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Sample records for agonist phenylephrine phe

  1. Phenylephrine

    MedlinePlus

    ... Formula® (as a combination product containing Aspirin, Dextromethorphan, Doxylamine, Phenylephrine) ... Sinus Relief® (as a combination product containing Acetaminophen, Doxylamine, Phenylephrine)

  2. Dorsal hand vein responses to the α₁-adrenoceptor agonist phenylephrine do not predict responses to the α₂-adrenoceptor agonist dexmedetomidine.

    PubMed

    Posti, Jussi P; Valve, Laura; Ruohonen, Saku; Akkila, Juha; Scheinin, Mika; Snapir, Amir

    2011-02-25

    Significant inter-individual variability exists in responses of human dorsal hand veins to activation of α-adrenoceptors. Simultaneous graded infusions of the α₁- and α₂-adrenoceptor agonists phenylephrine (3.66-8000 ng/min) and dexmedetomidine (0.0128-1000 ng/min) were given into dorsal veins of both hands and responses of 75 subjects were analyzed to assess whether a subject's sensitivity to phenylephrine (ED(50)) predicts his sensitivity to dexmedetomidine. Individual ED(50) estimates of dexmedetomidine and phenylephrine ranged between 0.06-412 and 14.2-7450 ng/min and exhibited only a weak positive relationship (r² =0.074, P=0.018). Finger temperature, body mass index, age and phenylephrine sensitivity together accounted for about 30% of dexmedetomidine ED(50) variation (r² =0.315, P<0.001). The large inter-individual variability observed in the responses of dorsal hand veins to both α₁- and α₂-adrenoceptor agonists is not explained by some common factors; instead, dorsal hand vein responsivity is separately determined for both receptor mechanisms.

  3. Effects of α1-adrenoceptor agonist phenylephrine on swelling-activated chloride currents in human atrial myocytes.

    PubMed

    Li, Yetao; Du, Xinling

    2015-02-01

    Swelling-activated chloride currents (ICl.swell) play an important role in cardiac electrophysiology and arrhythmogenesis. However, the regulation of these currents has not been clarified to date. In this research, we focused on the function of phenylephrine, an α1-adrenoceptor agonist, in the regulation of I(Cl.swell) in human atrial myocytes. We recorded I(Cl.swell) evoked by a hypotonic bath solution with the whole-cell patch-clamp technique. We found that I(Cl.swell) increased over time, and it was difficult to achieve absolute steady state. Phenylephrine potentiated I(Cl.swell) from -1.00 ± 0.51 pA/pF at -90 mV and 2.58 ± 1.17 pA/pF at +40 mV to -1.46 ± 0.70 and 3.84 ± 1.67 pA/pF, respectively (P < 0.05, n = 6), and the upward trend in ICl.swell was slowed after washout. This effect was concentration-dependent, and the α1-adrenoceptor antagonist prazosin shifted the dose-effect curve rightward. Addition of prazosin or the protein kinase C (PKC) inhibitor bisindolylmaleimide (BIM) attenuated the effect of phenylephrine. The PKC activator phorbol 12,13-dibutyrate (PDBu) activated I(Cl.swell) from -1.69 ± 1.67 pA/pF at -90 mV and 5.58 ± 6.36 pA/pF at +40 mV to -2.41 ± 1.95 pA/pF and 7.05 ± 6.99 pA/pF, respectively (P < 0.01 at -90 mV and P < 0.05 at +40 mV; n = 6). In conclusion, the α1-adrenoceptor agonist phenylephrine augmented I(Cl.swell), a result that differs from previous reports in other animal species. The effect was attenuated by BIM and mimicked by PDBu, which indicates that phenylephrine might modulate I(Cl,swell) in a PKC-dependent manner.

  4. From the potent and selective mu opioid receptor agonist H-Dmt-d-Arg-Phe-Lys-NH(2) to the potent delta antagonist H-Dmt-Tic-Phe-Lys(Z)-OH.

    PubMed

    Balboni, Gianfranco; Cocco, Maria Teresa; Salvadori, Severo; Romagnoli, Romeo; Sasaki, Yusuke; Okada, Yoshio; Bryant, Sharon D; Jinsmaa, Yunden; Lazarus, Lawrence H

    2005-08-25

    H-Dmt-d-Arg-Phe-Lys-NH(2) ([Dmt(1)]DALDA) binds with high affinity and selectivity to the mu opioid receptor and is a potent and long-acting analgesic. Substitution of d-Arg in position 2 with Tic and masking of the lysine amine side chain by Z protection and of the C-terminal carboxylic function instead of the amide function transform a potent and selective mu agonist into a potent and selective delta antagonist H-Dmt-Tic-Phe-Lys(Z)-OH. Such a delta antagonist could be used as a pharmacological tool.

  5. The cytotoxic and pro-apoptotic effects of phenylephrine on corneal stromal cells via a mitochondrion-dependent pathway both in vitro and in vivo.

    PubMed

    Zhao, Jun; Qiu, Yue; Tian, Cheng-Lei; Fan, Ting-Jun

    2016-08-01

    Phenylephrine (PHE), a selective α1-adrenergic receptor agonist, is often used as a decongestant for mydriasis prior to cataract surgery, and its abuse might be cytotoxic to the cornea and result in blurred vision. However, the cytotoxicity of PHE to the cornea and its cellular and molecular mechanisms remain unknown. To provide references for secure medication and prospective therapeutic interventions of PHE, we investigated the cytotoxicity of PHE to corneal stroma and its possible mechanisms using an in vitro model of human corneal stromal (HCS) cells and an in vivo model of cat keratocytes. We found that PHE, above the concentration of 0.0781125% (1/128 of its clinical therapeutic dosage), had a dose- and time-dependent cytotoxicity to HCS cells by inducing morphological abnormality and viability decline, as well as S phase arrest. Moreover, PHE induced apoptosis of HCS cells by inducing plasma membrane permeability elevation, phosphatidylserine externalization, DNA fragmentation and apoptotic body formation. Furthermore, PHE could induce activations of caspase-3 and -9, disruption of mitochondrial transmembrane potential, downregulation of anti-apoptotic Bcl-xL, upregulation of pro-apoptotic Bax, along with upregulation of cytoplasmic cytochrome c and apoptosis-inducing factor. The cytotoxic and pro-apoptotic effects of PHE were also proven by the induced apoptotic-like ultrastructural alterations of keratocytes in vivo. Taken together, our results suggest that PHE has a significant cytotoxicity to corneal stroma cells both in vitro and in vivo by inducing cell apoptosis, and the pro-apoptotic effect of PHE is achieved via a Bcl-2 family proteins-mediated mitochondrion-dependent pathway.

  6. Phenylephrine Nasal Spray

    MedlinePlus

    ... not treat the cause of the symptoms or speed recovery. Phenylephrine is in a class of medications ... are clear. Wash your hands with soap and water. Shake the bottle gently before each use and ...

  7. Action of phenylephrine on protein synthesis in liver cells.

    PubMed Central

    Menaya, J; Parrilla, R; Ayuso, M S

    1987-01-01

    The alpha-adrenergic agonist phenylephrine was found to inhibit protein labelling from [3H]valine in isolated liver cells. This effect is only observable under conditions of partial Ca2+ depletion and in cells displaying maximal rates of protein labelling, i.e. cells isolated from fed animals or from starved animals when incubated in the presence of alanine. The ability of phenylephrine to inhibit protein labelling at near-saturating concentrations of the amino acid precursor indicates that this alpha-agonist actually decreases the rate of protein synthesis. The possibility that phenylephrine acts by making cellular Ca2+ availability further limiting can be ruled out, since alanine stimulates protein labelling under conditions of severe Ca2+ depletion obtained by pretreatment of the cells with EGTA. The following observations indicate that the phenylephrine action may be mediated by an increase in cellular cyclic AMP content: (1) a close relationship was found between the abilities of phenylephrine to inhibit protein labelling and to increase cyclic AMP content; (2) cyclic AMP mimics the phenylephrine action only in cells partially depleted of Ca2+; (3) the alpha 1-antagonist prazosin, which inhibited the phenylephrine-mediated increase in cyclic AMP, also abolished the effect on protein synthesis. PMID:2829846

  8. Effects of the CRF receptor antagonist D-Phe CRF(12-41) and the α2-adrenergic receptor agonist clonidine on stress-induced reinstatement of nicotine-seeking behavior in rats

    PubMed Central

    Zislis, George; Desai, Tina V.; Prado, Melissa; Shah, Hina P.; Bruijnzeel, Adrie W.

    2008-01-01

    Summary Tobacco dependence is a chronic disorder that is characterized by relapse after periods of abstinence. It has been hypothesized that the activation of brain stress systems mediates stress-induced relapse to smoking. The aim of these experiments was to investigate the role of corticotropin-releasing factor (CRF) and norepinephrine in stress-induced reinstatement of extinguished nicotine-seeking behavior. Rats were allowed to self-administer nicotine under a fixed-ratio 5 schedule for 14 days and then nicotine-seeking behavior was extinguished by substituting saline for nicotine. In the first experiment, footshocks reinstated extinguished nicotine-seeking behavior. In the second experiment, there was a trend for the CRF1/2 receptor antagonist D-Phe CRF(12-41) (5, 25 μg, icv) to decrease stress-induced reinstatement of nicotine-seeking behavior. Footshock-induced reinstatement of nicotine-seeking behavior was observed only in a subset of stress-responsive rats (71%). D-Phe CRF(12-41) significantly attenuated stress-induced reinstatement of nicotine-seeking behavior in this subset of rats. In the third experiment, the α2-adrenergic receptor agonist clonidine (20, 40 μg/kg, sc) attenuated footshock-induced reinstatement of nicotine-seeking behavior. In the fourth experiment, the effects of D-Phe CRF(12-41) and clonidine on responding for chocolate-flavored food pellets was investigated in order to determine if these compounds have sedative effects. D-Phe CRF(12-41) did not affect responding for food pellets. Clonidine slightly, but significantly, decreased responding for food pellets. Clonidine decreased responding for food to a lesser degree than it decreased stress-induced reinstatement of nicotine-seeking behavior. These data provide support for the hypothesis that an increased activity of brain CRF and norepinephrine systems mediates stress-induced relapse to nicotine-seeking behavior. PMID:17976662

  9. Pseudoephedrine, Phenylephrine and Pregnancy

    MedlinePlus

    ... you should not use them if you have high blood pressure. Your health care provider can help you choose the medication that is best for you. Can I use pseudoephedrine or phenylephrine if I am breastfeeding? At recommended doses, only a small amount of ...

  10. Enhancement of blood-tumor barrier permeability by Sar-[D-Phe8]des-Arg9BK, a metabolically resistant bradykinin B1 agonist, in a rat C6 glioma model

    PubMed Central

    Cardoso, Ronie Cleverson; Lobão-Soares, Bruno; Bianchin, Marino Muxfeldt; Carlotti, Carlos Gilberto; Walz, Roger; Alvarez-Silva, Márcio; Trentin, Andréa Gonçalves; Nicolau, Mauro

    2004-01-01

    Background While it is well known that bradykinin B2 agonists increase plasma protein extravasation (PPE) in brain tumors, the bradykinin B1 agonists tested thus far are unable to produce this effect. Here we examine the effect of the selective B1 agonist bradykinin (BK) Sar-[D-Phe8]des-Arg9BK (SAR), a compound resistant to enzymatic degradation with prolonged activity on PPE in the blood circulation in the C6 rat glioma model. Results SAR administration significantly enhanced PPE in C6 rat brain glioma compared to saline or BK (p < 0.01). Pre-administration of the bradykinin B1 antagonist [Leu8]-des-Arg (100 nmol/Kg) blocked the SAR-induced PPE in the tumor area. Conclusions Our data suggest that the B1 receptor modulates PPE in the blood tumor barrier of C6 glioma. A possible role for the use of SAR in the chemotherapy of gliomas deserves further study. PMID:15458573

  11. Phenylephrine enhances glutamate release in the medial prefrontal cortex through interaction with N-type Ca2+ channels and release machinery.

    PubMed

    Luo, Fei; Li, Si-Hai; Tang, Hua; Deng, Wei-Ke; Zhang, Yu; Liu, Ying

    2015-01-01

    α1 -adrenoceptors (α1 -ARs) stimulation has been found to enhance excitatory processes in many brain regions. A recent study in our laboratory showed that α1 -ARs stimulation enhances glutamatergic transmission via both pre- and post-synaptic mechanisms in layer V/VI pyramidal cells of the rat medial prefrontal cortex (mPFC). However, a number of pre-synaptic mechanisms may contribute to α1 -ARs-induced enhancement of glutamate release. In this study, we blocked the possible post-synaptic action mediated by α1 -ARs to investigate how α1 -ARs activation regulates pre-synaptic glutamate release in layer V/VI pyramidal neurons of mPFC. We found that the α1 -ARs agonist phenylephrine (Phe) induced a significant enhancement of glutamatergic transmission. The Phe-induced potentiation was mediated by enhancing pre-synaptic glutamate release probability and increasing the number of release vesicles via a protein kinase C-dependent pathway. The mechanisms of Phe-induced potentiation included interaction with both glutamate release machinery and N-type Ca(2+) channels, probably via a pre-synaptic Gq /phospholipase C/protein kinase C pathway. Our results may provide a cellular and molecular mechanism that helps explain α1 -ARs-mediated influence on PFC cognitive functions. Alpha1 -adrenoceptor (α1 -ARs) stimulation has been reported to enhance glutamatergic transmission in layer V/VI pyramidal neurons of the rat medial prefrontal cortex (mPFC). We found that α1 -ARs agonist phenylephrine (Phe) increases pre-synaptic glutamate release probability and the number of released vesicles via interaction with both glutamate release machinery and N-type Ca(2+) channels. Our results may provide a cellular and molecular mechanism that helps explain α1 -ARs-mediated influence on PFC cognitive functions. Gq, Gq protein; PLC, phospholipase C; PKC, protein kinase C; AMPA, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid; NMDA, N-methyl-d-aspartate; Glu, glutamate; Phe

  12. N-terminal guanidinylation of TIPP (Tyr-Tic-Phe-Phe) peptides results in major changes of the opioid activity profile.

    PubMed

    Weltrowska, Grazyna; Nguyen, Thi M-D; Chung, Nga N; Wilkes, Brian C; Schiller, Peter W

    2013-09-15

    Derivatives of peptides of the TIPP (Tyr-Tic-Phe-Phe; Tic=1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) family containing a guanidino (Guan) function in place of the N-terminal amino group were synthesized in an effort to improve their blood-brain barrier permeability. Unexpectedly, N-terminal amidination significantly altered the in vitro opioid activity profiles. Guan-analogues of TIPP-related δ opioid antagonists showed δ partial agonist or mixed δ partial agonist/μ partial agonist activity. Guanidinylation of the mixed μ agonist/δ antagonists H-Dmt-Tic-Phe-Phe-NH2 (DIPP-NH2) and H-Dmt-TicΨ[CH2NH]Phe-Phe-NH2 (DIPP-NH2[Ψ]) converted them to mixed μ agonistagonists. A docking study revealed distinct positioning of DIPP-NH2 and Guan-DIPP-NH2 in the δ receptor binding site. Lys(3)-analogues of DIPP-NH2 and DIPP-NH2[Ψ] (guanidinylated or non-guanidinylated) turned out to be mixed μ/κ agonists with δ antagonist-, δ partial agonist- or δ full agonist activity. Compounds with some of the observed mixed opioid activity profiles have therapeutic potential as analgesics with reduced side effects or for treatment of cocaine addiction.

  13. The Effects of Guanfacine and Phenylephrine on a Spiking Neuron Model of Working Memory.

    PubMed

    Duggins, Peter; Stewart, Terrence C; Choo, Xuan; Eliasmith, Chris

    2017-01-01

    We use a spiking neural network model of working memory (WM) capable of performing the spatial delayed response task (DRT) to investigate two drugs that affect WM: guanfacine (GFC) and phenylephrine (PHE). In this model, the loss of information over time results from changes in the spiking neural activity through recurrent connections. We reproduce the standard forgetting curve and then show that this curve changes in the presence of GFC and PHE, whose application is simulated by manipulating functional, neural, and biophysical properties of the model. In particular, applying GFC causes increased activity in neurons that are sensitive to the information currently being remembered, while applying PHE leads to decreased activity in these same neurons. Interestingly, these differential effects emerge from network-level interactions because GFC and PHE affect all neurons equally. We compare our model to both electrophysiological data from neurons in monkey dorsolateral prefrontal cortex and to behavioral evidence from monkeys performing the DRT.

  14. Derivative emission spectrofluorimetry for the simultaneous determination of guaifenesin and phenylephrine hydrochloride in pharmaceutical tablets.

    PubMed

    Maher, Hadir M; Alshehri, Mona M; Al-taweel, Shorog M

    2015-05-01

    Rapid, simple and sensitive derivative emission spectrofluorimetric methods have been developed for the simultaneous analysis of binary mixtures of guaifenesin (GUA) and phenylephrine hydrochloride (PHE). The methods are based upon measurement of the native fluorescence intensity of the two drugs at λex = 275 nm in methanolic solutions, followed by differentiation using first (D1) and second (D2) derivative techniques. The derivative fluorescence intensity-concentration plots were rectilinear over a range of 0.1-2 µg/mL for both GUA and PHE. The limits of detection were 0.027 (D1, GUA), 0.025 (D2, GUA), 0.031 (D1, PHE) and 0.033 (D2, PHE) µg/mL and limits of quantitation were 0.089 (D1, GUA), 0.083 (D2, GUA), 0.095 (D1, PHE) and 0.097 (D2, PHE) µg/mL. The proposed derivative emission spectrofluorimetric methods (D1 and D2) were successfully applied for the determination of the two compounds in binary mixtures and tablets with high precision and accuracy. The proposed methods were fully validated as per ICH guidelines.

  15. Dexmedetomidine Inhibits Phenylephrine-induced Contractions via Alpha-1 Adrenoceptor Blockade and Nitric Oxide Release in Isolated Rat Aortae

    PubMed Central

    Byon, Hyo-Jin; Ok, Seong-Ho; Lee, Soo Hee; Kang, Sebin; Cho, Youngil; Han, Jeong Yeol; Sohn, Ju-Tae

    2017-01-01

    The goal of this in vitro study was to examine the effect of the alpha-2 adrenoceptor agonist dexmedetomidine on phenylephrine (alpha-1 adrenoceptor agonist)-induced contraction in isolated rat aortae and to elucidate the associated cellular mechanisms, with a particular focus on alpha-1 adrenoceptor antagonism. Dexmedetomidine dose-response curves were generated in isolated endothelium-intact and endothelium-denuded rat aortae precontracted with phenylephrine or 5-hydroxytryptamine. Endothelium-denuded aortic rings were pretreated with either dexmedetomidine or the reversible alpha-1 adrenoceptor antagonist phentolamine, followed by post-treatment with the irreversible alpha-1 adrenoceptor blocker phenoxybenzamine. Control rings were treated with phenoxybenzamine alone. All rings were repeatedly washed with Krebs solution to remove all pretreatment drugs, including phenoxybenzamine, phentolamine and dexmedetomidine. Phenylephrine dose-response curves were then generated. The effect of rauwolscine on the dexmedetomidine-mediated change in phenylephrine-induced endothelial nitric oxide synthase (eNOS) phosphorylation in human umbilical vein endothelial cells was examined using western blotting. The magnitude of the dexmedetomidine-mediated inhibition of phenylephrine-induced contraction was higher in endothelium-intact aortae than in endothelium-denuded aortae or endothelium-intact aortae treated with Nω-nitro-L-arginine methyl ester. However, dexmedetomidine did not significantly alter 5-hydroxytryptamine-induced contraction. In further experiments, prazosin attenuated dexmedetomidine-induced contraction. Additionally, pretreatment with either dexmedetomidine plus phenoxybenzamine or phentolamine plus phenoxybenzamine produced greater phenylephrine-induced contraction than phenoxybenzamine alone, suggesting that dexmedetomidine protects aortae from the alpha-1 adrenoceptor blockade induced by phenoxybenzamine. Rauwolscine attenuated the dexmedetomidine

  16. Differential regulation of the mitogen-activated protein and stress-activated protein kinase cascades by adrenergic agonists in quiescent and regenerating adult rat hepatocytes.

    PubMed Central

    Spector, M S; Auer, K L; Jarvis, W D; Ishac, E J; Gao, B; Kunos, G; Dent, P

    1997-01-01

    To study the mechanisms by which catecholamines regulate hepatocyte proliferation after partial hepatectomy (PHX), hepatocytes were isolated from adult male rats 24 h after sham operation or two-thirds PHX and treated with catecholamines and other agonists. In freshly isolated sham cells, p42 mitogen-activated protein (MAP) kinase activity was stimulated by the alpha1-adrenergic agonist phenylephrine (PHE). Activation of p42 MAP kinase by growth factors was blunted by pretreatment of sham hepatocytes with glucagon but not by that with the beta2-adrenergic agonist isoproterenol (ISO). In PHX cells, the ability of PHE to activate p42 MAP kinase was dramatically reduced, whereas ISO became competent to inhibit p42 MAP kinase activation. PHE treatment of sham but not PHX and ISO treatment of PHX but not sham hepatocytes also activated the stress-activated protein (SAP) kinases p46/54 SAP kinase and p38 SAP kinase. These data demonstrate that an alpha1- to beta2-adrenergic receptor switch occurs upon PHX and results in an increase in SAP kinase versus MAP kinase signaling by catecholamines. In primary cultures of hepatocytes, ISO treatment of PHX but not sham cells inhibited [3H]thymidine incorporation. In contrast, PHE treatment of sham but not PHX cells stimulated [3H]thymidine incorporation, which was reduced by approximately 25 and approximately 95% with specific inhibitors of p42 MAP kinase and p38 SAP kinase function, respectively. Inhibition of the p38 SAP kinase also dramatically reduced basal [3H]thymidine incorporation. These data suggest that p38 SAP kinase plays a permissive role in liver regeneration. Alterations in the abilities of catecholamines to modulate the activities of protein kinase A and the MAP and SAP kinase pathways may represent one physiological mechanism by which these agonists can regulate hepatocyte proliferation after PHX. PMID:9199291

  17. Immunoassay cross-reactivity of phenylephrine and methamphetamine.

    PubMed

    Curtin, Lindsay B; Cawley, Michael J

    2012-05-01

    Phenylephrine, an α(1) -adrenergic agonist, and methamphetamine, a prescription drug and substance of abuse, have similar chemical structures and thus have the potential to cross-react in qualitative screening tools such as a urine drug screening (UDS) performed by immunoassay. This cross-reactivity may yield a false-positive result that may affect the provision of care in certain patient populations and clinical situations. We describe a 36-year-old woman with confirmed brain death after a short hospital stay who had an initial UDS that was negative for methamphetamine. The patient was assessed for potential organ donation, which included obtaining a follow-up UDS. A urine sample was obtained after being hospitalized for 36 hours, which tested positive for methamphetamine, with no suspected ingestion of the target substance. Confirmatory laboratory testing indicated that intravenous phenylephrine and its metabolites were the likely cause of the false-positive UDS. However, the patient was not deemed to be a suitable candidate for organ donation, but clear documentation of the reason for denial of organ donation was not available in the patient's medical record. To our knowledge, this is the first case published in the English-language literature that describes the clinical occurrence of apparent immunoassay cross-reactivity of methamphetamine and phenylephrine that resulted in a false-positive UDS for methamphetamine. In addition, this report describes the potential implications of this situation on clinical care, including organ donation acceptance. Toxicology screening in the emergency department and intensive care unit is a tool to assist in the diagnosis of medical conditions, but it may not always be reliable. Therefore, positive immunoassay results that may change the management of a patient's condition should be quickly verified with confirmatory testing to minimize unfavorable consequences.

  18. Effect of oleic, lauric and myristic acids on phenylephrine-induced contractions of isolated rat vas deferens.

    PubMed

    Arruzazabala, M L; Pérez, Y; Ravelo, Y; Molina, V; Carbajal, D; Mas, R; Rodríguez, E

    2011-09-01

    D-004, a lipid extract of Roystonea regia fruits that contains oleic, lauric and myristic acids as major components inhibits alpha1-adrenoreceptors-mediated contractile responses in isolated rat vas deferens and prostate trips; no study has demonstrated a similar effect for oleic, lauric or myristic acids individually. Therefore, the effects of D-004 (250 microg/mL), oleic (100 microg/mL), lauric (50 microg/mL) or myristic (25 microg/mL) acids and their combined effects on phenylephrine (PHE: 10(-7)-10(-4) mol/L) induced contractions has been studied. No treatment changed the basal tone of the preparations, but all inhibited PHE-induced contractions. D-004 produced the highest inhibition, followed by lauric acid, which was more effective than myristic and oleic acids against PHE-induced contractions of control group. D-004 and the mixture of the three acids produced similar inhibitions.

  19. In vitro and in vivo pharmacological profile of PL-3994, a novel cyclic peptide (Hept-cyclo(Cys-His-Phe-d-Ala-Gly-Arg-d-Nle-Asp-Arg-Ile-Ser-Cys)-Tyr-[Arg mimetic]-NH(2)) natriuretic peptide receptor-A agonist that is resistant to neutral endopeptidase and acts as a bronchodilator.

