activity, silencing of ERK5 or pharmacological disruption of ERK1/2 activation significantly abrogates this response. Thus, TGF{beta}2 promotes Has2 expression and HA production through a MEKK3/ERK1/2/5-dependent cascade. Furthermore, TGF{beta}2 is able to induce epicardial cell invasion and differentiation but not proliferation. However, inhibition of MEKK3-dependent pathways, degradation of HA by hyaluronidases or blockade of CD44, significantly impairs the biological response to TGF{beta}2. Taken together, these findings demonstrate that TGF{beta}2 activation of MEKK3/ERK1/2/5 signaling modulates Has2 expression and HA production leading to the induction of EMT events. This is an important and novel mechanism showing how TGF{beta}2 and HA signals are integrated to regulate changes in epicardial cell behavior.

  17. Molecular characterization of an. alpha. sub 2B -adrenergic receptor

    SciTech Connect

    Harrison, J.K.; Dewan Zeng; D'Angelo, D.D.; Tucker, A.L.; Zhihong Lu; Barber, C.M.; Lynch, K.R. )

    1990-02-26

    {alpha}{sub 2}-Adrenergic receptors comprise a heterogeneous population based on pharmacologic and molecular evidence. The authors have isolated a cDNA clone (pRNG{alpha}2) encoding a previously undescribed third subtype of an {alpha}{sub 2}-adrenergic receptor from a rat kidney cDNA library. The library was screened with an oligonucleotide encoding a highly conserved region found in all biogenic amine receptors described to date. The deduced amino acid sequence displays many features of G-protein coupled receptors with exception of the absence of the consensus N-linked glycosylation site at the amino terminus. Membranes prepared from COS-1 cells transfected with pRNG{alpha}2 display high affinity and saturable binding to {sup 3}H-rauwolscine (K{sub d}=2 nM).Competition curve data analysis shows that pRNG{alpha}2 protein binds to a variety of adrenergic drugs with the following rank order of potency: yohimbine {ge} cholorpromazine > prazosin {ge} clonidine > norepinephrine {ge} oxymetazoline. pRNG{alpha}2 RNA accumulates in both adult rat kidney and rat neonatal lung (predominant species is 4.0 kb). They conclude that pRNG{alpha}2 likely represents a cDNA for the {alpha}{sub 2B}-adrenergic receptor.

  18. Adrenergic receptor subtypes in the cerebral circulation of newborn piglets

    SciTech Connect

    Wagerle, L.C.; Delivoria-Papadopoulos, M.

    1987-06-01

    The purpose of this study was to identify the ..cap alpha..-adrenergic receptor subtype mediating cerebral vasoconstriction during sympathetic nerve stimulation in the newborn piglet. The effect of ..cap alpha../sub 1/- and ..cap alpha../sub 2/-antagonists prazosin and yohimbine on the cerebrovascular response to unilateral electrical stimulation (15 Hz, 15 V) of the superior cervical sympathetic trunk was studied in 25 newborn piglets. Regional cerebral blood flow was measured with tracer microspheres. Sympathetic stimulation decreased blood flow to the ipsilateral cerebrum hippocampus, choroid plexus, and masseter muscle. ..cap alpha../sub 1/-Adrenergic receptor blockade with prazosin inhibited the sympathetic vasoconstriction in the cerebrum, hippocampus, and masseter muscle and abolished it in the choroid plexus. ..cap alpha../sub s/-Adrenergic receptor blockade with yohimbine had no effect. Following the higher dose of yohimbine, however, blood flow to all brain regions was increased by approximately two-fold, possibly due to enhanced cerebral metabolism. These data demonstrate that vascular ..cap alpha../sub 1/-adrenergic receptors mediate vasoconstriction to neuroadrenergic stimulation in cerebral resistance vessels in the newborn piglet.

  19. The adrenergic-neurone blocking action of some coumaran compounds

    PubMed Central

    Fielden, R.; Roe, A. M.; Willey, G. L.

    1964-01-01

    Ethyldimethyl(7-methylcoumaran-3-yl)ammonium iodide (SK&F 90,109) and its guanidine analogue [N-(7-methylcoumaran-3-yl)guanidine nitrate] (SK&F 90,238) abolish the effects of adrenergic nerve stimulation in cats, as do xylocholine and bretylium. SK&F 90,109 has slight sympathomimetic actions; these are less marked than in SK&F 90,238. Large doses of SK&F 90,109 have an action, dependent on local noradrenaline stores, that delays the appearance of adrenergic-neurone blockade in conscious cats. Responses to adrenaline are, in general, enhanced by each drug, but SK&F 90,238 transiently antagonizes tachycardia induced by adrenaline and isoprenaline. Both drugs inhibit the release of noradrenaline from the spleen during splenic nerve stimulation, but the release of catechol amines from the adrenal glands, in response to electrical or chemical stimulation, is unimpaired. In contrast to the prolonged adrenergic-neurone blocking action, any inhibition of the effects of cholinergic nerve stimulation is transient. Large intravenous doses produce neuromuscular blockade. The compounds have a slight central depressant action. In contrast to reserpine and guanethidine the noradrenaline content of rat hearts is not appreciably lowered 24 hr after a single dose of either drug. Unlike xylocholine they are not local anaesthetics. Related compounds also block the effects of adrenergic-nerve stimulation. The possible modes of action of these drugs are discussed. PMID:14256809

  20. The Alpha-1A Adrenergic Receptor in the Rabbit Heart

    PubMed Central

    Myagmar, Bat-Erdene; Swigart, Philip M.; Baker, Anthony J.; Simpson, Paul C.

    2016-01-01

    The alpha-1A-adrenergic receptor (AR) subtype is associated with cardioprotective signaling in the mouse and human heart. The rabbit is useful for cardiac disease modeling, but data on the alpha-1A in the rabbit heart are limited. Our objective was to test for expression and function of the alpha-1A in rabbit heart. By quantitative real-time reverse transcription PCR (qPCR) on mRNA from ventricular myocardium of adult male New Zealand White rabbits, the alpha-1B was 99% of total alpha-1-AR mRNA, with <1% alpha-1A and alpha-1D, whereas alpha-1A mRNA was over 50% of total in brain and liver. Saturation radioligand binding identified ~4 fmol total alpha-1-ARs per mg myocardial protein, with 17% alpha-1A by competition with the selective antagonist 5-methylurapidil. The alpha-1D was not detected by competition with BMY-7378, indicating that 83% of alpha-1-ARs were alpha-1B. In isolated left ventricle and right ventricle, the selective alpha-1A agonist A61603 stimulated a negative inotropic effect, versus a positive inotropic effect with the nonselective alpha-1-agonist phenylephrine and the beta-agonist isoproterenol. Blood pressure assay in conscious rabbits using an indwelling aortic telemeter showed that A61603 by bolus intravenous dosing increased mean arterial pressure by 20 mm Hg at 0.14 μg/kg, 10-fold lower than norepinephrine, and chronic A61603 infusion by iPRECIO programmable micro Infusion pump did not increase BP at 22 μg/kg/d. A myocardial slice model useful in human myocardium and an anthracycline cardiotoxicity model useful in mouse were both problematic in rabbit. We conclude that alpha-1A mRNA is very low in rabbit heart, but the receptor is present by binding and mediates a negative inotropic response. Expression and function of the alpha-1A in rabbit heart differ from mouse and human, but the vasopressor response is similar to mouse. PMID:27258143

  1. The Alpha-1A Adrenergic Receptor in the Rabbit Heart.

    PubMed

    Thomas, R Croft; Cowley, Patrick M; Singh, Abhishek; Myagmar, Bat-Erdene; Swigart, Philip M; Baker, Anthony J; Simpson, Paul C

    2016-01-01

    The alpha-1A-adrenergic receptor (AR) subtype is associated with cardioprotective signaling in the mouse and human heart. The rabbit is useful for cardiac disease modeling, but data on the alpha-1A in the rabbit heart are limited. Our objective was to test for expression and function of the alpha-1A in rabbit heart. By quantitative real-time reverse transcription PCR (qPCR) on mRNA from ventricular myocardium of adult male New Zealand White rabbits, the alpha-1B was 99% of total alpha-1-AR mRNA, with <1% alpha-1A and alpha-1D, whereas alpha-1A mRNA was over 50% of total in brain and liver. Saturation radioligand binding identified ~4 fmol total alpha-1-ARs per mg myocardial protein, with 17% alpha-1A by competition with the selective antagonist 5-methylurapidil. The alpha-1D was not detected by competition with BMY-7378, indicating that 83% of alpha-1-ARs were alpha-1B. In isolated left ventricle and right ventricle, the selective alpha-1A agonist A61603 stimulated a negative inotropic effect, versus a positive inotropic effect with the nonselective alpha-1-agonist phenylephrine and the beta-agonist isoproterenol. Blood pressure assay in conscious rabbits using an indwelling aortic telemeter showed that A61603 by bolus intravenous dosing increased mean arterial pressure by 20 mm Hg at 0.14 μg/kg, 10-fold lower than norepinephrine, and chronic A61603 infusion by iPRECIO programmable micro Infusion pump did not increase BP at 22 μg/kg/d. A myocardial slice model useful in human myocardium and an anthracycline cardiotoxicity model useful in mouse were both problematic in rabbit. We conclude that alpha-1A mRNA is very low in rabbit heart, but the receptor is present by binding and mediates a negative inotropic response. Expression and function of the alpha-1A in rabbit heart differ from mouse and human, but the vasopressor response is similar to mouse. PMID:27258143

  2. Solution conformation of alpha-conotoxin GIC, a novel potent antagonist of alpha3beta2 nicotinic acetylcholine receptors.

    PubMed Central

    Chi, Seung-Wook; Kim, Do-Hyoung; Olivera, Baldomero M; McIntosh, J Michael; Han, Kyou-Hoon

    2004-01-01

    Alpha-conotoxin GIC is a 16-residue peptide isolated from the venom of the cone snail Conus geographus. Alpha-conotoxin GIC potently blocks the alpha3beta2 subtype of human nicotinic acetylcholine receptor, showing a high selectivity for neuronal versus muscle subtype [McIntosh, Dowell, Watkins, Garrett, Yoshikami, and Olivera (2002) J. Biol. Chem. 277, 33610-33615]. We have now determined the three-dimensional solution structure of alpha-conotoxin GIC by NMR spectroscopy. The structure of alpha-conotoxin GIC is well defined with backbone and heavy atom root mean square deviations (residues 2-16) of 0.53 A and 0.96 A respectively. Structure and surface comparison of alpha-conotoxin GIC with the other alpha4/7 subfamily conotoxins reveals unique structural aspects of alpha-conotoxin GIC. In particular, the structural comparison between alpha-conotoxins GIC and MII indicates molecular features that may confer their similar receptor specificity profile, as well as those that provide the unique binding characteristics of alpha-conotoxin GIC. PMID:14992691

  3. The Multitarget Ligand 3-Iodothyronamine Modulates β-Adrenergic Receptor 2 Signaling

    PubMed Central

    Dinter, Juliane; Khajavi, Noushafarin; Mühlhaus, Jessica; Wienchol, Carolin Leonie; Cöster, Maxi; Hermsdorf, Thomas; Stäubert, Claudia; Köhrle, Josef; Schöneberg, Torsten; Kleinau, Gunnar; Mergler, Stefan; Biebermann, Heike

    2015-01-01

    Background 3-Iodothyronamine (3-T1AM), a signaling molecule with structural similarities to thyroid hormones, induces numerous physiological responses including reversible body temperature decline. One target of 3-T1AM is the trace amine-associated receptor 1 (TAAR1), which is a member of the rhodopsin-like family of G protein-coupled receptors (GPCRs). Interestingly, the effects of 3-T1AM remain detectable in TAAR1 knockout mice, suggesting further targets for 3-T1AM such as adrenergic receptors. Therefore, we evaluated whether β-adrenergic receptor 1 (ADRB1) and 2 (ADRB2) signaling is affected by 3-T1AM in HEK293 cells and in human conjunctival epithelial cells (IOBA-NHC), where these receptors are highly expressed endogenously. Methods A label-free EPIC system for prescreening the 3-T1AM-induced effects on ADRB1 and ADRB2 in transfected HEK293 cells was used. In addition, ADRB1 and ADRB2 activation was analyzed using a cyclic AMP assay and a MAPK reporter gene assay. Finally, fluorescence Ca2+ imaging was utilized to delineate 3-T1AM-induced Ca2+ signaling. Results 3-T1AM (10−5−10−10M) enhanced isoprenaline-induced ADRB2-mediated Gs signaling but not that of ADRB1-mediated signaling. MAPK signaling remained unaffected for both receptors. In IOBA-NHC cells, norepinephrine-induced Ca2+ influxes were blocked by the nonselective ADRB blocker timolol (10 µM), indicating that ADRBs are most likely linked with Ca2+ channels. Notably, timolol was also found to block 3-T1AM (10−5M)-induced Ca2+ influx. Conclusions The presented data support that 3-T1AM directly modulates β-adrenergic receptor signaling. The relationship between 3-T1AM and β-adrenergic signaling also reveals a potential therapeutic value for suppressing Ca2+ channel-mediated inflammation processes, occurring in eye diseases such as conjunctivitis. PMID:26601070

  4. Lack of effect of chronic calcium antagonist treatment on beta 1- and beta 2-adrenoceptors in right atria from patients with or without heart failure.

    PubMed Central

    Brodde, O E; Hundhausen, H J; Zerkowski, H R; Michel, M C

    1992-01-01

    1. We studied the effects of chronic calcium antagonist (calcium entry blocker, CEB; nifedipine, verapamil, diltiazem) treatment on beta-adrenoceptor density (assessed by (-)-[125I]-iodocyanopindolol [ICYP] binding) and subtype distribution in right atria from 65 patients without apparent heart failure undergoing elective coronary artery bypass grafting (CAD-patients) and from 13 patients with moderate heart failure (NYHA class III to class III-IV) undergoing mitral valve replacement (MVD-patients). 2. In CAD-patients atrial beta-adrenoceptor density was 79.3 +/- 7.9 fmol ICYP bound mg-1 protein (n = 18), the beta 1:beta 2-adrenoceptor ratio 69:31%. Chronic CEB-treatment did not affect either atrial beta-adrenoceptor density or beta 1:beta 2-adrenoceptor ratio. 3. In contrast, in CAD-patients chronically treated with beta 1-adrenoceptor antagonists (atenolol, bisoprolol, metoprolol) and CEB, atrial beta-adrenoceptor density was significantly increased (108.6 +/- 10.5 fmol ICYP bound mg-1 protein, n = 21); this increase was due to a selective increase in beta 1-adrenoceptors. 4. In MVD-patients atrial beta-adrenoceptor density (55.5 +/- 8.7 fmol ICYP bound mg-1 protein, n = 7) was significantly lower (P less than 0.05) than in CAD-patients; beta 1:beta 2-adrenoceptor ratio, however, was not changed (67:33%). Chronic CEB-treatment of MVD-patients did not prevent the decrease in atrial beta-adrenoceptors. 5. We conclude that chronic CEB-treatment does not affect human right atrial beta-adrenoceptor density, either in patients without apparent heart failure or in patients with moderate heart failure.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1315561

  5. Thrust augmentation options for the Beta 2 two-stage-to-orbit vehicle

    NASA Technical Reports Server (NTRS)

    Snyder, Christopher A.

    1993-01-01

    NASA LeRC is continuing to study propulsion concepts for a horizontal takeoff and landing, fully reusable, two-stage-to-orbit vehicle. This will be capable of launching and returning a 10,000 pound payload to a 100 nautical mile polar orbit using low-risk technology. The vehicle, Beta 2, is a derivative of the USAF/Boeing Beta vehicle which was designed to deliver a 50,000 pound payload to a similar orbit. Beta 2 stages at Mach 6.5 and about 100,000 ft altitude. The propulsion system for the booster is an over/under turbine bypass engine/ramjet configuration. In this paper, several options for thrust augmentation were studied in order to improve the performance of this engine where there was a critical need. Options studies were turbine engine overspeed in the transonic region, water injection at a various turbine engine locations also during the transonic region, and water injection at the turbine engine face during high speed operation. The methodology, constraints, propulsion performance, and mission study results are presented.

  6. Triiodothyronine receptor beta-2 messenger ribonucleic acid expression by somatotropes and thyrotropes: effect of propylthiouracil-induced hypothyroidism in rats.

    PubMed

    Childs, G V; Taub, K; Jones, K E; Chin, W W

    1991-11-01

    mRNA for a thyroid hormone receptor isoform that is unique to the pituitary gland (TR beta-2) is down-regulated by T3. Increases in the expression of this mRNA are seen in rats rendered hypothyroid by treatment with propylthiouracil (PTU). This study used dual labeling to determine which pituitary cells expressed TR beta-2 mRNA in normal and PTU-treated rats. In situ hybridization protocols localized the mRNA (with biotinylated complementary oligonucleotide probes detected by avidin-biotin-peroxidase), and immunoperoxidase protocols identified the pituitary hormone proteins. In dispersed pituitary cells, 20 +/- 2% (average +/- SD) of cells from normal rats and 30 +/- 3% of cells from PTU-treated rats were labeled for TR beta-2 mRNA. PTU caused increases in the area of the labeled cells (from 114 +/- 11 to 225 +/- 7 microns 2), the area of the label per cell (from 27 +/- 3 to 71 +/- 11 microns 2), and label density. PTU produced increases in the percentage of TSH cells from 8 +/- 1% to 19 +/- 2%, decreases in the percentage of GH cells from 27 +/- 3% to 11 +/- 2%, and no change in other cell types. After dual labeling, 73% of cells that expressed TR beta-2 mRNA stored either TSH (35 +/- 8) or GH (38 +/- 6). Less than 10% stored other hormones. When each cell type was analyzed, 56 +/- 3% of TSH cells and 43 +/- 4% of GH cells expressed TR beta-2 mRNA. When these percentages were multiplied by the percentages of each cell type in the overall population, TSH and GH cells with TR beta-2 mRNA represented 6.8 +/- 1% and 11.6 +/- 1% of the pituitary cells, respectively. Less than 1% of all pituitary cells expressed TR beta-2 and ACTH (0.9 +/- 0.06), LH (0.8 +/- 0.1), FSH (0.8 +/- 0.1), and PRL (0.9 +/- 0.04). PTU treatment increased the percentage of TSH cells with TR beta-2 mRNA to 72 +/- 4% and decreased the percentage of GH cells with TR beta-2 mRNA to 30 +/- 3%. However, some enlarged putative TSH cells could not be identified by immunolabel because the storage levels

  7. Beta-adrenergic Blockade at Memory Encoding, but Not Retrieval, Decreases the Subjective Sense of Recollection.

    PubMed

    Rimmele, Ulrike; Lackovic, Sandra F; Tobe, Russell H; Leventhal, Bennett L; Phelps, Elizabeth A

    2016-06-01

    Humans remember emotional events not only better but also exhibit a qualitatively distinct recollective experience-that is, emotion intensifies the subjective vividness of the memory, the sense of reliving the event, and confidence in the accuracy of the memory [Phelps, E. A., & Sharot, T. How (and why) emotion enhances the subjective sense of recollection. Current Directions in Psychological Science, 17, 147-152, 2008]. Although it has been demonstrated that activation of the beta-adrenergic system, linked to increases in stress hormone levels and physiological arousal, mediates enhanced emotional memory accuracy, the mechanism underlying the increased subjective sense of recollection is unknown. Behavioral evidence suggests that increased arousal associated with emotional events, either at encoding or retrieval, underlies their increased subjective sense of recollection. Using a double-blind, placebo-controlled, within-subject design, we showed that reducing arousal at encoding through oral intake of 80-mg of the beta-adrenergic receptor antagonist propranolol decreases the subjective sense of recollection for both negative and neutral stimuli 24 hr later. In contrast, administration of propranolol before memory retrieval did not alter the subjective sense of recollection. These results suggest that the neurohormonal changes underlying increased arousal at the time of memory formation, rather than the time of memory retrieval, modulate the subjective sense of recollection. PMID:26942318

  8. Sustained adrenergic signaling leads to increased metastasis in ovarian cancer via increased PGE2 synthesis

    PubMed Central

    Nagaraja, Archana S.; Dorniak, Piotr L.; Sadaoui, Nouara C.; Kang, Yu; Lin, Tan; Armaiz-Pena, Guillermo; Wu, Sherry Y.; Rupaimoole, Rajesha; Allen, Julie K.; Gharpure, Kshipra M.; Pradeep, Sunila; Zand, Behrouz; Previs, Rebecca A.; Hansen, Jean M.; Ivan, Cristina; Rodriguez-Aguayo, Cristian; Yang, Peiying; Lopez-Berestein, Gabriel; Lutgendorf, Susan K.; Cole, Steve W.; Sood, Anil K.

    2015-01-01

    Adrenergic stimulation adversely affects tumor growth and metastasis, but the underlying mechanisms are not well understood. Here, we uncovered a novel mechanism by which catecholamines induce inflammation by increasing prostaglandin E2 (PGE2) levels in ovarian cancer cells. Metabolic changes in tumors isolated from patients with depression and mice subjected to restraint stress showed elevated PGE2 levels. Increased metabolites and PTGS2 and PTGES protein levels were found in Skov3-ip1 and HeyA8 cells treated with norepinephrine, and these changes were shown to be mediated by ADRB2 receptor signaling. Silencing PTGS2 resulted in significantly decreased migration and invasion in ovarian cancer cells in the presence of norepinephrine and decreased tumor burden and metastasis in restraint stress orthotopic models. In human ovarian cancer samples, concurrent increased ADRB2, PTGS2 and PTGES expression was associated with reduced overall and progression-free patient survival. In conclusion, increased adrenergic stimulation results in increased PGE2 synthesis via ADRB2-Nf-kB-PTGS2 axis, which drives tumor growth and metastasis. PMID:26257064

  9. A Single-Nucleotide Polymorphism in ABCC4 Is Associated with Tenofovir-Related Beta2-Microglobulinuria in Thai Patients with HIV-1 Infection

    PubMed Central

    Likanonsakul, Sirirat; Suntisuklappon, Bussakorn; Nitiyanontakij, Ravee; Prasithsirikul, Wisit; Nakayama, Emi E.; Shioda, Tatsuo; Sangsajja, Chariya

    2016-01-01

    Background In Thailand, the combined generic anti-retroviral drug stavudine/lamivudine/nevirapine (d4T/3TC/NVP) has been used to treat human immunodeficiency virus (HIV)-infected individuals since 2001. Due to relatively frequent adverse effects, d4T gradually has been replaced with tenofovir disoproxil fumarate (TDF). Although the frequency of adverse drug effects with TDF is lower than that with d4T, TDF is known to induce kidney dysfunction, especially in the proximal tubules. It has been reported that renal tubular transporters, including members of the multi-drug resistant (MDR) protein family, are implicated in tenofovir extrusion and may, therefore, confer susceptibility to TDF-induced kidney tubular dysfunction (KTD). We have explored the association between KTD and polymorphisms in genes that encode adenosine triphosphate-binding cassette (ABC)-type MDRs. Methods HIV-infected patients receiving TDF-containing antiretroviral regimens for at least one year were enrolled in the study. The levels of beta2-microglobulin in urine and creatinine (Cr) were measured. Three single-nucleotide polymorphisms, ABCC2 C-24T (rs717620), ABCC2 G1429A (rs2273697), and ABCC4 T4976C (rs1059751), were analyzed using TaqMan SNP genotyping assays. Results A total of 273 HIV-infected patients were recruited. The median number of years of TDF treatment was 5.04 with interquartile range (IQR) of 3.9–6.7. Despite the length of treatment with TDF, 98.5% patients maintained an estimated glomerular filtration rate (eGFR) of >60 mL/min as calculated by the CKD-EPI formula. Fifty-four patients (19.8%) showed beta2-microglobulinuria (median 2636 μg/g Cr with IQR of 1519–13197 μg/g Cr). The allele frequency of ABCC4 T4976C among those 54 patients was 0.602, compared to 0.475 among the 219 remaining patients (p = 0.018). Conclusions Approximately 20% of HIV-infected patients receiving TDF showed beta2-microglobulinuria. The C allele at position 4976 of the ABCC4 gene was associated

  10. Norepinephrine-Induced Adrenergic Activation Strikingly Increased the Atrial Fibrillation Duration through β1- and α1-Adrenergic Receptor-Mediated Signaling in Mice

    PubMed Central

    Hasegawa, Nozomi; Cai, Wenqian; Jin, Huiling; Hidaka, Yuko; Prajapati, Rajesh; Umemura, Masanari; Yokoyama, Utako; Sato, Motohiko; Okumura, Satoshi; Ishikawa, Yoshihiro

    2015-01-01

    Background Atrial fibrillation (AF) is the most common arrhythmias among old people. It causes serious long-term health problems affecting the quality of life. It has been suggested that the autonomic nervous system is involved in the onset and maintenance of AF in human. However, investigation of its pathogenesis and potential treatment has been hampered by the lack of suitable AF models in experimental animals. Objectives Our aim was to establish a long-lasting AF model in mice. We also investigated the role of adrenergic receptor (AR) subtypes, which may be involved in the onset and duration of AF. Methods and Results Trans-esophageal atrial burst pacing in mice could induce AF, as previously shown, but with only a short duration (29.0±8.1 sec). We found that adrenergic activation by intraperitoneal norepinephrine (NE) injection strikingly increased the AF duration. It increased the duration to more than 10 minutes, i.e., by more than 20-fold (656.2±104.8 sec; P<0.001). In this model, a prior injection of a specific β1-AR blocker metoprolol and an α1-AR blocker prazosin both significantly attenuated NE-induced elongation of AF. To further explore the mechanisms underlying these receptors’ effects on AF, we assessed the SR Ca2+ leak, a major trigger of AF, and consequent spontaneous SR Ca2+ release (SCR) in atrial myocytes. Consistent with the results of our in-vivo experiments, both metoprolol and prazosin significantly inhibited the NE-induced SR Ca2+ leak and SCR. These findings suggest that both β1-AR and α1-AR may play important roles in the development of AF. Conclusions We have established a long-lasting AF model in mice induced by adrenergic activation, which will be valuable in future AF study using experimental animals, such as transgenic mice. We also revealed the important role of β1- and α1-AR-mediated signaling in the development of AF through in-vivo and in-vitro experiments. PMID:26203906

  11. Alpha 2-adrenergic receptor turnover in adipose tissue and kidney: irreversible blockade of alpha 2-adrenergic receptors by benextramine

    SciTech Connect

    Taouis, M.; Berlan, M.; Lafontan, M.

    1987-01-01

    The recovery of post- and extrasynaptic alpha 2-adrenergic receptor-binding sites was studied in vivo in male golden hamsters after treatment with an irreversible alpha-adrenoceptor antagonist benextramine, a tetramine disulfide that possesses a high affinity for alpha 2-binding sites. The kidney alpha 2-adrenergic receptor number was measured with (/sup 3/H)yohimbine, whereas (/sup 3/H)clonidine was used for fat cell and brain membrane alpha 2-binding site identification. Benextramine treatment of fat cell, kidney, and brain membranes reduced or completely suppressed, in an irreversible manner, (/sup 3/H) clonidine and (/sup 3/H)yohimbine binding without modifying adenosine (A1-receptor) and beta-adrenergic receptor sites. This irreversible binding was also found 1 and 2 hr after intraperitoneal administration of benextramine to the hamsters. Although it bound irreversibly to peripheral and central alpha 2-adrenergic receptors on isolated membranes, benextramine was unable to cross the blood-brain barrier of the hamster at the concentrations used (10-20 mg/kg). After the irreversible blockade, alpha 2-binding sites reappeared in kidney and adipose tissue following a monoexponential time course. Recovery of binding sites was more rapid in kidney than in adipose tissue; the half-lives of the receptor were 31 and 46 hr, respectively in the tissues. The rates of receptor production were 1.5 and 1.8 fmol/mg of protein/hr in kidney and adipose tissue. Reappearance of alpha 2-binding sites was associated with a rapid recovery of function (antilipolytic potencies of alpha 2-agonists) in fat cells inasmuch as occupancy of 15% of (/sup 3/H)clonidine-binding sites was sufficient to promote 40% inhibition of lipolysis. Benextramine is a useful tool to estimate turnover of alpha 2-adrenergic receptors under normal and pathological situations.

  12. Alpha/sub 2/-adrenergic receptors on a platelet precursor cell line, HEL

    SciTech Connect

    McKernan, R.M.; Motulsky, H.J.; Rozansky, D.; Insel, P.A.

    1986-03-01

    The authors have identified ..cap alpha../sub 2/-adrenergic receptors on human erythroleukemia HEL cells, a suspension-growing, bone-marrow-derived cell line related to human platelets. Intact HEL cells were studied using radioligand binding and cAMP accumulation assays. The authors identified saturable specific binding of the ..cap alpha../sub 2/-antagonist (/sup 3/H)yohimbine (yoh) in cells incubated at 37/sup 0/C for 1 hr (B/sub max/ 5900 +/- 2100 sites/cell, K/sub d/ 3.6 +/- 0.9 nM, n = 7). Competition for (/sup 3/H)yoh binding sites with antagonists confirmed that these sites were similar to human ..cap alpha../sub 2/-adrenoceptors from platelets and other resources, as typified by their high affinity for WY-26392, yohimbine and idazoxan, and very low affinity for prazosin. Studies at 37/sup 0/C revealed a low affinity of these sites for catecholamines (K/sub i/ for (-)-epinephrine, 21 ..mu..M; (-)-norepinephrine, 45 ..mu..M, (+)-epinephrine, 80 ..mu..M). When experiments were conducted at 4 /sup 0/C, (-)-epinephrine was able to compete for only 50-60% of the sites specifically labelled by (/sup 3/H)yoh at 37/sup 0/, but (-)-epinephrine had an approximately 10-fold greater affinity for these sites (K/sub i/ at 4 /sup 0/C = 2.4 ..mu..M). In addition, epinephrine inhibited cAMP accumulation stimulated by forskolin and PGE/sub 1/ in HEL cells; this response was inhibited by pertussis toxin. The authors conclude that HEL cells possess ..cap alpha../sub 2/-adrenergic receptors linked to G/sub i/ and thus should serve as a useful model to explore metabolism and regulation of these receptors in human cells.

