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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. 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.

  14. 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

  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 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

  6. 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

  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. 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

  10. 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

  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. 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.

  10. 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

  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. 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

  7. 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

  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. 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

  13. 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.

  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. [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

  10. 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.

  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

    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

  14. 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

  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. 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

  18. 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

  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. 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.

  7. 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

  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.

    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

  12. 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.

  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. 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.

  16. 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.

  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. 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

  2. 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.

  3. 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

  4. 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

  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. 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

  18. 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

  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