    PubMed

    Edelson, Jeffrey D; Makhlina, Marie; Silvester, Kevin R; Vengurlekar, Shailesh S; Chen, Xiaomei; Zhang, Jie; Koziol-White, Cynthia J; Cooper, Philip R; Hallam, Trevor J; Hay, Douglas W P; Panettieri, Reynold A

    2013-04-01

    The pharmacological and airways relaxant profiles of PL-3994 (Hept-cyclo(Cys-His-Phe-d-Ala-Gly-Arg-d-Nle-Asp-Arg-Ile-Ser-Cys)-Tyr-[Arg mimetic]-NH(2)), a novel natriuretic peptide receptor-A (NPR-A) agonist, were evaluated. PL-3994, a full agonist, has high affinity for recombinant human (h), dog, or rat NPR-As (K(i)s of 1, 41, and 10 nm, respectively), and produced concentration-dependent cGMP generation in human, dog and rat NPR-As (respective EC(50)s of 2, 3 and 14 nm). PL-3994 has a K(i) of 7 nm for hNPR-C but was without effect on cGMP generation in hNPR-B. PL-3994 (1 μm) was without significant effect against 75 diverse molecular targets. PL-3994 or BNP, a natural NPR ligand, produced concentration-dependent relaxation of pre-contracted guinea-pig trachea (IC(50)s of 42.7 and 10.7 nm, respectively). PL-3994, and also BNP, (0.1 nm-100 μm) elicited a potent, concentration-dependent but small relaxation of pre-contracted human precision-cut lung slices (hPCLS). Intratracheal PL-3994 (1-1000 μg/kg) produced a dose-dependent inhibition of the bronchoconstrictor response evoked by aerosolized methacholine, but was without significant effect on cardiovascular parameters. PL-3994 was resistant to degradation by human neutral endopeptidase (hNEP) (92% remaining after 2 h), whereas the natural ligands, ANP and CNP, were rapidly metabolized (≤1% remaining after 2 h). PL-3994 is a potent, selective NPR agonist, resistant to NEP, with relaxant effects in guinea-pig and human airway smooth muscle systems. PL-3994 has the profile predictive of longer clinical bronchodilator activity than observed previously with ANP, and suggests its potential utility in the treatment of asthma, in addition to being a useful research tool to evaluate NPR biology.

  20. Chromatographic Determination of Cyclopentolate Hydrochloride and Phenylephrine Hydrochloride in the Presence of Their Potential Degradation Products.

    PubMed

    Rezk, Mamdouh R; Fayed, Ahmed S; Marzouk, Hoda M; Abbas, Samah S

    2017-03-01

    Two sensitive, selective, and precise stability-indicating methods have been developed for the simultaneous determination of the active pharmaceutical ingredients cyclopentolate hydrochloride (CLO) and phenylephrine hydrochloride (PHE) in their pure forms and in the presence of their degradation products. The methods were applied for the determination of CLO and PHE in a pharmaceutical formulation. Method A was based on isocratic elution HPLC determination. Separation was achieved using a Waters Spherisorb ODS2 C18 analytical column (5 μm particle size) and a mobile phase of 0.1% heptane-1-sulphonic acid sodium salt in methanol-water (80 + 20, v/v). The flow rate was 1.0 mL/min and detection was performed at 210 nm. Method B was an HPTLC- densitometric method using HPTLC silica gel 60 F254 plates and an optimized mobile phase of ethyl acetate-methanol-ammonia (8 + 2 + 0.1, v/v/v). The separated spots were densitometrically scanned at 210 nm. Polynomial equations were used for regression. The developed methods are suitable for the determination of CLO and PHE in their binary mixture and in the presence of their corresponding degradation products. The two methods were validated in compliance with International Conference on Harmonization guidelines and successfully applied for the determination of CLO and PHE as synthetically prepared in laboratory mixtures and in the presence of their possible degradation products. CLO alkaline degradation products were stated as potential impurities in British Pharmacopoeia. The degradation products were separated and identified by mass spectra. Postulation of a PHE oxidative degradation pathway was suggested. The obtained results were statistically analyzed and compared with those obtained by applying the official methods for both drugs.

  1. Validated spectrophotometric and chromatographic methods for simultaneous determination of ketorolac tromethamine and phenylephrine hydrochloride.

    PubMed

    Belal, T S; El-Kafrawy, D S; Mahrous, M S; Abdel-Khalek, M M; Abo-Gharam, A H

    2016-07-01

    This work describes five simple and reliable spectrophotometric and chromatographic methods for analysis of the binary mixture of ketorolac tromethamine (KTR) and phenylephrine hydrochloride (PHE). Method I is based on the use of conventional Amax and derivative spectrophotometry with the zero-crossing technique where KTR was determined using its Amax and (1)D amplitudes at 323 and 341nm respectively, while PHE was determined by measuring the (1)D amplitudes at 248.5nm. Method II involves the application of the ratio spectra derivative spectrophotometry. For KTR, 12μg/mL PHE was used as a divisor and the (1)DD amplitudes at 265nm were plotted against KTR concentrations; while - by using 4μg/mL KTR as divisor - the (1)DD amplitudes at 243.5nm were found proportional to PHE concentrations. Method III depends on ratio-difference measurement where the peak to trough amplitudes between 260 and 284nm were measured and correlated to KTR concentration. Similarly, the peak to trough amplitudes between 235 and 260nm in the PHE ratio spectra were recorded. For method IV, the two compounds were separated using Merck HPTLC sheets of silica gel 60 F254 and a mobile phase composed of chloroform/methanol/ammonia (70:30:2, by volume) followed by densitometric measurement of KTR and PHE spots at 320 and 278nm respectively. Method V depends on HPLC-DAD. Effective chromatographic separation was achieved using Zorbax eclipse plus C8 column (4.6×250mm, 5μm) with a mobile phase consisting of 0.05M o-phosphoric acid and acetonitrile (50:50, by volume) at a flow rate 1mL/min and detection at 313 and 274nm for KTR and PHE respectively. Analytical performance of the developed methods was statistically validated according to the ICH guidelines with respect to linearity, ranges, precision, accuracy, detection and quantification limits. The validated spectrophotometric and chromatographic methods were successfully applied to the simultaneous analysis of KTR and PHE in synthetic mixtures

  2. Metformin exaggerates phenylephrine-induced AMPK phosphorylation independent of CaMKKβ and attenuates contractile response in endothelium-denuded rat aorta.

    PubMed

    Pyla, Rajkumar; Osman, Islam; Pichavaram, Prahalathan; Hansen, Paul; Segar, Lakshman

    2014-11-15

    Metformin, a widely prescribed antidiabetic drug, has been shown to reduce the risk of cardiovascular disease, including hypertension. Its beneficial effect toward improved vasodilation results from its ability to activate AMPK and enhance nitric oxide formation in the endothelium. To date, metformin regulation of AMPK has not been fully studied in intact arterial smooth muscle, especially during contraction evoked by G protein-coupled receptor (GPCR) agonists. In the present study, ex vivo incubation of endothelium-denuded rat aortic rings with 3mM metformin for 2h resulted in significant accumulation of metformin (∼ 600 pmoles/mg tissue), as revealed by LC-MS/MS MRM analysis. However, metformin did not show significant increase in AMPK phosphorylation under these conditions. Exposure of aortic rings to a GPCR agonist (e.g., phenylephrine) resulted in enhanced AMPK phosphorylation by ∼ 2.5-fold. Importantly, in metformin-treated aortic rings, phenylephrine challenge showed an exaggerated increase in AMPK phosphorylation by ∼ 9.7-fold, which was associated with an increase in AMP/ATP ratio. Pretreatment with compound C (AMPK inhibitor) prevented AMPK phosphorylation induced by phenylephrine alone and also that induced by phenylephrine after metformin treatment. However, pretreatment with STO-609 (CaMKKβ inhibitor) diminished AMPK phosphorylation induced by phenylephrine alone but not that induced by phenylephrine after metformin treatment. Furthermore, attenuation of phenylephrine-induced contraction (observed after metformin treatment) was prevented by AMPK inhibition but not by CaMKKβ inhibition. Together, these findings suggest that, upon endothelial damage in the vessel wall, metformin uptake by the underlying vascular smooth muscle would accentuate AMPK phosphorylation by GPCR agonists independent of CaMKKβ to promote vasorelaxation.

  3. Phenylephrine protects autotransplanted rabbit submandibular gland from apoptosis

    SciTech Connect

    Xiang Bin; Zhang Yan; Li Yuming; Gao Yan; Gan Yehua; Wu Liling Yu Guangyan

    2008-12-05

    Submandibular gland (SMG) autotransplantation is an effective treatment for severe keratoconjunctivitis sicca. Our previous studies have shown that phenylephrine attenuates structural injury and promotes cell proliferation in autotransplanted rabbit SMG. However, the mechanism by which phenylephrine reduces the injury has not been fully evaluated. In this study, we investigate the ability of phenylephrine to inhibit apoptosis in autotransplanted rabbit SMG. We observed that apoptosis occurred in the early phase of SMG transplantation and that phenylephrine treatment protected transplanted SMG from apoptosis. Furthermore, we found that phenylephrine could significantly upregulate the expression of Bcl-2, downregulate the expression of Bax, and inhibit the activation of both caspase-3 and p38 mitogen-activated protein kinase in autotransplanted SMG. Therefore, the cytoprotective effects of phenylephrine on autotransplanted SMG may be a novel clinical strategy for autotransplanted SMG protection during the early postoperative stage of transplantation.

  4. Sulfation of phenylephrine by the human cytosolic sulfotransferases.

    PubMed

    Yamamoto, Akihiro; Kim, Jiwan; Liu, Ming-Yih; Kurogi, Katsuhisa; Sakakibara, Yoichi; Suiko, Masahito; Liu, Ming-Cheh

    2014-01-01

    Previous studies had demonstrated that sulfation constituted a major pathway for the metabolism of phenylephrine in vivo. The current study was designed to identify the major human SULT(s) responsible for the sulfation of phenylephrine. Of the twelve human SULTs analyzed, SULT1A3 displayed the strongest sulfating activity toward phenylephrine. The enzyme exhibited a pH optimum spanning 7 - 10.5. Kinetic analysis revealed that SULT1A3- mediated sulfation of phenylephrine occurred in the same order of magnitude compared with that previously reported for SULT1A3-mediated sulfation of dopamine. Moreover, sulfation of phenylephrine was shown to occur in HepG2 cells under metabolic setting. Collectively, these results provided useful information concerning the biochemical basis underlying the metabolism of phenylephrine in vivo as previously reported.

  5. Contribution of α-adrenoceptor stimulation by phenylephrine to basal nitric oxide production in the isolated mouse aorta.

    PubMed

    van Langen, Johanna T H; Van Hove, Cor E; Schrijvers, Dorien M; Martinet, Wim; De Meyer, Guido R Y; Fransen, Paul; Bult, Hidde

    2013-04-01

    In the mouse aorta, contractions evoked by the α(1)-adrenoceptor agonist phenylephrine are strongly suppressed by the continuous production of nitric oxide (NO). We investigated whether phenylephrine itself stimulated NO production by activating endothelial α(2)-adrenoceptors. On a prostaglandin F(2α) contraction, the α(2)-adrenoceptor agonist 5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)-6-quinoxalinamine (UK14304) induced 29.3 ± 7.4% relaxation, which was inhibited by 0.1 μM 2-[(4,5-Dihydro-1H-imidazol-2-yl)methyl]-2,3-dihydro-1-methyl-1H-isoindole (BRL44408) with a pKB' corresponding to α(2)-antagonism. In the presence of NO synthase blockers, UK14304 elicited small contractions above 1 μM that were inhibited by 0.1 μM prazosin, but not influenced by 0.1 μM rauwolscine. At 3 μM or higher concentrations, phenylephrine caused only modest relaxation (up to 7.4 ± 2.3%) of segments constricted with prostaglandin F(2α) in the presence of prazosin, which was abolished with 0.1 μM BRL44408. Furthermore, BRL44408 did not increase contractions induced with 1 μM phenylephrine. These results confirm that α(1)- but not α(2)-adrenoceptors are expressed on aortic smooth muscle cells, whereas endothelial cells only express α(2)-adrenoceptors. Moreover, phenylephrine exerted a very modest relaxing effect through nonspecific stimulation of α(2)-adrenoceptors, but only at concentrations higher than 1 μM. It is concluded that the high basal output of NO in the isolated mouse aorta is not due to stimulation of α-adrenoceptors.

  6. Compatibility study of paracetamol, chlorpheniramine maleate and phenylephrine hydrochloride in physical mixtures.

    PubMed

    de Oliveira, G G G; Feitosa, A; Loureiro, K; Fernandes, A R; Souto, E B; Severino, P

    2017-01-01

    Paracetamol (PAR), phenylephrine hydrochloride (PHE) and chlorpheniramine maleate (CPM) are commonly used in clinical practice as antipyretic and analgesic drugs to ameliorate pain and fever in cold and flu conditions. The present work describes the use of thermal analysis for the characterization of the physicochemical compatibility between drugs and excipients during the development of solid dosage forms. Thermogravimetric analysis (TGA) and Differential Scanning Calorimetry (DSC) were used to study the thermal stability of the drug and of the physical mixture (drug/excipients) in solid binary mixtures (1:1). DSC thermograms demonstrated reproducible melting event of the prepared physical mixture. Starch, mannitol, lactose and magnesium stearate influence thermal parameters. Information recorded from the derivative thermogravimetric (DTG) and TGA curves demonstrated the decomposition of drugs in well-defined thermal events, translating the suitability of these techniques for the characterization of the drug/excipients interactions.

  7. Acute ischaemic colitis associated with oral phenylephrine decongestant use.

    PubMed

    Ward, Paul W; Shaneyfelt, Terrence M; Roan, Ronald M

    2014-06-03

    In this case, the authors have presented for the first time that ischaemic colitis may be associated with phenylephrine use. Since phenylephrine is the more common active ingredient in over-the-counter (OTC) cold medications, other presentations may follow this case. A MEDLINE search was performed for all case reports or case series of ischaemic colitis secondary to pseudoephedrine or phenylephrine use published between 1966 and 2013. The search resulted in four case reports and one case series describing patients with acute onset ischaemic colitis with exposure to pseudoephedrine immediately prior to onset. However, we found no case reports of ischaemic colitis associated with phenylephrine use. We present this case as an unexpected clinical outcome of phenylephrine, which has not been associated with ischaemic colitis in the literature. Also, this case serves as a reminder of the important clinical lesson to question all patients' use of OTC and prescribed medications.

  8. Simultaneous determination of naphazoline, diphenhydramine and phenylephrine in nasal solutions by capillary electrophoresis.

    PubMed

    Marchesini, A F; Williner, M R; Mantovani, V E; Robles, J C; Goicoechea, H C

    2003-02-05

    A capillary zone electrophoresis (CZE) method has been developed to separate and quantitate naphazoline (NAPH), dyphenhydramine (DIP) and phenylephrine (PHE) in nasal solutions. Samples were diluted 1:25 in ultrapure water and injected at the anodic end. A central composite design has been used to optimise the experimental conditions for a complete and fast separation of the active ingredients studied. Critical parameters such as voltage, pH and buffer concentration have been studied to evaluate how they affect responses such as resolution and migration times. Separation was performed on a silica capillary with 75 microm I.D. and 70 cm total length at an applied voltage of 17.7 kV with a phosphate run buffer of pH 3.72 and 0.063 mol l(-1). Calibration curves were prepared for NAPH, DIP and PHE. For each analyte, the correlation coefficients were >0.999 (n=15). The RSD% of six replicate injections for each analyte were reasonably good. The method was applied to the quantitation of the three components in a commercial dosage form. The proposed method has the advantage of needing a very simple sample pretreatment and being faster than a typical HPLC chromatographic method.

  9. Structure-activity study on the Phe side chain arrangement of endomorphins using conformationally constrained analogues.

    PubMed

    Tömböly, Csaba; Kövér, Katalin E; Péter, Antal; Tourwé, Dirk; Biyashev, Dauren; Benyhe, Sándor; Borsodi, Anna; Al-Khrasani, Mahmoud; Rónai, András Z; Tóth, Géza

    2004-01-29

    Endomorphins-1 and -2 were substituted with all the beta-MePhe stereoisomers in their Phe residues to generate a conformationally constrained peptide set. This series of molecules was subjected to biological assays, and for beta-MePhe(4)-endomorphins-2, a conformational analysis was performed. Incorporation of (2S,3S)-beta-MePhe(4) resulted in the most potent analogues of both endomorphins with enhanced enzymatic stability. Their micro opioid affinities were 4-times higher than the parent peptides, they stimulated [(35)S]GTPgammaS binding, and they were found to be full agonists. NMR experiments revealed that C-terminal (2S,3S)-beta-MePhe in endomorphin-2 strongly favored the gauche (-) spatial orientation which implies the presence of the chi(1) = -60 degrees rotamer of Phe(4) in the binding conformer of endomorphins. Our results emphasize that the appropriate orientation of the C-terminal aromatic side chain of endomorphins is substantial for binding to the micro opioid receptor.

  10. Effect of phenylephrine infusion on atrial electrophysiological properties.

    PubMed Central

    Leitch, J. W.; Basta, M.; Fletcher, P. J.

    1997-01-01

    OBJECTIVE: To determine the effect of changes in autonomic tone induced by phenylephrine infusion on atrial refractoriness and conduction. DESIGN: Left and right atrial electrophysiological properties were measured before and after a constant phenylephrine infusion designed to increase sinus cycle length by 25%. SUBJECTS: 20 patients, aged 53 (SD 6) years, undergoing electrophysiological study for investigation of idiopathic paroxysmal atrial fibrillation (seven patients) or for routine follow up after successful catheter ablation of supraventricular tachycardia (13 patients). MAIN OUTCOME MEASURES: Changes in left and right atrial effective refractory periods, atrial activation times, and frequency of induction of atrial fibrillation. RESULTS: Phenylephrine (mean dose 69 (SD 18) mg/min) increased mean blood pressure by 22 (12) mm Hg (range 7 to 44) and lengthened sinus cycle length by 223 (94) ms (20 to 430). Left atrial effective refractory period lengthened following phenylephrine infusion from 250 (25) to 264 (21) ms (P < 0.001) but there was no significant change in right atrial effective refractory period: 200 (20) v 206 (29), P = 0.11. There was a significant relation between the effect of phenylephrine on sinus cycle length and on right atrial refractoriness (r = 0.6, P = 0.005) with shortening of right atrial refractoriness in patients with the greatest prolongation in sinus cycle length. During phenylephrine infusion, the right atrial stimulus to left atrial activation time at the basic pacing cycle length of 600 ms was unchanged, at 130 (18) v 131 (17) ms, but activation delay with a premature extrastimulus increased: 212 (28) v 227 (38) ms, P = 0.002. Atrial fibrillation was induced by two of 58 refractory period measurements at baseline and by 12 of 61 measurements during phenylephrine infusion (P < 0.01). Phenylephrine increased the difference between left and right atrial refractory periods by 22.8 (19.4) ms in the five patients with induced atrial

  11. Gradient HPLC-DAD determination of paracetamol, phenylephrine hydrochloride, cetirizine in tablet formulation.

    PubMed

    Dewani, A P; Shelke, P G; Bakal, R L; Jaybhaye, S S; Chandewar, A V; Patra, S

    2014-05-01

    Present work describes the development and validation of a simple and reliable high-performance liquid chromatography-diode array detection (HPLC-DAD) procedure for the analysis of phenylephrine hydrochloride (PHE), paracetamol (PAR) and cetirizine dihydrochloride (CET), in pharmaceutical mixture. The method was applied successfully on tablet dosage form. Effective chromatographic separation of PHE, PAR and CET was achieved using a Kinetex-C18 (4.6, 150 mm, 5 mm) column with gradient elution of the mobile phase composed of 10 mM phosphate buffer (pH 3.3) and acetonitrile. The elution was a 3 step gradient elution program step-1 started initially with 2% (by volume) acetonitrile and 98% phosphate buffer (pH 3.3) for first 2 min. In step-2 acetonitrile concentration changed linearly to 20% upto 12 min the analysis was concluded by step-3 changing acetonitrile to 2% upto 20 min. The reliability and analytical performance of the proposed HPLC procedure were statistically validated with respect to linearity, ranges, precision, accuracy, selectivity and robustness. Calibration curves were linear in the ranges 5-15, 250-750 and 2.5-7.5 μg/ml for PHE, PAR and CET, with correlation coefficients >0.9996. The validated HPLC method was applied to a pharmaceutical mixture of a marketed preparation tablet in which the analytes were successfully quantified with good recovery values with no interfering peaks from the excipents.

  12. Effect of Phenylephrine on the Accommodative System

    PubMed Central

    Del Águila-Carrasco, Antonio J.; Bernal-Molina, Paula; Ferrer-Blasco, Teresa; López-Gil, Norberto; Montés-Micó, Robert

    2016-01-01

    Accommodation is controlled by the action of the ciliary muscle and mediated primarily by parasympathetic input through postganglionic fibers that originate from neurons in the ciliary and pterygopalatine ganglia. During accommodation the pupil constricts to increase the depth of focus of the eye and improve retinal image quality. Researchers have traditionally faced the challenge of measuring the accommodative properties of the eye through a small pupil and thus have relied on pharmacological agents to dilate the pupil. Achieving pupil dilation (mydriasis) without affecting the accommodative ability of the eye (cycloplegia) could be useful in many clinical and research contexts. Phenylephrine hydrochloride (PHCl) is a sympathomimetic agent that is used clinically to dilate the pupil. Nevertheless, first investigations suggested some loss of functional accommodation in the human eye after PHCl instillation. Subsequent studies, based on different measurement procedures, obtained contradictory conclusions, causing therefore an unexpected controversy that has been spread almost to the present days. This manuscript reviews and summarizes the main research studies that have been performed to analyze the effect of PHCl on the accommodative system and provides clear conclusions that could help clinicians know the real effects of PHCl on the accommodative system of the human eye. PMID:28053778

  13. Patient considerations in cataract surgery - the role of combined therapy using phenylephrine and ketorolac.

    PubMed

    Gonzalez-Salinas, Roberto; Guarnieri, Adriano; Guirao Navarro, María Concepción; Saenz-de-Viteri, Manuel

    2016-01-01

    Cataract, a degradation of the optical quality of the crystalline lens, progressive and age-related, is the leading cause of treatable blindness worldwide. Cataract surgery is the most common surgical procedure performed by ophthalmologists and is the only effective treatment for cataracts. Advances in the surgical techniques and better postoperative visual outcomes have progressively changed the primary concern of cataract surgery to become a procedure refined to yield the best possible refractive results. Sufficient mydriasis during cataract removal is critical to a successful surgical outcome. Poor pupil dilation can lead to serious sight-threatening complications that significantly increase the cost of surgery and decrease patients comfort. Mydriasis is obtained using anticholinergic and sympathomimetic drugs. Phenylephrine, an α1-adrenergic receptor agonist, can efficiently dilate the pupil when administered by intracameral injection. Additionally, nonsteroidal anti-inflammatory drugs (NSAIDs) like ketorolac, which inhibit the synthesis of prostaglandins, are used to decrease intraoperative miosis, control pain and inflammation associated with cataract surgery, and to prevent the development of cystoid macular edema following surgery. Recently, a new combination of phenylephrine and ketorolac (Omidria(®)) has been approved by United States Food and Drug Administration for use during cataract surgery to maintain intraoperative mydriasis, prevent miosis, and reduce postoperative pain and inflammation. Clinical trials have shown that this new combination is effective, combining the positive effects of both drugs with a good safety profile and patient tolerability. Moreover, recent reports suggest that this combination is also effective in patients with high risk of poor pupil dilation. In conclusion, cataract is a global problem that significantly affects patients' quality of life. However, they can be managed with a safe and minimally invasive surgery

  14. Patient considerations in cataract surgery – the role of combined therapy using phenylephrine and ketorolac

    PubMed Central

    Gonzalez-Salinas, Roberto; Guarnieri, Adriano; Guirao Navarro, María Concepción; Saenz-de-Viteri, Manuel

    2016-01-01

    Cataract, a degradation of the optical quality of the crystalline lens, progressive and age-related, is the leading cause of treatable blindness worldwide. Cataract surgery is the most common surgical procedure performed by ophthalmologists and is the only effective treatment for cataracts. Advances in the surgical techniques and better postoperative visual outcomes have progressively changed the primary concern of cataract surgery to become a procedure refined to yield the best possible refractive results. Sufficient mydriasis during cataract removal is critical to a successful surgical outcome. Poor pupil dilation can lead to serious sight-threatening complications that significantly increase the cost of surgery and decrease patients comfort. Mydriasis is obtained using anticholinergic and sympathomimetic drugs. Phenylephrine, an α1-adrenergic receptor agonist, can efficiently dilate the pupil when administered by intracameral injection. Additionally, nonsteroidal anti-inflammatory drugs (NSAIDs) like ketorolac, which inhibit the synthesis of prostaglandins, are used to decrease intraoperative miosis, control pain and inflammation associated with cataract surgery, and to prevent the development of cystoid macular edema following surgery. Recently, a new combination of phenylephrine and ketorolac (Omidria®) has been approved by United States Food and Drug Administration for use during cataract surgery to maintain intraoperative mydriasis, prevent miosis, and reduce postoperative pain and inflammation. Clinical trials have shown that this new combination is effective, combining the positive effects of both drugs with a good safety profile and patient tolerability. Moreover, recent reports suggest that this combination is also effective in patients with high risk of poor pupil dilation. In conclusion, cataract is a global problem that significantly affects patients’ quality of life. However, they can be managed with a safe and minimally invasive surgery

  15. Computationally-designed phenylephrine prodrugs - a model for enhancing bioavailability

    NASA Astrophysics Data System (ADS)

    Karaman, Rafik; Karaman, Donia; Zeiadeh, Isra'

    2013-11-01

    DFT calculations at B3LYP 6-31G (d,p) for intramolecular proton transfer in a number of Kirby's enzyme models demonstrated that the driving force for the proton transfer efficiency is the distance between the two reactive centres (rGM) and the attack angle (α); and the rate of the reaction is linearly correlated with rGM2 and sin (180°- α). Based on these results three phenylephrine prodrugs were designed to provide phenylephrine with higher bioavailability than their parent drug. Using the experimental t1/2 (the time needed for the conversion of 50% of the reactants to products) and EM (effective molarity) values for these processes the t1/2 values for the conversion of the three prodrugs to the parent drug, phenylephrine were calculated. The calculated t1/2 values for ProD 1 and ProD 2 were very high (145 days and several years, respectively) whereas that of ProD 3 was found to be about 35 hours. Therefore, the intra-conversion rates of the phenylephrine prodrugs to phenylephrine can be programmed according to the nature of the prodrug linker.