  13. Retinoic acid receptor beta2 promotes functional regeneration of sensory axons in the spinal cord.

    PubMed

    Wong, Liang-Fong; Yip, Ping K; Battaglia, Anna; Grist, John; Corcoran, Jonathan; Maden, Malcolm; Azzouz, Mimoun; Kingsman, Susan M; Kingsman, Alan J; Mazarakis, Nicholas D; McMahon, Stephen B

    2006-02-01

    The embryonic CNS readily undergoes regeneration, unlike the adult CNS, which has limited axonal repair after injury. Here we tested the hypothesis that retinoic acid receptor beta2 (RARbeta2), critical in development for neuronal growth, may enable adult neurons to grow in an inhibitory environment. Overexpression of RARbeta2 in adult rat dorsal root ganglion cultures increased intracellular levels of cyclic AMP and stimulated neurite outgrowth. Stable RARbeta2 expression in DRG neurons in vitro and in vivo enabled their axons to regenerate across the inhibitory dorsal root entry zone and project into the gray matter of the spinal cord. The regenerated neurons enhanced second-order neuronal activity in the spinal cord, and RARbeta2-treated rats showed highly significant improvement in sensorimotor tasks. These findings show that RARbeta2 induces axonal regeneration programs within injured neurons and may thus offer new therapeutic opportunities for CNS regeneration. PMID:16388307

  14. Augmented muscle vasodilatory responses in obese children with Glu27 beta-2-adrenoceptor polymorphism.

    PubMed

    da Silva, Alexandre G; Ribeiro, Mauricio M; Trombetta, Ivani C; Nicolau, Christiane; Frazzatto, Eliana; Guazzelli, Isabel; Matos, Luciana N J; Halbern, Alfredo; Negrão, Carlos E; Villares, Sandra M F

    2008-05-01

    This study examined forearm vasodilatation during mental challenge and exercise in 72 obese children (OC; age = 10 +/- 0.1 years) homozygous with polymorphism in the allele 27 of the beta-2-adrenoceptors: Gln27 (n = 61) and Glu27 (n = 11). Forearm blood flow was recorded during 3 min of each using the Stroop color-word test (MS) and handgrip isometric exercise. Baseline hemodynamic and vascular measurements were similar. During the MS, peak forearm vascular conductance was significantly greater in group Glu27 (Delta = 0.35 +/- 0.4 vs. 0.12 +/- 0.1 units, respectively, p = .042). Similar results were found during exercise (Delta = 0.64 +/- 0.1 vs. 0.13 +/- 0.1 units, respectively, p = .035). Glu27 OC increased muscle vasodilatory responsiveness upon the MS and exercise. PMID:18579897

  15. Urinary cadmium and beta2-microglobulin: correlation with nutrition and smoking history (journal version)

    SciTech Connect

    Kowal, N.E.

    1988-01-01

    Urinary cadmium and beta2-microglobulin concentrations from approximately 1000 samples from the general adult U.S. population, collected as part of the National Health and Nutritional Examination Survey II (NHANES II), were related to nutritional and smoking history of the individuals. Urinary cadmium concentration was negatively correlated with dietary iron (significance level of 0.0065), negatively correlated with dietary calcium (significance level of less than 0.0001), and significantly (level of less than 0.001) higher in past or present smokers than in those who had never smoked. The results suggest increased cadmium absorption in the presence of low dietary intake of iron, low dietary intake of calcium, and cigarette smoking in the general population of the United States.

  16. A Study of Anti Beta-2 Glycoprotein I and Anti-Prothrombin Antibodies in Patients with Unexplained Recurrent Pregnancy Losses.

    PubMed

    Singh, Angad; Nangia, Anita; Sharma, Sunita; Puri, Manju

    2016-06-01

    To compare the levels of IgG and IgM anti beta-2 glycoprotein I antibodies and IgG and IgM anti prothrombin antibodies among women with unexplained recurrent pregnancy losses and women with at least 2 live issues. To compare the prevalence of newer anti beta-2 glycoprotein I & anti prothrombin antibodies with conventional Lupus anticoagulant & anticardiolipin antibodies. 50 women with recurrent pregnancy losses & 50 matched controls were evaluated for the presence of: Lupus anticoagulant-screened by LA sensitive aPTT& DRVV and confirmatory Staclot Assay. ELISA kits were used for detecting IgG & IgM anticardiolipin, anti beta-2 glycoprotein I & anti prothrombin antibodies. 11/50 (22 %) women in study group and none in control group had circulating antiphospholipid antibodies. 2 cases (4 %) had lupus anticoagulant. 1 case (2 %) had anticardiolipin antibody & 6 cases (12 %) were positive for anti beta-2 Glycoprotein I antibody (p value = 0.027). 3 cases (6 %) had anti prothrombin antibody. All were mutually exclusive except for one. Women with recurrent pregnancy losses should be tested for anti beta-2 Glycoprotein I antibodies & anti prothrombin antibodies in addition to conventional lupus anticoagulant and anticardiolipin antibodies. This approach can decrease the incidence of SNAP (seronegative antiphospholipid syndrome) cases while establishing the true prevalence of antiphospholipid syndrome. PMID:27065583

  17. Murine Hematopoietic Stem cells and Progenitors Express Adrenergic Receptors

    PubMed Central

    Muthu, Kuzhali; Iyer, Sivaraman; He, L-K.; Szilagyi, Andrea; Gamelli, Richard L; Shankar, Ravi; Jones, Stephen B

    2007-01-01

    Association between the nervous and immune system is well documented. Immune cells originate within the bone marrow that is innervated. Thermal injury induces adrenergic stimulation, augments monocytopoiesis and alters the β-adrenergic receptor (AR) profile of bone marrow monocyte committed progenitors. This provides an impetus to study AR expression in hematopoietic progenitors along myeloid lineage. Using FACS analysis and confocal microscopy, we report the expression of α1-, α2- and β2- AR in enriched populations of ER-MP20+ and ER-MP12+ myeloid progenitors, CD117+ and CD34+ multi-potential progenitors and more importantly pluripotent stem cells suggesting a plausible role for catecholamine in hematopoietic development. PMID:17428548

  18. Cardiac and neuroprotection regulated by α1-adrenergic receptor subtypes

    PubMed Central

    Perez, Dianne M.; Doze, Van A.

    2013-01-01

    Sympathetic nervous system regulation by the α1-adrenergic receptor (AR) subtypes (α1A, α1B, α1D) is complex, whereby chronic activity can be either detrimental or protective for both heart and brain function. This review will summarize the evidence that this dual regulation can be mediated through the different α1-AR subtypes in the context of cardiac hypertrophy, heart failure, apoptosis, ischemic preconditioning, neurogenesis, locomotion, neurodegeneration, cognition, neuroplasticity, depression, anxiety, epilepsy, and mental illness. PMID:21338248

  19. Thyrotoxic periodic paralysis triggered by β2-adrenergic bronchodilators.

    PubMed

    Yeh, Fu-Chiang; Chiang, Wen-Fang; Wang, Chih-Chiang; Lin, Shih-Hua

    2014-05-01

    Hypokalemic periodic paralysis is the most common form of periodic paralysis and is characterized by attacks of muscle paralysis associated with a low serum potassium (K+) level due to an acute intracellular shifting. Thyrotoxic periodic paralysis (TPP), characterized by the triad of muscle paralysis, acute hypokalemia, and hyperthyroidism, is one cause of hypokalemic periodic paralysis. The triggering of an attack of undiagnosed TPP by β2-adrenergic bronchodilators has, to our knowledge, not been reported previously. We describe two young men who presented to the emergency department with the sudden onset of muscle paralysis after administration of inhaled β2-adrenergic bronchodilators for asthma. In both cases, the physical examination revealed an enlarged thyroid gland and symmetrical flaccid paralysis with areflexia of lower extremities. Hypokalemia with low urine K+ excretion and normal blood acid-base status was found on laboratory testing, suggestive of an intracellular shift of K+, and the patients' muscle strength recovered at serum K+ concentrations of 3.0 and 3.3 mmol/L. One patient developed hyperkalemia after a total potassium chloride supplementation of 110 mmol. Thyroid function testing was diagnostic of primary hyperthyroidism due to Graves disease in both cases. These cases illustrate that β2-adrenergic bronchodilators should be considered a potential precipitant of TPP. PMID:24852589

  20. Circadian 5-HT production regulated by adrenergic signaling

    PubMed Central

    Sun, Xing; Deng, Jie; Liu, Tiecheng; Borjigin, Jimo

    2002-01-01

    Using on-line microdialysis, we have characterized in vivo dynamics of pineal 5-hydroxytryptamine (5-HT; serotonin) release. Daily pineal 5-HT output is triphasic: (i) 5-HT levels are constant and high during the day; (ii) early in the night, there is a novel sharp rise in 5-HT synthesis and release, which precedes the nocturnal rise in melatonin synthesis; and (iii) late in the night, levels are low. This triphasic 5-HT production persists in constant darkness and is influenced strongly by intrusion of light at night. We demonstrate that both diurnal 5-HT synthesis and 5-HT release are activated by sympathetic innervation from the superior cervical ganglion and show that these processes are controlled by distinct receptors. The increase in 5-HT synthesis is controlled by β-adrenergic receptors, whereas the increase in 5-HT release is mediated by α-adrenergic signaling. On the other hand, the marked decrease in 5-HT content and release late at night is a passive process, influenced by the extent of melatonin synthesis. In the absence of melatonin synthesis, the late-night decline in 5-HT release is prevented, reaching levels roughly twice as high as that of the day value. In summary, our results demonstrate that 5-HT levels display marked circadian rhythms that depend on adrenergic signaling. PMID:11917109

  1. Adrenergic and noradrenergic regulation of poultry behavior and production.

    PubMed

    Dennis, R L

    2016-07-01

    Norepinephrine and epinephrine (noradrenaline and adrenaline) are integral in maintaining behavioral and physiological homeostasis during both aversive and rewarding events. They regulate the response to stressful stimuli through direct activation of adrenergic receptors in the central and sympathetic nervous systems, hormonal activity and through the interaction of the brain, gut, and microbiome. The multiple functions of these catecholamines work synergistically to prepare an individual for a "fight or flight" response. However, hyper-reactivity of this system can lead to increased fearfulness and aggression, decreased health and productivity, and a reduction in overall well-being. Behaviors, such as aggression and certain fear-related behaviors, are a serious problem in the poultry industry that can lead to injury and cannibalism. For decades, catecholamines have been used as a measure of stress in animals. However, few studies have specifically targeted the adrenergic systems as means to reduce behaviors that are damaging or maladapted to their rearing environments and improve animal well-being. This article attempts to address our current understanding of specific, adrenergic-regulated behaviors that impact chicken well-being and production. PMID:27345328

  2. Ontogeny of alpha- and beta-adrenergic anorexia in rats.

    PubMed

    Lora-Vilchis, M C; Chambert, G; Rodriguez-Zendejas, A M; Soto-Mora, L M; Russek, M; Epstein, A N

    1988-12-01

    The anorectic action of alpha- (phenylephrine) and beta- (isoproterenol) adrenergic agonists was studied in mildly deprived neonatal, weanling, prepubescent, and adult rats. Intraperitoneal phenylephrine produced a reduction of food intake at all ages but with reduced potency and with a maximum of 50% in neonates. Contrary to intramuscular epinephrine that has no effect on feeding at any age, intramuscular phenylephrine was as effective as intraperitoneal in neonates, probably because it is not as rapidly destroyed in tissues as epinephrine. However, in weanlings and adults intramuscular phenylephrine was much less anorectic than intraperitoneal, suggesting that this effect is exerted via the liver. Isoproterenol did not reduce milk intake at any age before adulthood. Lactate had no effect on milk intake before the age of 40 days. Thus catecholamine anorexia is a purely alpha-adrenergic effect in young rats and appears before the metabolic effect of lactate. beta-Adrenergic anorexia, on the other hand, can be obtained only after puberty, suggesting that the mechanism mediating it matures after the preparatory action of the sexual hormones. PMID:2849323

  3. Modulation of beta2- and beta3-adrenoceptor-mediated relaxation of rat oesophagus smooth muscle by protein kinase C.

    PubMed

    Oostendorp, Jaap; Obels, Peter Ph; Terpstra, A Rene; Nelemans, S Adriaan; Zaagsma, Johan

    2004-07-01

    Although a prominent role for protein kinase C (PKC) in the cross-talk between the phosphoinositide pathway and beta2-adrenoceptor signalling has been indicated, modulation of beta3-adrenoceptor function by PKC has not been studied thus far. In the present study, we have compared the relative capacity of PKC in modulating beta2- and beta3-adrenoceptor-mediated relaxation of methacholine-contracted rat oesophagus smooth muscle. To this purpose the effects of the PKC-inhibitor GF 109203X (2-[1-(3-dimethylaminopropyl)-1H-indol-3-yl]-3-(1H-indol-3-yl)-maleimide) on relaxation induced by fenoterol, formoterol, (-)-noradrenaline, BRL 35135 (4-[2-[(2-hydroxy-2-(chlorophenyl)ethyl)amino]-propyl]-phenoxyacetic-acidmethylester) and IBMX (3-isobutyl-1-methyl-xanthine) were studied, in the absence and presence of the selective beta2-adrenoceptor antagonist ICI 118,551 (erythro-1(7-methylindan-4-yloxy)-3-(isopropylamin)-butan-2-ol). Our results show that inhibition of PKC resulted in differential augmentation of both beta2- and beta3-adrenoceptor-mediated relaxation. In contrast, relaxation induced by IBMX was not influenced at all by GF 109203X. The beta2-adrenoceptor bears phosphorylation sites for several kinases, including PKC. Since the beta3-adrenoceptor lacks these consensus sites, the results may also indicate that PKC-mediated Galphas phosphorylation is involved in the cross-talk between the muscarinic receptor-mediated phosphoinositide pathway and beta2- and, particularly, beta3-adrenoceptor signalling. PMID:15219823

  4. α2-Adrenergic blockade mimics the enhancing effect of chronic stress on breast cancer progression.

    PubMed

    Lamkin, Donald M; Sung, Ha Yeon; Yang, Gyu Sik; David, John M; Ma, Jeffrey C Y; Cole, Steve W; Sloan, Erica K

    2015-01-01

    Experimental studies in preclinical mouse models of breast cancer have shown that chronic restraint stress can enhance disease progression by increasing catecholamine levels and subsequent signaling of β-adrenergic receptors. Catecholamines also signal α-adrenergic receptors, and greater α-adrenergic signaling has been shown to promote breast cancer in vitro and in vivo. However, antagonism of α-adrenergic receptors can result in elevated catecholamine levels, which may increase β-adrenergic signaling, because pre-synaptic α2-adrenergic receptors mediate an autoinhibition of sympathetic transmission. Given these findings, we examined the effect of α-adrenergic blockade on breast cancer progression under non-stress and stress conditions (chronic restraint) in an orthotopic mouse model with MDA-MB-231HM cells. Chronic restraint increased primary tumor growth and metastasis to distant tissues as expected, and non-selective α-adrenergic blockade by phentolamine significantly inhibited those effects. However, under non-stress conditions, phentolamine increased primary tumor size and distant metastasis. Sympatho-neural gene expression for catecholamine biosynthesis enzymes was elevated by phentolamine under non-stress conditions, and the non-selective β-blocker propranolol inhibited the effect of phentolamine on breast cancer progression. Selective α2-adrenergic blockade by efaroxan also increased primary tumor size and distant metastasis under non-stress conditions, but selective α1-adrenergic blockade by prazosin did not. These results are consistent with the hypothesis that α2-adrenergic signaling can act through an autoreceptor mechanism to inhibit sympathetic catecholamine release and, thus, modulate established effects of β-adrenergic signaling on tumor progression-relevant biology. PMID:25462899

  5. Pseudotumoral amyloidosis of beta 2-microglobulin origin in the buttock of a patient receiving long term haemodialysis.

    PubMed Central

    Fernández-Alonso, J; Rios-Camacho, C; Valenzuela-Castaño, A; Rocha-Castilla, J L

    1993-01-01

    A 52 year old man who had been receiving haemodialysis for 13 years, with a history of renal tuberculosis, right ischial tuberculous osteomyelitis, and dialysis arthropathy, developed a soft tissue tumour in his left buttock. Histological analysis, immunohistological staining, and electron microscopic examination of the surgically removed tumour showed massive deposits of beta 2-microglobulin (beta 2-M) amyloid. This case shows the expanding clinical spectrum of this type of amyloidosis, and it is suggested that amyloid infiltration should be considered in the differential diagnosis of gluteal tumours in these patients. Images PMID:8408708

  6. Beta 2-microglobulin-dependent T cells are dispensable for allergen-induced T helper 2 responses.

    PubMed

    Zhang, Y; Rogers, K H; Lewis, D B

    1996-10-01

    CD4+ and CD8+ alpha/beta+ T cells of the T helper cell (Th)2 phenotype produce the cytokines IL-4, IL-5, and IL-13 that promote IgE production and eosinophilic inflammation. IL-4 may play an important role in mediating the differentiation of antigenically naive alpha/beta+ T cells into Th2 cells. Murine NK1.1+ (CD4+ or CD4-CD8-) alpha/beta+ T cells comprise a beta 2-microglobulin (beta 2m)-dependent cell population that rapidly produces IL-4 after cell activation in vitro and in vivo and has been proposed as a source of IL-4 for Th2 cell differentiation. alpha/beta+ CD8+ T cells, most of which require beta 2m for their development, have also been proposed as positive regulators of allergen-induced Th2 responses. We tested whether beta 2m-dependent T cells were essential for Th2 cell-mediated allergic reactions by treating wild-type, beta 2m-deficient (beta 2m -/-), and IL-4-deficient (IL-4 -/-) mice of the C57BL/6 genetic background with ovalbumin (OVA), using a protocol that induces robust allergic pulmonary disease in wild-type mice. OVA-treated beta 2m -/- mice had circulating levels of total and OVA-specific IgE, pulmonary eosinophilia, and expression of IL-4, IL-5, and IL-13 mRNA in bronchial lymph node tissue similar to that of OVA-treated wild-type mice. In contrast, these responses in OVA-treated IL-4 -/- mice were all either undetectable or markedly reduced compared with wild-type mice, confirming that IL-4 was required in this allergic model. These results indicate that the NK1.1+ alpha/beta+ T cell population, as well as other beta 2m-dependent populations, such as most peripheral alpha/beta+ CD8+ T cells, are dispensable for the Th2 pulmonary response to protein allergens. PMID:8879221

  7. Chiral recognition in adrenergic receptor binding mimics prepared by molecular imprinting.

    PubMed

    Ramström, O; Yu, C; Mosbach, K

    1996-01-01

    Molecularly imprinted polymers were prepared against the adrenomimetic agents ephedrine and pseudoephedrine. These compounds each incorporate two chiral centres. The polymers were evaluated with respect to enantiodiscrimination of various adrenergic ligands. The selectivity of the polymeric binding sites for the imprinted molecules was very high, and it was found that binding of both the enantiomeric and diastereomeric isomers of the imprint species were effectively obstructed, it was found that these polymers could selectively recognize the enantiomers of the endogenous adrenergic ligand epinephrine as well as several beta-adrenergic blockers. These observations suggest that these polymers effectively mimic the recognition patterns exhibited by natural adrenergic receptors. PMID:9174958

  8. Blunted cardiac beta-adrenergic response as an early indication of cardiac dysfunction in Duchenne muscular dystrophy

    PubMed Central

    Li, Ying; Zhang, Shuai; Zhang, Xiaoying; Li, Jing; Ai, Xiaojie; Zhang, Li; Yu, Daohai; Ge, Shuping; Peng, Yizhi; Chen, Xiongwen

    2014-01-01

    Aims To determine whether altered beta-adrenergic responses contribute to early cardiac dysfunction in mdx (X-linked muscular dystrophy) mice, an animal model for human Duchenne muscular dystrophy. Methods and results Replacement fibrosis in mdx hearts gradually increased with age, suggesting a gradual loss of cardiomyocytes. Echocardiography and intra-left ventricular haemodynamic measurements detected baseline cardiac dysfunction in mdx mice at ≥8 months. However, a reduction of cardiac beta-adrenergic response to isoproterenol (ISO) was already present in mdx mice at 4 months. Ventricular myocytes (VMs) isolated from 4- and 8-month-old mdx mice had greater baseline contractile function {fractional shortening, [Ca2+]i, and sarcoplasmic reticulum (SR) Ca2+ content} and ICa-L than age-matched control VMs and than myocytes isolated from 2-month-old mdx mice. ISO increased myocyte function in the VMs of 4- and 8-month-old mdx mice to the same level as in age-matched control VMs. In the VMs of 12-month-old mdx mice, ISO failed to increase myocyte function to the level in VMs of 12-month-old control mice and could not further increaseICa-L. No differences were observed in the expression of Cav1.2α1c, Cav1.2β1, Cav1.2β2, sarco/endoplasmic reticulum Ca2+ ATPase (SERCA), and the Na+/Ca2+ exchanger. In contrast, total ryanodine receptor 2 (RyR2) and basal phosphorylation of RyR2, phospholamban, and Cav1.2α1c were found to be increased in hearts of 4-month-old mdx mice; baseline protein kinase A activity was also increased. After ISO treatment, phosphorylation levels were the same in mdx and control hearts. VMs of 4-month-old mdx mice had reduced beta1-adrenergic receptor (β1-AR) density and beta-adrenergic sensitivity. Conclusion In young mdx mice, the myocyte increases its contractile function to compensate for myocyte loss. However, these myocytes with enhanced baseline function have reduced potential for stimulation, decreased β1-AR density/sensitivity, leading

  9. Adrenaline Rush: The Role of Adrenergic Receptors in Stimulant-Induced Behaviors

    PubMed Central

    Schmidt, Karl T.

    2014-01-01

    Psychostimulants, such as cocaine and amphetamines, act primarily through the monoamine neurotransmitters dopamine (DA), norepinephrine, and serotonin. Although stimulant addiction research has largely focused on DA, medication development efforts targeting the dopaminergic system have thus far been unsuccessful, leading to alternative strategies aimed at abating stimulant abuse. Noradrenergic compounds have shown promise in altering the behavioral effects of stimulants in rodents, nonhuman primates, and humans. In this review, we discuss the contribution of each adrenergic receptor (AR) subtype (α1, α2, and β) to five stimulant-induced behaviors relevant to addiction: locomotor activity, conditioned place preference, anxiety, discrimination, and self-administration. AR manipulation has diverse effects on these behaviors; each subtype profoundly influences outcomes in some paradigms but is inconsequential in others. The functional neuroanatomy and intracellular signaling mechanisms underlying the impact of AR activation/blockade on these behaviors remain largely unknown, presenting a new frontier for research on psychostimulant–AR interactions. PMID:24499709

  10. Postcountershock myocardial damage after pretreatment with adrenergic and calcium channel antagonists in halothane-anesthetized dogs

    SciTech Connect

    Gaba, D.M.; Metz, S.; Maze, M.

    1985-05-01

    Transthoracic electric countershock can cause necrotic myocardial lesions in humans as well as experimental animals. The authors investigated the effect on postcountershock myocardial damage of pretreatment with prazosin, an alpha-1 antagonist; L-metoprolol, a beta-1 antagonist, and verapamil, a calcium channel-blocking agent. Twenty dogs were anesthetized with halothane and given two transthoracic countershocks of 295 delivered joules each after drug or vehicle treatment. Myocardial injury was quantitated 24 h following countershock by measuring the uptake of technetium-99m pyrophosphate in the myocardium. Elevated technetium-99m pyrophosphate uptake occurred in visible lesions in most dogs regardless of drug treatment. For each of four parameters of myocardial damage there was no statistically significant difference between control animals and those treated with prazosin, metoprolol, or verapamil. These data suggest that adrenergic or calcium channel-mediated mechanisms are not involved in the pathogenesis of postcountershock myocardial damage.

  11. Transient Intrapulmonary Shunting in a Patient Treated With β2-Adrenergic Agonists for Status Asthmaticus

    PubMed Central

    Jacobson, Joseph E.; Eldridge, Marlowe W.

    2014-01-01

    Intrapulmonary arteriovenous anastomoses (IPAVs) are large-diameter pathways that directly connect the arterial and venous networks, bypassing the pulmonary capillaries. Ubiquitously present in healthy humans, these pathways are recruited in experimental conditions by exercise, hypoxia, and catecholamines and have been previously shown to be closed by hyperoxia. Whether they play a role in pulmonary pathophysiology is unknown. Here, we describe IPAV recruitment associated with hypoxemia and right-to-left shunt in a patient with status asthmaticus, treated with agonists of the B2-adrenergic pathway. Our observation of IPAVs in a pediatric patient, mechanically ventilated with 100% O2, suggests that these pathways are recruited in clinically important circumstances and challenges the notion that IPAVs are always closed by alveolar hyperoxia. PMID:24639274

  12. Antinociception mediated by alpha2-adrenergic activation involves increasing TNFα expression and restoring TNFα and alpha2-adrenergic inhibition of norepinephrine release

    PubMed Central

    Spengler, Robert N.; Sud, Reeteka; Knight, Paul R.; Ignatowski, Tracey A.

    2007-01-01

    The central component that establishes chronic pain from peripheral nerve injury is associated with increased tumor necrosis factor-α (TNFα) production in the brain. This study examined TNFα and its reciprocally permissive role with α2-adrenergic activation during peak and progressive decline of thermal hyperalgesia in sciatic nerve chronic constriction injury (CCI). Accumulation of TNFα mRNA (in situ hybridization) increases in the hippocampus and locus coeruleus during the onset of neuropathic pain and persists as hyperalgesia abates. Activation of α2-adrenergic receptors in control rats decreases TNFα mRNA accumulation in these brain regions. In contrast, during hyperalgesia, α2-adrenergic activation enhances TNFα mRNA accumulation. Whether this enhanced TNFα production is associated with changes in the regulation of norepinephrine (NE) release was tested. Hippocampal slices were electrically depolarized to evaluate α2-adrenergic and TNFα regulation of NE release. While inhibition of NE release by TNFα is maximal during peak hyperalgesia, it subsequently transforms to facilitate NE release. In addition, α2-adrenergic receptor activation with clonidine (0.2 mg/kg, i.p.) in CCI rats experiencing hyperalgesia restores TNFα and α2-adrenergic inhibition of NE release. While TNFα directs the development of hyperalgesia, it also directs its resolution. Transformed sensitivity to α2-adrenergic agonists during hyperalgesia demonstrates a mechanism for therapy. PMID:17055005

  13. The α2B adrenergic receptor is mutant in cortical myoclonus and epilepsy

    PubMed Central

    De Fusco, Maurizio; Vago, Riccardo; Striano, Pasquale; Di Bonaventura, Carlo; Zara, Federico; Mei, Davide; Kim, Min Seuk; Muallem, Shmuel; Chen, Yunjia; Wang, Qin; Guerrini, Renzo; Casari, Giorgio

    2013-01-01

    Objective Autosomal dominant cortical myoclonus and epilepsy (ADCME) is characterized by distal, fairly rhythmic myoclonus and epilepsy with variable severity. We have previously mapped the disease locus on chromosome 2p11.1-q12.2 by genome-wide linkage analysis. Additional pedigrees affected by similar forms of epilepsy have been associated to chromosome 8q, 5p and 3q, but none of the causing genes has been identified. We aim at identifying the mutant gene responsible for this epileptic form. Methods Genes included in the ADCME critical region were prioritized and directly sequenced. Co-immunoprecipitation, immunofluorescence and electrophysiology approaches on transfected human cells have been utilized for testing the functional significance of the identified mutation. Results Here we show that mutation in the α2-adrenergic receptor subtype B (α2B-AR) associates to ADCME by identifying a novel in-frame insertion/deletion in two Italian families. The mutation alters several conserved residues of the third intracellular (3i) loop, neither hampering the α2B-AR plasma membrane localization nor the arrestin-mediated internalization capacity, but altering the binding with the scaffolding protein spinophilin upon neurotransmitter activation. Spinophilin, in turn, regulates interaction of GPCRs with Regulators of G proteins Signaling proteins. Accordingly, the mutant α2B-AR increases the epinephrine-stimulated calcium signaling. Interpretation The identified mutation is responsible for ADCME, as the loss of α2B-AR/spinophilin interaction causes a gain of function effect. This work implicates for the first time the α-adrenergic system in human epilepsy and opens new ways for understanding the molecular pathway of epileptogenesis, widening the spectrum of possible therapeutic targets. PMID:24114805

  14. The relationship between the renal clearance of creatinine and the apparent renal clearance of beta-2-microglobulin in patients with normal and impaired kidney function.

    PubMed

    Vree, T B; Guelen, P J; Jongman-Nix, B; Walenkamp, G H

    1981-07-18

    The renal clearances of creatinine and beta 2-microglobulin of patients with either normal or impaired kidney function were measured. The renal clearance of beta 2-microglobulin depends on the urinary pH and must be considered as an apparent renal clearance because after tubular reabsorption the compound is metabolized in the kidney. Impaired kidney function reduces the percentage of tubular reabsorption of beta 2-microglobulin. PMID:6166414

  15. The rapid and effective administration of a beta 2-agonist to horses with heaves using a compact inhalation device and metered-dose inhalers.

    PubMed Central

    Tesarowski, D B; Viel, L; McDonell, W N; Newhouse, M T

    1994-01-01

    The purpose of the study was to administer therapeutic aerosol generated by metered-dose inhalers to horses exhibiting clinical signs of heaves using a compact inhalation device developed for human medicine. It was fitted to a custom face mask in order to study the effect of an inhaled beta 2-agonist, fenoterol. Pulmonary function testing was performed on six horses following an acute exacerbation of heaves, characterized by tachypnea, wheezes, crackles, and spasmodic cough. Horses inhaled fenoterol in 1 mg increments administered as one 200 microgram puff every 5-10 s with the recording of data 5 min after the cessation of drug inhalation. A significant effect of fenoterol was shown for maximum change in transpulmonary pressure, dynamic compliance, lung resistance, and work of breathing, and the wheezes and crackles disappeared when auscultation was performed at the end of the test. This study demonstrates a novel, highly effective method for the rapid administration of inhaled medication in horses. PMID:8055432

  16. Homology modeling and antagonist binding site study of the human histamine H2 receptor.

    PubMed

    Zhang, Jing; Qi, Tao; Wei, Jing

    2012-11-01

    On the basis of the high resolution crystal structures of bovine rhodopsin, human beta2-adrenergic receptor and human A(2a) adenosine receptor, three-dimensional structure of the human histamine H2 receptor (HHR2) was developed by homology modeling. Results of the evaluations suggest that a high quality homology model for HHR2 has been obtained. Three antagonists, cimetidine, ranitidine and nizatidine, were applied to binding site study with this model through molecular docking, molecular dynamics simulations and the molecular mechanics-Poisson-Boltzmann surface area calculations. One aspartic acid, Asp98 in transmembrane domain 7 (TM3), has been identified as major contributors to ligand binding by H-bond interactions. Asn159 in TM4 and Asp186 in TM5 are of great importance in stabilizing HHR2- antagonist complexes. Two hydrophobic sites especially two residues, Val99 in TM3 and Phe254 in TM6, were identified to be essential for their strong hydrophobic interactions with antagonists. The findings reported here are in agreement with available experimental mutagenesis data. This study should be very helpful for a better understanding of the action mode of the antagonist and for guiding further drug design and mutagenesis studies. PMID:22779803

  17. Enterotoxemia associated with beta2 toxin-producing Clostridium perfringens type A in two Asiatic black bears (Selenarctos thibetanus).

    PubMed

    Greco, Grazia; Madio, Anna; Martella, Vito; Campolo, Marco; Corrente, Marialaura; Buonavoglia, Domenico; Buonavoglia, Canio

    2005-03-01

    Beta2 (beta2) toxin-producing Clostridium perfringens type A strains were found to be associated with necrotic and hemorrhagic intestinal lesions in 2 Asiatic black bears (Selenarctos thibetanus) that died suddenly. Ten isolates were obtained from the liver, lungs, heart, and small and large intestine of the animals and were examined by multiplex polymerase chain reaction for the genes encoding the 4 lethal toxins (alpha, beta, epsilon, and iota) for classification into toxin types as well as for the genes encoding enterotoxin and the novel beta2-toxin for subclassification. In addition, the cpb2 sequence of the 10 isolates was different from the published sequence of cpb2 of pig type C isolate CWC245, whereas it was highly similar to the cpb2 sequence of the C. perfringens type A strain 13. This finding suggests the existence of 2 cpb2 subtypes. This is the first report of enterotoxemia associated with the presence of C. perfringens producing beta2-toxin in the tissues and intestinal content of Asiatic black bears. PMID:15825503

  18. Neuroprotection of microglial conditioned medium on 6-hydroxydopamine-induced neuronal death: role of transforming growth factor beta-2.

    PubMed

    Polazzi, Elisabetta; Altamira, Luis Emiliano Peña; Eleuteri, Simona; Barbaro, Raffaella; Casadio, Chiara; Contestabile, Antonio; Monti, Barbara

    2009-07-01

    Microglia, the immune cells of the CNS, play essential roles in both physiological and pathological brain states. Here we have used an in vitro model to demonstrate neuroprotection of a 48 h-microglial conditioned medium (MCM) towards cerebellar granule neurons (CGNs) challenged with the neurotoxin 6-hydroxydopamine, which induces a Parkinson-like neurodegeneration, and to identify the protective factor(s). MCM nearly completely protects CGNs from 6-hydroxydopamine neurotoxicity and at least some of the protective factor(s) are peptidic in nature. While the fraction of the medium containing molecules < 30 kDa completely protects CGNs, fractions containing molecules < 10 kDa or > 10 kDa are not neuroprotective. We further demonstrate that microglia release high amounts of transforming growth factor-beta2 (TGF-beta2) and that its exogenous addition to the fraction of the medium not containing it (< 10 kDa) fully restores the neuroprotective action. Moreover, MCM neuroprotection is significantly counteracted by an inhibitor of TGF-beta2 transduction pathway. Our results identify TGF-beta2 as an essential neuroprotective factor released by microglia in its culture medium that requires to be fully effective the concomitant presence of other factor(s) of low molecular weight. PMID:19457129

  19. Retinoic acid receptor beta2 and neurite outgrowth in the adult mouse spinal cord in vitro.

    PubMed

    Corcoran, Jonathan; So, Po-Lin; Barber, Robert D; Vincent, Karen J; Mazarakis, Nicholas D; Mitrophanous, Kyriacos A; Kingsman, Susan M; Maden, Malcolm

    2002-10-01

    Retinoic acid, acting through the nuclear retinoic acid receptor beta2 (RARbeta2), stimulates neurite outgrowth from peripheral nervous system tissue that has the capacity to regenerate neurites, namely, embryonic and adult dorsal root ganglia. Similarly, in central nervous system tissue that can regenerate, namely, embryonic mouse spinal cord, retinoic acid also stimulates neurite outgrowth and RARbeta2 is upregulated. By contrast, in the adult mouse spinal cord, which cannot regenerate, no such upregulation of RARbeta2 by retinoic acid is observed and no neurites are extended in vitro. To test our hypothesis that the upregulation of RARbeta2 is crucial to neurite regeneration, we have transduced adult mouse or rat spinal cord in vitro with a minimal equine infectious anaemia virus vector expressing RARbeta2. After transduction, prolific neurite outgrowth occurs. Outgrowth does not occur when the cord is transduced with a different isoform of RARbeta nor does it occur following treatment with nerve growth factor. These data demonstrate that RARbeta2 is involved in neurite outgrowth, at least in vitro, and that this gene may in the future be of some therapeutic use. PMID:12235288

  20. Day-to-day variation of bronchodilatory response to an inhaled beta-2-stimulant in asthmatics.

    PubMed

    Lindgren, S; Bake, B; Larsson, S

    1987-01-01

    The effect of inhaling 0.25 and 2.0 mg of terbutaline sulphate, a beta-2-stimulant, from a metered dose aerosol was studied in five asthmatic patients during two periods of five days each. During the first period, the patients used a good spontaneous inhalation technique; during the second period, the inhalation technique was optimized and controlled. The variation of basal FEV1 and of the increase (delta FEV1) caused by 0.25 mg of inhaled terbutaline was considerable. The effect was only slightly better and the variation only slightly smaller when the controlled inhalation technique was used. The differences were not significant. In individual patients, there was no or negative correlation between delta FEV1 and the corresponding basal FEV1 value. Accordingly, the most commonly used way of expressing delta FEV1 as a percentage of basal FEV1 value was found to be insensitive. Delta FEV1, expressed as a percentage of the maximum available FEV1 increase on the same day after 2.25 mg terbutaline sulphate, was found to be most sensitive. This way of expressing delta FEV1 will increase the possibilities of detecting differences between treatments in clinical trials. PMID:3453755

  1. NeuroD1/beta2 contributes to cell-specific transcription of the proopiomelanocortin gene.

    PubMed Central

    Poulin, G; Turgeon, B; Drouin, J

    1997-01-01

    NeuroD1/beta2 is a basic helix-loop-helix (bHLH) factor expressed in the endocrine cells of the pancreas and in a subset of neurons as they undergo terminal differentiation. We now show that NeuroD1 is expressed in corticotroph cells of the pituitary gland and that it is involved in cell-specific transcription of the proopiomelanocortin (POMC) gene. It was previously shown that corticotroph-specific POMC transcription depends in part on the action of cell-restricted bHLH factors that were characterized as the CUTE (corticotroph upstream transcription element) (M. Therrien and J. Drouin, Mol. Cell. Biol. 13:2342-2353, 1993) complexes. We now demonstrate that these complexes contain NeuroD1 in association with various ubiquitous bHLH dimerization partners. The NeuroD1-containing heterodimers specifically recognize and activate transcription from the POMC promoter E box that confers transcriptional specificity. Interestingly, the NeuroD1 heterodimers activate transcription in synergy with Ptx1, a Bicoid-related homeodomain protein, which also contributes to corticotroph specificity of POMC transcription. In the adult pituitary gland, NeuroD1 transcripts are detected in POMC-expressing corticotroph cells. Taken together with the restricted pattern of Ptx1 expression, these results suggest that these two factors establish the basis of a combinatorial code for the program of corticotroph-specific gene expression. PMID:9343431

  2. Desformylflustrabromine: A Novel Positive Allosteric Modulator for beta2 Subunit Containing Nicotinic Receptor Sub-Types.

    PubMed

    Pandya, Anshul A

    2016-01-01

    Nicotinic acetylcholine receptors are ligand-gated transmembrane ion channels that are present at the neuromuscular junction and in different locations in the nervous system. The different subtypes of neuronal nicotinic acetylcholine receptors that are found in the brain are thought to be involved in many neurological processes such as pain, cognitive function and depression, as well as in the pathophysiology of numerous neurological diseases and conditions. While the neurotransmitter acetylcholine is an endogenous agonist for all nicotinic receptors subtypes, many drugs that act as agonists and antagonists have also been identified or developed for these receptors. In addition, a novel class of compounds described as allosteric modulators have also been identified or developed for nicotinic acetylcholine receptors. Allosteric modulators are ligands that bind to nicotinic receptors at sites other than the orthosteric site where acetylcholine binds. One such allosteric modulator is desformylflustrabromine. Five chemical analogs along with desformylflustrabromine act as positive allosteric modulator for nAChRs that contain the beta2 subunit in their pentameric structure. Here the discovery and development, medicinal chemistry and pharmacological actions of desformylflustrabromine have been discussed. Desformylflustrabromine and its chemical analogs have the potential to develop into clinically used drugs for neurological diseases and conditions where nicotinic acetylcholine receptors are involved. PMID:26818864

  3. Cross-over study of the efficacy of four beta 2-sympathomimetic bronchodilator aerosols.

    PubMed Central

    Madsen, B W; Tandon, M K; Paterson, J W

    1979-01-01

    1 Bronchodilator efficacy of four beta 2-sympathomimetic aerosols, fenoterol, orciprenaline, salbutamol and terbutaline has been compared in nine patients with chronic stable reversible airways obstruction using a double-blind placebo controlled cross-over design. Two puffs of each agent were given on two separate occasions to each of the patients and the forced expiratory volume in one second (FEV1) and the vital capacity (VC) were measured before and 30, 90, 150 and 210 min after administration. 2 Multivariate analysis of the data at 30 min showed FEV1 and VC in these patients to be so highly correlated that they could be considered as a single variable. 3 When absolute change in VC at 30 min was used as the response criterion, efficacy of the four drugs was significantly better than placebo (P < 0.01). It was not possible to rank all four drugs in order of effectiveness; fenoterol and salbutamol were significantly better than terbutaline and orciprenaline (P < 0.01) but this was complicated by a significant interaction effect between drugs and patients (P < 0.01). 4 Similar results were obtained when absolute and relative changes in FEV1 and VC and area under the curve were used as response variables. 5 The study demonstrates that important individual differences in patient response may be concealed if only average drug effects are considered. PMID:45195

  4. The asthmatic athlete: inhaled Beta-2 agonists, sport performance, and doping.

    PubMed

    McKenzie, Donald C; Fitch, Kenneth D

    2011-01-01

    The asthmatic athlete has a long history in competitive sport in terms of success in performance and issues related to doping. Well documented are detailed objective tests used to evaluate the athlete with symptoms of asthma or airway hyperresponsiveness and the medical management. Initiated at the 2002 Salt Lake City Games, the International Olympic Committee's Independent Asthma Panel required testing to justify the use of inhaled beta-2 agonists (IBAs) in Olympic athletes and has provided valuable guidelines to the practicing physician. This program was educational and documented the variability in prevalence of asthma and/or airway hyperresponsiveness and IBA use between different sports and different countries. It provided a standard of care for the athlete with respiratory symptoms and led to the discovery that asthmatic Olympic athletes outperformed their peers at both Summer and Winter Olympic Games from 2002 to 2010. Changes to the World Anti-Doping Agency's Prohibited List in 2010 permitted the use of 2 IBA produced by the same pharmaceutical company. All others remain prohibited. However, there is no pharmacological difference between the permitted and prohibited IBAs. As a result of these changes, asthmatic athletes are being managed differently based on a World Anti-Doping Agency directive that has no foundation in pharmacological science or in clinical practice. PMID:21200170

  5. The Implication and Significance of Beta 2 Microglobulin: A Conservative Multifunctional Regulator

    PubMed Central

    Li, Ling; Dong, Mei; Wang, Xiao-Guang

    2016-01-01

    Objective: This review focuses on the current knowledge on the implication and significance of beta 2 microglobulin (β2M), a conservative immune molecule in vertebrate. Data Sources: The data used in this review were obtained from PubMed up to October 2015. Terms of β2M, immune response, and infection were used in the search. Study Selections: Articles related to β2M were retrieved and reviewed. Articles focusing on the characteristic and function of β2M were selected. The exclusion criteria of articles were that the studies on β2M-related molecules. Results: β2M is critical for the immune surveillance and modulation in vertebrate animals. The dysregulation of β2M is associated with multiple diseases, including endogenous and infectious diseases. β2M could directly participate in the development of cancer cells, and the level of β2M is deemed as a prognostic marker for several malignancies. It also involves in forming major histocompatibility complex (MHC class I or MHC I) or like heterodimers, covering from antigen presentation to immune homeostasis. Conclusions: Based on the characteristic of β2M, it or its signaling pathway has been targeted as biomedical or therapeutic tools. Moreover, β2M is highly conserved among different species, and overall structures are virtually identical, implying the versatility of β2M on applications. PMID:26879019

  6. Triiodothyronine Attenuates Prostate Cancer Progression Mediated by β-Adrenergic Stimulation

    PubMed Central

    Delgado-González, Evangelina; Sánchez-Tusie, Ana Alicia; Morales, Giapsy; Aceves, Carmen; Anguiano, Brenda

    2016-01-01

    Prostate cancer cells are responsive to adrenergic and thyroid stimuli. It is well established that β-adrenergic activation (protein kinase A [PKA]/cAMP response element binding protein [CREB]) promotes cancer progression, but the role of thyroid hormones is poorly understood. We analyzed the effects of β-adrenergic stimulation (isoproterenol [ISO]) and/or thyroid hormone on neuroendocrine (NE) differentiation and cell invasion, using in vivo (LNCaP tumor) and in vitro models (LNCaP and DU145 human cells). Nude mice were inoculated with LNCaP cells and were treated for 6 wks with ISO (200 μg/d), triiodothyronine (T3, 2.5 μg/d) or both. ISO alone reduced tumor growth but increased tumor expression of cAMP response element (CRE)-dependent genes (real-time polymerase chain reaction, chromogranin A, neuron-specific enolase, survivin, vascular endothelial growth factor [VEGF], urokinase plasmin activator [uPA] and metalloproteinase-9 [MMP-9]) and some proteins related to NE differentiation and/or invasiveness (synaptophysin, VEGF, pCREB). T3 reduced tumor growth and prevented the overexpression of ISO-stimulated factors through a pCREB-independent mechanism. In low invasive LNCaP cells, 50 μmol/L ISO or 100 nmol/L thyroxine (T4) induced the acquisition of NE-like morphology (phase-contrast microscopy), increased VEGF secretion (ELISA) and invasive capacity (Transwell assay), but no synergistic effects were observed after the coadministration of ISO + T4. In contrast, 10 nmol/L T3 alone had no effect, but it prevented the NE-like morphology and invasiveness stimulated by ISO. None of these treatments had any effect on highly invasive DU145 cells. In summary, this study showed that ISO and T4 increase cancer progression, and T3 attenuates ISO-stimulated progression. Further studies are required to determine if changes in the ratio of T4/T3 could be relevant for prostate cancer progression. PMID:26928389

  7. Combined corticosteroid and long-acting beta2-agonist in one inhaler versus long-acting beta2-agonists for chronic obstructive pulmonary disease

    PubMed Central

    Nannini, Luis Javier; Lasserson, Toby J; Poole, Phillippa

    2014-01-01

    Background Both inhaled steroids (ICS) and long-acting beta2-agonists (LABA) are used in the management of chronic obstructive pulmonary disease (COPD). This updated review compared compound LABA plus ICS therapy (LABA/ICS) with the LABA component drug given alone. Objectives To assess the efficacy of ICS and LABA in a single inhaler with mono-component LABA alone in adults with COPD. Search methods We searched the Cochrane Airways Group Specialised Register of trials. The date of the most recent search was November 2011. Selection criteria We included randomised, double-blind controlled trials. We included trials comparing compound ICS and LABA preparations with their component LABA preparations in people with COPD. Data collection and analysis Two authors independently assessed study risk of bias and extracted data. The primary outcomes were exacerbations, mortality and pneumonia, while secondary outcomes were health-related quality of life (measured by validated scales), lung function, withdrawals due to lack of efficacy, withdrawals due to adverse events and side-effects. Dichotomous data were analysed as random-effects model odds ratios or rate ratios with 95% confidence intervals (CIs), and continuous data as mean differences and 95% CIs. We rated the quality of evidence for exacerbations, mortality and pneumonia according to recommendations made by the GRADE working group. Main results Fourteen studies met the inclusion criteria, randomising 11,794 people with severe COPD. We looked at any LABA plus ICS inhaler (LABA/ICS) versus the same LABA component alone, and then we looked at the 10 studies which assessed fluticasone plus salmeterol (FPS) and the four studies assessing budesonide plus formoterol (BDF) separately. The studies were well-designed with low risk of bias for randomisation and blinding but they had high rates of attrition, which reduced our confidence in the results for outcomes other than mortality. Primary outcomes There was low quality

  8. Effects of cigarette smoke exposure on nicotinic acetylcholine receptor subunits {alpha}7 and {beta}2 in the sudden infant death syndrome (SIDS) brainstem

    SciTech Connect

    Machaalani, Rita; Say, Meichien; Waters, Karen A.

    2011-12-15

    It is postulated that nicotine, as the main neurotoxic constituent of cigarette smoke, influences SIDS risk through effects on nicotinic acetylcholine receptors (nAChRs) in brainstem nuclei that control respiration and arousal. This study compared {alpha}7 and {beta}2 nAChR subunit expression in eight nuclei of the caudal and rostral medulla and seven nuclei of the pons between SIDS (n = 46) and non-SIDS infants (n = 14). Evaluation for associations with known SIDS risk factors included comparison according to whether infants had a history of exposure to cigarette smoke in the home, and stratification for sleep position and gender. Compared to non-SIDS infants, SIDS infants had significantly decreased {alpha}7 in the caudal nucleus of the solitary tract (cNTS), gracile and cuneate nuclei, with decreased {beta}2 in the cNTS and increased {beta}2 in the facial. When considering only the SIDS cohort: 1-cigarette smoke exposure was associated with increased {alpha}7 in the vestibular nucleus and increased {beta}2 in the rostral dorsal motor nucleus of the vagus, rNTS and Cuneate, 2-there was a gender interaction for {alpha}7 in the gracile and cuneate, and {beta}2 in the cNTS and rostral arcuate nucleus, and 3-there was no effect of sleep position on {alpha}7, but prone sleep was associated with decreased {beta}2 in three nuclei of the pons. In conclusion, SIDS infants demonstrate differences in expression of {alpha}7 and {beta}2 nAChRs within brainstem nuclei that control respiration and arousal, which is independent on prior history of cigarette smoke exposure, especially for the NTS, with additional differences for smoke exposure ({beta}2), gender ({alpha}7 and {beta}2) and sleep position ({beta}2) evident. -- Highlights: Black-Right-Pointing-Pointer The 'normal' response to smoke exposure is decreased {alpha}7 and {beta}2 in certain nuclei. Black-Right-Pointing-Pointer SIDS infants have decreased {alpha}7 in cNTS, Grac and Cun. Black-Right-Pointing-Pointer SIDS

  9. Mapping Neuronal Activation and the Influence of Adrenergic Signaling during Contextual Memory Retrieval

    ERIC Educational Resources Information Center

    Zhang, Wei-Ping; Guzowski, John F.; Thomas, Steven A.

    2005-01-01

    We recently described a critical role for adrenergic signaling in the hippocampus during contextual and spatial memory retrieval. To determine which neurons are activated by contextual memory retrieval and its sequelae in the presence and absence of adrenergic signaling, transcriptional imaging for the immediate-early gene "Arc" was used in…

  10. Antagonism of Lateral Amygdala Alpha1-Adrenergic Receptors Facilitates Fear Conditioning and Long-Term Potentiation

    ERIC Educational Resources Information Center

    Lazzaro, Stephanie C.; Hou, Mian; Cunha, Catarina; LeDoux, Joseph E.; Cain, Christopher K.

    2010-01-01

    Norepinephrine receptors have been studied in emotion, memory, and attention. However, the role of alpha1-adrenergic receptors in fear conditioning, a major model of emotional learning, is poorly understood. We examined the effect of terazosin, an alpha1-adrenergic receptor antagonist, on cued fear conditioning. Systemic or intra-lateral amygdala…

  11. Influence of adrenergic drugs upon vital organ perfusion during CPR.

    PubMed

    Holmes, H R; Babbs, C F; Voorhees, W D; Tacker, W A; de Garavilla, B

    1980-03-01

    To determine whether adrenergic drugs administered during CPR alter the distribution of artificial cardiac output, the authors measured regional blood flow and cardiac output using radioactive microspheres in 12 dogs. Ventricular fibrillation was induced electrically and CPR was immediately begun with a mechanical chest compressor and ventilator (Thumper) at 60 compressions/min, with a ventilation: compression ratio of 1:5, a compression duration of 0.5 sec, and a ventilation pressure of 20 cm H2O. Compression force was sufficient to develop 40--50 mm Hg peak intraesophageal pressure. After 30 sec of CPR, either 0.9% saline vehicle or 50 micrograms/kg of epinephrine, phenylephrine, or isoproterenol was administered through a central venous catheter. One min later, microspheres were injected into the left ventricle. After 250 sec of CPR, the ventricles were defibrillated electrically. Between each drug injection, 20-min recovery periods were interposed. Each dog received all three drugs and saline according to a predetermined sequence. After saline, epinephrine, phenylephrine, and isoproterenol treatment, respective, cardiac output averaged 392, 319, 255, and 475 ml/min; brain blood flow averaged 37, 54, 29, and 28 ml/min; coronary blood flow averaged 25, 79, 26, and 15 ml/min; and kidney blood flow averaged 44, 4, 16, and 29 ml/min. Epinephrine improved blood flow to the brain, probably because of its alpha-adrenergic activity. Epinephrine improved blood flow to the heart during CPR much more than the other agents, probably because of its combined alpha- and beta-adrenergic activity. This effect may explain its superiority in restoring circulation after prolonged arrest and resuscitation. Isoproterenol should not be used in CPR because it shunts blood away from vital organs. PMID:7363628

  12. Adrenergic signaling and oxidative stress: a role for sirtuins?

    PubMed Central

    Corbi, Graziamaria; Conti, Valeria; Russomanno, Giusy; Longobardi, Giancarlo; Furgi, Giuseppe; Filippelli, Amelia; Ferrara, Nicola

    2013-01-01

    The adrenergic system plays a central role in stress signaling and stress is often associated with increased production of ROS. However, ROS overproduction generates oxidative stress, that occurs in response to several stressors. β-adrenergic signaling is markedly attenuated in conditions such as heart failure, with downregulation and desensitization of the receptors and their uncoupling from adenylyl cyclase. Transgenic activation of β2-adrenoceptor leads to elevation of NADPH oxidase activity, with greater ROS production and p38MAPK phosphorylation. Inhibition of NADPH oxidase or ROS significantly reduced the p38MAPK signaling cascade. Chronic β2-adrenoceptor activation is associated with greater cardiac dilatation and dysfunction, augmented pro-inflammatory and profibrotic signaling, while antioxidant treatment protected hearts against these abnormalities, indicating ROS production to be central to the detrimental signaling of β2-adrenoceptors. It has been demonstrated that sirtuins are involved in modulating the cellular stress response directly by deacetylation of some factors. Sirt1 increases cellular stress resistance, by an increased insulin sensitivity, a decreased circulating free fatty acids and insulin-like growth factor (IGF-1), an increased activity of AMPK, increased activity of PGC-1a, and increased mitochondrial number. Sirt1 acts by involving signaling molecules such P-I-3-kinase-Akt, MAPK and p38-MAPK-β. βAR stimulation antagonizes the protective effect of the AKT pathway through inhibiting induction of Hif-1α and Sirt1 genes, key elements in cell survival. More studies are needed to better clarify the involvement of sirtuins in the β-adrenergic response and, overall, to better define the mechanisms by which tools such as exercise training are able to counteract the oxidative stress, by both activation of sirtuins and inhibition of GRK2 in many cardiovascular conditions and can be used to prevent or treat diseases such as heart failure

  13. Immunological release of histamine from bovine leucocytes. Unusual adrenergic modulation.

    PubMed Central

    Holroyde, M C; Eyre, P

    1976-01-01

    Sensitized bovine granulocytes release histamine when exposed to specific antigen. In comparison with in vitro systems in several other species, the modulation of this release by adrenergic agents is unique. Beta-Adrenoceptor stimulation potentiates (rather than inhibits), whereas alpha-adrenoceptor stimulation inhibits (rather than potentiates) histamine release. Adrenaline, which is generally considered to be a physiological antagonist of the anaphylactic reaction, potentiated histamine release in this study. Dopamine, which is present in high concentration in bovine mast cells, was without effect. The results are discussed in terms of the possible role of granulocytes in bovine hypersensitivity. PMID:60282

  14. Tubulin polymerization disrupts cardiac β-adrenergic regulation of late INa

    PubMed Central

    Dybkova, Nataliya; Wagner, Stefan; Backs, Johannes; Hund, Thomas J.; Mohler, Peter J.; Sowa, Thomas; Nikolaev, Viacheslav O.; Maier, Lars S.