  16. Phenylephrine Decreases Vascular Tension in Goat Arteries in Specific Circumstances

    PubMed Central

    Raj, Renu R.

    2016-01-01

    Phenylephrine (PE) causes vasoconstriction through alpha adrenergic receptors. PE-induced vasodilatation has also been reported earlier in pre-constricted vessels. Here we demonstrate in spiral strips of goat arteries that addition of PE can decrease tone even from base-line levels (i.e. not pre-constricted) and show that this process requires nitric oxide (NO) and alpha adrenergic stimulation, but is cGMP-independent. Under control conditions, PE caused vasoconstriction, but under conditions where NO levels are higher, as with L-Arginine or sodium nitroprusside, PE decreased vessel tension. L-Arginine/PE combination was not able to decrease tension when alpha adrenoceptors were blocked with Phentolamine or endothelial nitric oxide synthase (eNOS) was blocked with Nω-Nitro-L-arginine (L-NNA). Propranolol, a beta blocker, was unable to prevent the reduction in tension by the L-Arginine/PE combination. Adrenaline and noradrenaline (and not isoproterenol) also reduced vessel tension in the presence of L-Arginine. Even when NO levels were not enhanced, relieving NO from having to stimulate the enzyme soluble guanylyl cyclase (sGC) (either by using sGC blockers, namely ODQ or methylene blue, or by enhancing cGMP levels (with sildenafil) which by negative feedback probably inhibits sGC) led to PE-induced reduction of vascular tension. PMA—phorbol myristate acetate—an agonist which stimulates Protein Kinase C was able to prevent the ability of PE to reduce vascular tension in a high NO environment. Our conclusion is that PE reduces vascular tension through alpha adrenoceptors if there is excess NO availability to activate a putative pathway. Though the reduction of vessel tone by PE is dependent on NO, it is independent of cGMP. Prior treatment with PMA or PE itself can prevent further PE-induced reduction of tension in a high NO environment. The results here suggest, counter-intuitively, that alpha blockers may be of help in the treatment of septic shock where

  17. Phenylephrine Decreases Vascular Tension in Goat Arteries in Specific Circumstances.

    PubMed

    Raj, Renu R; Subramani, Sathya

    2016-01-01

    Phenylephrine (PE) causes vasoconstriction through alpha adrenergic receptors. PE-induced vasodilatation has also been reported earlier in pre-constricted vessels. Here we demonstrate in spiral strips of goat arteries that addition of PE can decrease tone even from base-line levels (i.e. not pre-constricted) and show that this process requires nitric oxide (NO) and alpha adrenergic stimulation, but is cGMP-independent. Under control conditions, PE caused vasoconstriction, but under conditions where NO levels are higher, as with L-Arginine or sodium nitroprusside, PE decreased vessel tension. L-Arginine/PE combination was not able to decrease tension when alpha adrenoceptors were blocked with Phentolamine or endothelial nitric oxide synthase (eNOS) was blocked with Nω-Nitro-L-arginine (L-NNA). Propranolol, a beta blocker, was unable to prevent the reduction in tension by the L-Arginine/PE combination. Adrenaline and noradrenaline (and not isoproterenol) also reduced vessel tension in the presence of L-Arginine. Even when NO levels were not enhanced, relieving NO from having to stimulate the enzyme soluble guanylyl cyclase (sGC) (either by using sGC blockers, namely ODQ or methylene blue, or by enhancing cGMP levels (with sildenafil) which by negative feedback probably inhibits sGC) led to PE-induced reduction of vascular tension. PMA-phorbol myristate acetate-an agonist which stimulates Protein Kinase C was able to prevent the ability of PE to reduce vascular tension in a high NO environment. Our conclusion is that PE reduces vascular tension through alpha adrenoceptors if there is excess NO availability to activate a putative pathway. Though the reduction of vessel tone by PE is dependent on NO, it is independent of cGMP. Prior treatment with PMA or PE itself can prevent further PE-induced reduction of tension in a high NO environment. The results here suggest, counter-intuitively, that alpha blockers may be of help in the treatment of septic shock where nitric

  18. Drug-excipient compatibility testing-Identification and characterization of degradation products of phenylephrine in several pharmaceutical formulations against the common cold.

    PubMed

    Douša, Michal; Gibala, Petr; Havlíček, Jaroslav; Plaček, Lukáš; Tkadlecová, Marcela; Břicháč, Jiří

    2011-07-15

    Different pharmaceutical preparations against the common cold containing phenylephrine (PHE) and saccharose were studied. New impurities were discovered in these preparations after exposure using isocratic ion-pair chromatography separation on a C18 column. LC-MS and NMR techniques were employed to identify and to fully characterize these new compounds. The products were identified as 1-[5-(hydroxymethyl)-2-furyl]-2-methyl-1,2,3,4-tetrahydroisochinolin-4,8-diol and 1-[5-(hydroxymethyl)-2-furyl]-2-methyl-1,2,3,4-tetrahydroisochinolin-4,6-diol. Identification of these degradation products allowed to understand and to confirm their formation mechanism. The developed HPLC method separates of all known impurities and impurities originated from PHE as well.

  19. Protein kinase Cδ contributes to phenylephrine-mediated contraction in the aortae of high fat diet-induced obese mice.

    PubMed

    Liu, Limei; Liu, Jian; Gao, Yuansheng; Yu, Xiaoxing; Dou, Dou; Huang, Yu

    2014-04-18

    The down-regulation of α-adrenoceptor-mediated signaling casacade has been implicated in obesity but the underlying mechanism remains largely unknown. The present study investigated whether inositol 1,4,5-trisphosphate (IP3) receptor and protein kinase C (PKC) were involved in the reduction of α1-adrenoceptor agonist phenylephrine-evoked contraction in aortae of high fat diet-induced obese (DIO) mice. C57BL/6 mice were fed with a rodent diet containing 45 kcal% fat for 16 weeks to induce obesity. Isolated mouse aortae were suspended in myograph for isometric force measurement. Protein phosphorylations and expressions were determined by Western blotting. In C57BL/6 mouse aortae, phenylephrine-induced contraction was partially inhibited by either IP3 receptor antagonist heparin or PKC inhibitor GFX, and the combined treatment with heparin and GFX abolished the contraction. Phenylephrine-induced contraction was significantly less in the aortae of DIO mice than those of control mice; only GFX but not heparin attenuated the contraction, indicating a diminishing role of IP3 receptor in DIO mice. Western blotting showed the reduced expression and phosphorylation of IP3 receptor and the down-regulated expression of PKC, PKCβ, PKCδ, and PKCζ in DIO mouse aortae. Importantly, PKCδ was more likely to maintain phenylephrine-mediated contraction in DIO mouse aortae because that (1) PKCδ inhibitor rottlerin but not PKCα and PKCβ inhibitor Gö6976, PKCβ inhibitor hispidin, or PKCζ pseudosubstrate inhibitor attenuated the contraction; and (2) PKCδ phosphorylation was increased but phosphorylations of PKCα, PKCβ, and PKCζ were reduced in DIO mouse aortae. The present study thus provides additional insights into the cellular mechanisms responsible for vascular dysfunction in obesity.

  20. Chemometrics resolution and quantification power evaluation: Application on pharmaceutical quaternary mixture of Paracetamol, Guaifenesin, Phenylephrine and p-aminophenol

    NASA Astrophysics Data System (ADS)

    Yehia, Ali M.; Mohamed, Heba M.

    2016-01-01

    Three advanced chemmometric-assisted spectrophotometric methods namely; Concentration Residuals Augmented Classical Least Squares (CRACLS), Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) and Principal Component Analysis-Artificial Neural Networks (PCA-ANN) were developed, validated and benchmarked to PLS calibration; to resolve the severely overlapped spectra and simultaneously determine; Paracetamol (PAR), Guaifenesin (GUA) and Phenylephrine (PHE) in their ternary mixture and in presence of p-aminophenol (AP) the main degradation product and synthesis impurity of Paracetamol. The analytical performance of the proposed methods was described by percentage recoveries, root mean square error of calibration and standard error of prediction. The four multivariate calibration methods could be directly used without any preliminary separation step and successfully applied for pharmaceutical formulation analysis, showing no excipients' interference.

  1. Chemometrics resolution and quantification power evaluation: Application on pharmaceutical quaternary mixture of Paracetamol, Guaifenesin, Phenylephrine and p-aminophenol.

    PubMed

    Yehia, Ali M; Mohamed, Heba M

    2016-01-05

    Three advanced chemmometric-assisted spectrophotometric methods namely; Concentration Residuals Augmented Classical Least Squares (CRACLS), Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) and Principal Component Analysis-Artificial Neural Networks (PCA-ANN) were developed, validated and benchmarked to PLS calibration; to resolve the severely overlapped spectra and simultaneously determine; Paracetamol (PAR), Guaifenesin (GUA) and Phenylephrine (PHE) in their ternary mixture and in presence of p-aminophenol (AP) the main degradation product and synthesis impurity of Paracetamol. The analytical performance of the proposed methods was described by percentage recoveries, root mean square error of calibration and standard error of prediction. The four multivariate calibration methods could be directly used without any preliminary separation step and successfully applied for pharmaceutical formulation analysis, showing no excipients' interference.

  2. D-004 ameliorates phenylephrine-induced urodynamic changes and increased prostate and bladder oxidative stress in rats

    PubMed Central

    Oyarzábal, Ambar; Pérez, Yohani; Mas, Rosa; Ravelo, Yazmin; Jiménez, Sonia

    2015-01-01

    Background Lower urinary tract symptoms (LUTS) in patients with benign prostatic hyperplasia (BPH) mainly depend on alpha1-adrenoreceptors (α1-ADR) stimulation, but a link with oxidative stress (OS) is also involved. D-004, a lipid extract of Roystonea regia fruits, antagonizes ADR-induced responses and produces antioxidant effects. The objective of this study was to investigate whether D-004 produce antioxidant effects in rats with phenylephrine (PHE)-induced urodynamic changes. Methods Rats were randomized into eight groups (ten rats/group): a negative vehicle control and seven groups injected with PHE: a positive control, three treated with D-004 (200, 400 and 800 mg/kg) and three others with tamsulosin (0.4 mg/kg), grape seed extract (GSE) (250 mg/kg) and vitamin E (VE) (250 mg/kg), respectively. Results Effects on urinary total volume (UTV), volume voided per micturition (VM), malondialdehyde (MDA) and carbonyl groups (CG) concentrations in prostate and bladder homogenates were study outcomes. While VM and UTV lowered significantly in the positive control as compared to the negative control group, the opposite occurred with prostate and bladder MDA and CG values. D-004 (200-800 mg/kg) increased significantly both VM and UTV, lowered significantly MDA in prostate and bladder homogenates, and reduced GC levels only in the prostate. Tamsulosin increased significantly VM and UTV, but unchanged oxidative variables. GSE and VE unchanged the UTV, whereas VE, not GSE, modestly but significantly attenuated the PHE-induced decrease of VM. Conclusions Single oral administration of D-004 (200-800 mg/kg) was the only treatment that ameliorated the urodynamic changes and reduced increased oxidative variables in the prostate of rats with PHE-induced prostate hyperplasia. PMID:26816837

  3. [Simultaneous isotachophoresis determination of dioxopromethazine and phenylephrine in eye drops].

    PubMed

    Kubacák, P; Valásková, I; Havránek, E

    2004-03-01

    Dioxopromethazine and phenylephrine were determined simultaneously in eye drops using the method of capillary isotachophoresis. Two electrolyte systems with different compositions and pH were examined. Prior to analysis, the eye drops are diluted with water in a ratio 1:50. Precision, correctness, linearity, robustness, and selectivity of the ITP method were evaluated for both electrolyte systems.

  4. Effect of topical application of phenylephrine hydrochloride on hyperplastic gingivitis.

    PubMed

    Pernsteiner, C L; Ash, M M

    1977-08-01

    A double blind study was conducted to evaluate the effectiveness of Phenodent Type A (brand of phenylephrine hydrochloride) on decongesting hyperplastic gingivitis. Three solutions were used: a 0.5% a placebo, and a 0.25% concentration of phenylephrine hydrochloride. The periodontal disease index was used to score variables which might have an effect on gingival response to local irritants. Impressions were taken and casts were made on 45 subjects at 0, 1, 3, and 6-week intervals. An instrument with accuracy of 0.001 inch was constructed to measure the changes in the interdental papillae of the stone casts. No significant reduction of gingival volume was established for any of the three solutions.

  5. An electrochemical sensor for phenylephrine based on molecular imprinting.

    PubMed

    Yao, Liuduan; Tang, Youwen; Zeng, Weipeng; Huang, Zhaofa

    2009-09-01

    Molecularly imprinted polymers (MIPs) were applied as molecular recognition elements to an electrochemical sensor for phenylephrine. A MIPs membrane was created on a glassy carbon electrode. SEM revealed a gradual change on the morphology of modified electrodes as the ratios of function monomer and cross-linking varied. When the ratio was 4:40, the surface morphology between the imprinted electrode (M-electrode) and the control electrode (N-electrode) became unambiguously different. This artificial receptor exhibited high selectivity for the template compared to closely related analogue. The response of the sensor varied in different concentration range might due to the heterogeneity of the MIPs membrane. This sensor was also used to determine phenylephrine in tablet samples.

  6. Phenylephrine promotes cardiac fibroblast proliferation through calcineurin-NFAT pathway.

    PubMed

    Wang, Jing; Wang, Yibing; Zhang, Wei; Zhao, Xi; Chen, Xiangfan; Xiao, Wenyan; Zhang, Lingling; Chen, Yunxuan; Zhu, Weizhong

    2016-01-01

    Ca(2+)/calmodulin-dependent calcineurin (CaN) plays an important role in various Ca(+2) signaling pathways, among which are those involved in cardiac diseases. It has also been shown that a heightened sympathetic tone accelerates the development of heart failure. The present study investigates whether the CaN-mediated nuclear factor of activated T-cells (NFAT) pathway is involved in cultured neonatal rat cardiac fibroblast proliferation induced by phenylephrine. CF proliferation was assessed by a cell survival assay and cell counts. Green fluorescent protein-tagged NFAT3 was used to determine the cellular location of NFAT3. CaN activity and protein levels were also determined by an activity assay kit and Western blotting, respectively. Results showed that phenylephrine promoted CF proliferation, which was abolished by α1-adrenergic receptor antagonist (prazosin), a blocker of Ca(+2) influx (nifedipine), an intracellular Ca(2+) buffer (BAPTA-AM), CaN inhibitors (cyclosporin A and FK506), and over-expression of dominant negative CaN. Phenylephrine activated CaN and evoked NFAT3 nuclear translocation, both of which were blocked by cyclosporine A (CsA) or over-expression of dominant negative CaN. These results suggest that the Ca(2+)/CaN/NFAT pathway mediates PE-induced CF proliferation, and this pathway might be a possible therapeutic target in cardiac fibrosis.

  7. Effects of D-004, a lipid extract from the royal palm (Roystonea regia) fruits, tamsulosin and their combined use on urodynamic changes induced with phenylephrine in rats.

    PubMed

    Arruzazabala, Maria de Lourdes; Molina, Vivian; Más, Rosa; Carbajal, Daisy

    2008-01-01

    5-alpha-Reductase inhibitors, alpha1-adrenoreceptors blockers and herbal drugs, like lipid extracts from saw palmetto fruits, are used to treat benign prostatic hyperplasia (BPH). D-004, a lipid extract from the Royal palm fruits, prevented prostate hyperplasia (PH) induced with testosterone and the atypical PH induced with phenylephrine (PHE) in the rat, its effect in this last model being comparable to that of saw palmetto, but lesser than that of tamsulosin (CAS 106133-20-4). It was investigated whether single doses of D-004, tamsulosin and their combined therapy can prevent urodynamic changes induced with PHE in the rat. Firstly, the effects of PHE on rat volume voided per micturition (VM) were explored in rats that were distributed in three groups: a negative control and two groups injected s. c. with PHE (5 and 10 mg/kg, respectively). In the other two experiments, rats were distributed in four groups: a negative control and three groups injected with PHE (a positive control and two groups treated with either tamsulosin 0.05 and 0.1 mg/kg, or D-004 400 and 800 mg/kg. In another experiment, the effects of the combined therapy were assessed using four groups: a negative control, a positive control and three groups treated orally with tamsulosin 0.05 mg/kg, D-004 400 mg/kg or D-004 400 mg/kg + tamsulosin 0.05 mg/kg, respectively. Sixty min later, all rats (except negative controls) were injected s. c. with PHE (5 mg/kg), and all (including the negative controls) received a fluid-loading dose. Thirty min later, they were placed in metabolic cages and theVM was measured for 1 h. The VM was significantly reduced with PHE (5 and 10 mg/kg), the high dose producing anuria in 50% of the rats. The reduction of VM was significantly and dose-dependently prevented with tamsulosin (0.05 and 0.1 mg/kg) (42.9% and 60.3%, respectively) and with D-004 (400 and 800 mg/kg) (25.2% and 43.1%, respectively). The inhibition reached (70.9%) with the combined therapy was greater than

  8. Beta-methyl substitution of cyclohexylalanine in Dmt-Tic-Cha-Phe peptides results in highly potent delta opioid antagonists.

    PubMed

    Tóth, Géza; Ioja, Eniko; Tömböly, Csaba; Ballet, Steven; Tourwé, Dirk; Péter, Antal; Martinek, Tamás; Chung, Nga N; Schiller, Peter W; Benyhe, Sándor; Borsodi, Anna

    2007-01-25

    The opioid peptide TIPP (H-Tyr-Tic-Phe-Phe-OH, Tic:1,2,3,4-tetrahydroisoquinoline-3-carboxylic acid) was substituted with Dmt (2',6'-dimethyltyrosine) and a new unnatural amino acid, beta-MeCha (beta-methyl-cyclohexylalanine). This double substitution led to a new series of opioid peptides displaying subnanomolar delta antagonist activity and mu agonist or antagonist properties depending on the configuration of the beta-MeCha residue. The most promising analog, H-Dmt-Tic-(2S,3S)-beta-MeCha-Phe-OH was a very selective delta antagonist both in the mouse vas deferens (MVD) assay (Ke = 0.241 +/- 0.05 nM) and in radioligand binding assay (K i delta = 0.48 +/- 0.05 nM, K i mu/K i delta = 2800). The epimeric peptide H-Dmt-Tic-(2S,3R)-beta-MeCha-Phe-OH and the corresponding peptide amide turned out to be mixed partial mu agonist/delta antagonists in the guinea pig ileum and MVD assays. Our results constitute further examples of the influence of Dmt and beta-methyl substitution as well as C-terminal amidation on the potency, selectivity, and signal transduction properties of TIPP related peptides. Some of these compounds represent valuable pharmacological tools for opioid research.

  9. Phenylephrine activates eNOS Ser 1177 phosphorylation and nitric oxide signaling in renal hypertensive rat aorta.

    PubMed

    Silva, Bruno R; Pernomian, Laena; Grando, Marcella D; Bendhack, Lusiane M

    2014-09-05

    The endothelial nitric oxide synthase (eNOS) plays an important role in the control of the vascular tone. This work aimed to evaluate the role of an α1-adrenoceptor agonist phenylephrine (PE) on eNOS activity and downstream signaling pathway activation in normotensive (2K) and renal hypertensive (2K-1C) intact-endothelium rat aortas. Concentration-effect curves were performed for PE in intact-endothelium aortas from 2K and 2K-1C rats, in the absence of or in the presence of NOS or soluble guanylyl cyclase (sGC) inhibitor. Intact endothelium aortas were stimulated with PE in organ chambers and eNOS Ser(1177)/Thr(495) phosphorylation expression was evaluated by western blot. Nitric Oxide (NO) production was evaluated in isolated endothelial cells from 2K and 2K-1C rat aortas by flow-cytometry using NO selective fluorescent probe, DAF-2DA. The sGC activity/expression was also evaluated. PE-induced contractile response is lower in 2K-1C than in 2K intact-endothelium rat aorta. This is due to higher eNOS Ser(1177) phosphorylation in 2K-1C, which induces the eNOS overactivation. It was abolished by NOS or sGC inhibition. Phenylephrine reduces NO production in 2K as compared to the basal level, but it is not modified in 2K-1C. In PE-stimulated endothelial cells, the NO production is higher in 2K-1C than in 2K. Phenylephrine induces higher cGMP production in 2K-1C than in 2K, despite the lower expression of sGC in 2K-1C. Our results suggest that alpha1-adrenoceptor activation contributes to the increased activity of the enzyme eNOS by Ser(1177) phosphorylation in 2K-1C intact-endothelium aorta, which consequently decreases PE-induced contractile response.

  10. Seasonal variation in maintenance of phenylephrine-induced tone in isolated equine digital arteries under hypoxic or hyperoxic conditions in vitro.

    PubMed

    Borer-Weir, K E; Bailey, S R; Harris, P A; Menzies-Gow, N J; Elliott, J

    2013-06-01

    Digital vasoconstriction, ischaemia and hypoxia may predispose to acute laminitis. Laminitis incidence varies seasonally, peaking in spring and summer. Direct seasonal influences on equine digital artery (EDA) contractility have not been investigated. This study assessed seasonal variation in maintenance of phenylephrine (PHE)-induced tone in isolated EDAs under hypoxic (95% nitrogen) and hyperoxic (95% oxygen) conditions. The objective was to measure change in arterial tone over time after constriction to a plateau with PHE. Tone was measured at plateau and over time and percentage change calculated. Hyperoxic EDAs maintained PHE-induced tone over 1 h with no seasonal variation. Hypoxic EDAs relaxed in fall (median [inter-quartile range] 59% [44-77%] decrease from plateau; P=0.008), contracted in spring (65% [20-192%] increase from plateau; P=0.03) and did not significantly change tone in winter (18% [0-28%] decrease; P=0.13). Continued contraction under hypoxic conditions in spring may contribute to digital vasoconstriction.

  11. Metal-Catalyzed Cleavage of tRNA[superscript Phe

    ERIC Educational Resources Information Center

    Kirk, Sarah R.; Silverstein, Todd P.; McFarlane Holman, Karen L.

    2008-01-01

    This laboratory project is one component of a semester-long advanced biochemistry laboratory course that uses several complementary techniques to study tRNA[superscript Phe] conformational changes induced by ligand binding. In this article we describe a set of experiments in which students assay metal-catalyzed hydrolysis of tRNA[superscript Phe]…

  12. The ncgl1108 (PheP (Cg)) gene encodes a new L-Phe transporter in Corynebacterium glutamicum.

    PubMed

    Zhao, Zhi; Ding, Jiu-Yuan; Li, Tang; Zhou, Ning-Yi; Liu, Shuang-Jiang

    2011-06-01

    Corynebacterium glutamicum played a central role in the establishment of fermentative production of amino acids, and it is a model for genetic and physiological studies. The general aromatic amino acid transporter, AroP(Cg), was the sole functionally identified aromatic amino acid transporter from C. glutamicum. In this study, the ncgl1108 (named as pheP (Cg), which is located upstream of the genetic cluster (ncgl1110 ~ ncgl1113) for resorcinol catabolism, was identified as a new L-Phe specific transporter from C. glutamicum RES167. The disruption of pheP (Cg) resulted in RES167∆ncgl1108, and this mutant showed decreased growth on L-Phe (as nitrogen source) but not on L-Tyr or L-Trp. Uptake assays with unlabeled and (14)C-labeled L-Phe and L-Tyr indicated that the mutants RES167∆ncgl1108 showed significant reduction in L-Phe uptake than RES167. Expression of pheP (Cg) in RES167∆ncgl1108/pGXKZ1 or RES167∆(ncgl1108-aroP (Cg))/pGXKZ1 restored their ability to uptake for L-Phe and growth on L-Phe. The uptake of L-Phe was not inhibited by nine amino acids but by L-Tyr. The K (m) and V (max) values of RES167∆(ncgl1108-aroP (Cg))/pGXKZ1 for L-Phe were determined to be 10.4 ± 1.5 μM and 1.2 ± 0.1 nmol min(-1) (mg DW)(-1), respectively, which are different from K (m) and V (max) values of RES167∆(ncgl1108-aroP (Cg)) for L-Phe [4.0 ± 0.4 μM and 0.6 ± 0.1 nmol min(-1) (mg DW)(-1)]. In conclusion, this PheP(Cg) is a new L-Phe transporter in C. glutamicum.