    2014-01-01

    Aims The anticancer drug paclitaxel (TXL) that polymerizes microtubules is associated with arrhythmias and sinus node dysfunction. TXL can alter membrane expression of Na channels (NaV1.5) and Na current (INa), but the mechanisms are unknown. Calcium/calmodulin-dependent protein kinase II (CaMKII) can be activated by β-adrenergic stimulation and regulates INa gating. We tested whether TXL interferes with isoproterenol (ISO)-induced activation of CaMKII and consequent INa regulation. Methods and results In wild-type mouse myocytes, the addition of ISO (1 µmol/L) resulted in increased CaMKII auto-phosphorylation (western blotting). This increase was completely abolished after pre-treatment with TXL (100 µmol/L, 1.5 h). The mechanism was further investigated in human embryonic kidney cells. TXL inhibited the ISO-induced β-arrestin translocation. Interestingly, both knockdown of β-arrestin2 expression using small interfering RNA and inhibition of exchange protein directly activated by cAMP (Epac) blocked the ISO-induced CaMKII auto-phosphorylation similar to TXL. The generation of cAMP, however, was unaltered (Epac1-camps). CaMKII-dependent Na channel function was measured using patch-clamp technique in isolated cardiomyoctes. ISO stimulation failed to induce CaMKII-dependent enhancement of late INa and Na channel inactivation (negative voltage shift in steady-state activation and enhanced intermediate inactivation) after pre-incubation with TXL. Consistent with this, TXL also inhibited ISO-induced CaMKII-specific Na channel phosphorylation (at serine 571 of NaV1.5). Conclusion Pre-incubation with TXL disrupts the ISO-dependent CaMKII activation and consequent Na channel regulation. This may be important for patients receiving TXL treatments, but also relevant for conditions of increased CaMKII expression and enhanced β-adrenergic stimulation like in heart failure. PMID:24812278

  15. Specificity and impact of adrenergic projections to the midbrain dopamine system.

    PubMed

    Mejias-Aponte, Carlos A

    2016-06-15

    Dopamine (DA) is a neuromodulator that regulates different brain circuits involved in cognitive functions, motor coordination, and emotions. Dysregulation of DA is associated with many neurological and psychiatric disorders such as Parkinson's disease and substance abuse. Several lines of research have shown that the midbrain DA system is regulated by the central adrenergic system. This review focuses on adrenergic interactions with midbrain DA neurons. It discusses the current neuroanatomy including source of adrenergic innervation, type of synapses, and adrenoceptors expression. It also discusses adrenergic regulation of DA cell activity and neurotransmitter release. Finally, it reviews several neurological and psychiatric disorders where changes in adrenergic system are associated with dysregulation of the midbrain DA system. This article is part of a Special Issue entitled SI: Noradrenergic System. PMID:26820641

  16. Adrenergic Drugs Blockers or Enhancers for Cognitive Decline ? What to Choose for Alzheimer's Disease Patients?

    PubMed

    Femminella, Grazia D; Leosco, Dario; Ferrara, Nicola; Rengo, Giuseppe

    2016-01-01

    The adrenergic system has an important role in normal central nervous system function as well as in brain disease. The locus coeruleus, the main source of norepinephrine in brain, is involved in the regulation of learning and memory, reinforcement of sleep-wake cycle and synaptic plasticity. In Alzheimer's disease, locus coeruleus degeneration is observed early in the course of the disease, years before the onset of clinical cognitive signs, with neurofibrillary detected at the stage of mild cognitive impairment, preceding amyloid deposition. Thus, in the last years, a great interest has grown in evaluating the possibility of central adrenergic system modulation as a therapeutic tool in Alzheimer's disease. However, evidences do not show univocal results, with some studies suggesting that adrenergic stimulation might be beneficial in Alzheimer's Disease and some others favoring adrenergic blockade. In this review, we summarize data from both hypothesis and describe the pathophysiological role of the adrenergic system in neurodegeneration. PMID:27189470

  17. POINT 2011: ENDF/B-VII.1 Beta2 Temperature Dependent Cross Section Library

    SciTech Connect

    Cullen, D E

    2011-04-07

    This report is one in the series of 'POINT' reports that over the years have presented temperature dependent cross sections for the then current version of ENDF/B. In each case I have used my personal computer at home and publicly available data and codes. I have used these in combination to produce the temperature dependent cross sections used in applications and presented in this report. I should mention that today anyone with a personal computer can produce these results. The latest ENDF/B-VII.1 beta2 data library was recently and is now freely available through the National Nuclear Data Center (NNDC), Brookhaven National Laboratory. This release completely supersedes all preceding releases of ENDF/B. As distributed the ENDF/B-VII.1 data includes cross sections represented in the form of a combination of resonance parameters and/or tabulated energy dependent cross sections, nominally at 0 Kelvin temperature. For use in our applications the ENDF/B-VII.1 library has been processed into cross sections at eight neutron reactor like temperatures, between 0 and 2100 Kelvin, in steps of 300 Kelvin (the exception being 293.6 Kelvin, for exact room temperature at 20 Celsius). It has also been processed to five astrophysics like temperatures, 1, 10, 100 eV, 1 and 10 keV. For reference purposes, 300 Kelvin is approximately 1/40 eV, so that 1 eV is approximately 12,000 Kelvin. At each temperature the cross sections are tabulated and linearly interpolable in energy. All results are in the computer independent ENDF-6 character format [R2], which allows the data to be easily transported between computers. In its processed form the POINT 2011 library is approximately 16 gigabyte in size and is distributed on one compressed DVDs (see, below for the details of the contents of each DVD).

  18. Serum beta-2 microglobulin as a prognostic biomarker in patients with mantle cell lymphoma.

    PubMed

    Yoo, Changhoon; Yoon, Dok Hyun; Kim, Shin; Huh, Jooryung; Park, Chan-Sik; Park, Chan-Jeong; Lee, Sang-Wook; Suh, Cheolwon

    2016-03-01

    Although serum beta-2 microglobulin (B2M) has been suggested as a prognostic factor for mantle cell lymphoma (MCL), additional data are necessary to confirm its role. Between November 2005 and July 2014, a total of 52 patients with MCL were identified from the database of Asan Medical Center, Seoul, Korea. Pretreatment serum B2M information was available in 50 patients (96%). Overall survival (OS) was compared according to the serum B2M level with a cut-off value of 2.5 mg/L. The median MCL international prognostic index (MIPI) score was 5.84 (range 4.72-7.80), and the median biologic MIPI (MIPI-b) score was 6.27 (4.93-8.47). Pretreatment serum B2M was elevated in 30 patients (60%) and was significantly related to advanced stage (p = 0.02) and high MIPI (p = 0.03) and MIPI-b (p = 0.03) scores. With median follow-up duration of 29.8 months (range 0.8-87.0 months), the median OS was 56.2 months [95% confidence interval (CI) 36.6-75.9 months] in all patients, and serum B2M was significantly associated with OS (p = 0.001). In multivariate analyses adjusted for MIPI or MIPI-b scores and rituximab, elevated serum B2M was significantly associated with poor OS (when adjusting MIPI, hazard ratio = 26.4, 95% CI 2.9-241.3, p = 0.004; when adjusting MIPI-b, hazard ratio = 20.1, 95% CI 2.4-170.1, p = 0.006). Thus, pretreatment serum B2M may be an independent and significant prognostic factor in patients with MCL. PMID:25689467

  19. Investigations into factors determining the duration of action of the beta 2-adrenoceptor agonist, salmeterol.

    PubMed Central

    Nials, A. T.; Sumner, M. J.; Johnson, M.; Coleman, R. A.

    1993-01-01

    1. This study has explored the mechanism underlying the long duration of action of the beta 2-adrenoceptor agonist, salmeterol. 2. Salmeterol, salbutamol and isoprenaline caused a concentration-related inhibition of electrically-induced contractile responses of the guinea-pig superfused trachea preparation. The effects of both isoprenaline and salbutamol were rapid in onset and rapidly reversed upon removal of the agonist. In contrast, the effects of salmeterol were slower in onset and could not be reversed by superfusion of the tissue with agonist-free Krebs solution even for periods of up to 10 h. 3. The effects of salmeterol were, however, readily reversed by a number of beta-adrenoceptor blocking drugs, as was the effect of a continuous infusion of isoprenaline. Upon removal of the antagonist, however, the effects of salmeterol and of the isoprenaline infusion were reasserted at a rate which was inversely related to the lipophilicity of a beta-adrenoceptor blocking drugs. 4. Salmeterol inhibited the binding of [125I]-(-)-iodopindolol (100 pM) to rat lung membranes (pIC50 7.1), with isoprenaline (pIC50 6.2) and salbutamol (pIC50 5.1) having lower potencies. The inhibition of binding by salmeterol was apparently non-competitive, whereas that produced by salbutamol and isoprenaline was competitive in nature. 5. Isoprenaline and salbutamol rapidly dissociated from their binding sites, whereas in marked contrast, the binding of salmeterol showed no dissociation for periods of up to 1 h.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8095419

  20. Loss of bone marrow adrenergic beta 1 and 2 receptors modifies transcriptional networks, reduces circulating inflammatory factors, and regulates blood pressure.

    PubMed

    Ahmari, Niousha; Schmidt, Jordan T; Krane, Gregory A; Malphurs, Wendi; Cunningham, Bruce E; Owen, Jennifer L; Martyniuk, Christopher J; Zubcevic, Jasenka

    2016-07-01

    Hypertension (HTN) is a prevalent condition with complex etiology and pathophysiology. Evidence exists of significant communication between the nervous system and the immune system (IS), and there appears to be a direct role for inflammatory bone marrow (BM) cells in the pathophysiology of hypertension. However, the molecular and neural mechanisms underlying this interaction have not been characterized. Here, we transplanted whole BM cells from the beta 1 and 2 adrenergic receptor (AdrB1(tm1Bkk)AdrB2(tm1Bkk)/J) knockout (KO) mice into near lethally irradiated C57BL/6J mice to generate a BM AdrB1.B2 KO chimera. This allowed us to evaluate the role of the BM beta 1 and beta 2 adrenergic receptors in mediating BM IS homeostasis and regulating blood pressure (BP) in an otherwise intact physiological setting. Fluorescence-activated cell sorting demonstrated that a decrease in systolic and mean BP in the AdrB1.B2 KO chimera is associated with a decrease in circulating inflammatory T cells, macrophage/monocytes, and neutrophils. Transcriptomics in the BM identified 7,419 differentially expressed transcripts between the C57 and AdrB1.B2 KO chimera. Pathway analysis revealed differentially expressed transcripts related to several cell processes in the BM of C57 compared with AdrB1.B2 KO chimera, including processes related to immunity (e.g., T-cell activation, T-cell recruitment, cytokine production, leukocyte migration and function), the cardiovascular system (e.g., blood vessel development, peripheral nerve blood flow), and the brain (e.g., central nervous system development, neurite development) among others. This study generates new insight into the molecular events that underlie the interaction between the sympathetic drive and IS in modulation of BP. PMID:27235450

  1. Purification and characterization of beta 2-tomatinase, an enzyme involved in the degradation of alpha-tomatine and isolation of the gene encoding beta 2-tomatinase from Septoria lycopersici.

    PubMed

    Sandrock, R W; DellaPenna, D; VanEtten, H D

    1995-01-01

    Lycopersicon species often contain the toxic glycoalkaloid alpha-tomatine, which is proposed to protect these plants from general microbial infection. however, fungal pathogens of tomato often are tolerant to alpha-tomatine and detoxification of alpha-tomatine may be how these pathogens avoid this potential barrier. As an initial step to evaluate this possibility, we have purfied to homogeneity a beta-1,2-D glucosidase from the tomato pathogen Septoria lycopersici that hydrolyzes the beta-1,2-D glucosyl bond on the tetrasaccharide moiety of alpha-tomatine to produce beta2-tomatine. The enzyme is a 110-kDa protein with a pI of 4.5 and a Km for alpha-tomatine of 62 microM. Little or no activity was detected on a variety of other glycosides. The gene encoding this protein was isolated and contains an open reading frame of 803 amino acids that shares sequence homology with several other beta-D-glucosidases. When S. lycopersici was incubated with alpha-tomatine, beta2-tomatinase mRNA accumulated, suggesting that the enzyme is substrate inducible. Aspergillus nidulans expressed ¿beta2-tomatinase¿ activity when transformed with this gene but transformants were still sensitive to alpha-tomatine. PMID:8664504

  2. Thromboxane agonist (U46619) potentiates norepinephrine efflux from adrenergic nerves

    SciTech Connect

    Trachte, G.J.

    1986-05-01

    The effect of the synthetic thromboxane/prostaglandin (PG) H2 agonist U46619 on the electrically stimulated rabbit isolated vas deferens was examined to test for thromboxane influences on adrenergic nerves. U46619 effects on force generation, (/sup 3/H) norepinephrine release and norepinephrine-induced contractions were assessed to determine the mechanism of action. U46619 maximally enhanced adrenergic force generation 135 +/- 24% at a concentration of 100 nM. U46619 potentiated maximal contractile effects of exogenously administered norepinephrine 16 +/- 4% and augmented (/sup 3/H)norepinephrine release from electrically stimulated preparations 142 +/- 44%. A competitive thromboxane/PGH2 receptor antagonist, SQ29548, significantly shifted the concentration-response curve for U46619 to the right in a concentration-dependent manner and blocked U46619-induced tritium release. Thus, U46619 appears to potentiate neurotransmitter release by interacting with thromboxane/PGH2 receptors. Because SQ29548 did not prevent the potentiation of norepinephrine contractions by U46619, the postjunctional effect may be independent of thromboxane/PGH2 receptors. We interpret these results to be indicative of both pre- and postjunctional sites of action of U46619. The physiological importance of these thromboxane effects is unknown currently.

  3. Blood flow distribution with adrenergic and histaminergic antagonists

    SciTech Connect

    Baker, C.H.; Davis, D.L.; Sutton, E.T.

    1989-03-01

    Superficial fibular nerve stimulation (SFNS) causes increased pre- and post-capillary resistances as well as increased capillary permeability in the dog hind paw. These responses indicate possible adrenergic and histaminergic interactions. The distribution of blood flow between capillaries and arteriovenous anastomoses (AVA) may depend on the relative effects of these neural inputs. Right hind paws of anesthetized heparinized dogs were vascularly and neurally isolated and perfused with controlled pressure. Blood flow distribution was calculated from the venous recovery of 85Sr-labeled microspheres (15 microns). The mean transit times of 131I-albumin and 85Sr-labeled microspheres were calculated. The effects of adrenergic and histaminergic antagonists with and without SFNS were determined. Phentolamine blocked the entire response to SFNS. Prazosin attenuated increases in total and AVA resistance. Yohimbine prevented increased total resistance, attenuated the AVA resistance increase, and revealed a decrease in capillary circuit resistance. Pyrilamine attenuated total resistance increase while SFNS increased capillary and AVA resistances. Metiamide had no effect on blood flow distribution with SFNS. The increase in AVA resistance with SFNS apparently resulted from a combination of alpha 1 and alpha 2 receptor stimulation but not histaminergic effects.

  4. Beta-adrenergic stimulation of brown adipocyte proliferation.

    PubMed

    Géloën, A; Collet, A J; Guay, G; Bukowiecki, L J

    1988-01-01

    The mechanisms of brown adipose tissue (BAT) growth were studied by quantitative photonic radioautography using tritiated thymidine to follow mitotic activity. To identify the nature of the adrenergic pathways mediating brown adipocyte proliferation and differentiation, the effects of cold exposure (4 days at 4 degrees C) on BAT growth were compared with those induced by treating rats at 25 degrees C with norepinephrine (a mixed agonist), isoproterenol (a beta-agonist), and phenylephrine (an alpha-agonist). The drugs were continuously administrated via osmotic minipumps (0.375 mumol/h during 4 days) implanted subcutaneously. Cold exposure markedly enhanced the mitotic activity in brown adipocyte precursor cells (interstitial cells and preadipocytes) and endothelial cells forming the numerous capillaries. Norepinephrine mimicked the effects of cold exposure, not only on the mitotic activity, but also on the distribution of the labeling among the various cellular types. Isoproterenol entirely reproduced the effects of norepinephrine both on the labeling index and on the cellular type labeling frequency. In contrast, phenylephrine did not stimulate cell division. These results demonstrate that norepinephrine triggers a coordinated proliferation of brown adipocytes and endothelial cells in warm-exposed rats that is similar to that observed after cold exposure. They also suggest that cold exposure stimulates BAT growth by increasing the release of norepinephrine from sympathetic nerves and that the neurohormone activates mitoses in BAT precursor cells via beta-adrenergic pathways. PMID:2892422

  5. Effect of alpha1-adrenergic receptors in cardiac pathophysiology.

    PubMed

    Shannon, Richard; Chaudhry, Mohammad

    2006-11-01

    Compelling evidence now exists that proves adrenergic blockade is at the center of neurohormonal antagonism in heart failure (HF). Catecholamines are well known to act through both beta- and alpha-adrenergic receptors (ARs), which mediate their effects through distinct receptor pathways. Beta-AR blockers are commonly used in the treatment of HF and have distinct receptor affinity profiles. The recent COMET trial comparing 2 important beta-blocking drugs showed a distinct advantage for carvedilol in decreasing the risk of mortality from HF. The mechanism of action for carvedilol differs from metoprolol tartrate in its ability to block both alpha- and beta-ARs, leading to renewed interest in the potential role of alpha-ARs in the progression of HF. In contrast, however, the ALLHAT study discontinued use of doxazosin, an alpha1-receptor blocker because of an increase in cardiovascular events among patients using this drug. The results of these studies appear to be in contrast with respect to the role of alpha-ARs in regards to cardiovascular pathophysiology. Further study of the alpha-receptor and understanding the role of alpha-ARs in HF is necessary to understand the therapeutic effect of alpha-blockade. This article reviews our understanding of the alpha-AR in HF. PMID:17070143

  6. Control of yeast mating signal transduction by a mammalian. beta. sub 2 -adrenergic receptor and G sub s. alpha. subunit

    SciTech Connect

    King, K.; Caron, M.G.; Lefkowitz, R.J. ); Dohlman, H.G.; Thorner, J. )

    1990-10-05

    To facilitate functional and mechanistic studies of receptor-G protein interactions by expression of the human {beta}{sub 2}-adrenergic receptor (h{beta}-AR) has been expressed in Saccharomyces cerevisiae. This was achieved by placing a modified h{beta}-AR gene under control of the galactose-inducible GAL1 promoter. After induction by galactose, functional h{beta}-AR was expressed at a concentration several hundred times as great as that found in any human tissue. As determined from competitive ligand binding experiments, h{beta}-AR expressed in yeast displayed characteristic affinities, specificity, and stereoselectivity. Partial activation of the yeast pheromone response pathway by {beta}-adrenergic receptor agonists was achieved in cells coexpressing h{beta}-AR and a mammalian G protein (G{sub s}) {alpha} subunit - demonstrating that these components can couple to each other and to downstream effectors when expressed in yeast. This in vivo reconstitution system provides a new approach for examining ligand binding and G protein coupling to cell surface receptors.

  7. Adrenergic Repression of the Epigenetic Reader MeCP2 Facilitates Cardiac Adaptation in Chronic Heart Failure

    PubMed Central

    Mayer, Sandra C.; Gilsbach, Ralf; Preissl, Sebastian; Monroy Ordonez, Elsa Beatriz; Schnick, Tilman; Beetz, Nadine; Lother, Achim; Rommel, Carolin; Ihle, Hannah; Bugger, Heiko; Rühle, Frank; Schrepper, Andrea; Schwarzer, Michael; Heilmann, Claudia; Bönisch, Ulrike; Gupta, Shashi Kumar; Wilpert, Jochen; Kretz, Oliver; von Elverfeldt, Dominik; Orth, Joachim; Aktories, Klaus; Beyersdorf, Friedhelm; Bode, Christoph; Stiller, Brigitte; Krüger, Markus; Thum, Thomas; Doenst, Torsten; Stoll, Monika

    2015-01-01

    Rationale: In chronic heart failure, increased adrenergic activation contributes to structural remodeling and altered gene expression. Although adrenergic signaling alters histone modifications, it is unknown, whether it also affects other epigenetic processes, including DNA methylation and its recognition. Objective: The aim of this study was to identify the mechanism of regulation of the methyl-CpG–binding protein 2 (MeCP2) and its functional significance during cardiac pressure overload and unloading. Methods and Results: MeCP2 was identified as a reversibly repressed gene in mouse hearts after transverse aortic constriction and was normalized after removal of the constriction. Similarly, MeCP2 repression in human failing hearts resolved after unloading by a left ventricular assist device. The cluster miR-212/132 was upregulated after transverse aortic constriction or on activation of α1- and β1-adrenoceptors and miR-212/132 led to repression of MeCP2. Prevention of MeCP2 repression by a cardiomyocyte-specific, doxycycline-regulatable transgenic mouse model aggravated cardiac hypertrophy, fibrosis, and contractile dysfunction after transverse aortic constriction. Ablation of MeCP2 in cardiomyocytes facilitated recovery of failing hearts after reversible transverse aortic constriction. Genome-wide expression analysis, chromatin immunoprecipitation experiments, and DNA methylation analysis identified mitochondrial genes and their transcriptional regulators as MeCP2 target genes. Coincident with its repression, MeCP2 was removed from its target genes, whereas DNA methylation of MeCP2 target genes remained stable during pressure overload. Conclusions: These data connect adrenergic activation with a microRNA—MeCP2 epigenetic pathway that is important for cardiac adaptation during the development and recovery from heart failure. PMID:26195221

  8. Loss of Hypermethylated in Cancer 1 (HIC1) in Breast Cancer Cells Contributes to Stress-induced Migration and Invasion through β-2 Adrenergic Receptor (ADRB2) Misregulation*

    PubMed Central

    Boulay, Gaylor; Malaquin, Nicolas; Loison, Ingrid; Foveau, Bénédicte; Van Rechem, Capucine; Rood, Brian R.; Pourtier, Albin; Leprince, Dominique

    2012-01-01

    The transcriptional repressor HIC1 (Hypermethylated in Cancer 1) is a tumor suppressor gene inactivated in many human cancers including breast carcinomas. In this study, we show that HIC1 is a direct transcriptional repressor of β-2 adrenergic receptor (ADRB2). Through promoter luciferase activity, chromatin immunoprecipitation (ChIP) and sequential ChIP experiments, we demonstrate that ADRB2 is a direct target gene of HIC1, endogenously in WI-38 cells and following HIC1 re-expression in breast cancer cells. Agonist-mediated stimulation of ADRB2 increases the migration and invasion of highly malignant MDA-MB-231 breast cancer cells but these effects are abolished following HIC1 re-expression or specific down-regulation of ADRB2 by siRNA treatment. Our results suggest that early inactivation of HIC1 in breast carcinomas could predispose to stress-induced metastasis through up-regulation of the β-2 adrenergic receptor. PMID:22194601

  9. Rosiglitazone stimulates the release and synthesis of insulin by enhancing GLUT-2, glucokinase and BETA2/NeuroD expression

    SciTech Connect

    Kim, Hyo-Sup; Noh, Jung-Hyun; Hong, Seung-Hyun; Hwang, You-Cheol; Yang, Tae-Young; Lee, Myung-Shik; Kim, Kwang-Won; Lee, Moon-Kyu

    2008-03-14

    Peroxisome proliferator-activated receptor (PPAR)-{gamma} is a member of the nuclear receptor superfamily, and its ligands, the thiazolidinediones, might directly stimulate insulin release and insulin synthesis in pancreatic {beta}-cells. In the present study, we examined the effects of rosiglitazone (RGZ) on insulin release and synthesis in pancreatic {beta}-cell (INS-1). Insulin release and synthesis were stimulated by treatment with RGZ for 24 h. RGZ upregulated the expressions of GLUT-2 and glucokinase (GCK). Moreover, it was found that RGZ increased the expression of BETA2/NeuroD gene which could regulate insulin gene expression. These results suggest that RGZ could stimulate the release and synthesis of insulin through the upregulation of GLUT-2, GCK, and BETA2/NeuroD gene expression.

  10. Plasticity of surface structures and β2-adrenergic receptor localization in failing ventricular cardiomyocytes during recovery from heart failure

    PubMed Central

    Lyon, Alexander R.; Nikolaev, Viacheslav O.; Miragoli, Michele; Sikkel, Markus B.; Paur, Helen; Benard, Ludovic; Hulot, Jean-Sebastien; Kohlbrenner, Erik; Hajjar, Roger J.; Peters, Nicholas S.; Korchev, Yuri E.; Macleod, Ken T.; Harding, Sian E.; Gorelik, Julia

    2016-01-01

    Background Cardiomyocyte surface morphology and T-tubular structure are significantly disrupted in chronic heart failure with important functional sequelae, including redistribution of sarcolemmal beta2adrenergic receptors (β2AR) and localized secondary messenger signaling. Plasticity of these changes in the reverse remodeled failing ventricle is unknown. We used AAV9.SERCA2a gene therapy to rescue failing rat hearts, and measured z-groove index, T-tubule density and compartmentalized β2AR-mediated cAMP signals using a combined nanoscale scanning ion conductance microscopy-Förster resonance energy transfer technique. Methods and Results Cardiomyocyte surface morphology, quantified by z-groove index and T-tubule density, was normalized in reverse remodeled hearts following SERCA2a gene therapy. Recovery of sarcolemmal microstructure correlated with functional β2AR redistribution back into the z-groove and T-tubular network, whereas minimal cAMP responses were initiated following local β2AR stimulation of crest membrane, as observed in failing cardiomyocytes. Improvement of β2AR localization was associated with recovery of βAR-stimulated contractile responses in rescued cardiomyocytes. Retubulation was associated with reduced spatial heterogeneity of electrically-stimulated calcium transients, and recovery of myocardial BIN-1 and TCAP protein expression, but not junctophilin-2. Conclusions In summary, abnormalities of sarcolemmal structure in heart failure show plasticity with reappearance of z-grooves and T-tubules in reverse remodeled hearts. Recovery of surface topology is necessary for normalization of β2AR location and signaling responses. PMID:22456061

  11. Adrenergic Regulation of IgE Involves Modulation of CD23 and ADAM10 Expression on Exosomes1

    PubMed Central

    Padro, Caroline J.; Shawler, Todd M.; Gormley, Matthew G.; Sanders, Virginia M.

    2013-01-01

    Soluble CD23 (sCD23) plays a role in the positive regulation of an IgE response. Engagement of the beta-2 adrenergic receptor (β2AR) on a B cell is known to enhance the level of both sCD23 and IgE, although the mechanism by which this occurs is not completely understood. We report herein that, in comparison to a CD40L/IL-4-primed murine B cell alone, β2AR engagement on a primed B cell increased gene expression of ADAM10, which is the primary sheddase of CD23, and protein expression of both CD23 and ADAM10, in a PKA- and p38 MAPK-dependent manner, and promoted the localization of these proteins to exosomes as early as two days after priming, as determined by both Western blot and flow cytometry, and confirmed by electron microscopy. In comparison to isolated exosomes released from primed B cells alone, the transfer of exosomes released from β2AR agonist-exposed primed B cells to cultures of recipient primed B cells resulted in an increase in the level of IgE produced per cell, without affecting the number of cells producing IgE, as determined by ELISPOT. These effects still occurred when a β2AR antagonist was added along with the transfer to block residual agonist, and failed to occur when exosomes were isolated from β2AR-deficient B cells. These findings suggest that the mechanism responsible for mediating the β2AR-induced increase in IgE involves a shuttling of the β2AR-induced increase in CD23 and ADAM10 proteins to exosomes that subsequently mediate an increase in IgE. PMID:24140643

  12. Combined inhalation of beta2 -agonists improves swim ergometer sprint performance but not high-intensity swim performance.

    PubMed

    Kalsen, A; Hostrup, M; Bangsbo, J; Backer, V

    2014-10-01

    There is a high prevalence of asthma and airway hyperresponsiveness (AHR) in elite athletes, which leads to a major use of beta2 -agonists. In a randomized double-blinded crossover study, we investigated the effects of combined inhalation of beta2 -agonists (salbutamol, formoterol, and salmeterol), in permitted doses within the World Anti-Doping Agency 2013 prohibited list, in elite swimmers with (AHR, n = 13) or without (non-AHR, n = 17) AHR. Maximal voluntary isometric contraction of m. quadriceps (MVC), sprint performance on a swim ergometer and performance in an exhaustive swim test at 110% of VO2max were determined. Venous plasma interleukin-6 (IL-6) and interleukin-8 (IL-8) were measured post-exercise. No improvement was observed in the exhaustive swim test, but swim ergometer sprint time was improved (P < 0.05) in both groups from 57 ± 1.7 to 56 ± 1.8 s in AHR and 58.3 ± 1 to 57.4 ± 1 s in non-AHR. MVC and post-exercise plasma IL-6 increased (P < 0.05) with beta2 -agonists in both groups, whereas IL-8 only increased in AHR. In summary, inhalation of beta2 -agonists, in permitted doses, did not improve swim performance in elite swimmers. However, swim ergometer sprint performance and MVC were increased, which should be considered when making future anti-doping regulations. PMID:23834392

  13. Transforming growth factor beta2 inhibits adipocyte differentiation induced by skeletal unloading in rat bone marrow stroma.

    PubMed

    Ahdjoudj, Souhila; Lasmoles, Françoise; Holy, Xavier; Zerath, Erik; Marie, Pierre J

    2002-04-01

    Skeletal unloading induced by hindlimb suspension in rats reduces bone formation and induces osteopenia, but its effect on adipogenesis is unknown. We assessed the effects of unloading and transforming growth factor (TGF) beta2 on bone marrow stromal cell adipocyte differentiation in relation with osteoblast differentiation. Skeletal unloading rapidly (4-7 days) decreased osteoblast transcription factor Runx2, osteocalcin (OC), and type I collagen messenger RNA (mRNA) levels and reduced bone formation in the long bone metaphysis. Conversely, unloading increased expression of the adipocyte transcription factor peroxisome proliferator-activated receptor gamma2 (PPARgamma2) at 4 days and increased expression of the adipocyte differentiation genes lipoprotein lipase (LPL) and aP2 in the bone marrow stroma at 7 days. Consistently, unloading increased the number and volume of adipocytes in the bone marrow stroma. Continuous (0-7 days) and late (4-7 days) treatments with TGF-beta2 corrected the abnormal expression of Cbfa1/Runx2, OC, and type I collagen mRNAs and normalized bone formation in unloaded metaphyseal bone. Moreover, both TGF-beta2 treatments decreased PPARy2 and C/EBPalpha mRNA levels at 4 days and normalized aP2 and LPL expression and adipocyte number and volume at 7 days. These results show that skeletal unloading increases adipocyte differentiation concomitantly with inhibition of osteoblast differentiation. These abnormalities are prevented and reversed by TGF-beta2, suggesting a role for TGF-beta in the control of adipogenic differentiation in the bone marrow stroma. PMID:11918224

  14. Cystatin C and beta2-microglobulin: markers of glomerular filtration in critically ill children

    PubMed Central

    Herrero-Morín, José David; Málaga, Serafín; Fernández, Nuria; Rey, Corsino; Diéguez, María Ángeles; Solís, Gonzalo; Concha, Andrés; Medina, Alberto

    2007-01-01

    Introduction Parameters allowing regular evaluation of renal function in a paediatric intensive care unit (PICU) are not optimal. The aim of the present study was to analyse the utility of serum cystatin C and beta2-microglobulin (B2M) in detecting decreased glomerular filtration rate in critically ill children. Methods This was a prospective, observational study set in an eight-bed PICU. Twenty-five children were included. The inverses of serum creatinine, cystatin C, and B2M were correlated with creatinine clearance (CrC) using a 24-hour urine sample and CrC estimation by Schwartz formula (Schwartz). The diagnostic value of serum creatinine, cystatin C, and B2M to identify a glomerular filtration rate under 80 ml/minute per 1.73 m2 was evaluated using receiver operating characteristic (ROC) curve analysis. Results Mean age was 2.9 years (range, 0.1 to 13.9 years). CrC was less than 80 ml/minute per 1.73 m2 in 14 children, and Schwartz was less than 80 ml/minute per 1.73 m2 in 9 children. Correlations between inverse of B2M and CrC (r = 0.477) and between inverse of B2M and Schwartz (r = 0.697) were better than correlations between inverse of cystatin C and CrC (r = 0.390) or Schwartz (r = 0.586) and better than correlations between inverse of creatinine and CrC (r = 0.104) or Schwartz (r = 0.442). The ability of serum cystatin C and B2M to identify a CrC rate and a Schwartz CrC rate under 80 ml/minute per 1.73 m2 was better than that of creatinine (areas under the ROC curve: 0.851 and 0.792 for cystatin C, 0.802 and 0.799 for B2M, and 0.633 and 0.625 for creatinine). Conclusion Serum cystatin C and B2M were confirmed as easy and useful markers, better than serum creatinine, to detect acute kidney injury in critically ill children. PMID:17519026

  15. Clinical-pharmacokinetic aspects of prolonged effect duration as illustrated by beta2-agonists.

    PubMed

    Rosenburg, Johan

    2002-07-01

    stimulation of beta2-adrenoceptors have their pros and cons. Bambuterol can be dosed orally once daily, but full effect is reached slowly. The effect of formoterol is reached within a few minutes, but administration must occur via the lungs, often twice daily. Both treatments, however, give 24-h symptom relief during regular treatment. PMID:12214578

  16. PYK2 is an adhesion kinase in macrophages, localized in podosomes and activated by beta(2)-integrin ligation.

    PubMed

    Duong, L T; Rodan, G A

    2000-11-01

    Pyk2 is a member of the focal adhesion kinase (FAK) family, highly expressed in the central nervous system and haemopoietic cells. Although Pyk2 is homologous to FAK, its role in signaling pathways was shown to be distinct from that of FAK. We show here that Pyk2 is highly expressed in peritoneal IC-21 macrophage and is tyrosine phosphorylated in response to cell attachment to fibronectin and fibrinogen. Upon IC-21 cell adhesion, Pyk2 tyrosine phosphorylation is inhibited by blocking antibodies to the integrin subunits alpha(M) and beta(2). Furthermore, Pyk2 is rapidly tyrosine phosphorylated in response to ligation of beta(2) integrins by antibodies. In migrating macrophages, Pyk2 localizes to perinuclear regions and to podosomes, where it is clustered with tyrosine phosphorylated proteins. Furthermore, in the podosomal ring structure, which surrounds the central actin core, Pyk2 co-localizes with vinculin, talin, and paxillin. In the podosomes, Pyk2 also co-localizes with the integrin alpha(M)beta(2). Lastly, reduction of Pyk2 expression in macrophages leads to inhibition of cell migration. We propose that Pyk2 is functionally linked to the formation of podosomes where it mediates the integrin-cytoskeleton interface and regulates cell spreading and migration. PMID:11056520

  17. Expression of beta 2 integrins on blood leukocytes of cows with or without bovine leukocyte adhesion deficiency.

    PubMed

    Cox, E; Mast, J; MacHugh, N; Schwenger, B; Goddeeris, B M

    1997-09-19

    Peripheral blood leukocytes of 11 normal cows, 7 cows heterozygous and 2 heifers homozygous for bovine leukocyte adhesion deficiency (BLAD) were analysed by flow cytometry for the intensity of their beta 2 integrin expression (LFA-1(CD11a/CD18), CR3 (CD11b/CD18) and CR4 (CD11c/CD18)). BLAD-homozygotes revealed no or a very weak expression of the beta 2 integrins and had a 10-fold and 4- to 5-fold increase in absolute number of neutrophils and monocytes, respectively, whereas the absolute number of lymphocytes remained normal. The mean fluorescence intensity (MFI) of the beta 2 integrins (CD18) in heterozygous animals was 56 to 90% of this in the normal cows (MFI between 14 and 512). The difference in the expression level was most pronounced for LFA-1 on the small cluster of lymphocytes with the highest MFI for LFA-1. Repeated analysis and phorbol myristate acetate stimulation revealed that the LFA-1 expression on this high-expressing cell population of the peripheral blood allowed a ready identification of BLAD-heterozygotes by flow cytometry. PMID:9436269

  18. Imaging of dialysis-related amyloid (AB-amyloid) deposits with sup 131 I-beta 2-microglobulin

    SciTech Connect

    Floege, J.; Burchert, W.; Brandis, A.; Gielow, P.; Nonnast-Daniel, B.; Spindler, E.; Hundeshagen, H.; Shaldon, S.; Koch, K.M. )

    1990-12-01

    The diagnosis of dialysis-related amyloid (AB-amyloid) has been based usually on clinical and radiological criteria. Following the discovery that beta 2-microglobulin was the major protein of this amyloid, we isolated and radiolabelled uremic plasma beta 2-microglobulin. After intravenous injection, gamma-camera images of selected joint areas were obtained from 42 patients who were on regular hemodialysis therapy. Positive scans involving the shoulder, hip, knee and carpal regions were found in 13 of 14 patients treated for more than 10 years and 10 of 16 patients treated for 5 to 10 years. Patients treated for less time had negative scans. Specificity was indicated by negative scans in non-amyloid inflammatory lesions in control hemodialysis patients. Up to 48-fold tracer enrichment was detected in excised AB-amyloid containing tissue as compared to amyloid-free tissue. These findings suggest that circulating radiolabelled beta 2-microglobulin is taken up by the amyloid deposits. This method may non-invasively detect tissue infiltrates of amyloid. It may also permit prospective evaluation of the efficacy of prophylactic dialysis strategies which are designed to prevent or delay the onset of this complication of long-term dialysis.

  19. Cardiac Alpha1-Adrenergic Receptors: Novel Aspects of Expression, Signaling Mechanisms, Physiologic Function, and Clinical Importance

    PubMed Central

    O’Connell, Timothy D.; Jensen, Brian C.; Baker, Anthony J.

    2014-01-01

    Adrenergic receptors (AR) are G-protein-coupled receptors (GPCRs) that have a crucial role in cardiac physiology in health and disease. Alpha1-ARs signal through Gαq, and signaling through Gq, for example, by endothelin and angiotensin receptors, is thought to be detrimental to the heart. In contrast, cardiac alpha1-ARs mediate important protective and adaptive functions in the heart, although alpha1-ARs are only a minor fraction of total cardiac ARs. Cardiac alpha1-ARs activate pleiotropic downstream signaling to prevent pathologic remodeling in heart failure. Mechanisms defined in animal and cell models include activation of adaptive hypertrophy, prevention of cardiac myocyte death, augmentation of contractility, and induction of ischemic preconditioning. Surprisingly, at the molecular level, alpha1-ARs localize to and signal at the nucleus in cardiac myocytes, and, unlike most GPCRs, activate “inside-out” signaling to cause cardioprotection. Contrary to past opinion, human cardiac alpha1-AR expression is similar to that in the mouse, where alpha1-AR effects are seen most convincingly in knockout models. Human clinical studies show that alpha1-blockade worsens heart failure in hypertension and does not improve outcomes in heart failure, implying a cardioprotective role for human alpha1-ARs. In summary, these findings identify novel functional and mechanistic aspects of cardiac alpha1-AR function and suggest that activation of cardiac alpha1-AR might be a viable therapeutic strategy in heart failure. PMID:24368739

  20. T-Tubular Electrical Defects Contribute to Blunted β-Adrenergic Response in Heart Failure.

    PubMed

    Crocini, Claudia; Coppini, Raffaele; Ferrantini, Cecilia; Yan, Ping; Loew, Leslie M; Poggesi, Corrado; Cerbai, Elisabetta; Pavone, Francesco S; Sacconi, Leonardo

    2016-01-01

    Alterations of the β-adrenergic signalling, structural remodelling, and electrical failure of T-tubules are hallmarks of heart failure (HF). Here, we assess the effect of β-adrenoceptor activation on local Ca(2+) release in electrically coupled and uncoupled T-tubules in ventricular myocytes from HF rats. We employ an ultrafast random access multi-photon (RAMP) microscope to simultaneously record action potentials and Ca(2+) transients from multiple T-tubules in ventricular cardiomyocytes from a HF rat model of coronary ligation compared to sham-operated rats as a control. We confirmed that β-adrenergic stimulation increases the frequency of Ca(2+) sparks, reduces Ca(2+) transient variability, and hastens the decay of Ca(2+) transients: all these effects are similarly exerted by β-adrenergic stimulation in control and HF cardiomyocytes. Conversely, β-adrenergic stimulation in HF cells accelerates a Ca(2+) rise exclusively in the proximity of T-tubules that regularly conduct the action potential. The delayed Ca(2+) rise found at T-tubules that fail to conduct the action potential is instead not affected by β-adrenergic signalling. Taken together, these findings indicate that HF cells globally respond to β-adrenergic stimulation, except at T-tubules that fail to conduct action potentials, where the blunted effect of the β-adrenergic signalling may be directly caused by the lack of electrical activity. PMID:27598150

  1. Antagonism of Nav channels and α1-adrenergic receptors contributes to vascular smooth muscle effects of ranolazine.

    PubMed

    Virsolvy, Anne; Farah, Charlotte; Pertuit, Nolwenn; Kong, Lingyan; Lacampagne, Alain; Reboul, Cyril; Aimond, Franck; Richard, Sylvain

    2015-01-01

    Ranolazine is a recently developed drug used for the treatment of patients with chronic stable angina. It is a selective inhibitor of the persistent cardiac Na(+) current (INa), and is known to reduce the Na(+)-dependent Ca(2+) overload that occurs in cardiomyocytes during ischemia. Vascular effects of ranolazine, such as vasorelaxation,have been reported and may involve multiple pathways. As voltage-gated Na(+) channels (Nav) present in arteries play a role in contraction, we hypothesized that ranolazine could target these channels. We studied the effects of ranolazine in vitro on cultured aortic smooth muscle cells (SMC) and ex vivo on rat aortas in conditions known to specifically activate or promote INa. We observed that in the presence of the Nav channel agonist veratridine, ranolazine inhibited INa and intracellular Ca(2+) calcium increase in SMC, and arterial vasoconstriction. In arterial SMC, ranolazine inhibited the activity of tetrodotoxin-sensitive voltage-gated Nav channels and thus antagonized contraction promoted by low KCl depolarization. Furthermore, the vasorelaxant effects of ranolazine, also observed in human arteries and independent of the endothelium, involved antagonization of the α1-adrenergic receptor. Combined α1-adrenergic antagonization and inhibition of SMCs Nav channels could be involved in the vascular effects of ranolazine. PMID:26655634

  2. Antagonism of Nav channels and α1-adrenergic receptors contributes to vascular smooth muscle effects of ranolazine

    PubMed Central

    Virsolvy, Anne; Farah, Charlotte; Pertuit, Nolwenn; Kong, Lingyan; Lacampagne, Alain; Reboul, Cyril; Aimond, Franck; Richard, Sylvain

    2015-01-01

    Ranolazine is a recently developed drug used for the treatment of patients with chronic stable angina. It is a selective inhibitor of the persistent cardiac Na+ current (INa), and is known to reduce the Na+-dependent Ca2+ overload that occurs in cardiomyocytes during ischemia. Vascular effects of ranolazine, such as vasorelaxation,have been reported and may involve multiple pathways. As voltage-gated Na+ channels (Nav) present in arteries play a role in contraction, we hypothesized that ranolazine could target these channels. We studied the effects of ranolazine in vitro on cultured aortic smooth muscle cells (SMC) and ex vivo on rat aortas in conditions known to specifically activate or promote INa. We observed that in the presence of the Nav channel agonist veratridine, ranolazine inhibited INa and intracellular Ca2+ calcium increase in SMC, and arterial vasoconstriction. In arterial SMC, ranolazine inhibited the activity of tetrodotoxin-sensitive voltage-gated Nav channels and thus antagonized contraction promoted by low KCl depolarization. Furthermore, the vasorelaxant effects of ranolazine, also observed in human arteries and independent of the endothelium, involved antagonization of the α1-adrenergic receptor. Combined α1-adrenergic antagonization and inhibition of SMCs Nav channels could be involved in the vascular effects of ranolazine. PMID:26655634

  3. Association between β1 adrenergic receptor gene Arg389Gly polymorphism and risk of heart failure: a meta-analysis.

    PubMed

    Ma, S T; Zhao, W; Liu, B; Jia, R Y; Zhao, C J; Cui, L Q

    2015-01-01

    Numerous studies have evaluated the association between Arg389Gly polymorphism in the β1 adrenergic receptor gene and heart failure risk. However, the specific association is still controversial. We performed a meta-analysis of all case-control studies that evaluated the association between Arg389Gly polymorphism and heart failure in humans. Studies were identified in the PubMed, Embase, and China National Knowledge Infrastructure databases. Two reviewers independently assessed the studies. Six case-control studies with a total of 1736 participants were included in the meta-analysis, including 882 cases with heart failure and 854 controls, and our results showed no association between the Arg389Gly polymorphism and heart failure [ArgArg vs GlyGly: odds ratio (OR) = 0.84, 95% confidence interval (CI) 0.59-1.20; ArgArg vs ArgGly: OR = 0.95, 95%CI 0.78-1.16; dominant model: OR = 1.08, 95%CI 0.89-1.31; recessive model: OR = 0.96, 95%CI 0.69-1.35]. No publication bias was found in the present study (all P values > 0.05). In conclusion, the β1 adrenergic receptor gene Arg389Gly polymorphism might not be associated with heart failure risk. Further large and well-designed studies are needed to confirm this conclusion. PMID:26125791

  4. The K+ channel TASK1 modulates β-adrenergic response in brown adipose tissue through the mineralocorticoid receptor pathway.

    PubMed

    Pisani, Didier F; Beranger, Guillaume E; Corinus, Alain; Giroud, Maude; Ghandour, Rayane A; Altirriba, Jordi; Chambard, Jean-Claude; Mazure, Nathalie M; Bendahhou, Saïd; Duranton, Christophe; Michiels, Jean-François; Frontini, Andrea; Rohner-Jeanrenaud, Françoise; Cinti, Saverio; Christian, Mark; Barhanin, Jacques; Amri, Ez-Zoubir

    2016-02-01

    Brown adipose tissue (BAT) is essential for adaptive thermogenesis and dissipation of caloric excess through the activity of uncoupling protein (UCP)-1. BAT in humans is of great interest for the treatment of obesity and related diseases. In this study, the expression of Twik-related acid-sensitive K(+) channel (TASK)-1 [a pH-sensitive potassium channel encoded by the potassium channel, 2-pore domain, subfamily K, member 3 (Kcnk3) gene] correlated highly with Ucp1 expression in obese and cold-exposed mice. In addition, Task1-null mice, compared with their controls, became overweight, mainly because of an increase in white adipose tissue mass and BAT whitening. Task1(-/-)-mouse-derived brown adipocytes, compared with wild-type mouse-derived brown adipocytes, displayed an impaired β3-adrenergic receptor response that was characterized by a decrease in oxygen consumption, Ucp1 expression, and lipolysis. This phenotype was thought to be caused by an exacerbation of mineralocorticoid receptor (MR) signaling, given that it was mimicked by corticoids and reversed by an MR inhibitor. We concluded that the K(+) channel TASK1 controls the thermogenic activity in brown adipocytes through modulation of β-adrenergic receptor signaling. PMID:26527067

  5. Anti-β1-adrenergic receptor autoantibodies in patients with chronic Chagas heart disease

    PubMed Central

    Labovsky, V; Smulski, C R; Gómez, K; Levy, G; Levin, M J

    2007-01-01

    Chronic Chagas heart disease (cChHD), a chronic manifestation of the Trypanosoma cruzi infection, is characterized by high antibody levels against the C-terminal region of the ribosomal P proteins (i.e. peptide R13, EEEDDDMGFGLFD) which bears similarity with the second extracellular loop of β1-adrenergic receptor (β1-AR, peptide H26R HWWRAESDEARRCYNDPKCCDFVTNR). Because it has not been demonstrated clearly that IgGs from cChHD patients bind to native human β1-AR, the aim of this study was to investigate further the physical interaction between cChHD IgGs and the human β1-AR. Immunofluorescence assays demonstrated the binding of these antibodies to the receptor expressed on stably transfected cells, together with a β1-AR agonist-like effect. In addition, immunoadsorption of the serum samples from cChHD patients with a commercially available matrix, containing peptides representing the first and the second extracellular loop of the β1-AR, completely abolished reactivity against the H26R peptide and the physiological response to the receptor. The follow-up of this specificity after in vitro immunoadsorption procedures suggests that this treatment might be used to diminish significantly the serum levels of anti-β1-AR antibodies in patients with Chagas heart disease. PMID:17419712

  6. β-Adrenergic blockade enhances coronary vasoconstrictor response to forehead cooling

    PubMed Central

    Gao, Zhaohui; Patel, Hardikkumar M.; Heffernan, Matthew J.; Leuenberger, Urs A.; Sinoway, Lawrence I.

    2014-01-01

    Forehead cooling activates the sympathetic nervous system and can trigger angina pectoris in susceptible individuals. However, the effect of forehead cooling on coronary blood flow velocity (CBV) is not well understood. In this human experiment, we tested the hypotheses that forehead cooling reduces CBV (i.e., coronary vasoconstriction) and that this vasoconstrictor effect would be enhanced under systemic β-adrenergic blockade. A total of 30 healthy subjects (age range, 23–79 years) underwent Doppler echocardiography evaluation of CBV in response to 60 s of forehead cooling (1°C ice bag on forehead). A subset of subjects (n = 10) also underwent the procedures after an intravenous infusion of propranolol. Rate pressure product (RPP) was used as an index of myocardial oxygen demand. Consistent with our first hypothesis, forehead cooling reduced CBV from 19.5 ± 0.7 to 17.5 ± 0.8 cm/s (P < 0.001), whereas mean arterial pressure increased by 11 ± 2 mmHg (P < 0.001). Consistent with our second hypothesis, forehead cooling reduced CBV under propranolol despite a significant rise in RPP. The current studies indicate that forehead cooling elicits a sympathetically mediated pressor response and a reduction in CBV, and this effect is augmented under β-blockade. The results are consistent with sympathetic activation of β-receptor coronary vasodilation in humans, as has been demonstrated in animals. PMID:24441550

  7. Dihydrotestosterone decreases beta-adrenergic receptor binding in the fetal rabbit lung

    SciTech Connect

    Moawad, A.H.; River, L.P.; River, J.M.

    1988-07-01

    Tritium-labeled dihydroalprenolol was used to quantify the beta-adrenergic receptor sites in day 30 fetal rabbit lung tissue. Each of the fetuses of New Zealand White rabbits on day 28 of gestation was injected with dihydrotestosterone (2.0 micrograms) in one horn of the uterus and 10% ethanol in normal saline (the solvent) in the contralateral one. The animals were sacrificed 48 hours later and the fetal lung tissue was assayed. Dihydrotestosterone decreased the beta-adrenergic receptor site number in the treatment group compared with the control group (86 versus 111 fmol/mg protein, p less than 0.05 by paired t-test). In the presence of dihydrotestosterone, beta-adrenergic receptor binding is inhibited in the preterm fetal rabbit. This effect may be implicated in the beta-adrenergic mediation of phospholipid synthesis and/or release by fetal alveolar cells.

  8. CENTRAL ADRENERGIC RECEPTOR CHANGES IN THE INHERITED NORADRENERGIC HYPERINNERVATED MUTANT MOUSE TOTTERING (JOURNAL VERSION)

    EPA Science Inventory

    Adrenergic receptor binding characteristics were analyzed in the mutant mouse tottering (tg/tg), a single gene locus autosomal recessive mutation causing hyperinnervation by locus coeuruleus neurons of their target regions, which results in epilepsy. Instead of the expected down-...

  9. Expression of mammalian beta-adrenergic receptors in Xenopus laevis oocytes

    SciTech Connect

    Bahouth, S.W.; Malbon, C.C.

    1987-05-01

    Xenopus laevis oocytes are a useful transcription and expression system for DNA and RNA, respectively. Total cellular RNA was extracted from mouse lymphoma S49 cells and poly(A)/sup +/mRNA prepared by affinity chromatography of RNA on oligo(dT) cellulose. The membranes of S49 cells contain beta-adrenergic receptors that display pharmacological characteristics of beta/sub 2/-subtype. Xenopus laevis oocytes were injected with 50 ng of mRNA/oocyte. Expression of beta-adrenergic receptors in oocytes incubated for 30 hr after microinjection was assessed in membranes by radioligand binding using (/sup 3/H) dihydroalprenolol. The injected oocytes displayed 0.34 fmol receptor/oocyte as compared to 0.02 fmol receptor/oocyte in the control oocytes. The affinity of beta-adrenergic receptors in injected oocytes for this radioligand was 2 nM, a value similar to the affinity of beta-adrenergic receptors for DHA in S49 cell membranes. The potency of beta-adrenergic agonists in competing for DHA binding to oocytes membranes was isoproterenol > epinephrine > norepineprine, indicating that the expressed beta-adrenergic receptors were of the beta/sub 2/-subtype. The K/sub I/ of these agonists for the beta-adrenergic receptor in oocyte membranes was 0.03, 0.15 and 1.2 ..mu..M, respectively. The role of post-translational modification in dictating receptor subtype is analyzed using mRNA of beta/sub 1/- as well as beta/sub 2/-adrenergic receptors.

  10. Measurement of glomerular filtration rate in homozygous sickle cell disease: a comparison of 51Cr-EDTA clearance, creatinine clearance, serum creatinine and beta 2 microglobulin.

    PubMed Central

    Aparicio, S A; Mojiminiyi, S; Kay, J D; Shepstone, B J; de Ceulaer, K; Serjeant, G R

    1990-01-01

    Glomerular filtration rates (GFR) were measured with 51Cr-EDTA in 38 patients (aged 40-75 years) with homozygous sickle cell disease and compared with serum beta 2 microglobulin concentrations in 38 patients and with creatinine clearance in 21 patients. GFR estimated with 51Cr-EDTA was closely correlated with single serum creatinine measurements and the inverse of serum beta 2 microglobulin. Creatinine clearance was also found to be correlated, but values were, on average, 32% below those obtained by the 51Cr-EDTA method, and this difference was significant. It is concluded that measurements of beta 2 microglobulin, single serum creatinine, and creatinine clearance are valuable indicators of GFR in homozygous sickle cell disease. Measurement of beta 2 microglobulin was a useful and reliable method of estimating GFR from single plasma measurements and is therefore a useful means of screening the population. PMID:2115049

  11. Actin filament barbed-end capping activity in neutrophil lysates: the role of capping protein-beta 2.

    PubMed

    DiNubile, M J; Cassimeris, L; Joyce, M; Zigmond, S H

    1995-12-01

    A barbed-end capping activity was found in high speed supernates of neutrophils lysed in submicromolar calcium. In dilute supernate (> or = 100-fold dilution of cytoplasm), this activity accounted for most of the inhibition of barbed-end elongation of pyrenyl-G-actin from spectrin-F-actin seeds. Pointed-end elongation from gelsolin-capped F-actin seeds was not inhibited at comparable concentrations of supernate, thus excluding actin monomer sequestration as a cause of the observed inhibition. Most of the capping activity was due to capping protein-beta 2 (a homologue of cap Z). Thus, while immunoadsorption of > or = 95% of the gelsolin in the supernate did not decrease capping activity, immunoadsorption of capping protein-beta 2 reduced capping activity proportionally to the amount of capping protein-beta 2 adsorbed. Depletion of > 90% of capping protein-beta 2 from the supernate removed 90% of its capping activity. The functional properties of the capping activity were defined. The dissociation constant for binding to barbed ends (determined by steady state and kinetic analyses) was approximately 1-2 nM; the on-rate of capping was between 7 x 10(5) and 5 x 10(6) M-1 s-1; and the off-rate was approximately 2 x 10(-3) s-1. The concentration of capper free in the intact cell (determined by adsorption of supernate with spectrin-actin seeds) was estimated to be approximately 1-2 microM. Thus, there appeared to be enough high affinity capper to cap all the barbed ends in vivo. Nevertheless, immediately after lysis with detergent, neutrophils contained sites that nucleate barbed-end elongation of pyrenyl-G-actin. These barbed ends subsequently become capped with a time course and concentration dependence similar to that of spectrin-F-actin seeds in high speed supernates. These observations suggest that, despite the excess of high affinity capper, some ends either are not capped in vivo or are transiently uncapped upon lysis and dilution. PMID:8590796

  12. Identification of beta 2-adrenoceptors on guinea pig alveolar macrophages using (-)-3-( sup 125 I)iodocyanopindolol

    SciTech Connect

    Leurs, R.; Beusenberg, F.D.; Bast, A.; Van Amsterdam, J.G.; Timmerman, H. )

    1990-08-01

    The beta-adrenoceptor antagonist (-)-3-({sup 125}I)iodocyanopindolol (({sup 125}I)ICYP) binds with high affinity and in saturable way to membranes of guinea pig alveolar macrophages. The equilibrium dissociation constant for ({sup 125}I)ICYP is 24.3 +/- 1.2 pM, and the number of binding sites is 166.3 +/- 13.7 fmol/mg protein (N = 4, +/- SEM). Displacement studies with selective antagonists showed that ({sup 125}I)ICYP labels beta 2-adrenoceptors on guinea pig alveolar macrophages.

  13. Modulation of. beta. -adrenergic response in rat brain astrocytes by serum and hormones

    SciTech Connect

    Wu, D.K.; Morrison, R.S.; de Vellis, J.

    1985-01-01

    Purified astrocyte cultures from neonatal rat cerebrum respond to isoproterenol, a ..beta..-adrenergic agonist, with a transient rise in cAMP production. This astroglial property was regulated by serum, a chemically defined medium (serum-free medium plus hydrocortisone, putrescine, prostaglandin F/sub 2/, insulin, and fibroblast growth factor) and epidermal growth factor. Compared to astrocytes grown in serum-supplemented medium, astrocytes grown in the chemically defined medium were nonresponsive to isoproterenol stimulation, and this difference did not appear to be due to selection of a subpopulation of cells by either medium. The data suggest that a decreased ..beta..-adrenergic receptor number and an increased degradation of cAMP may account for the reduced response to ..beta..-adrenergic stimulation. The nonresponsive state of astrocytes in the defined medium was reversible when the medium was replaced with serum-supplemented medium. An active substance(s) in serum was responsible for restoring the responsiveness of astrocytes. Each of the five components of the defined medium had little effect by itself; however, together they acted synergistically to desensitize astrocytes to ..beta..-adrenergic stimulation. On the other hand, epidermal growth factor, a potent mitogen for astrocytes, was very competent by itself in reducing the cAMP response of astrocytes to ..beta..-adrenergic stimulation. Thus purified astrocytes grown in the chemically defined medium appear to be a good model for the study of hormonal interactions and of serum factors which may modulate the ..beta..-adrenergic response.

  14. Adrenergic DNA damage of embryonic pluripotent cells via β2 receptor signalling

    PubMed Central

    Sun, Fan; Ding, Xu-Ping; An, Shi-Min; Tang, Ya-Bin; Yang, Xin-Jie; Teng, Lin; Zhang, Chun; Shen, Ying; Chen, Hong-Zhuan; Zhu, Liang

    2015-01-01

    Embryonic pluripotent cells are sensitive to genotoxicity though they need more stringent genome integrity to avoid compromising multiple cell lineages and subsequent generations. However it remains unknown whether the cells are susceptible to adrenergic stress which can induce somatic cell genome lesion. We have revealed that adrenergic stress mediators cause DNA damage of the cells through the β2 adrenergic receptor/adenylate cyclase/cAMP/PKA signalling pathway involving an induction of intracellular reactive oxygen species (ROS) accumulation. The adrenergic stress agonists adrenaline, noradrenaline, and isoprenaline caused DNA damage and apoptosis of embryonic stem (ES) cells and embryonal carcinoma stem cells. The effects were mimicked by β2 receptor-coupled signalling molecules and abrogated by selective blockade of β2 receptors and inhibition of the receptor signalling pathway. RNA interference targeting β2 receptors of ES cells conferred the cells the ability to resist the DNA damage and apoptosis. In addition, adrenergic stimulation caused a consistent accumulation of ROS in the cells and the effect was abrogated by β2 receptor blockade; quenching of ROS reversed the induced DNA damage. This finding will improve the understanding of the stem cell regulatory physiology/pathophysiology in an adrenergic receptor subtype signalling mechanism. PMID:26516061

  15. On the adrenergic system of ganoid fish: the beluga, Huso huso (chondrostei).

    PubMed

    Balashov, N V; Fänge, R; Govyrin, V A; Leont'eva, G R; Nilsson, S; Prozorovskaya, M P

    1981-04-01

    The adrenergic system of the beluga, Huso huso, was studied by glyoxylic acid fluorescence histochemistry, analyses of catecholamine content in various organs and studies of the effects of acetylcholine and adrenaline on isolated strip preparations from blood vessels, spleen, atrium and ventricle. Chromaffin cells were found mainly in the walls of the posterior cardinal veins, and to some extent also in the wall of the celiaco-mesenteric artery. The plasma concentration of adrenaline was high enough to affect the contraction force of the isolated atrial and ventricular strips, thus adding an adrenergic component to a possible cholinergic inhibitory vagal control of the heart. Fluorescence histochemistry revealed no direct adrenergic innervation of the heart, but blood vessels in the heart and elsewhere received a rich supply of adrenergic nerve terminals. Adrenaline contracted the celiaco-mesenteric artery and the spleen, and produced positive inotropic effects on the paced atrial and ventricular strip preparations. Acetylcholine contracted the ventral aorta and the celiaco-mesenteric artery, and reduced the contraction force of paced ventricular and, especially, atrial preparations. It is concluded that the beluga has a well developed adrenergic system consisting of both chromaffin cells and adrenergic neurons with varicose nerve terminals of the type found in the higher vertebrates. PMID:7304205

  16. beta. -adrenergic relaxation of smooth muscle: differences between cells and tissues

    SciTech Connect

    Scheid, C.R.