  13. Effect of phenylephrine on glutamate and glutamine metabolism in isolated perfused rat liver.

    PubMed Central

    Häussinger, D; Sies, H

    1984-01-01

    Addition of phenylephrine to isolated perfused rat liver is followed by an increased 14CO2 production from [1-14C]glutamate, [1-14C]glutamine, [U-14C]proline and [3-14C]pyruvate, but by a decreased 14CO2 production from [1-14C]pyruvate. Simultaneously, there is a considerable decrease in tissue content of 2-oxoglutarate, glutamate and citrate. Stimulation of 14CO2 production from [1-14C]glutamate is also observed in the presence of amino-oxyacetate, suggesting a stimulation of glutamate dehydrogenase and 2-oxoglutarate dehydrogenase fluxes by phenylephrine. Inhibition of pyruvate dehydrogenase flux by phenylephrine is due to an increased 2-oxoglutarate dehydroxygenase flux. Phenylephrine stimulates glutaminase flux and inhibits glutamine synthetase flux to a similar extent, resulting in an increased hepatic glutamine uptake. Whereas the effects of NH4+ ions and phenylephrine on glutaminase flux were additive, activation of glutaminase by glucagon was considerably diminished in the presence of phenylephrine. The reported effects are largely overcome by prazosin, indicating the involvement of alpha-adrenergic receptors in the action of phenylephrine. It is concluded that stimulation of gluconeogenesis from various amino acids by phenylephrine is due to an increased flux through glutamate dehydrogenase and the citric acid cycle. PMID:6148074

  14. Pulsational stability of the SX Phe star AE UMa

    NASA Astrophysics Data System (ADS)

    Pena, J. H.; Renteria, A.; Villarreal, C.; Pina, D. S.; Soni, A. A.; Guillen, J.; Vargas, K.; Trejo, O.

    2016-11-01

    From newly determined times of maxima of the SX Phe star AE UMa and a compilation of previous times of maxima, we were able to determine the nature of this star. With uv photometry we determined its physical parameters.

  15. Cardiovascular effects of dobutamine and phenylephrine infusion in sevoflurane-anesthetized Thoroughbred horses.

    PubMed

    Ohta, Minoru; Kurimoto, Shinjiro; Ishikawa, Yuhiro; Tokushige, Hirotaka; Mae, Naomi; Nagata, Shun-ichi; Mamada, Masayuki

    2013-11-01

    To determine dose-dependent cardiovascular effects of dobutamine and phenylephrine during anesthesia in horses, increasing doses of dobutamine and phenylephrine were infused to 6 healthy Thoroughbred horses. Anesthesia was induced with xylazine, guaifenesin and thiopental and maintained with sevoflurane at 2.8% of end-tidal concentration in all horses. The horses were positioned in right lateral recumbency and infused 3 increasing doses of dobutamine (0.5, 1.0 and 2.0 µg/kg/min) for 15 min each dose. Following to 30 min of reversal period, 3 increasing doses of phenylephrine (0.25, 0.5 and 1.0 µg/kg/min) were infused. Cardiovascular parameters were measured before and at the end of each 15-min infusion period for each drug. Blood samples were collected every 5 min during phenylephrine infusion period. There were no significant changes in heart rate throughout the infusion period. Both dobutamine and phenylephrine reversed sevoflurane-induced hypotension. Dobutamine increased both mean arterial blood pressure (MAP) and cardiac output (CO) as the result of the increase in stroke volume, whereas phenylephrine increased MAP but decreased CO as the result of the increase in systemic vascular resistance. Plasma phenylephrine concentration increased dose-dependently, and these values at 15, 30 and 45 min were 6.2 ± 1.2, 17.0 ± 4.8 and 37.9 ± 7.3 ng/ml, respectively.

  16. Stimulation by alpha-adrenergic agonists of Ca2+ fluxes, mitochondrial oxidation and gluconeogenesis in perfused rat liver.

    PubMed Central

    Taylor, W M; Reinhart, P H; Bygrave, F L

    1983-01-01

    Glucose output from perfused livers of 48 h-starved rats was stimulated by phenylephrine (2 microM) when lactate, pyruvate, alanine, glycerol, sorbitol, dihydroxyacetone or fructose were used as gluconeogenic precursors. Phenylephrine-induced increases in glucose output were immediately preceded by a transient efflux of Ca2+ and a sustained increase in oxygen uptake. Phenylephrine decreased the perfusate [lactate]/[pyruvate] ratio when sorbitol or glycerol was present, but increased the ratio when alanine, dihydroxyacetone or fructose was present. Phenylephrine induced a rapid increase in the perfusate [beta-hydroxybutyrate]/[acetoacetate] ratio and increased total ketone-body output by 40-50% with all substrates. The oxidation of [1-14C]octanoate or 2-oxo[1-14C]glutarate to 14CO2 was increased by up to 200% by phenylephrine. All responses to phenylephrine infusion were diminished after depletion of the hepatic alpha-agonist-sensitive pool of Ca2+ and returned toward maximal responses after Ca2+ re-addition. Phenylephrine-induced increases in glucose output from lactate, sorbitol and glycerol were inhibited by the transaminase inhibitor amino-oxyacetate by 95%, 75% and 66% respectively. Data presented suggest that the mobilization of an intracellular pool of Ca2+ is involved in the activation of gluconeogenesis by alpha-adrenergic agonists in perfused rat liver. alpha-Adrenergic activation of gluconeogenesis is apparently accompanied by increases in fatty acid oxidation and tricarboxylic acid-cycle flux. An enhanced transfer of reducing equivalents from the cytoplasmic to the mitochondrial compartment may also be involved in the stimulation of glucose output from the relatively reduced substrates glycerol and sorbitol and may arise principally from an increased flux through the malate-aspartate shuttle. PMID:6882384

  17. A signaling network in phenylephrine-induced benign prostatic hyperplasia.

    PubMed

    Kim, Jayoung; Yanagihara, Yutaka; Kikugawa, Tadahiko; Ji, Mihee; Tanji, Nozomu; Masayoshi, Yokoyama; Freeman, Michael R

    2009-08-01

    Benign prostatic hyperplasia (BPH) is an age-related disease of unknown etiology characterized by prostatic enlargement and coinciding with distinctive alterations in tissue histomorphology. To identify the molecular mechanisms underlying the development of BPH, we conducted a DNA microarray study using a previously described animal model in which chronic alpha(1)-adrenergic stimulation by repeated administration of phenylephrine evokes histomorphological changes in the rat prostate that resemble human BPH. Bioinformatic tools were applied to microarray data obtained from prostate tissue to construct a network model of potentially relevant signal transduction pathways. Significant involvement of inflammatory pathways was demonstrable, including evidence for activation of a TGF-beta signaling cascade. The heterodimeric protein clusterin (apolipoprotein J) was also identified as a prominent node in the network. Responsiveness of TGF-beta signaling and clusterin gene and protein expression were confirmed independently of the microarray data, verifying some components of the model. This is the first attempt to develop a comprehensive molecular network for histological BPH induced by adrenergic activation. The study also implicated clusterin as a novel biochemical target for therapy.

  18. Alpha 1-adrenergic agonists selectively suppress voltage-dependent K+ current in rat ventricular myocytes.

    PubMed Central

    Apkon, M; Nerbonne, J M

    1988-01-01

    The effects of alpha 1-adrenergic agonists on the waveforms of action potentials and voltage-gated ionic currents were examined in isolated adult rat ventricular myocytes by the whole-cell patch-clamp recording technique. After "puffer" applications of either of two alpha 1 agonists, phenylephrine and methoxamine, action-potential durations were increased. In voltage-clamped cells, phenylephrine (5-20 microM) or methoxamine (5-10 microM) reduced the amplitudes of Ca2+-independent voltage-activated outward K+ currents (Iout); neither the kinetics nor the voltage-dependent properties of Iout were significantly affected. The effects of phenylephrine or methoxamine on Iout were larger and longer-lasting at higher concentrations and after prolonged or repeated exposures; in all experiments, however, Iout recovered completely when puffer applications were discontinued. The suppression of Iout is attributed to the activation of alpha 1-adrenergic receptors, as neither beta- nor alpha 2-adrenergic agonists had measurable effects on Iout; in addition, the effect of phenylephrine was attenuated in the presence of the alpha antagonist phentolamine (10 microM), but not in the presence of the beta antagonist propranolol (10 microM). Voltage-gated Ca2+ currents, in contrast, were not altered measurably by phenylephrine or methoxamine and no currents were activated directly by these agents. Suppression of Iout was also observed during puffer applications of either of two protein kinase C activators, phorbol 12-myristate 13-acetate (10 nM-1 microM) and 1-oleoyl-2-acetylglycerol (60 microM). We conclude that the activation of alpha 1-adrenergic receptors in adult rat ventricular myocytes leads to action-potential prolongation as a result of the specific suppression of Iout and that this effect may be mediated by activation of protein kinase C. PMID:2903506

  19. Comparing prophylactic effect of phenylephrine and ephedrine on hypotension during spinal anesthesia for hip fracture surgery

    PubMed Central

    Abbasivash, Rahman; Sane, Shahryar; Golmohammadi, Mitra; Shokuhi, Shahram; Toosi, Fereshteh Danaye

    2016-01-01

    Background: Spinal anesthesia is an accepted technique in hip fracture surgery and prevention of this complication by sympathomimetic agents is of potential clinical significance. The aim of this study is to compare the effect of prophylactic phenylephrine versus ephedrine in the prevention of hypotension during spinal anesthesia in hip fracture surgery. Materials and Methods: Ninety-two patients undergoing hip fracture surgery with the American Society of Anesthesiologists I and II were randomized to receive prophylaxis with ephedrine or phenylephrine immediately before the spinal anesthesia. Patients in the ephedrine group received an intravenous (IV) bolus of 10 mg ephedrine, and patients in the phenylephrine group received an IV bolus of 50 μg phenylephrine. We recorded mean arterial pressure (MAP), systolic and diastolic blood pressure, heart rate every 3 min in the first 10 min and then every 5 min until 30 min after spinal anesthesia, nausea and vomiting, additional vasopressor, and atropine administration. Results: The frequency of hypotension was significantly lower in MAP, systolic and diastolic pressure in group phenylephrine in 3, 6, and 9 min after spinal anesthesia (P = 0.002, P = 0.001). There were no significant differences between two groups in heart rate at different time of study. In the phenylephrine group, lower additional vasopressor was used (8.7% and 23.9%) (P = 0.04). There were no significant differences between two groups in the use of atropine (P = 0.24), nausea and vomiting. Conclusion: At the doses of ephedrine and phenylephrine administered in this trial, phenylephrine was better to prevent hypotension during hip fracture surgery with spinal anesthesia. Higher frequency of hypotension was observed in the ephedrine group. PMID:27995106

  20. A uniform molecular model of δ opioid agonist and antagonist pharmacophore conformations

    NASA Astrophysics Data System (ADS)

    Brandt, Wolfgang

    1998-11-01

    On the basis of a model of the pharmacophore conformations of agonist of the δ-opioid receptor the corresponding δ-antagonist conformations were determined by means of force field calculations. The results explain the unusual behavior of several cyclic β-casomorphin analogues on the molecular level. Thus, for instance, the model helps to understand why Tyr-c[D-Orn-2-Nal-D-Pro-Gly] is a mixed μ-agonist and δ-antagonist. Furthermore, the model is consistent with low energy conformations of other δ-antagonists such as Tyr-Tic-Phe, Tyr-Tic-Phe-Phe, naltrindole and BNTX. The occupation of a special spatial area by bulky groups close to the protonated N-terminus of opioid peptides is assumed to be highly critical for the switch from agonist to antagonist behavior.

  1. Indigo carmine enhances phenylephrine-induced contractions in an isolated rat aorta

    PubMed Central

    Choi, Yun Suk; Ok, Seong-Ho; Lee, Seung Min; Park, Sang-Seung; Ha, Yu Mi; Chang, Ki Churl; Kim, Hye Jung; Shin, Il-Woo

    2011-01-01

    Background The intravenous administration of indigo carmine has been reported to produce transiently increased blood pressure in patients. The goal of this in vitro study was to examine the effect of indigo carmine on phenylephrine-induced contractions in an isolated rat aorta and to determine the associated cellular mechanism with particular focus on the endothelium-derived vasodilators. Methods The concentration-response curves for phenylephrine were generated in the presence or absence of indigo carmine. Phenylephrine concentration-response curves were generated for the endothelium-intact rings pretreated independently with a nitric oxide synthase inhibitor, Nω-nitro-L-arginine methyl ester (L-NAME), a cyclooxygenase inhibitor, indomethacin, and a low-molecular-weight superoxide anion scavenger, tiron, in the presence or absence of indigo carmine. The fluorescence of oxidized dichlorofluorescein was measured in rat aortic vascular smooth muscle cells cultured in the control, indigo carmine alone and tiron plus indigo carmine. Results Indigo carmine (10-5 M) increased the phenylephrine-induced maximum contraction in the endothelium-intact rings with or without indomethacin, whereas indigo carmine produced a slight leftward shift in the phenylephrine concentration-response curves in the endothelium-denuded rings and L-NAME-pretreated endothelium-intact rings. In the endothelium-intact rings pretreated with tiron (10-2 M), indigo carmine did not alter phenylephrine concentration-response curves significantly. Indigo carmine (10-5 M) increased the fluorescence of oxidized dichlorofluorescein in the vascular smooth muscle cells, whereas tiron abolished the indigo carmine-induced increase in oxidized dichlorofluorescein fluorescence. Conclusions Indigo carmine increases the phenylephrine-induced contraction mainly through an endothelium-dependent mechanism involving the inactivation of nitric oxide caused by the increased production of reactive oxygen species. PMID

  2. α1 -AR agonist induced piloerection protects against the development of traction alopecia.

    PubMed

    Goren, Andy; Shapiro, Jerry; Sinclair, Rodney; Kovacevic, Maja; McCoy, John

    2016-05-01

    Traction alopecia is hair loss that occurs after persistent pulling (e.g., during cosmetic procedures) on the roots of hair over time. Unlike plucking, which is painful, persistent pulling may go unnoticed until a patient presents with either bald spots or diffuse telogen shedding. Each hair follicle in the scalp contains an arrector pili muscle that, when contracted, erects the hair. The smooth muscle in the arrector pili expresses α1 adrenergic receptors (α1 -AR). As such, we hypothesized that contraction of the arrector pili muscle via an α1 -AR agonist would increase the threshold of force required to pluck hair during cosmetic procedures. Female subjects, ages 18-40, were recruited to study the effect of topically applied phenylephrine, a selective α1 -AR agonist, on epilation force and hair shedding during cosmetic procedures. In our blinded study, 80% of subjects demonstrated reduced shedding on days using phenylephrine compared to days using a placebo solution. The average reduction in hair loss was approximately 42%. In addition, the force threshold required for epilation increased by approximately 172% following topical phenylephrine application. To our knowledge this is the first study demonstrating the utility of α1 -AR agonists in the treatment of traction alopecia and hair shedding during cosmetic procedures.

  3. Influence of education and neighborhood poverty on pressor responses to phenylephrine in African-Americans and Caucasian-Americans.

    PubMed

    Thomas, KaMala S; Nelesen, Richard A; Ziegler, Michael G; Natarajan, Loki; Dimsdale, Joel E

    2009-09-01

    Although neighborhood disadvantage has been linked to the development of cardiovascular disease, the mechanism through which living in impoverished neighborhoods is associated with poor cardiovascular health is not well understood. Additionally, it is not clear whether individual socioeconomic status (SES) interacts with neighborhood factors to influence cardiovascular outcomes. Using multilevel modeling, we examined the interaction between neighborhood poverty and individual SES on pressor responses to an alpha agonist, phenylephrine (PE), in an adult sample of 105 African-Americans and 106 Caucasian-Americans. Neighborhood poverty was assessed using census block data gathered from the Census Bureau. Education and occupation were used to assess individual SES. Pressor responsiveness was calculated as the systolic and diastolic blood pressure (BP) response to a 100-microg PE bolus administered intravenously. There was a significant interaction between education and neighborhood poverty on pressor responses. Higher education was associated with smaller BP responses to PE; but only in individuals who lived in neighborhoods in which less than 5% of the residents lived below the poverty line. Occupation was unrelated to pressor responses to PE. These results suggest that neighborhood characteristics play an important role in cardiovascular functioning.

  4. Influence of Education and Neighborhood Poverty on Pressor Responses to Phenylephrine in African-Americans and Caucasian-Americans

    PubMed Central

    Thomas, KaMala S.; Nelesen, Richard A.; Ziegler, Michael G.; Natarajan, Loki; Dimsdale, Joel E.

    2009-01-01

    Although neighborhood disadvantage has been linked to the development of cardiovascular disease, the mechanism through which living in impoverished neighborhoods is associated with poor cardiovascular health is not well understood. Additionally, it is not clear whether individual socioeconomic status (SES) interacts with neighborhood factors to influence cardiovascular outcomes. Using multilevel modeling, we examined the interaction between neighborhood poverty and individual SES on pressor responses to an alpha agonist, Phenylephrine (PE), in an adult sample of 105 African-Americans and 106 Caucasian-Americans. Neighborhood poverty was assessed using census block data gathered from the Census Bureau. Education and occupation were used to assess individual SES. Pressor responsiveness was calculated as the systolic and diastolic blood pressure (BP) response to a 100-microgram PE bolus administered intravenously. There was a significant interaction between education and neighborhood poverty on pressor responses. Higher education was associated with smaller BP responses to PE; but only in individuals who lived in neighborhoods in which less than 5% of the residents lived below the poverty line. Occupation was unrelated to pressor responses to PE. These results suggest that neighborhood characteristics play an important role in cardiovascular functioning. PMID:19427353

  5. Hydrogen sulfide differentially affects the hepatic vasculature in response to phenylephrine and endothelin 1 during endotoxemia.

    PubMed

    Norris, Eric J; Larion, Sebastian; Culberson, Catherine R; Clemens, Mark G

    2013-02-01

    Despite being protective in many disease states, hydrogen sulfide (H(2)S) contributes to organ injury in sepsis. Like the other gasotransmitters, nitric oxide and carbon monoxide, H(2)S is a modulator of the microcirculation. Because microcirculatory dysfunction is a main cause of organ injury during sepsis, the present study was designed to test the effect of H(2)S on microvascular dysfunction in isolated perfused livers. In most microcirculatory beds, endotoxin activates the endothelium, resulting in hyporesponsiveness to catecholamines and a derangement in blood flow distribution. We demonstrate that H(2)S treatment attenuates the increase in portal pressure during infusion of the α1 adrenergic agonist, phenylephrine (PE) (P < 0.01). Hydrogen sulfide almost completely negated the increase in portal pressure in livers isolated from endotoxemic rats. Treatment with an inhibitor of endogenous H(2)S, DL-propargylglycine (PAG), reversed lipopolysaccharide-induced hyporesponsiveness to PE. Because hepatic microcirculatory dysfunction is associated with excessive sinusoidal vasoconstriction and not dilation, we investigated whether H(2)S affects endothelin 1 (ET-1)-induced vasoconstriction in isolated livers. Contrary to PE treatment, H(2)S did not affect the increase in portal pressure during infusion of ET-1, nor did it attenuate the hypersensitization of the liver to ET-1 during endotoxemia. Hepatic resistance in control rats was increased by PAG treatment during ET-1 infusion, but this increase was not exacerbated during endotoxemia. We monitored hepatic O(2) consumption to assess the effect of vascular changes on oxygen consumption following ET-1 treatment. Low-dose ET-1 infusion caused an increase in hepatic O(2)consumption, whereas low-dose ET-1 infusion decreased O(2) consumption in endotoxemic livers. Interestingly, whereas we observed no effect of PAG on the vascular response to ET-1 infusion during endotoxemia, PAG treatment did maintain O(2), suggesting a

  6. Visualizing the endocytosis of phenylephrine in living cells by quantum dot-based tracking.

    PubMed

    Ma, Jing; Wu, Lina; Hou, Zhun; Song, Yao; Wang, Lei; Jiang, Wei

    2014-08-01

    To study the intracellular receptor-drug transportation, a fluorescent probe consisting of phenylephrine-polyethylene glycol-quantum dots conjugate was employed to track endocytosis process of phenylephrine in living cells. This type of movement was studied by continuously filming fluorescent images in the same cell. We also calculated the movement parameters, and divided the endocytosis process into 6 stages. Furthermore, the movement parameters of this probe in different organelles were determined by co-localization of the probe fluorescent images and different cellular organelles. After comparing the parameters in cellular organelles with these in 6 stages, the whole endocytosis pathway was demonstrated. These results verified that this probe successfully tracked the whole intracellular dynamic endocytosis process of phenylephrine. Our method realized the visual tracking the whole receptor-mediated endocytosis, which is a new approach on investigating the molecular mechanisms and kinetic properties of intracellular receptor-drug transportation.

  7. Opioid receptor agonists reduce brain edema in stroke.

    PubMed

    Yang, Li; Wang, Hezhen; Shah, Kaushik; Karamyan, Vardan T; Abbruscato, Thomas J

    2011-04-06

    Cerebral edema is a leading cause of mortality in stroke patients. The purpose of this study was to assess a non-selective opioid receptor agonist, biphalin, in decreasing reducing brain edema formation using both in vitro and in vivo models of stroke. For the in situ model of ischemia, hippocampal slices were exposed to oxygen glucose deprivation (OGD) conditions and we observed that hippocampal water content was increased, compared to normoxia. Treatment with the mu agonist, Tyr-D-Ala', N-CH, -Phe4, Glyol-Enkephalin (DAMGO), delta opioid agonists, D-pen(2), D-phe(5) enkephalin (DPDPE), and kappa agonist, U50 488, all significantly decreased brain slice water gain. Interestingly, the non-selective agonist, biphalin, exhibited a statistically significant (P<0.01) greater effect in decreasing water content in OGD-exposed hippocampal slices, compared with mu, delta, and kappa selective opioid agonists. Moreover, biphalin exhibited anti-edematous effects in a dose responsive manner. The non-selective opioid antagonist, naloxone, returned the water content nearly back to original OGD values for all opioid agonist treatments, supporting that these effects were mediated by an opioid receptor pathway. Furthermore, biphalin significantly decreased edema (53%) and infarct (48%) ratios, and neuronal recovery from stroke, compared with the vehicle-treated groups in a 12h permanent middle cerebral artery occlusion (MCAO) model of focal ischemia. Biphalin also significantly decreased the cell volume increase in primary neuronal cells exposed to OGD condition. These data suggest that opioid receptor activation may provide neuroprotection during stroke and further investigations are needed in the development of novel opioid agonist as efficacious treatments for brain ischemia.

  8. Phenylephrine potentiates the anticonvulsant effect and neutralizes the sedative effect of diazepam in rats upon combined intragastric administration.

    PubMed

    Serdyuk, S E; Gmiro, V E

    2014-12-01

    High doses of phenylephrine and diazepam (1 and 10 mg/kg, respectively) suppressed the development of generalized tonic-clonic pentylenetetrazole-induced convulsions in 86-100% rats, but did not prevent local clonic pentylenetetrazole-induced convulsions. Diazepam in the specified dose produced strong sedation, while phenylephrine had no sedative effect in the open-field test. Combined intragastric administration of phenylephrine in a medium and individually ineffective dose (0.3 mg/kg) and diazepam in a high dose (10 mg/kg) potentiated the anticonvulsant effect of diazepam: it prevented not only tonic-clonic, but also clonic pentylenetetrazole-induced convulsions in 100% rats and 2.6-fold increased anticonvulsant activity of diazepam. The specified combination of diazepam and phenylephrine had no sedative effect. The mechanism of potentiation of the anticonvulsive effect and elimination of the sedative side effect is based on stimulation of gastric mucosa afferents by phenylephrine.

  9. Human sympathetic and vagal baroreflex responses to sequential nitroprusside and phenylephrine

    NASA Technical Reports Server (NTRS)

    Rudas, L.; Crossman, A. A.; Morillo, C. A.; Halliwill, J. R.; Tahvanainen, K. U.; Kuusela, T. A.; Eckberg, D. L.

    1999-01-01

    We evaluated a method of baroreflex testing involving sequential intravenous bolus injections of nitroprusside followed by phenylephrine and phenylephrine followed by nitroprusside in 18 healthy men and women, and we drew inferences regarding human sympathetic and vagal baroreflex mechanisms. We recorded the electrocardiogram, photoplethysmographic finger arterial pressure, and peroneal nerve muscle sympathetic activity. We then contrasted least squares linear regression slopes derived from the depressor (nitroprusside) and pressor (phenylephrine) phases with 1) slopes derived from spontaneous fluctuations of systolic arterial pressures and R-R intervals, and 2) baroreflex gain derived from cross-spectral analyses of systolic pressures and R-R intervals. We calculated sympathetic baroreflex gain from integrated muscle sympathetic nerve activity and diastolic pressures. We found that vagal baroreflex slopes are less when arterial pressures are falling than when they are rising and that this hysteresis exists over pressure ranges both below and above baseline levels. Although pharmacological and spontaneous vagal baroreflex responses correlate closely, pharmacological baroreflex slopes tend to be lower than those derived from spontaneous fluctuations. Sympathetic baroreflex slopes are similar when arterial pressure is falling and rising; however, small pressure elevations above baseline silence sympathetic motoneurons. Vagal, but not sympathetic baroreflex gains vary inversely with subjects' ages and their baseline arterial pressures. There is no correlation between sympathetic and vagal baroreflex gains. We recommend repeated sequential nitroprusside followed by phenylephrine doses as a simple, efficientmeans to provoke and characterize human vagal and sympathetic baroreflex responses.

  10. Epinephrine and phenylephrine pretreatments for preventing postreperfusion syndrome during adult liver transplantation.