    1987-09-01

    The present studies were carried out in an attempt to resolve the controversy about the Na/sup +/ dependence of ..beta..-adrenergic relaxation in smooth muscle. Previous studies on isolated smooth muscle cells from the toad stomach had suggested that at least some of the actions of ..beta..-adrenergic agents, including a stimulatory effect on /sup 45/Ca efflux, were dependent on the presence of a normal transmembrane Na/sup +/ gradient. Studies by other investigators using tissues derived from mammalian sources had suggested that the relaxing effect of ..beta..-adrenergic agents was Na/sup +/ independent. Uncertainty remained as to whether these discrepancies reflected differences between cells and tissues or differences between species. Thus, in the present studies, the authors utilized both tissues and cells from the same source, the stomach muscle of the toad Bufo marinus, and assessed the Na/sup +/ dependence of ..beta..-adrenergic relaxation. They found that elimination of a normal Na/sup +/ gradient abolished ..beta..-adrenergic relaxation of isolated cells. In tissues, however, similar manipulations had no effect on relaxation. The reasons for this discrepancy are unclear but do not appear to be attributable to changes in smooth muscle function following enzymatic dispersion. Thus the controversy concerning the mechanisms of ..beta..-adrenergic relaxation may reflect inherent differences between tissues and cells.

  17. alpha1B-Adrenergic receptor phosphorylation and desensitization induced by transforming growth factor-beta.

    PubMed Central

    Romero-Avila, M Teresa; Flores-Jasso, C Fabián; García-Sáinz, J Adolfo

    2002-01-01

    Transforming growth factor-beta (TGF-beta) induced alpha(1B)-adrenergic receptor phosphorylation in Rat-1 fibroblasts stably expressing these adrenoceptors. This effect of TGF-beta was rapid, reaching a maximum within 30 min and decreasing thereafter, and concentration-dependent (EC(50) 0.3 pM). The phosphoinositide 3-kinase inhibitors wortmannin and LY294002, and the protein kinase C inhibitors staurosporine, Ro 318220 and bisindolylmaleimide, blocked the effect of this growth factor. alpha(1B)-Adrenergic receptor phosphorylation was associated with desensitization, as indicated by a reduction in the adrenergic-mediated production of [(3)H]inositol phosphates. Phosphorylation of alpha(1B)-adrenergic receptors by TGF-beta was also observed in Cos-1 cells transfected with the receptor. Co-transfection of the dominant-negative mutant of the regulatory subunit of phosphoinositide 3-kinase (Deltap85) inhibited the phosphorylation of alpha(1B)-adrenergic receptors induced by TGF-beta. Our results indicate that activation of TGF-beta receptors induces alpha(1B)-adrenergic receptor phosphorylation and desensitization. The data suggest that phosphoinositide 3-kinase and protein kinase C play key roles in this effect of TGF-beta. PMID:12234252

  18. alpha1B-Adrenergic receptor phosphorylation and desensitization induced by transforming growth factor-beta.

    PubMed

    Romero-Avila, M Teresa; Flores-Jasso, C Fabián; García-Sáinz, J Adolfo

    2002-12-01

    Transforming growth factor-beta (TGF-beta) induced alpha(1B)-adrenergic receptor phosphorylation in Rat-1 fibroblasts stably expressing these adrenoceptors. This effect of TGF-beta was rapid, reaching a maximum within 30 min and decreasing thereafter, and concentration-dependent (EC(50) 0.3 pM). The phosphoinositide 3-kinase inhibitors wortmannin and LY294002, and the protein kinase C inhibitors staurosporine, Ro 318220 and bisindolylmaleimide, blocked the effect of this growth factor. alpha(1B)-Adrenergic receptor phosphorylation was associated with desensitization, as indicated by a reduction in the adrenergic-mediated production of [(3)H]inositol phosphates. Phosphorylation of alpha(1B)-adrenergic receptors by TGF-beta was also observed in Cos-1 cells transfected with the receptor. Co-transfection of the dominant-negative mutant of the regulatory subunit of phosphoinositide 3-kinase (Deltap85) inhibited the phosphorylation of alpha(1B)-adrenergic receptors induced by TGF-beta. Our results indicate that activation of TGF-beta receptors induces alpha(1B)-adrenergic receptor phosphorylation and desensitization. The data suggest that phosphoinositide 3-kinase and protein kinase C play key roles in this effect of TGF-beta. PMID:12234252

  19. Beta-adrenergic receptors of lymphocytes in children with allergic respiratory diseases

    SciTech Connect

    Bittera, I.; Gyurkovits, K.; Falkay, G.; Eck, E.; Koltai, M.

    1988-01-01

    The beta-adrenergic receptor binding sites on peripheral lymphocytes in children with bronchial asthma (n = 16) and seasonal allergic rhinitis (n = 8) were examined in comparison with normal controls (n = 18) by means of /sup 124/I-cyanopindolol. The number of beta-adrenergic receptors was significantly lower in the asthmatic group (858 +/- 460/lymphocyte) than in the controls (1564 +/- 983/lymphocyte). The value (1891 +/- 1502/lymphocyte in children with allergic rhinitis was slightly higher than that in healthy controls. Of the 24 patients suffering from allergic diseases of the lower or upper airways, the bronchial histamine provocation test was performed in 21; 16 gave positive results, while 5 were negative. No difference in beta-adrenergic receptor count was found between the histamine-positive and negative patients. Neither was there any correlation between the number of beta-adrenergic receptors and the high (16/24) and low (8/24) serum IgE concentrations found in allergic patients. The significant decrease in beta-adrenergic receptor count in asthmatic children lends support to Szentivanyi's concept. Further qualitative and quantitative analysis of lymphocyte beta-adrenergic receptors may provide an individual approach to the treatment of bronchial asthma with beta-sympathomimetic drugs.

  20. Competitive receptor binding radioassay for US -1 and US -2 adrenergic agents

    SciTech Connect

    Hussain, M.N.; Culbreth, W.; Dalrymple, R.; Fung, C.; Ricks, C.

    1987-05-01

    A rapid and sensitive competitive receptor bonding assay for US -1 and US -2 adrenergic binding for adrenergic agents has been developed. The steps that are critical for the success of the assay are given in detail so that the assay can be set up in any routine laboratory with relative ease. The rationale behind the use of specific reagents is discussed. The assay requires microgram quantities of test compound, a radiolabeled specific US adrenergic antagonist (TH)dihydroalprenolol (DHA), and turkey erythrocyte US -1 and rat erythrocyte US -2 receptor membranes. Serial dilutions of sample are incubated with appropriate receptor membranes and DHA for 1 hr at room temperature. After equilibrium is attained, the bound radioligand is separated by rapid filtration under vacuum through Whatman GF/B filters. The amount of bound DHA trapped on the filter is inversely proportional to the degree of US -1 and US -2 adrenergic binding of the sample. Separation of bound from free radioligand by filtration permits rapid determination of a large number of samples. This assay quantitates and differentiates US -1 and US -2 adrenergic binding of synthetic adrenergic agents.

  1. Elevated level of. beta. -adrenergic receptors in hepatocytes from regenerating rat liver

    SciTech Connect

    Sandnes, D.; Sand, T.E.; Sager, G.; Broenstad, G.O.; Refsnes, M.R.; Gladhaug, I.P.; Jacobsen, S.; Christoffersen, T.

    1986-01-01

    Hepatocytes from regenerating rat liver show an enhanced epinephrine-sensitive adenylate cyclase activity and cAMP response, which may be involved in triggering of the cell proliferation. We have determined adrenergic receptors and adenylate cyclase activity in hepatocytes isolated at various time points after partial hepatectomy. The number of ..beta..-adrenergic receptors, measured by binding of (/sup 125/I)iodocyanopindolol ((/sup 125/I)CYP) to a particulate fraction prepared from isolated hepatocytes, increased rapidly after partial hepatectomy as compared with sham-operated or untreated controls. The maximal increase, which was observed at 48 h, was between 5- and 6-fold (from approx.1800 to approx.10,500 sites per cell). Thereafter, the number of ..beta..- adrenergic receptors decreased gradually. Competition experiments indicated ..beta../sub 2/-type receptors. Parallelism was found between the change in the number of ..beta../sub 2/-adrenergic receptors and the isoproterenol-responsive adenylate cyclase activity. The number of ..cap alpha../sub 1/-adrenergic receptors, determined by binding of (/sup 3/H)prazosin, was transiently lowered by about 35% at 18-24 h. with no significant change in K/sub d/. Although the results of this study do not exclude the possibility of post-receptor events, they suggest that the increased number of..beta../sub 2/-adrenergic receptors is a major factor responsible for the enhanced catecholamine-responsive adenylate cyclase activity in regenerating liver.

  2. β-Adrenergic modulation of skeletal muscle contraction: key role of excitation-contraction coupling.

    PubMed

    Cairns, Simeon P; Borrani, Fabio

    2015-11-01

    Our aim is to describe the acute effects of catecholamines/β-adrenergic agonists on contraction of non-fatigued skeletal muscle in animals and humans, and explain the mechanisms involved. Adrenaline/β-agonists (0.1-30 μm) generally augment peak force across animal species (positive inotropic effect) and abbreviate relaxation of slow-twitch muscles (positive lusitropic effect). A peak force reduction also occurs in slow-twitch muscles in some conditions. β2 -Adrenoceptor stimulation activates distinct cyclic AMP-dependent protein kinases to phosphorylate multiple target proteins. β-Agonists modulate sarcolemmal processes (increased resting membrane potential and action potential amplitude) via enhanced Na(+) -K(+) pump and Na(+) -K(+) -2Cl(-) cotransporter function, but this does not increase force. Myofibrillar Ca(2+) sensitivity and maximum Ca(2+) -activated force are unchanged. All force potentiation involves amplified myoplasmic Ca(2+) transients consequent to increased Ca(2+) release from sarcoplasmic reticulum (SR). This unequivocally requires phosphorylation of SR Ca(2+) release channels/ryanodine receptors (RyR1) which sensitize the Ca(2+) -induced Ca(2+) release mechanism. Enhanced trans-sarcolemmal Ca(2+) influx through phosphorylated voltage-activated Ca(2+) channels contributes to force potentiation in diaphragm and amphibian muscle, but not mammalian limb muscle. Phosphorylation of phospholamban increases SR Ca(2+) pump activity in slow-twitch fibres but does not augment force; this process accelerates relaxation and may depress force. Greater Ca(2+) loading of SR may assist force potentiation in fast-twitch muscle. Some human studies show no significant force potentiation which appears to be related to the β-agonist concentration used. Indeed high-dose β-agonists (∼0.1 μm) enhance SR Ca(2+) -release rates, maximum voluntary contraction strength and peak Wingate power in trained humans. The combined findings can explain how adrenaline

  3. Activation of mTORC1 is essential for β-adrenergic stimulation of adipose browning.

    PubMed

    Liu, Dianxin; Bordicchia, Marica; Zhang, Chaoying; Fang, Huafeng; Wei, Wan; Li, Jian-Liang; Guilherme, Adilson; Guntur, Kalyani; Czech, Michael P; Collins, Sheila

    2016-05-01

    A classic metabolic concept posits that insulin promotes energy storage and adipose expansion, while catecholamines stimulate release of adipose energy stores by hydrolysis of triglycerides through β-adrenergic receptor (βARs) and protein kinase A (PKA) signaling. Here, we have shown that a key hub in the insulin signaling pathway, activation of p70 ribosomal S6 kinase (S6K1) through mTORC1, is also triggered by PKA activation in both mouse and human adipocytes. Mice with mTORC1 impairment, either through adipocyte-specific deletion of Raptor or pharmacologic rapamycin treatment, were refractory to the well-known βAR-dependent increase of uncoupling protein UCP1 expression and expansion of beige/brite adipocytes (so-called browning) in white adipose tissue (WAT). Mechanistically, PKA directly phosphorylated mTOR and RAPTOR on unique serine residues, an effect that was independent of insulin/AKT signaling. Abrogation of the PKA site within RAPTOR disrupted βAR/mTORC1 activation of S6K1 without affecting mTORC1 activation by insulin. Conversely, a phosphomimetic RAPTOR augmented S6K1 activity. Together, these studies reveal a signaling pathway from βARs and PKA through mTORC1 that is required for adipose browning by catecholamines and provides potential therapeutic strategies to enhance energy expenditure and combat metabolic disease. PMID:27018708

  4. β2-Adrenergic agonists augment air pollution–induced IL-6 release and thrombosis

    PubMed Central

    Chiarella, Sergio E.; Soberanes, Saul; Urich, Daniela; Morales-Nebreda, Luisa; Nigdelioglu, Recep; Green, David; Young, James B.; Gonzalez, Angel; Rosario, Carmen; Misharin, Alexander V.; Ghio, Andrew J.; Wunderink, Richard G.; Donnelly, Helen K.; Radigan, Kathryn A.; Perlman, Harris; Chandel, Navdeep S.; Budinger, G.R. Scott; Mutlu, Gökhan M.

    2014-01-01

    Acute exposure to particulate matter (PM) air pollution causes thrombotic cardiovascular events, leading to increased mortality rates; however, the link between PM and cardiovascular dysfunction is not completely understood. We have previously shown that the release of IL-6 from alveolar macrophages is required for a prothrombotic state and acceleration of thrombosis following exposure to PM. Here, we determined that PM exposure results in the systemic release of catecholamines, which engage the β2-adrenergic receptor (β2AR) on murine alveolar macrophages and augment the release of IL-6. In mice, β2AR signaling promoted the development of a prothrombotic state that was sufficient to accelerate arterial thrombosis. In primary human alveolar macrophages, administration of a β2AR agonist augmented IL-6 release, while the addition of a beta blocker inhibited PM-induced IL-6 release. Genetic loss or pharmacologic inhibition of the β2AR on murine alveolar macrophages attenuated PM-induced IL-6 release and prothrombotic state. Furthermore, exogenous β2AR agonist therapy further augmented these responses in alveolar macrophages through generation of mitochondrial ROS and subsequent increase of adenylyl cyclase activity. Together, these results link the activation of the sympathetic nervous system by β2AR signaling with metabolism, lung inflammation, and an enhanced susceptibility to thrombotic cardiovascular events. PMID:24865431

  5. Structural insights and functional implications of inter-individual variability in β2-adrenergic receptor

    PubMed Central

    Tandale, Aditi; Joshi, Manali; Sengupta, Durba

    2016-01-01

    The human β2-adrenergic receptor (β2AR) belongs to the G protein-coupled receptor (GPCR) family and due to its central role in bronchodilation, is an important drug target. The inter-individual variability in β2AR has been implicated in disease susceptibility and differential drug response. In this work, we identified nine potentially deleterious non-synonymous single nucleotide polymorphisms (nsSNPs) using a consensus approach. The deleterious nsSNPs were found to cluster near the ligand binding site and towards the G-protein binding site. To assess their molecular level effects, we built structural models of these receptors and performed atomistic molecular dynamics simulations. Most notably, in the Phe290Ser variant we observed the rotameric flip of Trp2866.48, a putative activation switch that has not been reported in β2AR thus far. In contrast, the variant Met82Lys was found to be the most detrimental to epinephrine binding. Additionally, a few of the nsSNPs were seen to cause perturbations to the lipid bilayer, while a few lead to differences at the G-protein coupling site. We are thus able to classify the variants as ranging from activating to damaging, prioritising them for experimental studies. PMID:27075228

  6. Activation of mTORC1 is essential for β-adrenergic stimulation of adipose browning

    PubMed Central

    Liu, Dianxin; Bordicchia, Marica; Zhang, Chaoying; Fang, Huafeng; Wei, Wan; Guilherme, Adilson; Guntur, Kalyani; Czech, Michael P.

    2016-01-01

    A classic metabolic concept posits that insulin promotes energy storage and adipose expansion, while catecholamines stimulate release of adipose energy stores by hydrolysis of triglycerides through β-adrenergic receptor (βARs) and protein kinase A (PKA) signaling. Here, we have shown that a key hub in the insulin signaling pathway, activation of p70 ribosomal S6 kinase (S6K1) through mTORC1, is also triggered by PKA activation in both mouse and human adipocytes. Mice with mTORC1 impairment, either through adipocyte-specific deletion of Raptor or pharmacologic rapamycin treatment, were refractory to the well-known βAR-dependent increase of uncoupling protein UCP1 expression and expansion of beige/brite adipocytes (so-called browning) in white adipose tissue (WAT). Mechanistically, PKA directly phosphorylated mTOR and RAPTOR on unique serine residues, an effect that was independent of insulin/AKT signaling. Abrogation of the PKA site within RAPTOR disrupted βAR/mTORC1 activation of S6K1 without affecting mTORC1 activation by insulin. Conversely, a phosphomimetic RAPTOR augmented S6K1 activity. Together, these studies reveal a signaling pathway from βARs and PKA through mTORC1 that is required for adipose browning by catecholamines and provides potential therapeutic strategies to enhance energy expenditure and combat metabolic disease. PMID:27018708

  7. Pinpointing beta adrenergic receptor in ageing pathophysiology: victim or executioner? Evidence from crime scenes

    PubMed Central

    2013-01-01

    G protein-coupled receptors (GPCRs) play a key role in cellular communication, allowing human cells to sense external cues or to talk each other through hormones or neurotransmitters. Research in this field has been recently awarded with the Nobel Prize in chemistry to Robert J. Lefkowitz and Brian K. Kobilka, for their pioneering work on beta adrenergic receptors (βARs), a prototype GPCR. Such receptors, and β2AR in particular, which is extensively distributed throughout the body, are involved in a number of pathophysiological processes. Moreover, a large amount of studies has demonstrated their participation in ageing process. Reciprocally, age-related changes in regulation of receptor responses have been observed in numerous tissues and include modifications of βAR responses. Impaired sympathetic nervous system function has been indeed evoked as at least a partial explanation for several modifications that occur with ageing. This article represents an updated presentation of the current knowledge in the field, summarizing in a systematic way the major findings of research on ageing in several organs and tissues (crime scenes) expressing βARs: heart, vessels, skeletal muscle, respiratory system, brain, immune system, pancreatic islets, liver, kidney and bone. PMID:23497413

  8. Pressor response to intravenous tyramine is a marker of cardiac, but not vascular, adrenergic function

    NASA Technical Reports Server (NTRS)

    Meck, Janice V.; Martin, David S.; D'Aunno, Dominick S.; Waters, Wendy W.

    2003-01-01

    Intravenous injections of the indirect sympathetic amine, tyramine, are used as a test of peripheral adrenergic function. The authors measured the time course of increases in ejection fraction, heart rate, systolic and diastolic pressure, popliteal artery flow, and greater saphenous vein diameter before and after an injection of 4.0 mg/m(2) body surface area of tyramine in normal human subjects. The tyramine caused moderate, significant increases in systolic pressure and significant decreases in total peripheral resistance. The earliest changes were a 30% increase in ejection fraction and a 16% increase in systolic pressure, followed by a 60% increase in popliteal artery flow and a later 11% increase in greater saphenous vein diameter. There were no changes in diastolic pressure or heart rate. These results suggest that pressor responses during tyramine injections are primarily due to an inotropic response that increases cardiac output and pressure and causes a reflex decrease in vascular resistance. Thus, tyramine pressor tests are a measure of cardiac, but not vascular, sympathetic function.

  9. Mechanism of concerted inhibition of alpha2beta2-type hetero-oligomeric aspartate kinase from Corynebacterium glutamicum.

    PubMed

    Yoshida, Ayako; Tomita, Takeo; Kuzuyama, Tomohisa; Nishiyama, Makoto

    2010-08-27

    Aspartate kinase (AK) is the first and committed enzyme of the biosynthetic pathway producing aspartate family amino acids, lysine, threonine, and methionine. AK from Corynebacterium glutamicum (CgAK), a bacterium used for industrial fermentation of amino acids, including glutamate and lysine, is inhibited by lysine and threonine in a concerted manner. To elucidate the mechanism of this unique regulation in CgAK, we determined the crystal structures in several forms: an inhibitory form complexed with both lysine and threonine, an active form complexed with only threonine, and a feedback inhibition-resistant mutant (S301F) complexed with both lysine and threonine. CgAK has a characteristic alpha(2)beta(2)-type heterotetrameric structure made up of two alpha subunits and two beta subunits. Comparison of the crystal structures between inhibitory and active forms revealed that binding inhibitors causes a conformational change to a closed inhibitory form, and the interaction between the catalytic domain in the alpha subunit and beta subunit (regulatory subunit) is a key event for stabilizing the inhibitory form. This study shows not only the first crystal structures of alpha(2)beta(2)-type AK but also the mechanism of concerted inhibition in CgAK. PMID:20573952

  10. Beta-2 microglobulin and lactate dehydrogenase levels are useful prognostic markers in early stage primary gastric lymphoma.

    PubMed

    Avilés, A; Narváez, B R

    1998-10-01

    The optimal management of primary gastric lymphoma (PGL) remains undecided because a definitive classification for therapeutic decision is not available. The International Index Project has proved to be useful in patients with nodal disease, but in extranodal presentation it has not been tested. We reviewed 297 patients with early stage PGL. They were initially classified according to the prognostic features of the International Index Project. No influence on duration of time to treatment failure (TTF) or overall survival was observed. For this reason we developed a logistical model to identify prognostic factors in patients with early stage PGL. Levels of beta-2 microglobulin and lactic dehydrogenase were observed to have prognostic significance in both univariate and multivariate analysis. With these parameters we constructed a logistical model to identify patients at low risk (TTF = 76%; at 7 years overall survival was 96%), statistically different to patients at high risk (TTF = 34% and overall survival = 22%). The number of patients at intermediate risk were too small to compare with the other groups. Because pathological or other clinical or laboratory prognostic features cannot help in the identification of a prognostic model, we propose that the use beta-2 microglobulin and lactic dehydrogenase can define different groups at risk and develop a prognostic system to define the best therapeutic approach in this patients. PMID:9807677

  11. Beta 2-microglobulin-, CD8+ T-cell-deficient mice survive inoculation with high doses of vaccinia virus and exhibit altered IgG responses.

    PubMed Central

    Spriggs, M K; Koller, B H; Sato, T; Morrissey, P J; Fanslow, W C; Smithies, O; Voice, R F; Widmer, M B; Maliszewski, C R

    1992-01-01

    Transgenic mice lacking an intact beta 2-microglobulin (beta 2m) gene fail to express major histocompatibility complex (MHC) class I proteins on the cell surface and, as a result, are virtually devoid of CD4- CD8+ lymphocytes. These animals provide a unique model system for directly assessing the role of CD8+ lymphocytes in the modulation of viral infection in vivo. beta 2m- CD8- mice and their normal littermates were inoculated at the base of the tail with the WR strain of vaccinia virus and monitored for serum antibody and lesion formation. Both groups developed similar lesions in response to a broad virus dose range, and all animals had completely recovered by day 28 after inoculation. Isotype-specific immunoglobulin levels were determined for each animal on day 7 and day 14 after primary inoculation, and again 7 days after a virus challenge. The virus-specific IgG1, IgG2a, and IgG2b levels were significantly different in the beta 2m-/- group (20-, 9-, and 30-fold lower, respectively, on day 7 after challenge) compared with the beta 2m+/- group. Virus-specific serum IgM levels for both groups remained similar throughout the experiment. In a separate experiment, beta 2m-/- mice were immunized with a nonviral antigen, 2,4,6-trinitrophenyl-conjugated keyhole limpet hemocyanin, and both total and antigen-specific isotype-specific immunoglobulin titers were determined. Total IgG1, IgG2a, IgG2b, and IgG3 tended to be lower overall in the beta 2m-/- mice compared with beta 2m+/- littermates. In contrast, total and antigen-specific IgE titers were similar in the two groups. These data indicate that CD8+ lymphocytes are not required to clear high doses of vaccinia virus, and they suggest that beta 2m-/- mice are less efficient at antigen-specific IgG production than their beta 2m+/- littermates. PMID:1631092

  12. Endogenous N-terminal Domain Cleavage Modulates α1D-Adrenergic Receptor Pharmacodynamics.

    PubMed

    Kountz, Timothy S; Lee, Kyung-Soon; Aggarwal-Howarth, Stacey; Curran, Elizabeth; Park, Ji-Min; Harris, Dorathy-Ann; Stewart, Aaron; Hendrickson, Joseph; Camp, Nathan D; Wolf-Yadlin, Alejandro; Wang, Edith H; Scott, John D; Hague, Chris

    2016-08-26

    The α1D-adrenergic receptor (ADRA1D) is a key regulator of cardiovascular, prostate, and central nervous system functions. This clinically relevant G protein-coupled receptor has proven difficult to study, as it must form an obligate modular homodimer containing the PDZ proteins scribble and syntrophin or become retained in the endoplasmic reticulum as non-functional protein. We previously determined that targeted removal of the N-terminal (NT) 79 amino acids facilitates ADRA1D plasma membrane expression and agonist-stimulated functional responses. However, whether such an event occurs in physiological contexts was unknown. Herein, we report the ADRA1D is subjected to innate NT processing in cultured human cells. SNAP near-infrared imaging and tandem-affinity purification revealed the ADRA1D is expressed as both full-length and NT truncated forms in multiple human cell lines. Serial truncation mapping identified the cleavage site as Leu(90)/Val(91) in the 95-amino acid ADRA1D NT domain, suggesting human cells express a Δ1-91 ADRA1D species. Tandem-affinity purification MS/MS and co-immunoprecipitation analysis indicate NT processing of ADRA1D is not required to form scribble-syntrophin macromolecular complexes. Yet, label-free dynamic mass redistribution signaling assays demonstrate that Δ1-91 ADRA1D agonist responses were greater than WT ADRA1D. Mutagenesis of the cleavage site nullified the processing event, resulting in ADRA1D agonist responses less than the WT receptor. Thus, we propose that processing of the ADRA1D NT domain is a physiological mechanism employed by cells to generate a functional ADRA1D isoform with optimal pharmacodynamic properties. PMID:27382054

  13. β-Adrenergic-stimulated macrophages: Comprehensive localization in the M1-M2 spectrum.

    PubMed

    Lamkin, Donald M; Ho, Hsin-Yun; Ong, Tiffany H; Kawanishi, Carly K; Stoffers, Victoria L; Ahlawat, Nivedita; Ma, Jeffrey C Y; Arevalo, Jesusa M G; Cole, Steve W; Sloan, Erica K

    2016-10-01

    β-Adrenergic signaling can regulate macrophage involvement in several diseases and often produces anti-inflammatory properties in macrophages, which are similar to M2 properties in a dichotomous M1 vs. M2 macrophage taxonomy. However, it is not clear that β-adrenergic-stimulated macrophages may be classified strictly as M2. In this in vitro study, we utilized recently published criteria and transcriptome-wide bioinformatics methods to map the relative polarity of murine β-adrenergic-stimulated macrophages within a wider M1-M2 spectrum. Results show that β-adrenergic-stimulated macrophages did not fit entirely into any one pre-defined category of the M1-M2 spectrum but did express genes that are representative of some M2 side categories. Moreover, transcript origin analysis of genome-wide transcriptional profiles located β-adrenergic-stimulated macrophages firmly on the M2 side of the M1-M2 spectrum and found active suppression of M1 side gene transcripts. The signal transduction pathways involved were mapped through blocking experiments and bioinformatics analysis of transcription factor binding motifs. M2-promoting effects were mediated specifically through β2-adrenergic receptors and were associated with CREB, C/EBPβ, and ATF transcription factor pathways but not with established M1-M2 STAT pathways. Thus, β-adrenergic-signaling induces a macrophage transcriptome that locates on the M2 side of the M1-M2 spectrum but likely accomplishes this effect through a signaling pathway that is atypical for M2-spectrum macrophages. PMID:27485040

  14. Optodynamic simulation of β-adrenergic receptor signalling

    PubMed Central

    Siuda, Edward R.; McCall, Jordan G.; Al-Hasani, Ream; Shin, Gunchul; Il Park, Sung; Schmidt, Martin J.; Anderson, Sonya L.; Planer, William J.; Rogers, John A.; Bruchas, Michael R.