    PubMed

    Ryu, Ho-Geol; Jung, Chul-Woo; Lee, Hyung-Chul; Cho, Youn-Joung

    2012-12-01

    Acute hypotension after reperfusion of the liver graft occurs frequently during liver transplantation. A randomized, prospective trial was performed to test the effects of epinephrine and phenylephrine pretreatments for attenuating postreperfusion syndrome (PRS). Ninety-three adult liver recipients were randomly allocated to receive an intravenous bolus of 10 μg of epinephrine, 100 μg of phenylephrine, or normal saline (the control group) at the time of graft reperfusion. The occurrence of PRS, the use of vasoactive drugs, and the postoperative courses were compared. The epinephrine and phenylephrine groups showed PRS less frequently (39% and 48%) than the control group (77%, P = 0.006) as well as higher mean arterial pressures (MAPs) immediately after reperfusion (P < 0.05). An overshoot of MAP was observed in one-third of the pretreated patients with minimal heart rate changes. Only 2 patients in each pretreatment group showed an increase in MAP that was greater than 20% of the baseline value. The intraoperative epinephrine and dopamine requirements were significantly lower in both pretreatment groups. Perioperative laboratory data, postoperative stays, and in-hospital mortality rates were similar for the 3 groups. In conclusion, pretreatment with 10 μg of epinephrine or 100 μg of phenylephrine significantly reduces the occurrence of PRS and vasopressor requirements without immediate or delayed adverse effects in adult liver transplantation.

  11. Prophylactic phenylephrine for caesarean section under spinal anaesthesia: systematic review and meta-analysis.

    PubMed

    Heesen, M; Kölhr, S; Rossaint, R; Straube, S

    2014-02-01

    We conducted a systematic review to determine the harm and benefit associated with prophylactic phenylephrine for caesarean section under spinal anaesthesia. We included 21 randomised controlled trials with 1504 women. The relative risk (95% CI) of hypotension with phenylephrine infusion – as defined by authors – before delivery was 0.36 (0.18–0.73) vs placebo, p = 0.004; 0.58 (0.39–0.88) vs an ephedrine infusion, p = 0.009; and 0.73 (0.55–0.96) when added to an ephedrine infusion, p = 0.02. After delivery, the relative risks of hypotension and nausea and vomiting with phenylephrine compared with placebo were 0.37 (0.19–0.71), p = 0.003, and 0.39 (0.17–0.91), p = 0.03, respectively. There was no evidence that hypertension, bradycardia or neonatal endpoints were affected. Phenylephrine reduced the risk for hypotension and nausea and vomiting after spinal doses of bupivacaine generally exceeding 8 mg, but there was no evidence that it reduced other maternal or neonatal morbidities.

  12. Phenylephrine-induced elevations in arterial blood pressure are attenuated in heat-stressed humans

    NASA Technical Reports Server (NTRS)

    Cui, Jian; Wilson, Thad E.; Crandall, Craig G.

    2002-01-01

    To test the hypothesis that phenylephrine-induced elevations in blood pressure are attenuated in heat-stressed humans, blood pressure was elevated via steady-state infusion of three doses of phenylephrine HCl in 10 healthy subjects in both normothermic and heat stress conditions. Whole body heating significantly increased sublingual temperature by 0.5 degrees C, muscle sympathetic nerve activity (MSNA), heart rate, and cardiac output and decreased total peripheral vascular resistance (TPR; all P < 0.005) but did not change mean arterial blood pressure (MAP; P > 0.05). At the highest dose of phenylephrine, the increase in MAP and TPR from predrug baselines was significantly attenuated during the heat stress [DeltaMAP 8.4 +/- 1.2 mmHg; DeltaTPR 0.96 +/- 0.85 peripheral resistance units (PRU)] compared with normothermia (DeltaMAP 15.4 +/- 1.4 mmHg, DeltaTPR 7.13 +/- 1.18 PRU; all P < 0.001). The sensitivity of baroreflex control of MSNA and heart rate, expressed as the slope of the relationship between MSNA and diastolic blood pressure, as well as the slope of the relationship between heart rate and systolic blood pressure, respectively, was similar between thermal conditions (each P > 0.05). These data suggest that phenylephrine-induced elevations in MAP are attenuated in heat-stressed humans without affecting baroreflex control of MSNA or heart rate.

  13. Fates of endocytosed somatostatin sst2 receptors and associated agonists.

    PubMed Central

    Koenig, J A; Kaur, R; Dodgeon, I; Edwardson, J M; Humphrey, P P

    1998-01-01

    Somatostatin agonists are rapidly and efficiently internalized with the somatostatin sst2 receptor. The fate of internalized agonists and receptors is of critical importance because the rate of ligand recycling back to the cell surface can limit the amount of radioligand accumulated inside the cells, whereas receptor recycling might be of vital importance in providing the cell surface with dephosphorylated, resensitized receptors. Furthermore the accumulation of radioisotope-conjugated somatostatin agonists inside cancer cells resulting from receptor-mediated internalization has been used as a treatment for cancers that overexpress somatostatin receptors. In the present study, radio-iodinated agonists at the sst2 somatostatin receptor were employed to allow quantitative analysis of the fate of endocytosed agonist. After endocytosis, recycling back to the cell surface was the main pathway for both 125I-labelled somatostatin-14 (SRIF-14) and the more stable agonist 125I-labelled cyclo(N-Me-Ala-Tyr-d-Trp-Lys-Abu-Phe) (BIM-23027; Abu stands for aminobutyric acid), accounting for 75-85% of internalized ligand when re-endocytosis of radioligand was prevented. We have shown that there is a dynamic cycling of both somatostatin agonist ligands and receptors between the cell surface and internal compartments both during agonist treatment and after surface-bound agonist has been removed, unless steps are taken to prevent the re-activation of receptors by recycled agonist. Internalization leads to increased degradation of 125I-labelled SRIF-14 but not 125I-labelled BIM-23027. The concentration of recycled agonist accumulating in the extracellular medium was sufficient to re-activate the receptor, as measured both by the inhibition of forskolin-stimulated adenylate cyclase and the recovery of surface receptor number after internalization. PMID:9820803

  14. The effects on Apgar scores and neonatal outcomes of switching from a combination of phenylephrine and ephedrine to phenylephrine alone as a prophylactic vasopressor during spinal anesthesia for cesarean section

    PubMed Central

    Jeon, Joo Yeon; Lee, In Ho; Jee, Young Seok; Lee, Pil Moo; Park, Seung In

    2014-01-01

    Background Ephedrine, unlike phenylephrine, has a dose-related propensity to depress fetal pH during spinal anesthesia during cesarean section. A low arterial umbilical cord pH has a strong association with neonatal mortality and morbidity. The purpose of this retrospective study was to investigate influences of vasopressor change on Apgar scores and adverse neonatal outcomes in cesarean section. Methods In obstetric anesthesia, we changed the prophylactic vasopressor from a combination of phenylephrine and ephedrine to phenylephrine alone in 2000. We evaluated the impact of vasopressor change on Apgar scores (1 and 5 min), incidence of Apgar score < 7 (1 and 5 min), neonatal seizure, continuous positive airway pressure (CPAP), intermittent positive pressure ventilation (IPPV), intraventricular hemorrhage (IVH), periventricular leucomalacia (PVL), and hypoxic ischemic encephalopathy (HIE) in low-risk elective cesarean sections during a period when the combination of phenylephrine and ephedrine was used (2008-2009, two years) and the period of phenylephrine use alone (2011-2012, two years). Results There were no differences in Apgar scores (1 and 5 min), the incidence of 5 min Apgar score < 7, neonatal seizure, CPAP, IPPV, IVH, PVL, and HIE between the two time periods. However, the incidence of 1 min Apgar < 7 was decreased during the period of phenylephrine use compared with the period of phenylephrine and ephedrine use (P = 0.002). Conclusions Conversion from a combination of phenylephrine and ephedrine to phenylephrine alone as a prophylactic anti-hypotensive drug during spinal anesthesia for cesarean section in low-risk pregnancy may be associated with a significant decrease in the incidence of 1 min Apgar < 7. PMID:25097737

  15. Deletion of Ac-NMePhe(1) from [NMePhe(1) ]arodyn under acidic conditions, part 2: effects of substitutions on pharmacological activity.

    PubMed

    Fang, Wei-Jie; Bennett, Marco A; Murray, Thomas F; Aldrich, Jane V

    2011-01-01

    Arodyn (Ac[Phe¹,²,³,Arg⁴,D-Ala⁸]Dyn A(1-11)NH₂) is an acetylated dynorphin A (Dyn A) analog that is a potent and selective κ opioid receptor antagonist (Bennett et al., J Med Chem 2002, 45, 5617), and its analog [NMePhe¹]arodyn shows even higher affinity and selectivity for κ opioid receptors (Bennett et al., J Pept Res 2005, 65, 322). However, the latter compound is prone to deletion of the Ac-NMePhe moiety from the N-terminus of the peptide during acidic cleavage as described in the accompanying paper. Several stable analogs of [NMePhe¹]arodyn and [NMePhe¹,Trp³]arodyn where the acetyl group was substituted with a heteroatom-containing group were evaluated for their opioid receptor affinity, selectivity, and efficacy. Methoxycarbonyl derivatives exhibited the highest κ opioid receptor affinity among the analogs. Additional [CH₃OCO-NMePhe¹]arodyn analogs where position 3 was substituted with other aromatic or nonaromatic residues were also evaluated for κ receptor affinity, selectivity, and efficacy. [CH₃OCO-NMePhe¹]arodyn has similar κ opioid receptor affinity as [NMePhe¹]arodyn, retains high κ opioid receptor selectivity, and is a potent κ opioid receptor antagonist.

  16. New SX Phe variables in the globular cluster NGC 288

    NASA Astrophysics Data System (ADS)

    Martinazzi, E.; Kepler, S. O.; Costa, J. E. S.; Pieres, A.; Bonatto, C.; Bica, E.; Fraga, L.

    2015-03-01

    We report the discovery of two new variable stars in the metal-poor globular cluster NGC 288, found by means of time series CCD photometry. We classified the new variables as SX Phoenicis (SX Phe) due to their characteristic fundamental mode periods (1.02 ± 0.01 and 0.69 ± 0.01 h), and refine the period estimates for other six known variables. SX Phe stars are known to follow a well-defined period-luminosity (P-L) relation and, thus, can be used for determining distances; they are more numerous than RR Lyraes in NGC 288. We obtain the P-L relation for the fundamental mode MV = (-2.59 ± 0.18) log P0(d) + (-0.34 ± 0.24) and for the first-overtone mode MV = (-2.59 ± 0.18) log P1(d) + (0.50 ± 0.25). Multichromatic isochrone fits to our UBV colour-magnitude diagrams, based on the Dartmouth Stellar Evolution Database, provide <[Fe/H]> = -1.3 ± 0.1, E(B - V) = 0.02 ± 0.01 and absolute distance modulus (m - M)0 = 14.72 ± 0.01 for NGC 288.

  17. Noninvasive assessment of baroreflex control in borderline hypertension. Comparison with the phenylephrine method.

    PubMed

    Watkins, L L; Grossman, P; Sherwood, A

    1996-08-01

    In this study, we examined the sensitivity of two recently developed noninvasive baroreflex measurement techniques to assess baroreflex control in hypertension. We assessed baroreflex sensitivity noninvasively from covariations of systolic pressure and RR interval using spectral analysis and sequence detection. The noninvasive estimates of baroreflex control were compared with estimates derived from phenylephrine-induced increases in systolic pressure and RR interval in normotensive subjects (n = 27) and borderline hypertensive subjects (n = 15). Baroreflex sensitivity was significantly reduced in the borderline hypertensive group relative to the normotensive group when assessed with the use of either the noninvasive or invasive methods to index baroreflex control. In addition, estimates obtained from the noninvasive methods were significantly correlated with baroreflex sensitivity assessed with the phenylephrine method (spectral: r = .48, P < .001; sequence: r = .50, P < .001). These findings suggest that spectral analysis and the sequence method provide viable alternatives to the pharmacological approach for estimation of baroreflex sensitivity in hypertension.

  18. Hepatic thiol and glutathione efflux under the influence of vasopressin, phenylephrine and adrenaline.

    PubMed Central

    Sies, H; Graf, P

    1985-01-01

    Thiol and glutathione (GSH) efflux across the sinusoidal plasma membrane in isolated perfused rat liver was stimulated by addition of hormones such as vasopressin, phenylephrine and adrenaline, whereas glucagon or dibutyryl cyclic AMP were without effect. Phenylephrine and adrenaline effects were sensitive to prazosin and phentolamine, respectively. The increase in thiol efflux was largely accounted for by an increase in GSH efflux. Thiol efflux and the hormone effects were abolished in GSH-depleted liver. Biliary GSH efflux was diminished upon hormone addition. The newly discovered hormone-dependence of GSH release across the sinusoidal plasma membrane may explain the known loss of GSH during conditions of experimental shock (traumatic or endotoxin) and stress and peripheral inflammation. PMID:3994671

  19. Phenylephrine versus norepinephrine for initial hemodynamic support of patients with septic shock: a randomized, controlled trial

    PubMed Central

    Morelli, Andrea; Ertmer, Christian; Rehberg, Sebastian; Lange, Matthias; Orecchioni, Alessandra; Laderchi, Amalia; Bachetoni, Alessandra; D'Alessandro, Mariadomenica; Van Aken, Hugo; Pietropaoli, Paolo; Westphal, Martin

    2008-01-01

    Introduction Previous findings suggest that a delayed administration of phenylephrine replacing norepinephrine in septic shock patients causes a more pronounced hepatosplanchnic vasoconstriction as compared with norepinephrine. Nevertheless, a direct comparison between the two study drugs has not yet been performed. The aim of the present study was, therefore, to investigate the effects of a first-line therapy with either phenylephrine or norepinephrine on systemic and regional hemodynamics in patients with septic shock. Methods We performed a prospective, randomized, controlled trial in a multidisciplinary intensive care unit in a university hospital. We enrolled septic shock patients (n = 32) with a mean arterial pressure below 65 mmHg despite adequate volume resuscitation. Patients were randomly allocated to treatment with either norepinephrine or phenylephrine infusion (n = 16 each) titrated to achieve a mean arterial pressure between 65 and 75 mmHg. Data from right heart catheterization, a thermodye dilution catheter, gastric tonometry, acid-base homeostasis, as well as creatinine clearance and cardiac troponin were obtained at baseline and after 12 hours. Differences within and between groups were analyzed using a two-way analysis of variance for repeated measurements with group and time as factors. Time-independent variables were compared with one-way analysis of variance. Results No differences were found in any of the investigated parameters. Conclusions The present study suggests there are no differences in terms of cardiopulmonary performance, global oxygen transport, and regional hemodynamics when phenylephrine was administered instead of norepinephrine in the initial hemodynamic support of septic shock. Trial registration ClinicalTrial.gov NCT00639015 PMID:19017409

  20. Antihypertensive effects of new dihydropyridine derivatives on phenylephrine-raised blood pressure in rats

    PubMed Central

    Fard, Sara Rowghani Haghighi; Miri, Ramin; Nekooeian, Ali Akbar

    2016-01-01

    Changes in the substitutions at C-3 and C-5 positions of 4-(1-methyl-5-nitro-2-imidazolyl) dihydropyridine analogs of nifedipine have led to changes in potency of the compounds. The objective of the present study was to examine the hypotensive effects of 5 newly synthesized dihydropyridine derivatives of nifedipine in rats with phenylephrine-raised blood pressure. Anesthetized Sprague-Dawley rats were randomly assigned to 19 groups of 7 animals each. Control group received the vehicle dimethylsulfoxide (0.05 mL), 3 groups were given nifedipine at 100, 300, or 1000 μg/kg, and 5 other groups each composed of 3 subgroups administered one of the 5 new dihydropyridine compound at 100, 300, or 1000 μg/kg. All animals were initially infused with 20 µg/kg/min phenylephrine for 45 min, and were then given a bolus of either dimethylsulfoxide, nifedipine, or new dihydropyridine compounds 20 min after the commencement of phenylephrine infusion. Blood pressure and heart rate (HR) of the animals were measured before and at the end of phenylephrine infusion, or 25 min after injection of vehicle or compounds. Compared to dimethylsulfoxide, nifedipine, and new 1, 4-dihydropyridine derivatives caused significant reductions in MBP. Moreover, cyclohexyl propyl, phenyl butyl, and cyclohexyl methyl analogs of 1, 4-dihydro-2,6-dimethyl-4-(1-methyl-5-nitro-2-imidazoyl)-3,5-pyridinedicarboxylase at 100 μg/kg, phenyl butyl, and cyclohexyl methyl analogs at 300 μg/kg, and cyclohexyl methyl analogs at 1000 μg/kg reduced MBP similar to nifedipine. There was no significant difference between HR of all groups before and after administration of the compounds. The findings indicated that changes in substitution at C-3 and C-5 positions of 2-(1-methyl-5-nitro-2-imidazolyl) dihydropyridine analogs of nifedipine were associated with changes in hypotensive activity of the compounds. PMID:28003844

  1. Genetic variation in the α1A-adrenergic receptor and phenylephrine-mediated venoconstriction.

    PubMed

    Adefurin, A; Ghimire, L V; Kohli, U; Muszkat, M; Sofowora, G G; Li, C; Paranjape, S Y; Stein, C M; Kurnik, D

    2015-08-01

    There is large interindividual variability and ethnic differences in phenylephrine-mediated vasoconstriction. We tested the hypothesis that genetic variation in ADRA1A, the α1A adrenergic receptor gene, contributes to the variability and ethnic differences. We measured local dorsal hand vein responses to increasing doses of phenylephrine in 64 Caucasians and 42 African-Americans and genotyped for 32 ADRA1A single nucleotide polymorphisms. The ED50 ranged from 11 to 5442 ng min(-1), and the Emax ranged from 13.5-100%. The rs574647 variant was associated with a trend towards lower logED50 in each race and in the combined cohort (P=0.008). In addition, rs1079078 was associated with a trend to higher logED50 in each race and in the combined cohort (P=0.011). Neither variant accounted for the ethnic differences in response. None of the ADRA1A haplotypes was associated with the outcomes. In conclusion, ADRA1A variants do not contribute substantially to the marked interindividual variability or ethnic differences in phenylephrine-mediated venoconstriction.

  2. Validation of a HPLC quantification of acetaminophen, phenylephrine and chlorpheniramine in pharmaceutical formulations: capsules and sachets.

    PubMed

    Marín, A; García, E; García, A; Barbas, C

    2002-07-20

    Acetaminophen, phenylephrine and chlorpheniramine are frequently associated in pharmaceutical formulations against the common cold. Their quantification presents several problems. A HPLC method for the simultaneous determination of these compounds in pharmaceutical formulations such as capsules and sachets, including the separation of impurities and excipients has been developed and validated. The selectivity of the method was also tested to be used if phenylpropanolamine hydrochloride were employed instead of phenylephrine. Final chromatographic conditions were a gradient elution, being solvent A: phosphate buffer 40 mM at pH 6.0 and solvent B: acetonitrile. At t=0, the mobile phase consisted of 92% A and 8% B and it changed with a linear gradient during 8 min to 75% A and 25% B. At min 8, it changed to 30% A and 70% B for 5 min and at t=15 min, it returns to the initial conditions (92% A and 8% B) during 1 min remaining at this composition until t=20 min. UV detection was performed at 215 nm for phenylephrine and chlorpheniramine, because at this wavelength sensitivity was higher than in other more characteristic wavelengths and it was necessary for the detection of minor compounds. For acetaminophen 280 nm was employed. Validation parameters permit to consider the method adequate.

  3. Phenylephrine-induced cardiac hypertrophy is attenuated by a histone acetylase inhibitor anacardic acid in mice.

    PubMed

    Peng, Chang; Luo, Xiaomei; Li, Shuo; Sun, Huichao

    2017-03-28

    Cardiac hypertrophy is a complex process involving highly coordinated but tight regulation of multiple elements, such as in epigenetics, which make an important contribution to myocardium remodeling and cardiac hypertrophy. Epigenetic regulations, particularly histone acetylation, have been implicated in cardiac hypertrophy, however, the exact mechanism is still largely unknown. In the present study, we explored the potential attenuating effects of Chinese herbal extract anacardic acid on phenylephrine-induced cardiac hypertrophy and the underlying mechanism. The mouse cardiac hypertrophy model was established and the hearts were collected from C57BL/6 mice for further analyses. The data showed that anacardic acid modulated the cardiac genes expression and attenuated the phenylephrine-induced cardiac hypertrophy via the suppression of histone acetylases activity and downstream cardiac genes. In addition, anacardic acid abrogated histone and MEF2A acetylation and DNA-binding activity by blocking p300-HAT and PCAF-HAT activities. In addition, anacardic acid normalized the cardiac hypertrophy-related genes expressions (ANP, BNP, cTnT, cTnI, β-MHC, and Cx43) induced by phenylephrine at the level of transcription and translation. In addition, anacardic acid did not affect the blood routine index, hepatic function, renal function, and myocardial enzymes. Therefore, anacardic acid may prove to be a candidate drug to cure hypertrophic cardiomyopathy.

  4. Reproducibility of dorsal hand vein responses to phenylephrine and prostaglandin F2 alpha using the dorsal hand vein compliance method.

    PubMed

    Schindler, C; Grossmann, M; Dobrev, D; Francke, K; Ravens, U; Kirch, W

    2003-03-01

    Assessment of drug-induced venodilation by the dorsal hand vein compliance method requires stable constriction of the vein. This study was designed to investigate intra- and intersubject reproducibility of the venous preconstriction technique in response to phenylephrine and prostaglandin F2 alpha and to determine the influence of basal vein size. Twelve healthy male nonsmokers participated in a prospective cross-over study. Inter- and intrasubject variability was tested in response to phenylephrine and PGF2 alpha on different study days in the same hand vein. The dose of the respective constrictor causing approximately 80% constriction of the vein (ED80) was determined and infused for another 100 minutes. Actual vein size was measured every 5 minutes. Coefficient of variation and regression analyses were performed to analyze influence of vessel size on ED80 of the respective constrictor. Adjusted constriction levels were stable and well reproducible in all subjects. The intersubject coefficient of variation of ED80 ranged from 0.9% to 6.7% for phenylephrine and from 0.9% to 6.9% for PGF2 alpha. Whereas responses to phenylephrine were independent of basal vein diameter, there was a positive correlation between ED80 of PGF2 alpha and basal vein size. Thus, the hand vein compliance method is a suitable method to study dilatory responses in phenylephrine- or PGF2 alpha-constricted veins with considerable interindividual but small intraindividual variability. However, in such studies, phenylephrine appears to be a more reliable tool than PGF2 alpha.

  5. 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

    2007-10-04

    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.

  6. Review on surgical management of ptosis and the use of phenylephrine: A national survey of British Oculoplastic Surgery Society (BOPSS) UK Consultants.

    PubMed

    Mota, Peter M; Norris, Jonathan H

    2016-12-01

    We assess current practice using topical phenylephrine by British Oculoplastic Surgery Society (BOPSS) consultants in the surgical management of ptosis. All UK consultant BOPSS members were invited to participate in a web-based survey, consisting of 8 questions relating to the surgical management of adult primary involutional ptosis with normal levator function and the use of phenylephrine in the management of ptosis. 53 BOPSS consultants (43%) completed the survey, of which 76% perform anterior approach levator advancement as first-line surgery. Then, 40% of consultants routinely use phenylephrine unilaterally in the ptotic eye, with 90% using 2.5% as opposed to 10%. Also, 77% of consultants use topical phenylephrine to illustrate the predicted outcome of surgery for the patient's benefit and 65% modify their approach on the basis of the test. If phenylephrine raises the ptotic eyelid >2 mm, those using an anterior approach reduces to 13.6%, with majority using a posterior approach (86.4%). If phenylephrine induces no improvement, then 76% use an anterior approach. If phenylephrine induces a contralateral ptosis 79% of consultants will perform simultaneous bilateral surgery. A number of interesting trends were observed amongst BOPSS consultants in their surgical approach to ptosis based on the phenylephrine test. The majority of consultants will switch from anterior to posterior approach surgery when the phenylephrine test is strongly positive and will also perform bilateral surgery when a contralateral ptosis is induced with phenylephrine.

  7. Metal-rich SX Phe stars in the Kepler field

    NASA Astrophysics Data System (ADS)

    Nemec, James M.; Balona, Luis A.; Murphy, Simon J.; Kinemuchi, Karen; Jeon, Young-Beom

    2017-04-01

    A spectroscopic and photometric analysis has been carried out for 32 candidate SX Phe variable blue straggler stars in the Kepler field. Radial velocities (RVs), space motions (U, V, W), projected rotation velocities (vsin i), spectral types and atmospheric characteristics (Teff, log g, [Fe/H], ξt, ζRT, etc.) are presented for 30 of the 32 stars. Although several stars are metal-weak with extreme halo orbits, the mean [Fe/H] of the sample is near-solar, thus the stars are more metal-rich than expected for a typical sample of Pop. II stars and more like halo metal-rich A-type stars. Two-thirds of the stars are fast rotators with vsin i > 50 km s-1, including four stars with vsin i > 200 km s-1. Three of the stars have (negative) RVs > 250 km s-1, five have retrograde space motions and 21 have total speeds (relative to the Local Standard of Rest) >400 km s-1. All but one of the 30 stars have positions in a Toomre diagram consistent with the kinematics of bona fide halo stars (the exception being a thick-disc star). Observed Rømer time delays, pulsation frequency modulations and light curves suggest that at least one-third of the stars are in binary (or triple) systems with orbital periods ranging from 2.3 d to more than four years.

  8. Probing Changes in the Conformation of tRNA[superscript Phe]: An Integrated Biochemistry Laboratory Course

    ERIC Educational Resources Information Center

    Kirk, Sarah R.; Silverstein, Todd P.; McFarlane Holman, Karen L.; Taylor, Buck L. H.

    2008-01-01

    We have designed a new guided-inquiry laboratory for an advanced biochemistry course. This integrated laboratory focuses on the biomolecule tRNA[superscript Phe] and combines elements of bioorganic and bioinorganic chemistry with biochemistry. Throughout the semester students work together to study tRNA[superscript Phe] structure and ligand…

  9. UV Thermal Melting Curves of tRNA[superscript Phe] in the Presence of Ligands

    ERIC Educational Resources Information Center

    Kirk, Sarah R.; Silverstein, Todd P.; McFarlane Holman, Karen L.

    2008-01-01

    This laboratory project is one component of a semester-long advanced biochemistry laboratory course that uses several complementary techniques to study tRNA[superscript Phe] conformational changes induced by ligand binding. In this article we describe a set of experiments in which the thermal unfolding of tRNA[superscript Phe] is studied with…

  10. Reliability of a new 4th generation FloTrac algorithm to track cardiac output changes in patients receiving phenylephrine.

    PubMed

    Ji, Fuhai; Li, Jian; Fleming, Neal; Rose, David; Liu, Hong

    2015-08-01

    Phenylephrine is often used to treat intra-operative hypotension. Previous studies have shown that the FloTrac cardiac monitor may overestimate cardiac output (CO) changes following phenylephrine administration. A new algorithm (4th generation) has been developed to improve performance in this setting. We performed a prospective observational study to assess the effects of phenylephrine administration on CO values measured by the 3rd and 4th generation FloTrac algorithms. 54 patients were enrolled in this study. We used the Nexfin, a pulse contour method shown to be insensitive to vasopressor administration, as the reference method. Radial arterial pressures were recorded continuously in patients undergoing surgery. Phenylephrine administration times were documented. Arterial pressure recordings were subsequently analyzed offline using three different pulse contour analysis algorithms: FloTrac 3rd generation (G3), FloTrac 4th generation (G4), and Nexfin (nf). One minute of hemodynamic measurements was analyzed immediately before phenylephrine administration and then repeated when the mean arterial pressure peaked. A total of 157 (4.6 ± 3.2 per patient, range 1-15) paired sets of hemodynamic recordings were analyzed. Phenylephrine induced a significant increase in stroke volume (SV) and CO with the FloTrac G3, but not with FloTrac G4 or Nexfin algorithms. Agreement between FloTrac G3 and Nexfin was: 0.23 ± 1.19 l/min and concordance was 51.1%. In contrast, agreement between FloTrac G4 and Nexfin was: 0.19 ± 0.86 l/min and concordance was 87.2%. In conclusion, the pulse contour method of measuring CO, as implemented in FloTrac 4th generation algorithm, has significantly improved its ability to track the changes in CO induced by phenylephrine.

  11. Towards the identification of the allosteric Phe-binding site in phenylalanine hydroxylase.

    PubMed

    Carluccio, Carla; Fraternali, Franca; Salvatore, Francesco; Fornili, Arianna; Zagari, Adriana

    2016-01-01

    The enzyme phenylalanine hydroxylase (PAH) is defective in the inherited disorder phenylketonuria. PAH, a tetrameric enzyme, is highly regulated and displays positive cooperativity for its substrate, Phe. Whether Phe binds to an allosteric site is a matter of debate, despite several studies worldwide. To address this issue, we generated a dimeric model for Phe-PAH interactions, by performing molecular docking combined with molecular dynamics simulations on human and rat wild-type sequences and also on a human G46S mutant. Our results suggest that the allosteric Phe-binding site lies at the dimeric interface between the regulatory and the catalytic domains of two adjacent subunits. The structural and dynamical features of the site were characterized in depth and described. Interestingly, our findings provide evidence for lower allosteric Phe-binding ability of the G46S mutant than the human wild-type enzyme. This also explains the disease-causing nature of this mutant.

  12. Magnetic properties of copper(II) complexes containing peptides. Crystal structure of [Cu(phe-leu)

    NASA Astrophysics Data System (ADS)

    Sanchiz, J.; Kremer, C.; Torre, M. H.; Facchin, G.; Kremer, E.; Castellano, E. E.; Ellena, J.

    2006-09-01

    A novel copper(II) complex containing the peptide phe-leu has been prepared and characterized. The crystal structure of [Cu(phe-leu)] ( 1) was determined by X-ray diffraction. The presence of carboxylate and amido bridges allows the formation of an extended 2D arrangement. This structure is similar to those found in [Cu(gly-val)] · 1/2H 2O ( 2), [Cu(val-gly)] ( 3), [Cu(val-phe)] ( 4), and [Cu(phe-phe)] ( 5). The magnetic properties of compounds 1- 5 were studied and analyzed comparatively. The experimental data show that the magnetic interactions are mainly transmitted through μ 2-COO - bridges, being ferromagnetic for 1 and 3, and antiferromagnetic for 2, 4 and 5.

  13. The Effects of Ephedrine and Phenylephrine on Placental Vascular Resistance During Cesarean Section Under Epidual Anesthesia.

    PubMed

    Guo, Ran; Xue, Qin; Qian, Yanning; Hu, Yongming; Tan, Jie

    2015-12-01

    The purpose of this article is to study the effect of ephedrine and phenylephrine on placental vascular resistance during cesarean section under epidural anesthesia via Doppler ultrasonography. Sixty female subjects, scheduled for elective cesarean section and had an intrathecal injection of bupivacaine, were randomly divided into two groups to receive phenylephrine (50 μg/min) or ephedrine (4 mg/min) via titration to maintain systolic blood pressure at baseline. Doppler ultrasonography was used to measure baseline vascular resistance values prior to administration of anesthesia, and resistance index (RI) and systolic peak velocity/diastolic velocity (S/D) values of umbilical artery and uterine artery were measured at each time point within first 20 min following intrathecal injection. Blood samples were collected from umbilical artery and umbilical vein during delivery to assess the blood gas values. No significant differences in RI and S/D values of umbilical artery and uterine artery after intrathecal injection were found between two groups. RI and S/D values of uterine artery slightly increased in both groups at each time point after anesthesia, but remained within the normal range. No significant differences were observed in blood gas values and the total amount of vasoconstriction drugs between two groups. In contrast to previous reports that used animal models, our study did not show increased placental vascular resistance in patients following phenylephrine (50 μg/min) or ephedrine (4 mg/min) infusion, as well as no significant differences in the effect of either of these two. The discrepancy between the results of human and animal studies may be related to species differences and the mechanism of human placental vascular remodeling.

  14. Flaxseed oil increases aortic reactivity to phenylephrine through reactive oxygen species and the cyclooxygenase-2 pathway in rats

    PubMed Central

    2014-01-01

    Background Flaxseed oil has the highest concentration of omega-3 α-linolenic acid, which has been associated with cardiovascular benefit. However, the mechanism underlying the vascular effects induced through flaxseed oil is not well known. Thus, in the present study, we investigated the effects of flaxseed oil on vascular function in isolated rat aortic rings. Methods Wistar rats were treated daily with flaxseed oil or a control (mineral oil) intramuscular (i.m.) for fifteen days. Isolated aortic segments were used to evaluate cyclooxygenase-2 (COX-2) protein expression, superoxide anion levels and vascular reactivity experiments. Results Flaxseed oil treatment increased the vasoconstrictor response of aortic rings to phenylephrine. Endothelium removal increased the response to phenylephrine in aortic segments isolated from both groups, but the effect was smaller in the treated group. L-NAME incubation similarly increased the phenylephrine response in segments from both groups. The TXA2 synthase inhibitor furegrelate, the selective COX-2 inhibitor NS 398, the TP receptor antagonist SQ 29.548, the reactive oxygen species (ROS) scavenger apocynin, the superoxide anion scavengers tiron and the phospholipase A2 inhibitor dexamethasone partially reversed the flaxseed oil-induced increase in reactivity to phenylephrine. Conclusions These findings suggest that flaxseed oil treatment increased vascular reactivity to phenylephrine through an increase in ROS production and COX-2-derived TXA2 production. The results obtained in the present study provide new insight into the effects of flaxseed oil treatment (i.m.) on vascular function. PMID:24993607

  15. Stereoselective synthesis of (R)-phenylephrine using recombinant Escherichia coli cells expressing a novel short-chain dehydrogenase/reductase gene from Serratia marcescens BCRC 10948.

    PubMed

    Peng, Guan-Jhih; Kuan, Yi-Chia; Chou, Hsiao-Yi; Fu, Tze-Kai; Lin, Jia-Shin; Hsu, Wen-Hwei; Yang, Ming-Te

    2014-01-20

    (R)-Phenylephrine [(R)-PE] is an α1-adrenergic receptor agonist and is widely used as a nasal decongestant to treat the common cold without the side effects of other ephedrine adrenergic drugs. We identified a short-chain dehydrogenase/reductase (SM_SDR) from Serratia marcescens BCRC 10948 that was able to convert 1-(3-hydroxyphenyl)-2-(methylamino) ethanone (HPMAE) into (R)-PE. The SM_SDR used NADPH and NADH as cofactors with specific activities of 17.35±0.71 and 5.57±0.07mU/mg protein, respectively, at 30°C and pH 7.0, thereby indicating that this enzyme could be categorized as an NADPH-preferring short-chain dehydrogenase/reductase. Escherichia coli strain BL21 (DE3) expressing SM_SDR could convert HPMAE into (R)-PE with more than 99% enantiomeric excess. The productivity and conversion yield were 0.57mmolPE/lh and 51.06%, respectively, using 10mM HPMAE. Fructose was the most effective carbon source for the conversion of HPMAE to (R)-PE.

  16. Alpha/sub 1/ receptor coupling events initiated by methoxy-substituted tolazoline partial agonists

    SciTech Connect

    Wick, P.; Keung, A.; Deth, R.

    1986-03-01

    A series of mono- and dimethyoxy substituted tolazoline derivatives, known to be partial agonists at the alpha/sub 1/ receptor, were compared with the ..cap alpha../sub 1/ selective full agonist phenylephrine (PE) on isolated strips of rabbit aorta Agonist activity was evaluated in contraction, /sup 45/Ca influx, /sup 45/Ca efflux, and /sup 32/P-Phospholipid labelling studies. Maximum contractile responses for the 2-, 3-, and 3, 5- methoxy substituted tolazoline derivatives (10/sup -5/M) were 53.8, 67.6 and 99.7% of the PE (10/sup -5/M) response respectively. These same partial agonists caused a stimulation of /sup 45/Ca influx to the extent of 64, 86, and 95% of the PE response respectively. In /sup 45/Ca efflux studies, (a measure of the intracellular Ca/sup +2/ release) the tolazolines caused: 30%, 63%, and 78% of the PE stimulated level. /sup 32/P-Phosphatidic acid (PA) labelling was measured as an index of PI turnover after ..cap alpha../sub 1/ receptor stimulation. Compared to PE, the 2-, 3-, and 3,5- methoxy substituted tolazoline derivatives caused 22, 46, and 72% PA labelling. The above values are all in reasonable accord with the rank order or agonist activity shown in maximum contractile responses. The results of this investigation suggest that partial agonists stimulate ..cap alpha.. receptor coupling events at a level which is quantitatively comparable to their potencies in causing contraction of arterial smooth muscle.

  17. Superstoichiometric binding of L-Phe to phenylalanine hydroxylase from Caenorhabditis elegans: evolutionary implications.

    PubMed

    Flydal, Marte I; Mohn, Tonje C; Pey, Angel L; Siltberg-Liberles, Jessica; Teigen, Knut; Martinez, Aurora

    2010-11-01

    Phenylalanine hydroxylase (PAH) catalyzes the hydroxylation of L-Phe to L-Tyr. Dysfunctional PAH results in phenylketonuria and mammalian PAH is therefore highly regulated and displays positive cooperativity for L-Phe (Hill coefficient (h)=2). L-Phe does not bind to the regulatory ACT domain in full-length tetrameric human PAH and cooperativity is elicited by homotropic binding to the catalytic site (Thórólfsson et al. in Biochemistry 41:7573-7585, 2002). PAH from Caenorhabditis elegans (cePAH) is devoid of cooperativity for L-Phe (h=0.9), and, as shown in this work, structural analysis reveal an additional L-Phe binding site at the regulatory domain of full-length cePAH. This site involves the GA(S)L/ISRP motifs, which are also found in ACT domains of other L-Phe binding proteins, such as prephenate dehydratase. Isothermal titration calorimetry further demonstrated 2 binding sites per subunit for cePAH versus ~1 for hPAH. Steric occlusion of the regulatory site, notably by residues Lys215/Tyr216 from the adjacent catalytic domain, appears to hinder regulatory binding in full-length hPAH. Accordingly, the humanized mutant Q215K/N216Y of cePAH binds ~1.4 L-Phe/subunit. This mutant also displays high catalytic activity and certain positive cooperativity for L-Phe (h=1.4). Our results support that the acquisition of positive cooperativity in mammalian forms of PAH is accompanied by a closure of the regulatory L: -Phe binding site. Concomitantly, the function of the regulatory ACT domain appears to be adapted from amino acid binding to serving the communication of conformational changes among catalytic subunits.

  18. [Ocular blood flow of cats after local administration of pilocarpine, phenylephrine, and of a mixture of both drugs (author's transl)].

    PubMed

    Kaskel, D; Spangenberg, U; Rudolf, H; Hübel, H; Witt, N; Baumgart, W

    1978-03-01

    Radioactively labelled microspheres (size 15 micron) were used to determine the regional blood flow in cats before and 15, 30 and 45 minutes after unilateral drug administration. In four experimental groups, each consisting of five animals, two drops of the drug were administered into the conjunctival sac. The blood flow increased in both eyes after administration of 2% pilocarpine and of Glauko Biciron, a mixture of 2% pilocarpine and 0.06% phenylephrine. No significant differences in the regional blood flows between the treated and untreated eye were found. After administration of 2% phenylephrine a decrease in blood flow was observed in both eyes, however earlier and more pronounced in the left eye. Thus, phenylephrine evoked the expected vasoconstrictive effect on the treated side. In the control group, which received physiological salt solution, the blood flow on the treated side decreased in most tissues, while an increase was observed on the untreated side.

  19. Phenylephrine infusion for spinal-induced hypotension in elective cesarean delivery: Does preload make a difference?

    PubMed Central

    Bottiger, Brandi A; Bezinover, Dmitri S; Mets, Berend; Dalal, Priti G; Prozesky, Jansie; Ural, Serdar; Vaida, Sonia

    2016-01-01

    Background and Aims: Patients undergoing elective cesarean delivery (CD) have a high-risk of spinal-induced hypotension (SIH). We hypothesized that a colloid preload would further reduce SIH when compared with a crystalloid preload. Material and Methods: Eighty-two healthy parturients undergoing elective CD were included in the study. Patients were randomly assigned to two groups (41 patients in each group) to receive either Lactated Ringer's solution (1500 ml) or hydroxyethyl starch (6% in normal saline, 500 ml) 30 min prior to placement of spinal anesthesia. All patients were treated with a phenylephrine infusion (100 mcg/min), titrated during the study. Results: There was no statistical difference between groups with regards to the incidence of hypotension (10.8% in the colloid group vs. 27.0% in the crystalloid group, P = 0.12). There was also no difference between groups with respect to bradycardia, APGAR scores, and nausea and vomiting. Significantly less phenylephrine (1077.5 ± 514 mcg) was used in the colloid group than the crystalloid group (1477 ± 591 mcg, P = 0.003). Conclusion: The preload with 6% of hydroxyethyl starch before CD might be beneficial for the prevention of SIH. PMID:27625478

  20. Poly(ethyleneglycol) column for the determination of acetaminophen, phenylephrine and chlorpheniramine in pharmaceutical formulations.

    PubMed

    García, A; Rupérez, F J; Marín, A; de la Maza, A; Barbas, C

    2003-03-05

    New polar reversed-phase stationary phases in HPLC provide specific selectivities which can help to solve traditional chromatographic problems related to the development of chromatographic methods with widely different retention times for the sample components. One such case is the analysis of pharmaceutical formulations against the common cold. Acetaminophen, phenylephrine and chlorpheniramine, compounds with different polarities, are frequently associated in these drugs. An isocratic and rapid HPLC method for the simultaneous determination of the three compounds, acetaminophen, phenylephrine and chlorpheniramine, in capsules as pharmaceutical formulations, including the separation of impurities (4-aminophenol and 4-chloracetanilide) and excipients, has been developed and validated. The final chromatographic conditions employed a Supelco Discovery HS PEG column poly(ethyleneglycol) 15x0.46 cm, 5 microm. The mobile phase was 20 mM phosphate buffer, pH 7.0-acetonitrile (90:10, v/v) at a flow-rate of 1 ml/min. UV detection was performed at 215 nm for all the compounds except acetaminophen, which was measured at 310 nm. Validation parameters permit us to consider this method suitable.

  1. Phenylephrine stimulated breakdown of phosphoinositides in brown adipocytes is attenuated by adenosine

    SciTech Connect

    Schimmel, R.J.

    1986-03-01

    Selective activation of alpha adrenergic receptors on brown adipocytes brings about increased mitochondrial respiration. This response is associated with a rapid breakdown of phosphoinositides in the plasma membrane. The authors have shown that respiration increased by alpha receptor activation can be inhibited by adenosine but the mechanisms underlying this effect are unknown. The present study probes the possibility that adenosine inhibition of alpha receptor stimulated respiration is secondary to an inhibition of stimulated breakdown of inositol phospholipids. Phospholipids were labeled with (/sup 32/P) by incubation with (/sup 32/P)-Pi for up to four hours. Phenylephrine and other ligands were then added and the radioactivity present in individual lipids determined following their resolution by thin layer chromatography. Addition of 2-chloroadenosine or phenylisopropyl adenosine, but not 2',5'-dideoxyadenosine, inhibited phenylephrine promoted breakdown of phosphoinositides. The dose response relation for this effect was similar to that for attenuation of stimulated respiration. This finding demonstrates adenosine inhibition of a phospholipase in brown fat cells and suggests the possibility that breakdown of inositol phospholipids is a critical control site for stimulation and attenuation of respiration.

  2. [Phenylephrine dosing error in Intensive Care Unit. Case of the trimester].

    PubMed

    2013-01-01

    A real clinical case reported to SENSAR is presented. A patient admitted to the surgical intensive care unit following a lung resection, suffered arterial hypotension. The nurse was asked to give the patient 1 mL of phenylephrine. A few seconds afterwards, the patient experienced a hypertensive crisis, which resolved spontaneously without damage. Thereafter, the nurse was interviewed and a dosing error was identified: she had mistakenly given the patient 1 mg of phenylephrine (1 mL) instead of 100 mcg (1 mL of the standard dilution, 1mg in 10 mL). The incident analysis revealed latent factors (event triggers) due to the lack of protocols and standard operating procedures, communication errors among team members (physician-nurse), suboptimal training, and underdeveloped safety culture. In order to preempt similar incidents in the future, the following actions were implemented in the surgical intensive care unit: a protocol for bolus and short lived infusions (<30 min) was developed and to close the communication gap through the adoption of communication techniques. The protocol was designed by physicians and nurses to standardize the administration of drugs with high potential for errors. To close the communication gap, repeated checks about saying and understanding was proposed ("closed loop"). Labeling syringes with the drug dilution was also recommended.

  3. Effect of different phenylephrine bolus doses for treatment of hypotension during spinal anaesthesia in patients undergoing elective caesarean section.

    PubMed

    Mohta, M; Harisinghani, P; Sethi, A K; Agarwal, D

    2015-01-01

    The efficacy of phenylephrine might be improved by giving doses higher than that traditionally used (100 µg). This study compared the effects of three initial bolus doses of intravenous phenylephrine; 100 µg (group P100), 125 µg (group P125) and 150 µg (group P150), for the treatment of post-spinal hypotension in patients undergoing elective caesarean delivery. If hypotension was not corrected by this dose, additional boluses of 25 µg were given every minute. Further hypotensive episodes were treated with half the initial bolus dose, followed by 25 µg boluses, as required. Umbilical arterial and venous blood samples were obtained for blood gas analysis and Apgar scores recorded. One hundred and twenty subjects (40 per group) who developed post-spinal hypotension (75%) were included in this randomised, double blind trial. Although systolic blood pressure was higher at certain time-points after 150 µg phenylephrine, there were no statistically significant differences in the effectiveness of the first bolus of phenylephrine to treat hypotension (85%, 95% and 95% in groups P100, P125 and P150, respectively, P=0.215); the additional dose of phenylephrine after the first bolus (P=0.810); the number of additional boluses (P=0.318) or of hypotensive episodes (P=0.118). There were no significant differences in the number of patients developing reactive hypertension or bradycardia, in maternal side-effects or in neonatal outcomes. Although the study may have been underpowered, initial phenylephrine bolus doses of 100 µg, 125 µg and 150 µg did not significantly differ in efficacy to treat post-spinal hypotension in these patients.

  4. Comparison of hydrodynamically closed isotachophoresis-capillary zone electrophoresis with hydrodynamically open capillary zone electrophoresis hyphenated with tandem mass spectrometry in drug analysis: pheniramine, its metabolite and phenylephrine in human urine.

    PubMed

    Piešťanský, Juraj; Maráková, Katarína; Kovaľ, Marián; Mikuš, Peter

    2014-09-05

    The advanced two dimensional isotachophoresis (ITP)-capillary zone electrophoresis (CZE) hyphenated with tandem mass spectrometry (MS/MS, here triple quadrupole, QqQ) was developed in this work to demonstrate analytical potentialities of this approach in the analysis of drugs in multicomponent ionic matrices. Pheniramine (PHM), phenylephrine (PHE), paracetamol (PCM) and their potential metabolic products were taken for the analysis by the ITP-CZE-ESI-QqQ technique working in hydrodynamically closed CE separation system and then a comparison with the conventional (hydrodynamically open) CZE-ESI-QqQ technique was made. The ITP-CZE-ESI-QqQ method was favorable in terms of obtainable selectivity (due to highly effective heart-cut analysis), concentration limits of detection (LOD at pgmL(-1) levels due to enhanced sample load capacity and ITP preconcentration), sample handling (on-line sample pretreatment, i.e. clean-up, preconcentration, preseparation), and, by that, possibilities for future automation and miniaturization. On the other hand, this experimental arrangement, in contrast to the CZE-ESI-QqQ arrangement supported by an electroosmotic flow, is principally limited to the analysis of uniformly (i.e. positively or negatively) charged analytes in one run without any possibilities to analyze neutral compounds (here, PCM and neutral or acidic metabolites of the drugs had to be excluded from the analysis). Hence, these general characteristics should be considered when choosing a proper analytical CE-MS approach for a given biomedical application. Here, the analytical potential of the ITP-CZE-ESI-QqQ method was demonstrated showing the real time profiles of excreted targeted drugs and metabolite (PHM, PHE, M-PHM) in human urine after the administration of one dose of Theraflu(®) to the volunteers.

  5. [Separation and determination of optical isomers of phenylephrine by chiral ligand exchange capillary elcctrophoresis coupling with the promoting effect of ionic liquid].

    PubMed

    Yang, Simei; Zhang, Jiayao; Li, Fei; Hu, Xufang; Cao, Qiue

    2016-01-01

    A method for the separation and determination of optical isomers of phenylephrine was developed based on the promoting effect of non-chiral ionic liquid on chiral ligand-exchange capillary electrophoresis after the electrophoretic parameters were optimized systematically. R-phenylephrine and S-phenylephrine can be separated and determined effectively in 20 mmol/L Tris-H3PO4 buffer solution (pH 5.4) composed of 4.0 mmol/L Cu(II), 8.0 mmol/L L-proline (L-Pro) and 15 mmol/L 1-butyl-3-methylimidazolium chloride ([BMIM] Cl) with the applied voltage of 20 kV, capillary temperature of 25 °C , detection wavelength of 254 nm, and injection of 5 s at 3,447 Pa. The resolution of R- and S-phenylephrines was 1. 42. The linear ranges for the determination of R-phenylephrine and S-phenylephrine were 12. 5 - 150 mg/L and 15. 0-150 mg/L, respectively. The method has been satisfactorily used for the determination of R-phenylephrine and S-phenylephrine in the spiked blood and urine samples. The spiked recoveries in the urine sample were in the range of 93. 7% -108. 2% with the RSDs lower than 3. 18% (n= 3) , and the spiked recoveries in the blood sample were in the range of 91. 4% and 113. 1% with the RSDs lower than 4. 82% (n =3).

  6. Phe317 Is Essential for Rubber Oxygenase RoxA Activity

    PubMed Central

    Birke, Jakob; Hambsch, Nadja; Schmitt, Georg; Altenbuchner, Josef

    2012-01-01

    RoxA is an extracellular c-type diheme cytochrome secreted by Xanthomonas sp. strain 35Y during growth on rubber. RoxA cleaves poly(cis-1,4-isoprene) to 12-oxo-4,8-dimethyltrideca-4,8-diene-1-al (ODTD). Analysis of the RoxA structure revealed that Phe317 is located in close proximity (≈5 Å) to the N-terminal heme that presumably represents the active site. To find evidence of whether Phe317 is important for catalysis, we changed it to tyrosine, tryptophan, leucine, histidine, or alanine. All five RoxA muteins were expressed after integration of the respective gene into the chromosome of a Xanthomonas sp. ΔroxA strain. Residual clearing zone formation on opaque latex agar was found for Xanthomonas sp. strains expressing the Phe317Leu, Phe317Ala, or Phe317His variant (wild type > Leu > Ala > His). Strains in which Phe317 was changed to tyrosine or tryptophan were inactive. Phe317Ala and Phe312Leu RoxA muteins were purified, and polyisoprene cleavage activities were reduced to ≈3% and 10%, respectively. UV-visible spectroscopy of RoxA muteins confirmed that both heme groups were present in an oxidized form, but spectral responses to the addition of low-molecular-weight (inhibitory) ligand molecules such as imidazole and pyridine were different from those of wild-type RoxA. Our results show that residue 317 is involved in interaction with substrates. This is the first report on structure-function analysis of a polyisoprene-cleaving enzyme and on the identification of an amino acid that is essential for polyisoprene cleavage activity. PMID:22941074

  7. Redoubling the ring size of an endomorphin-2 analog transforms a centrally acting mu-opioid receptor agonist into a pure peripheral analgesic.