    2015-01-01

    Optogenetics has provided a revolutionary approach to dissecting biological phenomena. However, the generation and use of optically active GPCRs in these contexts is limited and it is unclear how well an opsin-chimera GPCR might mimic endogenous receptor activity. Here we show that a chimeric rhodopsin/β2 adrenergic receptor (opto-β2AR) is similar in dynamics to endogenous β2AR in terms of: cAMP generation, MAP kinase activation and receptor internalization. In addition, we develop and characterize a novel toolset of optically active, functionally selective GPCRs that can bias intracellular signalling cascades towards either G-protein or arrestin-mediated cAMP and MAP kinase pathways. Finally, we show how photoactivation of opto-β2AR in vivo modulates neuronal activity and induces anxiety-like behavioural states in both fiber-tethered and wireless, freely moving animals when expressed in brain regions known to contain β2ARs. These new GPCR approaches enhance the utility of optogenetics and allow for discrete spatiotemporal control of GPCR signalling in vitro and in vivo. PMID:26412387

  15. Adrenergic activation attenuates astrocyte swelling induced by hypotonicity and neurotrauma.

    PubMed

    Vardjan, Nina; Horvat, Anemari; Anderson, Jamie E; Yu, Dou; Croom, Deborah; Zeng, Xiang; Lužnik, Zala; Kreft, Marko; Teng, Yang D; Kirov, Sergei A; Zorec, Robert

    2016-06-01

    Edema in the central nervous system can rapidly result in life-threatening complications. Vasogenic edema is clinically manageable, but there is no established medical treatment for cytotoxic edema, which affects astrocytes and is a primary trigger of acute post-traumatic neuronal death. To test the hypothesis that adrenergic receptor agonists, including the stress stimulus epinephrine protects neural parenchyma from damage, we characterized its effects on hypotonicity-induced cellular edema in cortical astrocytes by in vivo and in vitro imaging. After epinephrine administration, hypotonicity-induced swelling of astrocytes was markedly reduced and cytosolic 3'-5'-cyclic adenosine monophosphate (cAMP) was increased, as shown by a fluorescence resonance energy transfer nanosensor. Although, the kinetics of epinephrine-induced cAMP signaling was slowed in primary cortical astrocytes exposed to hypotonicity, the swelling reduction by epinephrine was associated with an attenuated hypotonicity-induced cytosolic Ca(2+) excitability, which may be the key to prevent astrocyte swelling. Furthermore, in a rat model of spinal cord injury, epinephrine applied locally markedly reduced neural edema around the contusion epicenter. These findings reveal new targets for the treatment of cellular edema in the central nervous system. GLIA 2016;64:1034-1049. PMID:27018061

  16. Beta-adrenergic blockade and atrio--ventricular conduction impairment.

    PubMed

    Giudicelli, J F; Lhoste, F; Boissier, J R

    1975-04-01

    Atrio--ventricular conduction and its modifications induced by six Beta-adrenergic blocking agents have been investigated in the dog. Premature atrial stimuli (St2) were applied at variable intervals following regular stimuli (St1) ensuring atrial pacing; atrial (AERP), nodoventricular (NERP) and global (GERP) effective refractory periods as well as global functional refractory period (GFRP) were determined before and after administration of each of the six drugs. When Beta-blockade was produced with d,1-propranolol which hwas membrane stabilizing effects (MSE) but no intrinsic sympathomimetic activity (ISA) or with sotalol, which has neither MSE nor ISA, all parameters were significantly increased. When Beta-blockade was achieved with pindolol or practolol, which have only a poor Beta-adrenolytic potency and no ISA. Alprenolol showed intermediate effects. Thus, it appears that Beta-blockade and not MSE, is responsible for the onset of A-V conduction impairment but that ISA, probably through a metabolic mechanism, affords protection against this impairment. On the other hand, measurement of ventricular effective refractory period (VERP) has shown that at the Purkinje-free junction, it is MSE which is mainly involved in conduction impairment. PMID:238853

  17. Noninvasive monitoring of beta-adrenergic tone during isoproterenol infusions.

    PubMed

    Easley, R B; Rodbard, D

    1977-12-01

    Sphygmo-Recording is a simple, noninvasive technique for analysis of pulse wave contour and timing which has been used to evaluate the change in cardiac dynamics during isoproterenol infusion. The QKd interval, i.e., the time interval between the onset of the QRS complex and the onset of the Korotkoff sound at the brachial artery when the sphygomomanometer cuff is at diastolic pressure, is normally 205 +/- 15 msec. Continuous intravenous infusion of isoproterenol at 0.01, 0.02, and 0.03 microgram/kg/min into 12 euthyroid normotensive adult volunteers for 10-min intervals resulted in decreases of 55, 79, and 89 msec in QKd and increases of heart rate of 14, 27, and 43 beats/min, respectively. The corresponding changes in dP/dt, i.e., slope of the pulse wave upstroke at the brachial artery determined noninvasively from the same records, were 0.65, 1.47, and 2.26 mm Hg/msec. These results confirm previous studies which indicate that the chronotropic response of normal subjects to isoproterenol infusion is comparable to that previously reported in patients with the putative "hyperdynamic beta-adrenergic state." PMID:200395

  18. Characterization of the Rac-GAP (Rac-GTPase-activating protein) activity of beta2-chimaerin, a 'non-protein kinase C' phorbol ester receptor.

    PubMed Central

    Caloca, Maria Jose; Wang, HongBin; Kazanietz, Marcelo G

    2003-01-01

    The regulation and function of beta2-chimaerin, a novel receptor for the phorbol ester tumour promoters and the second messenger DAG (diacylglycerol), is largely unknown. As with PKC (protein kinase C) isoenzymes, phorbol esters bind to beta2-chimaerin with high affinity and promote its subcellular distribution. beta2-Chimaerin has GAP (GTPase-activating protein) activity for the small GTP-binding protein Rac1, but for not Cdc42 or RhoA. We show that acidic phospholipids enhanced its catalytic activity markedly in vitro, but the phorbol ester PMA had no effect. beta2-Chimaerin and other chimaerin isoforms decreased cellular levels of Rac-GTP markedly in COS-1 cells and impaired GTP loading on to Rac upon EGF (epidermal growth factor) receptor stimulation. Deletional and mutagenesis analysis determined that the beta2-chimaerin GAP domain is essential for this effect. Interestingly, PMA has a dual effect on Rac-GTP levels in COS-1 cells. PMA increased Rac-GTP levels in the absence of a PKC inhibitor, whereas under conditions in which PKC activity is inhibited, PMA markedly decreased Rac-GTP levels and potentiated the effect of beta2-chimaerin. Chimaerin isoforms co-localize at the plasma membrane with active Rac, and these results were substantiated by co-immunoprecipitation assays. In summary, the novel phorbol ester receptor beta2-chimaerin regulates the activity of the Rac GTPase through its GAP domain, leading to Rac inactivation. These results strongly emphasize the high complexity of DAG signalling due to the activation of PKC-independent pathways, and cast doubts regarding the selectivity of phorbol esters and DAG analogues as selective PKC activators. PMID:12877655

  19. Adrenalectomy mediated alterations in adrenergic activation of adenylate cyclase in rat liver

    SciTech Connect

    El-Refai, M.; Chan, T.

    1986-05-01

    Adrenalectomy caused a large increase in the number of ..beta..-adrenergic binding sites on liver plasma membranes as measured by /sup 125/I-iodocyanopindolol (22 and 102 fmol/mg protein for control and adrenalectomized (ADX) rats). Concomitantly an increase in the number of binding sites for /sup 3/H-yohimbine was also observed (104 and 175 fmol/mg protein for control and adx membranes). Epinephrine-stimulated increase in cyclic AMP accumulation in isolated hepatocytes were greater in cells from ADX rats. This increase in ..beta..-adrenergic mediated action was much less than what may be expected as a result of the increase in the ..beta..-adrenergic binding in ADX membranes. In addition phenoxybenzamine (10 ..mu..M) further augmented this action of epinephrine in both control and ADX cells. To test the hypothesis that the increase in the number of the inhibitory ..cap alpha../sub 2/-adrenergic receptors in adrenalectomy is responsible for the muted ..beta..-adrenergic response, the authors injected rats with pertussis toxin (PT). This treatment may cause the in vivo ribosylation of the inhibitory binding protein (Ni). Adenylate cyclase (AC) activity in liver plasma membranes prepared from treated and untreated animals was measured. In contrast with control rats, treatment of ADX rats with PT resulted in a significant increase in the basal activity of AC (5.5 and 7.7 pmol/mg protein/min for untreated and treated rats respectively). Isoproterenol (10 ..mu..M), caused AC activity to increase to 6.5 and 8.4 pmol/mg protein/min for membranes obtained from ADX untreated and ADX treated rats respectively. The ..cap alpha..-adrenergic antagonists had no significant effect on the ..beta..-adrenergic-mediated activation of AC in liver plasma membranes from PT treated control and ADX rats. The authors conclude that the ..beta..-adrenergic activation of AC is attenuated by Ni protein both directly and as a result of activation of ..cap alpha..-adrenergic receptors.

  20. Functions of adrenergic and cholinergic nerves in canine effectors of seminal emission.

    PubMed

    Arver, S; Sjöstrand, N O

    1982-05-01

    Spontaneous activity responses to acetylcholine (ACh), adrenaline (A), noradrenaline (NA) and barium chloride as well as the effects of various autonomic drugs on effects of field stimulation of nerves and muscle cells of isolated pieces or strips of cauda epididymidis, vas deferens, ampulla ductus deferentis and prostate of dog were studied. The main results and conclusions are: the muscles show little spontaneous activity but rhythmicity can easily be produced by e.g. stimulating agonists. The muscles are contracted by alpha-adrenoceptor stimulants. ACh has usually no or a very weak contractile effect in high concentrations. Muscles of young dogs are more sensitive to ACh. The excitatory innervation of the muscles is adrenergic and completely blocked by adrenergic neuron blockers as well as alpha-adrenoceptor blocking drugs. Stimulation of adrenergic nerves leads to maximum response already at low frequencies (4-6 Hz). This response is very similar to that provoked by a supramaximal dose of NA. Scopolamine enhances neurogenic contractile effects while physostigmine suppresses them. Hence cholinergic nerves may act by muscarinic prejunctional inhibition of the excitatory adrenergic neurotransmission rather than act directly upon the smooth muscle cells. Since secretory cells receive cholinergic innervation prejunctional inhibition of the adrenergic myomotor nerves may be of functional significance in at least the long copulatory events of the dog. PMID:6127870

  1. The adrenergic system in pulmonary arterial hypertension: bench to bedside (2013 Grover Conference series)

    PubMed Central

    Quaife, Robert A.

    2015-01-01

    Abstract In heart failure with reduced left ventricular ejection fraction (HFrEF), adrenergic activation is a key compensatory mechanism that is a major contributor to progressive ventricular remodeling and worsening of heart failure. Targeting the increased adrenergic activation with β-adrenergic receptor blocking agents has led to the development of arguably the single most effective drug therapy for HFrEF. The pressure-overloaded and ultimately remodeled/failing right ventricle (RV) in pulmonary arterial hypertension (PAH) is also adrenergically activated, which raises the issue of whether an antiadrenergic strategy could be effectively employed in this setting. Anecdotal experience suggests that it will be challenging to administer an antiadrenergic treatment such as a β-blocking agent to patients with established moderate-severe PAH. However, the same types of data and commentary were prevalent early in the development of β-blockade for HFrEF treatment. In addition, in HFrEF approaches have been developed for delivering β-blocker therapy to patients who have extremely advanced heart failure, and these general principles could be applied to RV failure in PAH. This review examines the role played by adrenergic activation in the RV faced with PAH, contrasts PAH-RV remodeling with left ventricle remodeling in settings of sustained increases in afterload, and suggests a possible approach for safely delivering an antiadrenergic treatment to patients with RV dysfunction due to moderate-severe PAH. PMID:26401244

  2. Scintigraphic detection of regional disruption of adrenergic neurons in the heart

    SciTech Connect

    Sisson, J.C.; Lynch, J.J.; Johnson, J.; Jaques, S. Jr.; Wu, D.; Bolgos, G.; Lucchesi, B.R.; Wieland, D.M.

    1988-07-01

    Experiments were designed to detect regional disruptions of adrenergic neurons in the hearts of living dogs. The neuron disruption was achieved by the application of phenol to the epicardium of the left ventricle. Evidence for denervation was the reduction in endogenous norepinephrine (NE) concentrations in the myocardium beneath the region of phenol treatment and toward the apex. Radiolabeled meta-iodobenzylguanidine (MIBG) acts as an analog of NE and as such is concentrated in adrenergic nerve terminals. Following phenol application, MIBG labeled with /sup 125/I was found, 20 hours after injection, to be distributed within myocardium in patterns comparable to those of NE. However, left stellectomy did not alter the distributions of NE or /sup 125/I-MIBG in the myocardium and apparently did not disrupt adrenergic innervation. MIBG labeled with /sup 123/I enabled scintigraphic images of heart neurons in the living dog 3 and 20 hours after injection; these images portrayed the regions of adrenergic neuron disruption caused by phenol treatment. Concentrations of thallium-201 depicted on scintigraphic image and of triphenyltetrazolium observed on in vitro staining demonstrated no myocardial injury. Thus, scintigraphy with /sup 123/I-MIBG will display regional adrenergic denervations in the heart.

  3. Bidirectional Modulation of Alcohol-Associated Memory Reconsolidation through Manipulation of Adrenergic Signaling

    PubMed Central

    Schramm, Moritz J W; Everitt, Barry J; Milton, Amy L

    2016-01-01

    Alcohol addiction is a problem of great societal concern, for which there is scope to improve current treatments. One potential new treatment for alcohol addiction is based on disrupting the reconsolidation of the maladaptive Pavlovian memories that can precipitate relapse to drug-seeking behavior. In alcohol self-administering rats, we investigated the effects of bidirectionally modulating adrenergic signaling on the strength of a Pavlovian cue-alcohol memory, using a behavioral procedure that isolates the specific contribution of one maladaptive Pavlovian memory to relapse, the acquisition of a new alcohol-seeking response for an alcohol-associated conditioned reinforcer. The β-adrenergic receptor antagonist propranolol, administered in conjunction with memory reactivation, persistently disrupted the memory that underlies the capacity of a previously alcohol-associated cue to act as a conditioned reinforcer. By contrast, enhancement of adrenergic signaling by administration of the adrenergic prodrug dipivefrin at reactivation increased the strength of the cue-alcohol memory and potentiated alcohol seeking. These data demonstrate the importance of adrenergic signaling in alcohol-associated memory reconsolidation, and suggest a pharmacological target for treatments aiming to prevent relapse through the disruption of maladaptive memories. PMID:26279079

  4. Effects of adrenergic agents on the expression of zebrafish (Danio rerio) vitellogenin Ao1

    SciTech Connect

    Yin Naida; Jin Xia; He Jiangyan; Yin Zhan

    2009-07-01

    Teleost vitellogenins (VTGs) are large multidomain apolipoproteins, traditionally considered to be estrogen-responsive precursors of the major egg yolk proteins, expressed and synthesized mainly in hepatic tissue. The inducibility of VTGs has made them one of the most frequently used in vivo and in vitro biomarkers of exposure to estrogen-active substances. A significant level of zebrafish vtgAo1, a major estrogen responsive form, has been unexpectedly found in heart tissue in our present studies. Our studies on zebrafish cardiomyopathy, caused by adrenergic agonist treatment, suggest a similar protective function of the cardiac expressed vtgAo1. We hypothesize that its function is to unload surplus intracellular lipids in cardiomyocytes for 'reverse triglyceride transportation' similar to that found in lipid transport proteins in mammals. Our results also demonstrated that zebrafish vtgAo1 mRNA expression in heart can be suppressed by both {alpha}-adrenergic agonist, phenylephrine (PE) and {beta}-adrenergic agonist, isoproterenol (ISO). Furthermore, the strong stimulation of zebrafish vtgAo1 expression in plasma induced by the {beta}-adrenergic antagonist, MOXIsylyl, was detected by Enzyme-Linked ImmunoSorbent Assay (ELISA). Such stimulation cannot be suppressed by taMOXIfen, an antagonist to estrogen receptors. Thus, our present data indicate that the production of teleost VTG in vivo can be regulated not only by estrogenic agents, but by adrenergic signals as well.

  5. alpha. - and. beta. -adrenergic receptors in proximal tubules of rat kidney

    SciTech Connect

    Sundaresan, P.R.; Fortin, T.L.; Kelvie, S.L. )

    1987-11-01

    Proximal tubules were isolated from the rat kidney by collagenase digestion of the cortical tissue followed by Percoll gradient centrifugation. Microscopic and hormone-stimulated adenylate cyclase activity studies proved the purity of the preparation. ({sup 3}H)Prazosin, ({sup 3}H)rauwolscine, and ({sup 125}I)iodocyanopindolol were used to identify and quantitate respectively the {alpha}{sub 1}-, {alpha}{sub 2}- and {beta}-adrenergic receptors. Proximal tubular (F{sub 4}) particulate fraction was compared against other cortical nephron segment (F{sub 1},F{sub 2}) fractions and the total collagenase-digested cortex particulate suspension (F{sub t}). Proximal tubules were enriched in {alpha}{sub 1}- and {alpha}{sub 2}-adrenergic receptors compared with. The fractions enriched in glomeruli and distal tubular segments had relatively low concentrations of {alpha}{sub 1}- and {alpha}{sub 2}-adrenergic receptors. Isoproterenol-stimulated adenylate cyclase activities in the different fractions corroborated well with the pattern suggested by the ({sup 125}I)iodocyanopindolol binding studies. The results suggest that whole-cortex preparation radioligand binding studies may reflect proximal tubular {alpha}{sub 1}- and {alpha}{sub 2}-adrenergic receptor changes quite well. They may, however, miss or give erroneous impressions about {beta}-adrenergic receptor changes occurring in different cortical nephron segments.

  6. A role for α1-adrenergic receptors in extinction of conditioned fear and cocaine conditioned preference

    PubMed Central

    Bernardi, Rick E.; Lattal, K. Matthew

    2010-01-01

    Previous work has demonstrated an important role for adrenergic receptors in memory processes in fear and drug conditioning paradigms. Recent studies have also demonstrated alterations in extinction in these paradigms using drug treatments targeting β- and α2-adrenergic receptors, but little is known about the role of α1-adrenergic receptors in extinction. The current study examined whether antagonism of α1-adrenergic receptors would impair the consolidation of extinction in fear and cocaine conditioned place preference (CPP) paradigms. After contextual fear conditioning, injections of prazosin (1.0 or 3.0 mg/kg) following nonreinforced context exposures slowed the loss of conditioned freezing over the course of five extinction sessions (Experiment 1). After cocaine place conditioning, prazosin had no effect on the rate of extinction over eight nonreinforced test sessions. Following post-extinction reconditioning, however, prazosin-treated mice showed a robust place preference, but vehicle-treated mice did not, suggesting that prazosin reduced the persistent effects of extinction (Experiment 2). These results confirm the involvement of the α1-adrenergic receptor in extinction processes in both appetitive and aversive preparations. PMID:20364880

  7. Effects of ovarian hormones on beta-adrenergic and muscarinic receptors in rat heart

    SciTech Connect

    Klangkalya, B.; Chan, A.

    1988-01-01

    The in vitro and in vivo effects of estrogen and progesterone on muscarinic and ..beta..-adrenergic receptors of cardiac tissue were studied in ovariectomized (OVX) rats. The binding assay for muscarinic receptors was performed under a nonequilibrium condition; whereas the binding assay for ..beta..-adrenergic receptors, under an equilibrium condition. Estrogenic compounds and progesterone were found to have no effect on the binding of the radioligand, (/sup 3/H)-dihydroalprenolol, to ..beta..-adrenergic receptors in vitro. However, progestins but not estrogenic compounds inhibited the binding of the radioligand, (/sup 3/H)-quinuclidinyl benzilate, to muscarinic receptors in vitro, with progesterone as the most potent inhibitor. Progesterone was found to decrease the apparent affinity of muscarinic receptors for (/sup 3/H)(-)QNB in vitro. Daily treatment of OVX rats with estradiol benzoate or progesterone for 4 days had no effect on the muscarinic or ..beta..-adrenergic receptors with respect to the binding affinity and receptor density. However, administrations of these hormones together for 4 days caused an increase in the receptor density of muscarinic receptors without a significant effect on their apparent binding affinity; also these hormones induced a decrease in the binding affinity and an increase in the receptor density of ..beta..-adrenergic receptors.

  8. Urinary excretion of beta 2-glycoprotein-1 (apolipoprotein H) and other markers of tubular malfunction in "non-tubular" renal disease.

    PubMed Central

    Flynn, F. V.; Lapsley, M.; Sansom, P. A.; Cohen, S. L.

    1992-01-01

    AIM: To determine whether urinary beta 2-glycoprotein-1 assays can provide improved discrimination between chronic renal diseases which are primarily of tubular or glomerular origin. METHODS: Urinary beta 2-glycoprotein-1, retinol-binding protein, alpha 1-microglobulin, beta 2-microglobulin, N-acetyl-beta-D-glucosa-minidase and albumin were measured in 51 patients with primary glomerular disease, 23 with obstructive nephropathy, and 15 with polycystic kidney disease, and expressed per mmol of creatinine. Plasma beta 2-glycoprotein-1 was assayed in 52 patients and plasma creatinine in all 89. The findings were compared between the diagnostic groups and with previously published data relating to primary tubular disorders. RESULTS: All 31 patients with plasma creatinine greater than 200 mumol/l excreted increased amounts of beta 2-glycoprotein-1, retinol-binding protein, and alpha 1-microglobulin, and 29 had increased N-acetyl-beta-D-glucosaminidase; the quantities were generally similar to those found in comparable patients with primary tubular pathology. Among 58 with plasma creatinine concentrations under 200 mumol/l, increases in beta 2-glycoprotein-1, retinol-binding protein, and alpha 1-microglobulin excretion were less common and much smaller, especially in those with obstructive nephropathy and polycystic disease. The ratios of the excretion of albumin to the other proteins provided the clearest discrimination between the patients with glomerular or tubular malfunction, but an area of overlap was present which embraced those with obstructive nephropathy and polycystic disease. CONCLUSIONS: Increased excretion of beta 2-glycoprotein-1 due to a raised plasma concentration or diminution of tubular reabsorption, or both, is common in all the forms of renal disease investigated, and both plasma creatinine and urinary albumin must be taken into account when interpreting results. Ratios of urinary albumin: beta 2-glycoprotein-1 greater than 1000 are highly suggestive

  9. Beta-Adrenergic Blockade Does not Prevent Polycythemia or Decrease in Plasma Volume in Men at 4300 m Altitude

    NASA Technical Reports Server (NTRS)

    Grover, R. F.; Selland, M. A.; McCullough, R. G.; Dahms, T. E.; Wolfel, E. E.; Butterfield, G. E.; Reeves, J. T.; Greenleaf, J. E.

    1998-01-01

    When humans ascend to high altitude (ALT) their plasma volume (PV) and total blood volume (BV) decrease during the first few days. With continued residence over several weeks, the hypoxia-induced stimulation of erythropoietin increases red cell production which tends to restore BV. Because hypoxia also activates the beta-adrenergic system, which stimulates red blood cell production, we investigated the effect of adrenergic beta-receptor inhibition with propranolol on fluid volumes and the polycythemic response in 11 healthy unacclimatized men (21-33 years old exposed to an ALT of 4300 m (barometric pressure 460 Torr) for 3 weeks on Pikes Peak, Colorado. PV was determined by the Evans blue dye method (PV(sub EB)), BV by the carbon monoxide method (BV(sub CO)), red cell volume (RCV)was calculated from hematocrit (Hct) and BV(sub CO), and serum erythropoietin concentration ([EPO]) and reticulocyte count, were also determined. All determinations were made at sea level and after 9-11 (ALT-10) and 9-20 (ALT-20) days at ALT. At sea level and ALT, six men received propranolol (pro, 240 mg/day), and five received a placebo (pla). Effective beta-blockade did not modify the mean (SE) maximal values of [EPO] [pla: 24.9 (3.5) vs pro: 24.5 (1.5) mU/ml] or reticulocyte count [pla: 2.7 (0.7) vs pro: 2.2 (0.5)%]; nor changes in PV(sub EB)[pla: -15.8 (3.8) vs pro: -19.9 (2.8)%], RCV(sub CO) [pla: +7.0 (6.7) vs pro: +10.1 (6.1)%], or BV(sub CO) [pla: -7.3 (2.3) vs pro: -7.1 (3.9)%]. In the absence of weight loss, a redistribution of body water with no net loss is implied. Hence, activation of the beta-adrenergic system did not appear to affect the hypovolemic or polycythemic responses that occurred during 3 weeks at 4300 m ALT in these subjects.

  10. Terbutaline slow-release tablets in children with asthma. A comparison with t.i.d. beta 2-agonist therapy.

    PubMed

    Croner, S; Gustafsson, M; Kjellman, N I; Säwedal, L

    1986-07-01

    The effects of 5 mg slow-release terbutaline sulphate tablets (Bricanyl Depot) given twice daily were compared with those of ordinary oral beta 2-agonist treatment given three times daily. The study was open, randomized and cross-over and was carried out over 8 weeks in 18 children with bronchial asthma. Compared with ordinary medication, the slow-release tablets obtained higher morning expiratory peak flow values and an improvement in the asthma symptoms during the night and during exercise (P less than 0.05). No differences were found in side effects in spite of a higher total daily dose during the period with terbutaline slow-release tablets. The slow-release tablets were preferred by 15 of 18 children and their families when the effects, side effects and dosage were evaluated. PMID:2876658

  11. [The disease of beta 2-amyloid deposition in the differential diagnosis of juxta-articular subchondral geode lesions].

    PubMed

    Marri, C; Romagnoli, C; Solano, G; Caldeo, A; Emiliani, G

    1993-01-01

    Beta-2 amyloidosis deposition is a new type of amyloidosis recently observed in long-term hemodialysis patients. One of the major osteoarticular complications of this disease is the appearance of subchondral bone cysts. In this paper the radiologic features of such radiolucencies are described and the criteria are outlined of the differential diagnosis from the geodes found in other arthropathies or para-physiologic conditions. The importance of the status of the joint space is stressed: on the basis of its patterns, arthropathies may be grouped as follows: inhomogeneous space narrowing in degenerative arthritis; homogeneous space narrowing in inflammatory arthritis; normal or nearly normal joint space if there is no/not-prevalent involvement of articular cartilage. PMID:8480044

  12. Sequestration of neutrophils in the hepatic vasculature during endotoxemia is independent of beta 2 integrins and intercellular adhesion molecule-1.

    PubMed

    Jaeschke, H; Farhood, A; Fisher, M A; Smith, C W

    1996-11-01

    Antibodies against cellular adhesion molecules protect against neutrophil-induced hepatic injury during ischemia-reperfusion and endotoxemia. To test if beta 2 integrins on neutrophils and intercellular adhesion molecule-1 (ICAM-1) on endothelial cells are involved in neutrophil sequestration in the hepatic vasculature, neutrophil accumulation in the liver was characterized during the early phase of endotoxemia. Intravenous injection of Salmonella enteritidis endotoxin induced a dose-dependent activation of complement, tumor necrosis factor-alpha (TNF-alpha) formation, and an increase of hepatic neutrophils with maximal numbers at 5 mg/kg (90 min: 339 +/- 14 cells/50 high power fields; controls: 18 +/- 2). Administration of 15 micrograms/kg TNF-alpha and intravascular complement activation with cobra venom factor (75 micrograms/kg) had additive effects on hepatic neutrophil accumulation compared with each mediator alone. Monoclonal antibodies (2 mg/kg) to ICAM-1 and the alpha-chain (CD11a, CD11b) or the beta-chain (CD18) of beta 2 integrins had no significant effect on hepatic neutrophil count after endotoxin. In contrast, these antibodies inhibited peritoneal neutrophil infiltration in response to glycogen administration by 28% (CD11b), 60% (CD11a, ICAM-1), and 92% (CD18). Our data suggest that TNF-alpha and complement factors contribute to hepatic neutrophil sequestration during the early phase of endotoxemia. Despite the fact that these inflammatory mediators can up-regulate integrins and ICAM-1, these adhesion molecules are not necessary for neutrophil accumulation in hepatic sinusoids. The protective effect of these antibodies against neutrophil-induced liver injury appears to be due to inhibition of transendothelial migration and adherence to parenchymal cells. PMID:8946651

  13. Selective β2-adrenergic Antagonist Butoxamine Reduces Orthodontic Tooth Movement

    PubMed Central

    Sato, T.; Miyazawa, K.; Suzuki, Y.; Mizutani, Y.; Uchibori, S.; Asaoka, R.; Arai, M.; Togari, A.; Goto, S.

    2014-01-01

    Recently, involvement of the sympathetic nervous system in bone metabolism has attracted attention. β2-Adrenergic receptor (β2-AR) is presented on osteoblastic and osteoclastic cells. We previously demonstrated that β-AR blockers at low dose improve osteoporosis with hyperactivity of the sympathetic nervous system via β2-AR blocking, while they may have a somewhat inhibitory effect on osteoblastic activity at high doses. In this study, the effects of butoxamine (BUT), a specific β2-AR antagonist, on tooth movement were examined in spontaneously hypertensive rats (SHR) showing osteoporosis with hyperactivity of the sympathetic nervous system. We administered BUT (1 mg/kg) orally, and closed-coil springs were inserted into the upper-left first molar. After sacrifice, we calculated the amount of tooth movement and analyzed the trabecular microarchitecture and histomorphometry. The distance in the SHR control was greater than that in the Wistar-Kyoto rat group, but no significant difference was found in the SHR treated with BUT compared with the Wistar-Kyoto rat control. Analysis of bone volume per tissue volume, trabecular number, and osteoclast surface per bone surface in the alveolar bone showed clear bone loss by an increase of bone resorption in SHR. In addition, BUT treatment resulted in a recovery of alveolar bone loss. Furthermore, TH-immunoreactive nerves in the periodontal ligament were increased by tooth movement, and BUT administration decreased TH-immunoreactive nerves. These results suggest that BUT prevents alveolar bone loss and orthodontic tooth movement via β2-AR blocking. PMID:24868013

  14. Alpha-2 adrenergic receptor-mediated inhibition of thermogenesis

    PubMed Central

    Madden, Christopher J.; Tupone, Domenico; Cano, Georgina; Morrison, Shaun F.