    PubMed

    Piekielna, Justyna; De Marco, Rossella; Gentilucci, Luca; Cerlesi, Maria Camilla; Calo', Girolamo; Tömböly, Csaba; Artali, Roberto; Janecka, Anna

    2016-05-01

    The study reports the synthesis and biological evaluation of two opioid analogs, a monomer and a dimer, obtained as products of the solid-phase, side-chain to side-chain cyclization of the pentapeptide Tyr-d-Lys-Phe-Phe-AspNH2 . The binding affinities to the mu, delta, and kappa opioid receptors, as well as results obtained in a calcium mobilization functional assay are reported. Tyr-[d-Lys-Phe-Phe-Asp]2 -NH2 1 was a potent and selective full agonist of mu with sub-nanomolar affinity, while the dimer (Tyr-[d-Lys-Phe-Phe-Asp]2 -NH2 )2 2 showed a significant mixed mu/kappa affinity, acting as an agonist at the mu. Molecular docking computations were utilized to explain the ability of the dimeric cyclopeptide 2 to interact with the receptor. Interestingly, in spite of the increased ring size, the higher flexibility allowed 2 to fold and fit into the mu receptor binding pocket. Both cyclopeptides were shown to elicit strong antinociceptive activity after intraventricular injection but only cyclomonomer 1 was able to cross the blood-brain barrier. However, the cyclodimer 2 displayed a potent peripheral antinociceptive activity in a mouse model of visceral inflammatory pain. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 309-317, 2016.

  8. Synthesis of tritium labeled Ac-(Nle/sup 4/, D-Phe/sup 7/)-. cap alpha. -MSH/sub 4-11/-NH/sub 2/: a superpotent melanotropin with prolonged biological activity

    SciTech Connect

    Wilkes, B.D.; Hruby, V.J.; Yamamura, H.I.; Akiyama, K.; Castrucci, A.M. de; Hadley, M.E.; Andrews, J.R.; Wan, Y.P.

    1984-03-05

    Ac-(Nle/sup 4/, D-Phe/sup 7/)-..cap alpha..-MSH/sub 4-11/-NH/sub 2/ an octapeptide, is a melanotropin analogue (Ac-Nle-Glu-His-D-Phe-Arg-Trp-Gly-Lys-NH/sub 2/), which is a superpotent agonist of frog and lizard skin melanocytes and mouse S 91 (Cloudman) melanoma cells. This melanotropin possesses ultraprolonged activity on melanocytes, both in vitro and in vivo, and the peptide is resistant to inactivation by serum enzymes. The tritium-labeled congener was prepared by direct incorporation of (/sup 3/H)-labeled norleucine into the peptide. The melanotropic activity of the labeled peptide is identical to the unlabeled analogue. This labeled peptide should be useful for studies on the localization and characterization of melanotropin receptors.

  9. Prophylactic Phenylephrine Infusions to Reduce Severe Spinal Anesthesia Hypotension During Cesarean Delivery in a Resource-Constrained Environment.

    PubMed

    Bishop, David G; Cairns, Carel; Grobbelaar, Mariette; Rodseth, Reitze N

    2017-02-24

    Phenylephrine infusions are considered as standard management for obstetric spinal hypotension, but there remains reluctance to implement them in resource-limited contexts. This prospective, alternating intervention study of patients undergoing elective or urgent cesarean delivery under spinal anesthesia compared a vasopressor bolus strategy to fixed-rate, low-dose prophylactic phenylephrine infusion with supplemental boluses. The primary outcome was the incidence of severe hypotension (mean arterial pressure <70% baseline or systolic blood pressure <80 mm Hg). Fewer patients receiving prophylactic phenylephrine infusions had severe hypotension (47.4% [n = 120/253] vs 62.1% [n = 157/253], P = .001, estimated relative risk 0.84, 95% confidence interval 0.69-1.02), with no significant difference in the rate of hypertension (15% [n = 39/253] vs 11% [n = 27/253], P = .11, estimated relative risk 1.39, confidence interval 0.87-2.20). Guidelines for resource-constrained settings should consider a fixed, low-dose phenylephrine infusion in combination with rescue vasopressor bolus therapy.

  10. 5HT4 agonists inhibit interferon-gamma-induced MHC class II and B7 costimulatory molecules expression on cultured astrocytes.

    PubMed

    Zeinstra, Esther M; Wilczak, Nadine; Wilschut, Jan C; Glazenburg, Lisa; Chesik, Daniel; Kroese, Frans G M; De Keyser, Jacques

    2006-10-01

    A failure of tight control of MHC class II expression on astrocytes may play a role in the development of autoimmune responses in multiple sclerosis. The 5-HT(4) serotonin receptor agonists cisapride and prucalopride, at concentrations between 10(-10) M and 10(-8) M, reduced interferon-gamma-induced MHC class II immunostaining in cultured astrocytes derived from newborn Wistar rats by approximately 50-60%. The magnitude of MHC class II inhibition by 5-HT(4) agonists was comparable to that of interferon-beta. The alpha(1)-adrenergic receptor agonist phenylephrine was without effect. Cisapride (10(-9) M) also prevented interferon-gamma-induced B7-1 and B7-2 immunostaining. Our results suggest that 5-HT(4) agonists may have therapeutic potential in multiple sclerosis by inhibiting the up-regulation of immune responsiveness of astrocytes in the central nervous system.

  11. Simultaneous determination of paracetamol, phenylephrine hydrochloride and chlorpheniramine maleate in pharmaceutical preparations using multivariate calibration 1

    NASA Astrophysics Data System (ADS)

    Samadi-Maybodi, Abdolraouf; Hassani Nejad-Darzi, Seyed Karim

    2010-04-01

    Resolution of binary mixtures of paracetamol, phenylephrine hydrochloride and chlorpheniramine maleate with minimum sample pre-treatment and without analyte separation has been successfully achieved by methods of partial least squares algorithm with one dependent variable, principal component regression and hybrid linear analysis. Data of analysis were obtained from UV-vis spectra of the above compounds. The method of central composite design was used in the ranges of 1-15 mg L -1 for both calibration and validation sets. The models refinement procedure and their validation were performed by cross-validation. Figures of merit such as selectivity, sensitivity, analytical sensitivity and limit of detection were determined for all three compounds. The procedure was successfully applied to simultaneous determination of the above compounds in pharmaceutical tablets.

  12. [Validation of the HPLC method in the determination of dioxopromethazine and phenylephrine in eye drops].

    PubMed

    Hudecová, T; Hatrík, S; Zimová, N; Havránek, E

    2002-03-01

    The present paper introduces a rapid HPLC method for the determination of dioxopromethazine and phenylephrine in eye drops. The method uses a modified C18 stationary phase optimized for the separation of basic compounds and a methanol/1.5 mM phosphoric acid (60/40 v/v, pH 3.02) mobile phase. The flow rate is set to 2 ml/min, sample volume 20 microliters, and compounds are detected at 275 nm. Prior to analysis, the eye drops are diluted with water in a ratio of 1:50. The elaborated HPLC method and the chromatographic system were validated according to the procedure for the validation of chromatographic systems and methods.

  13. Simultaneous determination of dextromethorphan, diphenhydramine and phenylephrine in expectorant and decongestant syrups by capillary electrophoresis.

    PubMed

    Gomez, María R; Olsina, Roberto A; Martínez, Luis D; Silva, María F

    2002-10-15

    The separation of basic nitrogenous compounds commonly used as active ingredients in cold medicine formulations by micellar electrokinetic capillary chromatography and capillary zone electrophoresis with direct absorptiometric detection was investigated. The type and composition of the background electrolyte (BGE) were investigated with respect to separation selectivity and BGE stability. BGE of 10 mM sodium dihydrogenphosphate-sodium tetraborate buffer containing 10 mM SDS and 10% acetonitrile, pH 9.0 was found to be optimal. Dextromethorphan hydrobhromide, diphenhydramine hydrochloride and phenylephrine hydrochloride were baseline-separated in less than 11 min, giving separation efficiencies of up to 494,000 theoretical plates, reproducibility of corrected peaks areas below 3% relative standard deviation and concentration detection limits from 2.5 to 5.5 microg ml(-1). Detection was performed at 196 and 214 nm.

  14. Simultaneous determination of paracetamol, phenylephrine hydrochloride and chlorpheniramine maleate in pharmaceutical preparations using multivariate calibration 1.

    PubMed

    Samadi-Maybodi, Abdolraouf; Hassani Nejad-Darzi, Seyed Karim

    2010-04-01

    Resolution of binary mixtures of paracetamol, phenylephrine hydrochloride and chlorpheniramine maleate with minimum sample pre-treatment and without analyte separation has been successfully achieved by methods of partial least squares algorithm with one dependent variable, principal component regression and hybrid linear analysis. Data of analysis were obtained from UV-vis spectra of the above compounds. The method of central composite design was used in the ranges of 1-15 mg L(-1) for both calibration and validation sets. The models refinement procedure and their validation were performed by cross-validation. Figures of merit such as selectivity, sensitivity, analytical sensitivity and limit of detection were determined for all three compounds. The procedure was successfully applied to simultaneous determination of the above compounds in pharmaceutical tablets.

  15. CE versus HPLC for the dissolution test in a pharmaceutical formulation containing acetaminophen, phenylephrine and chlorpheniramine.

    PubMed

    Marín, A; Barbas, C

    2004-06-29

    A new polar reverse phase stationary phase has permitted our group to develop and validate an isocratic HPLC method for the simultaneous determination of acetaminophen, phenylephrine and chlorpheniramine in capsules as pharmaceutical formulation after their dissolution test. Final optimised chromatographic conditions employed a Supelco Discovery HS PEG column (polyethylene glycol), 5 microm, 15 cm x 0.46 cm. The mobile phase was 20 mM phosphate buffer at pH 7.0/acetonitrile 80:20 (v/v) at a flow rate of 1 ml/min. UV detection was performed at 210 nm for phenylephrine and chlorpheniramine and at 305 nm for acetaminophen. On the other hand, to evaluate the capability of CE to work in a routine analytical method fulfilling the pharmaceutical requirements and to study the behaviour of the technique with these compounds, we developed a CE method with the same objective. Normal and reverted polarity, the pH and concentration of the buffer, and the presence and concentration of surfactants were assayed. Forty millimolar phosphate buffer at pH 6.20 with 0.5 mM SDS at 30k V in an uncoated silica capillary provided a runtime of 4.5 min to separate the three analytes and the excipients. Moreover, parameters affecting precision in CE, such as the injection of buffer after the sample to refill the capillary were also tested. After development, the validation was performed in parallel for HPLC and CE with the same standards and samples to avoid differences due to the manipulation. The validation parameters of both techniques were adequate for the intended purpose.

  16. Silibinin protects H9c2 cardiac cells from oxidative stress and inhibits phenylephrine-induced hypertrophy: potential mechanisms.

    PubMed

    Anestopoulos, Ioannis; Kavo, Anthula; Tentes, Ioannis; Kortsaris, Alexandros; Panayiotidis, Mihalis; Lazou, Antigone; Pappa, Aglaia

    2013-03-01

    Cardiac hypertrophy is the main response of the heart to various extrinsic and intrinsic stimuli, and it is characterized by specific molecular and phenotypic changes. Recent in vitro and in vivo studies indicate the involvement of reactive oxygen species in the hypertrophic response. In this study, silibinin, a plant flavonolignan extracted from milk thistle with potent antioxidant activity, was evaluated for its effects in (a) preventing hydrogen peroxide (H2O2)-induced cellular damage and (b) blocking the phenylephrine-induced hypertrophic response. Using the in vitro model of embryonic rat heart-derived H9c2 cells, we showed that silibinin has a rather safe profile as concentrations up to 200μM did not affect cell viability. Pretreatment of H9c2 cells with silibinin resulted in better protection of H9c2 cells under conditions of H2O2-induced cellular stress compared to untreated cells as indicated by cell viability and DNA fragmentation assays. Furthermore, silibinin attenuated the phenylephrine-induced hypertrophic response as evidenced by the measurement of cell surface, up-regulation of atrial natriuretic peptide and increase of cellular protein levels. Moreover, silibinin repressed the phenylephrine-induced phosphorylation of ERK1/2 kinases, while it appeared to inhibit the weakly activated by phenylephrine phosphorylation of Akt. Based on our results, silibinin may attenuate the phenylephrine-induced hypertrophic response of H9c2 cells via antioxidant mechanisms involving mainly the inhibition of the intracellular signaling pathways mediated by ERK1/2 MAPKs and Akt.

  17. Effects of Peripherally Restricted κ Opioid Receptor Agonists on Pain-Related Stimulation and Depression of Behavior in Rats

    PubMed Central

    O'Connell, Robert; Morrissey, Ember; Cheng, Kejun; Rice, Kenner C.

    2012-01-01

    κ Opioid receptor agonists that do not readily cross the blood-brain barrier are peripherally restricted and distribute poorly to the central nervous system after systemic administration. Peripherally restricted κ agonists have promise as candidate analgesics, because they may produce antinociception mediated by peripheral κ receptors more potently than they produce undesirable sedative and psychotomimetic effects mediated by central κ receptors. The present study used assays of pain-related stimulation and depression of behavior in rats to compare effects of 1) two peripherally restricted κ agonists [the tetrapeptide d-Phe-d-Phe-d-Ile-d-Arg-NH2 (ffir) and the nonpeptidic compound ((R,S)-N-[2-(N-methyl-3,4-dichlorophenylacetamido)-2-(3-carboxyphenyl)-ethyl]pyrrolidine hydrochloride (ICI204448)], 2) a centrally penetrating κ agonist (salvinorin A), and 3) several reference drugs, including a nonsteroidal anti-inflammatory drug (NSAID; ketoprofen). Intraperitoneal injection of dilute lactic acid served as a noxious stimulus to stimulate a stretching response and depress intracranial self-stimulation (ICSS) maintained by the delivery of electrical brain stimulation to the medial forebrain bundle. Acid-stimulated stretching was blocked by ketoprofen, the peripherally restricted κ agonists, and salvinorin A. However, acid-induced depression of ICSS was blocked only by ketoprofen. The peripherally restricted κ agonists had little effect, and salvinorin A exacerbated acid-induced depression of ICSS. These results suggest that peripherally restricted κ agonists may be safer than centrally penetrating κ agonists but less efficacious than NSAIDS or μ opioid receptor agonists to block pain-related depression of behavior; however, the peripheral selectivity of ffir and ICI204448 is limited, and future studies with κ agonists capable of greater peripheral selectivity are warranted. PMID:22128346

  18. VizieR Online Data Catalog: SX Phe stars in globular clusters (Cohen+, 2012)

    NASA Astrophysics Data System (ADS)

    Cohen, R. E.; Sarajedini, A.

    2012-06-01

    To compile a current list of SX Phe in GGCs, we began with the catalogue of Rodriguez & Lopez-Gonzalez (2000, Cat. J/A+A/359/597), which was updated by Santolamazza et al. (2001ApJ...554.1124S). We then added to this list all SX Phe in GGCs found in the literature since the publication of those studies. This more than doubled the number of SX Phe in GGCs, from 117 listed by Santolamazza et al. (2001ApJ...554.1124S) to 263 currently known. For the sake of homogeneity, we have excluded the small number of SX Phe in E 3, IC 4499 and Ruprecht 106 from our analysis because isochrone fits to those clusters were not performed by D10. In addition, we have excluded all stars from the original Rodriguez & Lopez-Gonzalez (2000, Cat. J/A+A/359/597) catalogue which were also excluded by Santolamazza et al. (2001ApJ...554.1124S), as well as all SX Phe in NGC 3201 and 4372 due to high differential reddening (Gerashchenko, Kadla & Malakhova, 1999ARep...43...20G; Piersimoni, Bono & Ripepi, 2002AJ....124.1528P). (1 data file).

  19. Effect of Phenylephrine Pretreatment on the Expressions of Aquaporin 5 and c-Jun N-Terminal Kinase in Irradiated Submandibular Gland.

    PubMed

    Han, Lichi; Wang, Lei; Zhang, Fuyin; Liu, Ke Jian; Xiang, Bin

    2015-06-01

    Radiotherapy for malignant tumors of the head and neck commonly leads to radiation-induced sialadenitis as a result of radiation-induced salivary gland dysfunction. We demonstrated previously that phenylephrine could protect the irradiated submandibular gland against apoptosis, although the mechanism is unclear. In this study, we investigated the influence of phenylephrine pretreatment on the expressions of aquaporin 5 (AQP5) and c-Jun N-terminal kinase (JNK) that were presumed to have a role in radiation-induced salivary gland dysfunction. Rats pretreated with phenylephrine (5 mg/kg) were locally irradiated (20 Gy) in the head and neck region. The submandibular glands were removed on day 7 after irradiation. The expression of AQP5 and activation of JNK were measured by immunohistochemistry and Western blot. The localization of AQP5 at the apical and lateral plasma membrane of acinar cells was significantly reduced by irradiation, but markedly enhanced with phenylephrine pretreatment. The protein expression of AQP5 was decreased by 84.91% in irradiated glands, whereas it was fully recovered to the control level in phenylephrine-pretreated glands. Moreover, many acinar, ductal and granular convoluted tubular cells in the irradiated glands exhibited intense immunoreactivity for p-JNK, while in the phenylephrine-pretreated irradiated glands, only a few acinar cells exhibited very faint immunoreactivity for p-JNK. The protein expression level of p-JNK was increased by 41.65% in the irradiated alone glands, but was significantly decreased in the phenylephrine-pretreated irradiated glands. These results suggest that the protective mechanism of phenylephrine might be related to the improved expression of AQP5 and decreased activation of JNK. Pretreatment with phenylephrine in patients undergoing radiotherapy may provide a helpful strategy for suppression of radiation-induced sialadenitis.

  20. [Melatonin receptor agonist].

    PubMed

    Uchiyama, Makoto

    2015-06-01

    Melatonin is a hormone secreted by the pineal gland and is involved in the regulation of human sleep-wake cycle and circadian rhythms. The melatonin MT1 and MT2 receptors located in the suprachiasmatic nucleus in the hypothalamus play a pivotal role in the sleep-wake regulation. Based on the fact that MT1 receptors are involved in human sleep onset process, melatonin receptor agonists have been developed to treat insomnia. In this article, we first reviewed functions of melatonin receptors with special reference to MT1 and MT2, and properties and clinical application of melatonin receptor agonists as hypnotics.

  1. Quantitative analysis of mitragynine, codeine, caffeine, chlorpheniramine and phenylephrine in a kratom (Mitragyna speciosa Korth.) cocktail using high-performance liquid chromatography.

    PubMed

    Chittrakarn, Somsmorn; Penjamras, Pimpimol; Keawpradub, Niwat

    2012-04-10

    A simple HPLC technique for determining mitragynine, codeine, caffeine, chlorpheniramine and phenylephrine in 'kratom cocktail' was developed. The analytical method for mitragynine, codeine and caffeine used an Eclipse XDB-C8 column. A Lichrospher CN column was using for analysing chlorpheniramine and phenylephrine. The correlation coefficient of each standard was between 0.9957 and 0.9993. The precision of the methods were between 0.700 and 7.108% RSD. The concentration of mitragynine, codeine, caffeine, chlorpheniramine and phenylephrine in 'kratom cocktail' was 90.021, 234.174, 73.986, 7.053 and 1.486 mg/L, respectively.

  2. Investigation of the encapsulation of metal cations (Cu(2+), Zn(2+), Ca(2+) and Ba(2+)) by the dipeptide Phe-Phe using natural bond orbital theory and molecular dynamics simulation.

    PubMed

    Bhunia, Snehasis; Singh, Ajeet; Ojha, Animesh K

    2017-03-01

    Complexes of the dipeptide phenylalanine-phenylalanine (Phe-Phe) with divalent metal cations (Cu(2+), Zn(2+), Ca(2+) and Ba(2+)) were studied at the B3LYP and MP2 levels of theory with the basis sets 6-311++G(d,p) and 6-31 + G(d) in the gas phase. The relative energies of these complexes indicated that cation-π bidentate/tridentate conformations are more favourable than other conformations with uncoordinated rings. These findings were confirmed by the calculated values of thermodynamic parameters such as the Gibbs free energy. Natural bond orbital (NBO) analysis was carried out to explore the metal-ligand coordination in Phe-Phe-Cu(2+)/Zn(2+) complexes. Possible orbital transitions, types of orbitals and their occupancies were determined for a range of Phe-Phe-Cu(2+)/Zn(2+) complexes. The charge transfer involved in various orbital transitions was explored by considering the second-order perturbation energy. NBO analysis revealed that the change transfer is stronger when the metal cation uses both the 4s + 4p subshells rather than just its 4p subshell. We also performed molecular dynamics (MD) simulations to check the stability and consistency of the most favourable binding motifs of Cu(2+), Zn(2+), Ca(2+) and Ba(2+) with Phe-Phe over time. The structures of the Phe-Phe-Cu(2+)/Zn(2+)/Ca(2+)/Ba(2+) complexes obtained using MD simulation were found to be in good agreement with those obtained in the DFT-based calculations. Graphical Abstract Conformational search on encapsulation of divalent metal cations (Ca(2+), Zn(2+), Ca(2+), Ba(2+)) by the Phe-Phe dipeptide.

  3. Molecular basis for agonist selectivity and activation of the orphan BRS-3-receptor

    PubMed Central

    Gonzalez, Nieves; Hocart, Simon J.; Portal-Nuñez, Sergio; Mantey, Samuel A.; Nakagawa, Tomoo; Zudaire, Enrique; Coy, David H.; Jensen, Robert T.

    2008-01-01

    Bombesin receptor subtype-3(BRS-3), a G protein-coupled orphan receptor, shares 51% identity with the mammalian bombesin(Bn) receptor for gastrin-releasing peptide(GRPR). There is increasing interest in BRS-3 because it is important in energy metabolism, glucose control,motility and tumor-growth. BRS-3 has low affinity for all Bn-related peptides, however, recently synthetic high-affinity agonists[D-Tyr6/D-Phe6,βAla11,Phe13,Nle14]Bn-(6–14) were described, but they are nonselective for BRS-3 over other Bn-receptors. Based on these peptides, three BRS-3 selective-ligands were developed: peptide#2,[D-Tyr6(R)-Apa11,Phe13,Nle14]Bn(6–14); peptide#3,[D-Tyr6,(R)-Apa11,4Cl-Phe13,Nle14]Bn(6–14); peptide #4,Ac-Phe-Trp-Ala-His(tBzl)-Nip-Gly-Arg-NH2. Their molecular determinants of selectivity/high affinity for BRS-3 are unknown. To address this we used a chimeric/site-mutagenesis approach. Substitution of extracellular domain2(EC2) of BRS-3 by the comparable GRPR domain decreased 26-,4,0-fold affinity for peptides#4,3,2. Substitution of EC3 decreased affinity 4-,11-,0-fold affinity for peptides#2,3,4. Ten point mutations in the EC2 and adjacent transmembrane regions (TM2) 2 and 3 of BRS-3 were made. His107(EC2-BRS-3) for lysine(H107K)(EC2-GRPR), decreased affinity(25-,0-fold) for peptide#4,1; however it could not be activated by either peptide. Its combination with Val101(TM2),Gly112(EC2),Arg127(TM3) resulted in complete loss-of-affinity of peptide#4. Receptor-modeling showed that each of these residues face inward and are within 4Å of the binding-pocket. These results demonstrate [Val101,His107,Gly112,Arg127] in the EC2/adjacent upper TMs of BRS-3 are critical for the high BRS3-selectivity of peptide#4. His107 in EC2 is essential for BRS-3 activation, suggesting amino-aromatic ligand/receptor interactions with peptide#4 are critical for both binding/ activation. Furthermore, these result demonstrate that even though these three BRS-3 selective agonists were developed

  4. Lacrimal gland PKC isoforms are differentially involved in agonist-induced protein secretion.

    PubMed

    Zoukhri, D; Hodges, R R; Sergheraert, C; Toker, A; Dartt, D A

    1997-01-01

    In the present study, we have synthesized and N-myristoylated peptides derived from the pseudosubstrate sequences of protein kinase C (PKC)-alpha, -delta, and -epsilon [Myr-PKC-alpha-(15-28), Myr-PKC-delta-(142-153), and Myr-PKC-epsilon-(149-164)], three isoforms present in rat lacrimal gland, and a peptide derived from the sequence of the endogenous inhibitor of protein kinase A [Myr-PKI-(17-25)]. Lacrimal gland acini were preincubated for 60 min with the myristoylated peptides (10(-10) to 3 x 10(-7) M), then protein secretion was stimulated with a phorbol ester, phorbol 12,13-dibutyrate (10(-6) M); vasoactive intestinal peptide (10(-8) M); a cholinergic agonist, carbachol (10(-5) M); or an alpha 1-adrenergic agonist, phenylephrine (10(-4) M), for 20 min. In intact lacrimal gland acini, Myr-PKC-alpha-(15-28) inhibited phorbol 12,13-dibutyrate-induced protein secretion. This effect was not reproduced by the acetylated peptide or by the myristoylated PKI, which inhibited vasoactive intestinal peptide-induced protein secretion, a response mediated by protein kinase A. Carbachol-induced protein secretion was inhibited by all three peptides. In contrast, phenylephrine-induced protein secretion was inhibited only by Myr-PKC-epsilon-(149-164), whereas Myr-PKC-alpha-(15-28) and Myr-PKC-delta-(142-153) had a stimulatory effect. None of these myristoylated peptides affected the calcium increase evoked by cholinergic or alpha 1-adrenergic agonists. We concluded that phorbol ester- and receptor-induced protein secretion involve different PKC isoforms in lacrimal gland.