    2013-01-01

    Alpha2-adrenergic receptor (α2-AR) agonists have been use as anti-hypertensive agents, in the management of drug withdrawal, and as sedative analgesics. Since α2-AR agonists also influence the regulation of body temperature, we explored their potential as antipyretic agents. This study delineates the central neural substrate for the inhibition of rat brown adipose tissue (BAT) and shivering thermogenesis by α2-AR agonists. Nanoinjection of the α2-AR agonist, clonidine (1.2 nmol), into the rostral raphe pallidus (rRPa) inhibited BAT sympathetic nerve activity (SNA) and BAT thermogenesis. Subsequent nanoinjection of the α2-AR antagonist, idazoxan (6nmol) into the rRPa reversed the clonidine-evoked inhibition of BAT SNA and BAT thermogenesis. Systemic administration of the α2-AR agonists, dexmedetomidine (25ug/kg, iv) or clonidine (100ug/kg, iv) inhibited shivering EMGs, BAT SNA and BAT thermogenesis effects that were reversed by nanoinjection of idazoxan (6nmol) into the rRPa. Dexmedetomidine (100µg/kg, ip) prevented and reversed lipopolysaccharide (10µg/kg ip)-evoked thermogenesis in free-behaving rats. Cholera toxin subunit b retrograde tracing from rRPa and pseudorabies virus transynaptic retrograde tracing from BAT combined with immunohistochemistry for catecholaminergic biosynthetic enzymes revealed the ventrolateral medulla as the source of catecholaminergic input to the rRPa and demonstrated that these catecholaminergic neurons are synaptically connected to BAT. Photostimulation of VLM neurons expressing of the PRSx8-ChR2-mCherry lentiviral vector inhibited BAT SNA via activation of α2-ARs in the rRPa. These results indicate a potent inhibition of BAT and shivering thermogenesis by α2-AR activation in the rRPa, and suggest a therapeutic potential of α2-AR agonists for reducing potentially-lethal elevations in body temperature during excessive fever. PMID:23365239

  15. β-Adrenergic receptor expression in vascular tumors.

    PubMed

    Chisholm, Karen M; Chang, Kay W; Truong, Mai T; Kwok, Shirley; West, Rob B; Heerema-McKenney, Amy E

    2012-11-01

    Propranolol has recently emerged as an effective therapy for infantile hemangiomas causing regression. The β-adrenergic receptor (AR) antagonist is thought to cause vasoconstriction by its effect on nitric oxide, block angiogenesis by its effect on vascular endothelial growth factor (VEGF), and induce apoptosis. In a prior report, we identified expression of β2-AR (B2-AR) and its phosphorylated form (B2-ARP) in a case of infantile hemangioma that responded to propranolol treatment. We now explore the expression of βARs on a variety of vascular lesions utilizing a tissue microarray containing 141 lesions, including infantile hemangiomas, angiosarcomas, hemangiomas, hemangioendotheliomas, and various vascular malformations. The array was immunostained for B2-AR, B2-ARP, and β3-AR (B3-AR), and the results scored for the intensity of endothelial cell expression as negative, weak positive, or strong positive. All phases of infantile hemangiomas had strong expression of all three receptors, with the exception of only weak expression of B2-ARP in the proliferative phase infantile hemangioma. Strong expression of all three receptors was present in many hemangiomas, hemangioendotheliomas, and vascular malformations. Absent to weak expression of all three receptors was seen in glomus tumor, hobnail hemangioendothelioma, pyogenic granuloma, and reactive vascular proliferations. This is the first study to report β-AR expression in a variety of vascular lesions. Although immunohistochemical expression of the receptors does not necessarily indicate that similar pathways of responsiveness to β-blockade are present, it does raises the possibility that β-blockade could potentially affect apoptosis and decrease responsiveness to VEGF. Additional study is warranted, as therapeutic options are limited for some patients with these lesions. PMID:22743651

  16. The Adrenergic Nervous System in Heart Failure: Pathophysiology and Therapy

    PubMed Central

    Lymperopoulos, Anastasios; Rengo, Giuseppe; Koch, Walter J.

    2013-01-01

    Heart failure (HF), the leading cause of death in the western world, develops when a cardiac injury or insult impairs the ability of the heart to pump blood and maintain tissue perfusion. It is characterized by a complex interplay of several neurohormonal mechanisms that get activated in the syndrome in order to try and sustain cardiac output in the face of decompensating function. Perhaps the most prominent among these neurohormonal mechanisms is the adrenergic (or sympathetic) nervous system (ANS), whose activity and outflow are enormously elevated in HF. Acutely, and if the heart works properly, this activation of the ANS will promptly restore cardiac function. However, if the cardiac insult persists over time, chances are the ANS will not be able to maintain cardiac function, the heart will progress into a state of chronic decompensated HF, and the hyperactive ANS will continue to “push” the heart to work at a level much higher than the cardiac muscle can handle. From that point on, ANS hyperactivity becomes a major problem in HF, conferring significant toxicity to the failing heart and markedly increasing its morbidity and mortality. The present review discusses the role of the ANS in cardiac physiology and in HF pathophysiology, the mechanisms of regulation of ANS activity and how they go awry in chronic HF, methods of measuring ANS activity in HF, the molecular alterations in heart physiology that occur in HF along with their pharmacological and therapeutic implications, and, finally, drugs and other therapeutic modalities used in HF treatment that target or affect the ANS and its effects on the failing heart. PMID:23989716

  17. Peripubertal ovariectomy influences thymic adrenergic network plasticity in adult rats.

    PubMed

    Pilipović, Ivan; Vujnović, Ivana; Arsenović-Ranin, Nevena; Dimitrijević, Mirjana; Kosec, Duško; Stojić-Vukanić, Zorica; Leposavić, Gordana

    2016-08-15

    The study investigated the influence of peripubertal ovariectomy on the thymic noradrenaline (NA) concentration, and the thymocyte NA content and β2- and α1-adrenoceptor (AR) expression in adult 2- and 11-month-old rats. In control rats, the thymic NA concentration increased with age. This increase reflected rise in the density of catecholamine (CA)-containing fluorescent nerve fibers and cells and their CA content. Additionally, the average β2- and α1-AR thymocyte surface density changed in the opposite direction with age; the density of β2-AR decreased, whereas that of α1-AR increased. Ovariectomy diminished the thymic NA concentration in 2-month-old rats. This reflected the decrease in the density of fluorescent nerve fibers, and CA content in fluorescent nerve fibers and non-lymphoid cells, since the thymocyte NA content was increased in ovariectomized (Ox) rats. Estrogen supplementation prevented the ovariectomy-induced changes. In Ox rats, the density of CA-synthesizing nerve fibers and non-lymphoid cells diminished with age. To the contrary, NA content in thymocytes increased with age, but it did not exceed that in 11-month-old controls. Additionally, ovariectomy diminished the average thymocyte surface density of β2-ARs, but it increased that of α1-ARs in 2-month-old-rats (due to estrogen, and estrogen and progesterone deficiency, respectively). These changes, despite of the rise in circulating estrogen level post-ovariectomy, remained stable with age. This most likely reflected a decreased sensitivity to estrogen action, as a consequence of the hormone misprinting in peripubertal age. The analysis of thymocyte proliferation in culture suggested that age- and ovariectomy-induced alterations in thymocyte NA synthesis and AR expression altered NA autocrine/paracrine action on thymocytes. In conclusion, the study indicates that the ovarian hormone deficiency in peripubertal age affects ovarian steroid-dependent remodeling of thymic adrenergic

  18. [Beta]-Adrenergic Receptors in the Insular Cortex are Differentially Involved in Aversive vs. Incidental Context Memory Formation

    ERIC Educational Resources Information Center

    Miranda, Maria Isabel; Sabath, Elizabeth; Nunez-Jaramillo, Luis; Puron-Sierra, Liliana

    2011-01-01

    The goal of this research was to determine the effects of [beta]-adrenergic antagonism in the IC before or after inhibitory avoidance (IA) training or context pre-exposure in a latent inhibition protocol. Pretraining intra-IC infusion of the [beta]-adrenergic antagonist propranolol disrupted subsequent IA retention and impaired latent inhibition…

  19. Beta-adrenergic agonists increase lung liquid clearance in anesthetized sheep.

    PubMed Central

    Berthiaume, Y; Staub, N C; Matthay, M A

    1987-01-01

    We did experiments to determine whether beta-adrenergic agonists increase lung liquid clearance in anesthetized ventilated adult sheep and, if so, whether the increase is mediated by beta receptors and what mechanism is involved. We instilled 100 ml of autologous serum either alone or with a beta-adrenergic agonist (terbutaline, 10(-5) M, or epinephrine, 5.5 X 10(-6) M) into one lower lobe. After 4 h both terbutaline and epinephrine increased lung liquid clearance. The increase in lung liquid clearance was inhibited when propranolol (a beta blocker) or amiloride (a sodium channel blocker) was added to the terbutaline. Increased clearance was not explained by changes in pulmonary hemodynamics, pulmonary blood flow, or lung lymph flow. We conclude that beta-adrenergic agonists increase lung liquid clearance in anesthetized intact adult sheep. This increase is mediated through beta receptors and probably depends on increased active transport of sodium across the alveolar barrier. Images PMID:2879851

  20. Effect of age on upregulation of the cardiac adrenergic beta receptors

    SciTech Connect

    Tumer, N.; Houck, W.T.; Roberts, J.

    1990-03-01

    Radioligand binding studies were performed to determine whether upregulation of postjunctional beta receptors occurs in sympathectomized hearts of aged animals. Fischer 344 rats 6, 12, and 24 months of age (n = 10) were used in these experiments. To produce sympathectomy, rats were injected with 6-hydroxydopamine hydrobromide (6-OHDA; 2 x 50 mg/kg iv) on days 1 and 8; the animals were decapitated on day 15. The depletion of norepinephrine in the heart was about 86% in each age group. 125I-Iodopindolol (IPIN), a beta adrenergic receptor antagonist, was employed to determine the affinity and total number of beta adrenergic receptors in the ventricles of the rat heart. The maximal number of binding sites (Bmax) was significantly elevated by 37%, 48%, and 50% in hearts from sympathectomized 6-, 12-, and 24-month-old rats, respectively. These results indicate that beta receptor mechanisms in older hearts can respond to procedures that cause upregulation of the beta adrenergic receptors.

  1. Localization of beta-adrenergic receptors on differentiated cells of the central nervous system in culture.

    PubMed Central

    Ventimiglia, R; Greene, M I; Geller, H M

    1987-01-01

    Hypothalamic neurons and cortical protoplasmic (type 1) astrocytes in dissociated cultures of rat brain express binding sites for antibodies specific for epitopes related to the beta-adrenergic receptor. Undifferentiated glial progenitor cells of the rat optic nerve do not detectably bind these antibodies, but both of the progeny [oligodendroglia and process-bearing (type 2) astrocytes] express immunologically identified beta-adrenergic receptors. Levels of receptor expression are variable: not all cells of each type express receptors nor is expression uniform on a given cell. The data suggest that cells of the central nervous system express beta-adrenergic receptors but that levels of expression may be determined by the differentiated state of the cells. Images PMID:3037533

  2. Effects of phorbol esters on adrenergic receptors of DDT MF-2 smooth muscle cells

    SciTech Connect

    Cowlen, M.; Toews, M.

    1986-03-05

    Phorbol esters have been reported to induce redistribution or internalization of several types of cell surface receptors, including beta-adrenergic receptors (BAR) in some cells. They investigated the effects of phorbol esters on adrenergic receptor distribution in DDT/sub 1/ MF-2 smooth muscle cells in suspension culture. Exposure of cells to epinephrine, an agonist for both BAR and alpha-1 adrenergic receptors (AAR), led to a shift of about half of BAR from plasma membrane to light vesicle fractions on sucrose density gradient centrifugation. This change correlates with other evidence for internalization or sequestration of BAR away from the cell surface. AAR distribution remained unaltered following agonist treatment. Pretreatment of cells with phorbol 12-myristate 13-acetate, which caused about 80% inhibition of epinephrine-stimulated turnover of inositol phospholipids, did not lead to redistribution of either BAR or AAR.

  3. DNA synthesis in mouse brown adipose tissue is under. beta. -adrenergic control

    SciTech Connect

    Rehnmark, S.; Nedergaard, J. )

    1989-02-01

    The rate of DNA synthesis in mouse brown adipose tissue was followed with injections of ({sup 3}H)thymidine. Cold exposure led to a large increase in the rate of ({sup 3}H)thymidine incorporation, reaching a maximum after 8 days, after which the activity abruptly ceased. A series of norepinephrine injections was in itself able to increase ({sup 3}H)thymidine incorporation. When norepinephrine was injected in combination with the {alpha}-adrenergic antagonist phentolamine or with the {beta}-adrenergic antagonist propranolol, the stimulation was fully blocked by propranolol. It is suggested that stimulation of DNA synthesis in brown adipose tissue is a {beta}-adrenergically mediated process and that the tissue is an interesting model for studies of physiological control of DNA synthesis.

  4. Characterization of. cap alpha. /sub 2/-adrenergic receptors in rat cerebral cortex

    SciTech Connect

    Nasseri, A.

    1987-01-01

    The properties of /sup 3/H-RX 781094 binding sites and the receptors inhibiting norepinephrine (NE) release and cyclic AMP accumulation in rat cerebral cortex were compared. /sup 3/H-RX 781094, a new ..cap alpha../sub 2/-adrenergic receptor antagonist radioligand, labelled a homogeneous population of binding sites at 37/sup 0/C with the pharmacological specificity expected of ..cap alpha../sub 2/-adrenergic receptors. Gpp(NH)p and NaCl decreased the potencies of agonists at /sup 3/H-RX 781094 binding sites 3-22 fold. Antagonists blocked the inhibition of potassium-evoked tritium release from cortical slices preloaded with /sup 3/H-NE by exogenous NE with potencies similar to those observed in competition for specific /sup 3/H-RX 781094 binding sites. EEDQ, an irreversible ..cap alpha../sub 2/-adrenergic receptors and determine whether there was a receptor reserve for the inhibition of tritium release.

  5. Structure-guided development of dual β2 adrenergic/dopamine D2 receptor agonists.

    PubMed

    Weichert, Dietmar; Stanek, Markus; Hübner, Harald; Gmeiner, Peter

    2016-06-15

    Aiming to discover dual-acting β2 adrenergic/dopamine D2 receptor ligands, a structure-guided approach for the evolution of GPCR agonists that address multiple targets was elaborated. Starting from GPCR crystal structures, we describe the design, synthesis and biological investigation of a defined set of compounds leading to the identification of the benzoxazinone (R)-3, which shows agonist properties at the adrenergic β2 receptor and substantial G protein-promoted activation at the D2 receptor. This directed approach yielded molecular probes with tuned dual activity. The congener desOH-3 devoid of the benzylic hydroxyl function was shown to be a β2 adrenergic antagonist/D2 receptor agonist with Ki values in the low nanomolar range. The compounds may serve as a promising starting point for the investigation and treatment of neurological disorders. PMID:27132867

  6. The β-adrenergic system as a possible new target for pharmacologic treatment of neovascular retinal diseases.

    PubMed

    Casini, Giovanni; Dal Monte, Massimo; Fornaciari, Irene; Filippi, Luca; Bagnoli, Paola

    2014-09-01

    Retinal neovascular pathologies, such as diabetic retinopathy, retinopathy of prematurity (ROP) and age-related macular degeneration, may be treated with intravitreal injections of drugs targeting vascular endothelial growth factor (VEGF), the main inducer of neoangiogenesis; however further improvements and alternative strategies are needed. In the last few years, an intense research activity has focused on the β-adrenergic system. The results indicate that, in different experimental models, a decrease of the β-adrenergic function may result either in reduction or in exacerbation of the vascular changes, thus suggesting possible dual effects of β-adrenoreceptor (β-AR) modulation depending on the experimental setting. In in vivo models of proliferative retinopathies, most of the data point to a strong inhibitory role against vascular changes exerted by the blockade of specific β-ARs. In particular, the β2-AR seems to be the mostly involved in these responses, and the β1-/β2-AR blocker propranolol results highly effective in inhibiting both the increase of VEGF expression caused by a hypoxic insult and the consequent neovascular response. These observations have prompted clinical trials in preterm infants with ROP, where oral administrations of propranolol produced positive results in terms of efficacy, although safety problems were also reported. In addition, the possibility of using topical propranolol administrations in the form of eye drops opens new potential routes of drug administration in humans. A further point that should be considered is that there are data demonstrating significant antiapoptotic effects exerted by β-ARs, therefore if β-AR blockers were used to inhibit aberrant neovascularization, there may be a burden to pay in terms of impaired neuronal viability. PMID:24933041

  7. KCNQ (Kv7) potassium channel activators as bronchodilators: combination with a β2-adrenergic agonist enhances relaxation of rat airways.

    PubMed

    Brueggemann, Lioubov I; Haick, Jennifer M; Neuburg, Samantha; Tate, Shawn; Randhawa, Devjit; Cribbs, Leanne L; Byron, Kenneth L

    2014-03-15

    KCNQ (Kv7 family) potassium (K(+)) channels were recently found in airway smooth muscle cells (ASMCs) from rodent and human bronchioles. In the present study, we evaluated expression of KCNQ channels and their role in constriction/relaxation of rat airways. Real-time RT-PCR analysis revealed expression of KCNQ4 > KCNQ5 > KCNQ1 > KCNQ2 > KCNQ3, and patch-clamp electrophysiology detected KCNQ currents in rat ASMCs. In precision-cut lung slices, the KCNQ channel activator retigabine induced a concentration-dependent relaxation of small bronchioles preconstricted with methacholine (MeCh; EC50 = 3.6 ± 0.3 μM). Bronchoconstriction was also attenuated in the presence of two other structurally unrelated KCNQ channel activators: zinc pyrithione (ZnPyr; 1 μM; 22 ± 7%) and 2,5-dimethylcelecoxib (10 μM; 24 ± 8%). The same three KCNQ channel activators increased KCNQ currents in ASMCs by two- to threefold. The bronchorelaxant effects of retigabine and ZnPyr were prevented by inclusion of the KCNQ channel blocker XE991. A long-acting β2-adrenergic receptor agonist, formoterol (10 nM), did not increase KCNQ current amplitude in ASMCs, but formoterol (1-1,000 nM) did induce a time- and concentration-dependent relaxation of rat airways, with a notable desensitization during a 30-min treatment or with repetitive treatments. Coadministration of retigabine (10 μM) with formoterol produced a greater peak and sustained reduction of MeCh-induced bronchoconstriction and reduced the apparent desensitization observed with formoterol alone. Our findings support a role for KCNQ K(+) channels in the regulation of airway diameter. A combination of a β2-adrenergic receptor agonist with a KCNQ channel activator may improve bronchodilator therapy. PMID:24441871

  8. Synthesis and characterization of arylamine derivatives of rauwolscine as molecular probes for alpha 2-adrenergic receptors

    SciTech Connect

    Lanier, S.M.; Graham, R.M.; Hess, H.J.; Grodski, A.; Repaske, M.G.; Nunnari, J.M.; Limbird, L.E.; Homcy, C.J.

    1987-06-01

    The selective alpha 2-adrenergic receptor antagonist rauwolscine was structurally modified to yield a series of arylamine carboxamide derivatives, which were investigated as potential molecular probes for the localization and structural characterization of alpha 2-adrenergic receptors. The arylamine carboxamides differ in the number of carbon atoms separating the reactive phenyl moiety from the fused ring structure of the parent compound, rauwolscine carboxylate. Competitive inhibition studies with (/sup 3/H)rauwolscine in rat kidney membranes indicate that the affinity for the carboxamide derivatives is inversely related to the length of the carbon spacer arm with rauwolscine 4-aminophenyl carboxamide exhibiting the highest affinity (Kd = 2.3 +/- 0.2 nM). Radioiodination of rau-AMPC yields a ligand, /sup 125/I-rau-AMPC, which binds to rat kidney alpha 2-adrenergic receptors with high affinity, as determined by both kinetic analysis (Kd = k2/k1 = 0.016 min-1/2.1 X 10(7) M-1 min-1 = 0.76 nM) and equilibrium binding studies (Kd = 0.78 +/- 0.16 nM). /sup 125/I-rau-AMPC was quantitatively converted to the photolabile arylazide derivative 17 alpha-hydroxy-20 alpha-yohimban-16 beta-(N-4-azido-3-(/sup 125/I)iodophenyl) carboxamide (/sup 125/I-rau-AZPC). In a partially purified receptor preparation from porcine brain, this compound photolabels a major (Mr = 62,000) peptide. The labeling of this peptide is inhibited by adrenergic agonists and antagonists with a rank order of potency consistent with an alpha 2-adrenergic receptor binding site. Both /sup 125/I-rau-AMPC and the photolabile arylazide derivative, /sup 125/I-rau-AZPC, should prove useful as molecular probes for the structural and biochemical characterization of alpha 2-adrenergic receptors.

  9. Flow-injection chemiluminescence method to detect a β2 adrenergic agonist.

    PubMed

    Zhang, Guangbin; Tang, Yuhai; Shang, Jian; Wang, Zhongcheng; Yu, Hua; Du, Wei; Fu, Qiang

    2015-02-01

    A new method for the detection of β2 adrenergic agonists was developed based on the chemiluminescence (CL) reaction of β2 adrenergic agonist with potassium ferricyanide-luminol CL. The effect of β2 adrenergic agonists including isoprenaline hydrochloride, salbutamol sulfate, terbutaline sulfate and ractopamine on the CL intensity of potassium ferricyanide-luminol was discovered. Detection of the β2 adrenergic agonist was carried out in a flow system. Using uniform design experimentation, the influence factors of CL were optimized. The optimal experimental conditions were 1 mmol/L of potassium ferricyanide, 10 µmol/L of luminol, 1.2 mmol/L of sodium hydroxide, a flow speed of 2.6 mL/min and a distance of 1.2 cm from 'Y2 ' to the flow cell. The linear ranges and limit of detection were 10-100 and 5 ng/mL for isoprenaline hydrochloride, 20-100 and 5 ng/mL for salbutamol sulfate, 8-200 and 1 ng/mL for terbutaline sulfate, 20-100 and 4 ng/mL for ractopamine, respectively. The proposed method allowed 200 injections/h with excellent repeatability and precision. It was successfully applied to the determination of three β2 adrenergic agonists in commercial pharmaceutical formulations with recoveries in the range of 96.8-98.5%. The possible CL reaction mechanism of potassium ferricyanide-luminol-β2 adrenergic agonist was discussed from the UV/vis spectra. PMID:24830367

  10. Excretion of urinary cadmium, copper, and zinc in cadmium-exposed and nonexposed subjects, with special reference to urinary excretion of beta2-microglobulin and metallothionein.

    PubMed

    Nakajima, Maki; Kobayashi, Etsuko; Suwazono, Yasushi; Uetani, Mirei; Oishi, Mitsuhiro; Inaba, Takeya; Kido, Teruhiko; Shaikh, Zahir A; Nogawa, Koji

    2005-01-01

    The objectives of this study were to examine the association between urinary excretion of cadmium (U-Cd), copper (U-Cu), and zinc (U-Zn) and the severity of two different indicators of renal toxicity (urinary excretion of beta2-microglobulin [U-beta2-MG] and metallothionein [U-MT]) in Cd-exposed subjects compared to controls, and to assess the physiologic mechanisms by which the exposure to environmental Cd affects U-Cd, U-Cu, and U-Zn. The target population included 3508 Cd-exposed and 294 nonexposed participants who received a health survey conducted among the population of the Kakehashi River basin. Increases of U-Cd, U-beta2-MG, and U-MT in the Cd-exposed population were observed relative to excretion of these substances in controls. Regression analysis using a general linear model revealed that the correlations between U-Cd or U-Cu, and U-beta2-MG and between U-Cd, U-Cu or U-Zn, and U-MT were statistically significant in both sexes, but the correlation between U-Zn and U-beta2-MG excretion was significant only in men. These results suggest U-Cd and U-Cu is affected by dysfunction in renal tubular absorption (indicated by U-beta2-MG), whereas not only U-Cd and U-Cu but also U-Zn appear to be a function of renal cellular desquamation (indicated by U-MT). PMID:16327056

  11. Lack of HLA class I antigen expression by melanoma cells SK-MEL-33 caused by a reading frameshift in beta 2-microglobulin messenger RNA.

    PubMed Central

    Wang, Z; Cao, Y; Albino, A P; Zeff, R A; Houghton, A; Ferrone, S

    1993-01-01

    The lack of HLA class I antigen expression by the melanoma cell line SK-MEL-33 is caused by a unique lesion in beta 2-microglobulin (beta 2-mu). Sequencing of beta 2-mu mRNA detected a guanosine deletion at position 323 in codon 76 that causes a frameshift with a subsequent introduction of a stop codon at a position 54 base upstream of the normal position of the stop codon in the message. The loss of 18 amino acids and the change of 6 amino acids, including a cysteine at position 80 in the carboxy terminus of beta 2-mu, are likely to cause marked changes in the structure of the polypeptide. The latter may account for the inability of beta 2-mu to associate with HLA class I heavy chains and for its lack of reactivity with the anti-beta 2-mu mAb tested. HLA class I antigen expression on SK-MEL-33 cells was reconstituted after transfection with a wild-type B2m gene, therefore indicating that the abnormality of endogenous B2m gene is the only mechanism underlying lack of HLA class I antigen expression by SK-MEL-33 cells. The guanosine deletion in B2m gene was detected also in the melanoma tissue from which SK-MEL-33 cells had originated. Therefore, the molecular lesion identified in the SK-MEL-33 melanoma cell line is not caused by a mutation acquired during growth in vitro but is likely to reflect a somatic mutation during tumor progression. Images PMID:8432869

  12. Altered β-adrenergic response in mice lacking myotonic dystrophy protein kinase.

    PubMed

    Llagostera, Esther; Álvarez López, María Jesús; Scimia, Cecilia; Catalucci, Daniele; Párrizas, Marcelina; Ruiz-Lozano, Pilar; Kaliman, Perla

    2012-01-01

    The protein kinase product of the gene mutated in myotonic dystrophy 1 (DMPK) is reported to play a role in cardiac pathophysiology. To gain insight into the molecular mechanisms modulated by DMPK, we characterize the impact of DMPK ablation in the context of cardiac β-adrenergic function. Our data demonstrate that DMPK knockout mice present altered β-agonist-induced responses and suggest that this is due, at least in part, to a reduced density of β(1)-adrenergic receptors in cardiac plasma membranes. PMID:22190319

  13. Altered β-adrenergic response in mice lacking myotonic dystrophy protein kinase (DMPK)

    PubMed Central

    Llagostera, Esther; López, María Jesús Álvarez; Scimia, Cecilia; Catalucci, Daniele; Párrizas, Marcelina; Ruiz-Lozano, Pilar; Kaliman, Perla

    2011-01-01

    The protein kinase product of the gene mutated in myotonic dystrophy 1 (DMPK) is reported to play a role in cardiac pathophysiology. To gain insight into the molecular mechanisms modulated by DMPK, we characterize the impact of DMPK ablation in the context of cardiac β-adrenergic function. Our data demonstrate that DMPK knock-out mice present altered β-agonist-induced responses and suggest that this is due, at least in part, to a reduced density of β1-adrenergic receptors in cardiac plasma membranes. PMID:22190319

  14. Responsiveness of superficial hand veins to phenylephrine in essential hypertension. Alpha adrenergic blockade during prazosin therapy.

    PubMed

    Eichler, H G; Ford, G A; Blaschke, T F; Swislocki, A; Hoffman, B B

    1989-01-01

    Patients with essential hypertension show an increase in vascular resistance. It is unclear whether this is caused by structural changes in the arterial wall or by hyperresponsiveness of vascular smooth muscle to endogenous alpha adrenergic agonists. Using the dorsal hand vein compliance technique we compared the changes in diameter of superficial veins in response to phenylephrine, an alpha 1 adrenergic receptor agonist, and to nitroglycerin, a venorelaxant, in patients with essential hypertension and in normotensive subjects. The dose of phenylephrine that produced 50% of maximal venoconstriction (ED50) in the hypertensive subjects was 257 ng/min (geometric mean; log mean +/- SD was 2.41 +/- 0.54). In the control subjects the ED50 was 269 ng/min (geometric mean; log mean was 2.43 +/- 0.43). Maximal response (Emax) for phenylephrine was 84 +/- 13% in the hypertensive subjects and 90 +/- 6% in the control subjects. Differences in the group means of the ED50 (P = 0.92) or the Emax (P = 0.27) were not significant. There were no significant differences in the ED50 (P = 0.54) or the Emax (P = 0.08) for nitroglycerin between the two groups. These results show no evidence for a generalized change in alpha adrenergic responsiveness in hypertension and support the concept that increased blood pressure responses to alpha adrenergic stimulation in hypertensives are due to structural and geometric changes in th