  5. Tributyltin chloride increases phenylephrine-induced contraction and vascular stiffness in mesenteric resistance arteries from female rats.

    PubMed

    Ribeiro Júnior, Rogério Faustino; Marques, Vinicius Bermond; Nunes, Dieli Oliveira; Ronconi, Karoline de Sousa; de Araújo, Julia F P; Rodrigues, Paula Lopes; Padilha, Alessandra Simão; Vassallo, Dalton Valentim; Graceli, Jones B; Stefanon, Ivanita

    2016-03-15

    Tributyltin chloride (TBT) is an organotin compound that reduces estrogen levels in female rats. We aimed to investigate the effects of TBT exposure on vascular tonus and vascular remodelling in the resistance arteries of female rats. Rats were treated daily with TBT (500 ng/kg) for 15 days. TBT did not change arterial blood pressure but did modify some morpho-physiological parameters of third-order mesenteric resistance arteries in the following ways: (1) decreased lumen and external diameters; (2) increased wall/lm ratio and wall thickness; (3) decreased distensibility and increased stiffness; (4) increased collagen deposition; and (5) increased pulse wave velocity. TBT exposure increased the phenylephrine-induced contractile response in mesenteric resistance arteries. However, vasodilatation responses induced by acetylcholine and sodium nitroprusside were not modified by TBT. It is suggested that TBT exposure reduces vascular nitric oxide (NO) production, because:(1) L-NAME incubation did not cause a leftward shift in the concentration-response curve for phenylephrine; (2) both eNOS protein expression; (3) in situ NO production were reduced. Incubation with L-NAME; and (4) SOD shifted the phenylephrine response curve to the left in TBT rats. Tiron, catalase, ML-171 and VAS2870 decreased vascular reactivity to phenylephrine only in TBT rats. Moreover, increased superoxide anion production was observed in the mesenteric resistance arteries of TBT rats accompanied by an increase in gp91phox, catalase, AT1 receptor and total ERK1/2 protein expression. In conclusion, these findings show that TBT induced alterations are most likely due to a reduction of NO production combined with increased O2(-) production derived from NADPH oxidase and ERK1/2 activation. These findings offer further evidence that TBT is an environmental risk factor for cardiovascular disease.

  6. Comparison Between Phenylephrine and Dopamine in Maintaining Cerebral Oxygen Saturation in Thoracic Surgery: A Randomized Controlled Trial.

    PubMed

    Choi, Ji Won; Joo Ahn, Hyun; JooAhn, Hyun; Yang, Mikyung; Kim, Jie Ae; Lee, Sangmin M; Ahn, Jin Hee

    2015-12-01

    Fluid is usually restricted during thoracic surgery, and vasoactive agents are often administered to maintain blood pressure. One-lung ventilation (OLV) decreases arterial oxygenation; thus oxygen delivery to the brain can be decreased. In this study, we compared phenylephrine and dopamine with respect to maintaining cerebral oxygenation during OLV in major thoracic surgery.Sixty-three patients undergoing lobectomies were randomly assigned to the dopamine (D) or phenylephrine (P) group. The patients' mean arterial pressure was maintained within 20% of baseline by a continuous infusion of dopamine or phenylephrine. Maintenance fluid was kept at 5 mL/kg/h. The depth of anesthesia was maintained with desflurane 1MAC and remifentanil infusion under bispectral index guidance. Regional cerebral oxygen saturation (rScO2) and hemodynamic variables were recorded using near-infrared spectroscopy and esophageal cardiac Doppler.The rScO2 was higher in the D group than the P group during OLV (OLV 60 min: 71 ± 6% vs 63 ± 12%; P = 0.03). The number of patients whose rScO2 dropped more than 20% from baseline was 0 and 6 in the D and P groups, respectively (P = 0.02). The D group showed higher cardiac output, but lower mean arterial pressure than the P group (4.7 ± 1.0 vs 3.9 ± 1.2 L/min; 76.7 ± 8.1 vs 84.5 ± 7.5 mm Hg; P = 0.02, P = 0.02). Among the variables, age, hemoglobin concentration, and cardiac output were associated with rScO2 by correlation analysis.Dopamine was superior to phenylephrine in maintaining cerebral oxygenation during OLV in thoracic surgery.

  7. Ultrasound-assisted (R)-phenylephrine whole-cell bioconversion by S. marcescens N10612.

    PubMed

    Zang, Chi-Zong; Kan, Shu-Chen; Yeh, Chiung-Wen; Lin, Chia-Chi; Shieh, Chwen-Jen; Liu, Yung-Chuan

    2015-09-01

    The strain Serratia marcescens N10612 is used to perform the bioconversion of 1-(3-hydroxyphenyl)-2-(methyamino)-ethanone (HPMAE) to (R)-phenylephrine ((R)-PE), which is an ephedrine drug substitute. The use of an ultrasound approach is found to improve the efficiency of the (R)-PE bioconversion. The optimization of the (R)-PE bioconversion is carried out by means of statistical experiment design. The optimal conditions obtained are 1.0mM HPMAE, 18.68 g/L glucose and ultrasound power of 120 W, where the predicted specific rate of the (R)-PE bioconversion is 31.46 ± 2.22 (ìmol/h/g-cells) and the experimental specific rate is 33.27 ± 1.46 (ìmol/h/g-cells), which is 3-fold higher than for the operation under ultrasound power of 200 W (11.11 ìmol/h/g-cells) and 4.3-fold higher than for the shaking operation (7.69 ìmol/h/g-cells). The kinetics study of the bioconversion also shows that under the ultrasound operation, the optimal rate (Vmax) of the (R)-PE bioconversion increases from 7.69 to 11.11 (μmol/h/g-cells) and the substrate inhibition constant (KSi) increases from 1.063 mM for the shaking operation to 1.490 mM for ultrasound operation.

  8. Preparation and in vitro characterization of thermosensitive and mucoadhesive hydrogels for nasal delivery of phenylephrine hydrochloride.

    PubMed

    Xu, Xiaofeng; Shen, Yan; Wang, Wei; Sun, Chunmeng; Li, Chang; Xiong, Yerong; Tu, Jiasheng

    2014-11-01

    The aim of the present work was to develop a nasal delivery system of phenylephrine hydrochloride (PE) in spray form to make prolonged remedy of nasal congestion. The formulations contain the thermosensitive hydrogel, i.e., Poloxamer 407 (P407) and Poloxamer 188 (P188) mixtures, and mucoadhesives, i.e., ε-polylysine (ε-PL) and low molecular weight sodium hyaluronate (MW 11,000Da). The in vitro characterizations of formulations including rheology studies, texture profiles and in vitro mucoadhesion potential were investigated after gelation temperatures measurements. The results showed that the concentration of P407 or P188 had significant influence on gelation temperature and texture profiles. The addition of mucoadhesives, though lowered the gel strength of formulations, increased interaction with mucin. After screening, two formulations (i.e., 1.0% PE/0.5% ε-PL/17% P407/0.5% P188 or Formulation A; and 1.0% PE/0.5% HA/17% P407/0.8% P188 or Formulation B) presenting suitable gelation temperatures (∼32°C) were used for further studies on in vitro release behaviors and mucosa ciliotoxicity. Both formulations showed sustained release of PE for up to 8h and similar toxicity to saline, the negative control. Thus, the thermosensitive and mucoadhesive PE-containing hydrogels are promising to achieve prolonged decongestion in nasal cavity.

  9. Simultaneous determination of phenylephrine hydrochloride, guaifenesin, and chlorpheniramine maleate in cough syrup by gradient liquid chromatography.

    PubMed

    Amer, Sawsan M; Abbas, Samah S; Shehata, Mostafa A; Ali, Nahed M

    2008-01-01

    A simple and reliable high-performance liquid chromatographic method was developed for the simultaneous determination of mixture of phenylephrine hydrochloride (PHENYL), guaifenesin (GUAIF), and chlorpheniramine maleate (CHLO) either in pure form or in the presence of methylparaben and propylparaben in a commercial cough syrup dosage form. Separation was achieved on a C8 column using 0.005 M heptane sulfonic acid sodium salt (pH 3.4 +/- 0.1) and acetonitrile as a mobile phase by gradient elution at different flow rates, and detection was done spectrophotometrically at 210 nm. A linear relationship in the range of 30-180, 120-1800, and 10-60 microg/mL was obtained for PHENYL, GUAIF, and CHLO, respectively. The results were statistically analyzed and compared with those obtained by applying the British Pharmacopoeia (2002) method and showed that the proposed method is precise, accurate, and can be easily applied for the determination of the drugs under investigation in pure form and in cough syrup formulations.

  10. New approaches with two cyano columns to the separation of acetaminophen, phenylephrine, chlorpheniramine and related compounds.

    PubMed

    Olmo, B; García, A; Marín, A; Barbas, C

    2005-03-25

    The development of new pharmaceutical forms with classical active compounds generates new analytical problems. That is the case of sugar-free sachets of cough-cold products containing acetaminophen, phenylephrine hydrochloride and chlorpheniramine maleate. Two cyanopropyl stationary phases have been employed to tackle the problem. The Discovery cyanopropyl (SUPELCO) column permitted the separation of the three actives, maleate and excipients (mainly saccharine and orange flavour) with a constant proportion of aqueous/ organic solvent (95:5, v/v) and a pH gradient from 7.5 to 2. The run lasted 14 min. This technique avoids many problems related to baseline shifts with classical organic solvent gradients and opens great possibilities to modify selectivity not generally used in reversed phase HPLC. On the other hand, the Agilent Zorbax SB-CN column with a different retention profile permitted us to separate not only the three actives and the excipients but also the three known related compounds: 4-aminophenol, 4-chloracetanilide and 4-nitrophenol in an isocratic method with a run time under 30 min. This method was validated following ICH guidelines and validation parameters showed that it could be employed as stability-indicating method for this pharmaceutical form.

  11. Metformin-induced AMP-activated protein kinase activation regulates phenylephrine-mediated contraction of rat aorta.

    PubMed

    Sung, Jin Young; Choi, Hyoung Chul

    2012-05-11

    The aim of the present study is to determine the effects and molecular mechanisms by which activation of LKB1-AMP-activated protein kinase (AMPK) by metformin regulates vascular smooth muscle contraction. The essential ability of vascular smooth muscle cells (VSMCs) to contract and relax in response to an elevation and reduction in intravascular pressure is necessary for appropriate blood flow regulation. Thus, vessel contraction is a critical mechanism for systemic blood flow regulation. In cultured rat VSMCs, AMPK activation through LKB1 by metformin-inhibited phenylephrine-mediated myosin light chain kinase (MLCK) and myosin light chain phosphorylation (p-MLC). Conversely, inhibition of AMPK and LKB1 reversed phenylephrine-induced MLCK and p-MLC phosphorylation. Measurement of the tension trace in rat aortic rings also showed that the effect of AMPK activation by metformin decreased phenylephrine-induced contraction. Metformin inhibited PE-induced p-MLC and α-smooth muscle actin co-localization. Our results suggest that activation of AMPK by LKB1 decreases VSMC contraction by inhibiting MLCK and p-MLC, indicating that induction by the AMPK-LKB1 pathway may be a new therapeutic target to lower high blood pressure.

  12. Mesenteric artery responsiveness to acetylcholine and phenylephrine in cirrhotic rats challenged with endotoxin: the role of TLR4.

    PubMed

    Ostadhadi, Sattar; Rezayat, Seyed-Mahdi; Ejtemaei-Mehr, Shahram; Tavangar, Seyed-Mohammad; Nikoui, Vahid; Jazaeri, Farahnaz; Eftekhari, Golnar; Abdollahi, Alireza; Dehpour, Ahmad-Reza

    2015-06-01

    Cirrhosis is associated with vascular dysfunction and endotoxemia. These experiments were designed to investigate the hypothesis that the administration of a low-dose of lipopolysaccharide (LPS) worsens vascular dysfunction in rats subjected to bile-duct ligation (BDL), and to determine whether LPS initiates changes in vascular Toll-like receptor 4 (TLR4) expression. Four weeks after BDL, the animals were given an intraperitoneal injection of either saline or LPS (1.0 mg/kg body mass). Three hours later, the superior mesenteric artery was isolated, perfused, and then subjected to the vasoconstriction and vasodilatation effects of phenylephrine and acetylcholine, respectively. Our results show that phenylephrine-induced vasoconstriction decreased in the cirrhotic vascular bed (BDL rats) compared with the vascular bed of the sham-operated animals, and that the LPS injections in the cirrhotic (BDL) rats worsened this response. LPS injection administered to the sham-operated animals had no such effect. On the other hand, both the BDL procedure and the LPS injection increased acetylcholine-induced vasorelaxation, but LPS administration to the BDL rats had no effect on this response. The mRNA levels of TLR4 did not change, but immunohistochemical studies showed that TLR4 localization switched from the endothelium to vascular smooth muscle cells following chronic BDL. In conclusion, acute endotoxemia in cirrhotic rats is associated with hyporesponsiveness to phenylephrine and tolerance to the effects of acetylcholine. Altered localization of TLR4 may be responsible for these effects.

  13. Arg-Phe-amide-related peptides influence gonadotropin-releasing hormone neurons

    PubMed Central

    Kelestimur, Haluk; Kacar, Emine; Uzun, Aysegul; Ozcan, Mete; Kutlu, Selim

    2013-01-01

    The hypothalamic Arg-Phe-amide-related peptides, gonadotropin-inhibitory hormone and orthologous mammalian peptides of Arg-Phe-amide, may be important regulators of the hypothalamus-pituitary-gonadal reproductive axis. These peptides may modulate the effects of kisspeptins because they are presently recognized as the most potent activators of the hypothalamus-pituitary-gonadal axis. However, their effects on gonadotropin-releasing hormone neurons have not been investigated. In the current study, the GT1–7 cell line-expressing gonadotropin-releasing hormone was used as a model to explore the effects of Arg-Pheamide-related peptides on kisspeptin activation. Intracellular calcium concentration was quantified using the calcium-sensitive dye, fura-2 acetoxymethyl ester. Gonadotropin-releasing hormone released into the medium was detected via enzyme-linked immunosorbent assay. Results showed that 100 nmol/L kisspeptin-10 significantly increased gonadotropin-releasing hormone levels (at 120 minutes of exposure) and intracellular calcium concentrations. Co-treatment of kisspeptin with 1 μmol/L gonadotropin-inhibitory hormone or 1 μmol/L Arg-Phe-amide-related peptide-1 significantly attenuated levels of kisspeptin-induced gonadotropin-releasing hormone but did not affect kisspeptin-induced elevations of intracellular calcium concentration. Overall, the results suggest that gonadotropin-inhibitory hormone and Arg-Phe-amide-related peptide-1 may have inhibitory effects on kisspeptin-activated gonadotropin-releasing hormone neurons independent of the calcium signaling pathway. PMID:25206468

  14. Arg-Phe-amide-related peptides influence gonadotropin-releasing hormone neurons.

    PubMed

    Kelestimur, Haluk; Kacar, Emine; Uzun, Aysegul; Ozcan, Mete; Kutlu, Selim

    2013-06-25

    The hypothalamic Arg-Phe-amide-related peptides, gonadotropin-inhibitory hormone and orthologous mammalian peptides of Arg-Phe-amide, may be important regulators of the hypothalamus-pituitary-gonadal reproductive axis. These peptides may modulate the effects of kisspeptins because they are presently recognized as the most potent activators of the hypothalamus-pituitary-gonadal axis. However, their effects on gonadotropin-releasing hormone neurons have not been investigated. In the current study, the GT1-7 cell line-expressing gonadotropin-releasing hormone was used as a model to explore the effects of Arg-Pheamide-related peptides on kisspeptin activation. Intracellular calcium concentration was quantified using the calcium-sensitive dye, fura-2 acetoxymethyl ester. Gonadotropin-releasing hormone released into the medium was detected via enzyme-linked immunosorbent assay. Results showed that 100 nmol/L kisspeptin-10 significantly increased gonadotropin-releasing hormone levels (at 120 minutes of exposure) and intracellular calcium concentrations. Co-treatment of kisspeptin with 1 μmol/L gonadotropin-inhibitory hormone or 1 μmol/L Arg-Phe-amide-related peptide-1 significantly attenuated levels of kisspeptin-induced gonadotropin-releasing hormone but did not affect kisspeptin-induced elevations of intracellular calcium concentration. Overall, the results suggest that gonadotropin-inhibitory hormone and Arg-Phe-amide-related peptide-1 may have inhibitory effects on kisspeptin-activated gonadotropin-releasing hormone neurons independent of the calcium signaling pathway.

  15. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... epoxy adduct. 721.1850 Section 721.1850 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical... as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is subject to reporting under...

  16. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... epoxy adduct. 721.1850 Section 721.1850 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical... as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is subject to reporting under...

  17. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... epoxy adduct. 721.1850 Section 721.1850 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical... as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is subject to reporting under...

  18. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... epoxy adduct. 721.1850 Section 721.1850 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical... as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is subject to reporting under...

  19. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... epoxy adduct. 721.1850 Section 721.1850 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical... as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is subject to reporting under...

  20. Synthesis of a Gln-Phe hydroxy-ethylene dipeptide isostere.

    PubMed

    Haug, Bengt Erik; Rich, Daniel H

    2004-12-09

    [structure: see text] The protected Gln-Phe hydroxyethylene dipeptide isostere 1 was synthesized as a precursor for preparation of potential inhibitors of Botulinum neurotoxin B metalloprotease. The method allows for the synthesis of additional hydroxyethylene dipeptide isosteres such as 2 with functionalized P1 side chains. The isosteres prepared were coupled with a dipeptide to produce protected pseudotetrapeptide derivatives.

  1. Identification of a pheA gene associated with Streptococcus mitis by using suppression subtractive hybridization.

    PubMed

    Park, Hee Kuk; Dang, Hien Thanh; Myung, Soon Chul; Kim, Wonyong

    2012-04-01

    We performed suppression subtractive hybridization to identify genomic differences between Streptococcus mitis and Streptococcus pneumoniae. Based on the pheA gene, a primer set specific to S. mitis detection was found in 18 out of 103 S. mitis-specific clones. Our findings would be useful for discrimination of S. mitis from other closely related cocci in the oral environment.

  2. Melatonin agonists and insomnia.

    PubMed

    Ferguson, Sally A; Rajaratnam, Shantha M W; Dawson, Drew

    2010-02-01

    The ability of melatonin to shift biological rhythms is well known. As a result, melatonin has been used in the treatment of various circadian rhythm sleep disorders, such as advanced and delayed sleep phase disorders, jet lag and shiftwork disorder. The current evidence for melatonin being efficacious in the treatment of primary insomnia is less compelling. The development of agents that are selective for melatonin receptors provides opportunity to further elucidate the actions of melatonin and its receptors and to develop novel treatments for specific types of sleep disorders. The agonists reviewed here - ramelteon, tasimelteon and agomelatine - all appear to be efficacious in the treatment of circadian rhythm sleep disorders and some types of insomnia. However, further studies are required to understand the mechanisms of action, particularly for insomnia. Clinical application of the agonists requires a good understanding of their phase-dependent properties. Long-term effects of melatonin should be evaluated in large-scale, independent randomized controlled trials.

  3. 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. PMID:27713285

  4. Secondary Structures in Phe-Containing Isolated Dipeptide Chains: Laser Spectroscopy vs Quantum Chemistry.

    PubMed

    Loquais, Yohan; Gloaguen, Eric; Habka, Sana; Vaquero-Vara, Vanesa; Brenner, Valérie; Tardivel, Benjamin; Mons, Michel

    2015-06-11

    The intrinsic conformational landscape of two phenylalanine-containing protein chain models (-Gly-Phe- and -Ala-Phe- sequences) has been investigated theoretically and experimentally in the gas phase. The near UV spectroscopy (first ππ* transition of the Phe ring) is obtained experimentally under jet conditions where the conformational features can be resolved. Single-conformation IR spectroscopy in the NH stretch region is then obtained by IR/UV double resonance in the ground state, leading to resolved vibrational spectra that are assigned in terms of conformation and H-bonding content from comparison with quantum chemistry calculations. For the main conformer, whose UV spectrum exhibits a significant Franck-Condon activity in low frequency modes involving peptide backbone motions relative to the Phe chromophore, excited state IR spectroscopy has also been recorded in a UV/IR/UV experiment. The NH stretch spectral changes observed in such a ππ* labeling experiment enable us to determine those NH bonds that are coupled to the phenyl ring; they are compared to CC2 excited state calculations to quantify the geometry change upon ππ* excitation. The complete and consistent series of data obtained enable us to propose an unambiguous assignment for the gallery of conformers observed and to demonstrate that, in these two sequences, three conceptually important local structural motifs of proteins (β-strands, 27 ribbons, and β-turns) are represented. The satisfactory agreement between the experimental conformational distribution and the predicted landscape anticipated from the DFT-D approach demonstrates the capabilities of a theoretical method that accounts for dispersive interactions. It also shows that the flaws, inherent to a resonant two-photon ionization detection scheme, often evoked for aromatic chromophores, do not seem to be significant in the case of Phe.

  5. Effect of adrenergic agonists and antagonists on alanine amino transferase, fructose-1:6-bisphosphatase and glucose production in hepatocytes.

    PubMed

    Begum, N A; Datta, A G

    1992-08-18

    Using rat hepatocytes we confirmed our previous results that glucagon and beta-adrenergic agonists increased the enzyme activity of alanine aminotransferase (AAT) and propranolol abolished their effects. Only the enzyme activity was measured and other parameters like quantity of the enzyme or activation due to modification were not looked for. As in perfusion experiment phenylephrine and phenoxybenzamine (alpha-agonist and alpha-antagonist respectively) also alpha-antagonist respectively) also increased the AAT activity in isolated rat hepatocytes and propranolol reversed these effects. The additive effect of glucagon and phenoxybenzamine on AAT was also persistent in hepatocyte system. Fructose-1:6-bisphosphatase (Fru-P2-ase), another key enzyme in gluconeogenic pathway, was elevated by glucagon and other beta-adrenergic agonists both in liver perfusion and isolated hepatocyte experiments and was brought back to the normal level by propranolol. In this case also only the enzyme activity was measured and no other parameters were looked for. Unlike AAT this enzyme was not stimulated by phenylephrine or phenoxybenzamine. But AAT and Fru-P2-ase activities were increased significantly by adenylate cyclase activators like fluoride or forskolin. Thus, it appears that the regulation of fru-P2-ase by glucagon is purely a b-receptor mediated process whereas AAT activation shows a mixed type of regulation where some well known alpha-agonist and antagonists are behaving as beta-agonists. Results further indicate the presence of phosphodiesterase in hepatocyte membrane which was stimulated by glucagon and brought back to the normal level by propranolol. The different adrenergic compounds stated above, not only modified the activity of the above two enzymes but also stimulated glucose production by hepatocytes from alanine which was in turn abolished by propranolol as well as amino oxyacetate (AOA), a highly specified inhibitor of AAT. This confirm the participation of AAT in

  6. Phenylephrine alteration of cerebral blood flow during orthostasis: effect on n-back performance in chronic fatigue syndrome.

    PubMed

    Medow, Marvin S; Sood, Shilpa; Messer, Zachary; Dzogbeta, Seli; Terilli, Courtney; Stewart, Julian M

    2014-11-15

    Chronic fatigue syndrome (CFS) with orthostatic intolerance is characterized by neurocognitive deficits and impaired working memory, concentration, and information processing. In CFS, upright tilting [head-up tilt (HUT)] caused decreased cerebral blood flow velocity (CBFv) related to hyperventilation/hypocapnia and impaired cerebral autoregulation; increasing orthostatic stress resulted in decreased neurocognition. We loaded the baroreflex with phenylephrine to prevent hyperventilation and performed n-back neurocognition testing in 11 control subjects and 15 CFS patients. HUT caused a significant increase in heart rate (109.4 ± 3.9 vs. 77.2 ± 1.6 beats/min, P < 0.05) and respiratory rate (20.9 ± 1.7 vs. 14.2 ± 1.2 breaths/min, P < 0.05) and decrease in end-tidal CO2 (ETCO2; 42.8 ± 1.2 vs. 33.9 ± 1.1 Torr, P < 0.05) in CFS vs. control. HUT caused CBFv to decrease 8.7% in control subjects but fell 22.5% in CFS. In CFS, phenylephrine prevented the HUT-induced hyperventilation/hypocapnia and the significant drop in CBFv with HUT (-8.1% vs. -22.5% untreated). There was no difference in control subject n-back normalized response time (nRT) comparing supine to HUT (106.1 ± 6.9 vs. 97.6 ± 7.1 ms at n = 4), and no difference comparing control to CFS while supine (97.1 ± 7.1 vs 96.5 ± 3.9 ms at n = 4). However, HUT of CFS subjects caused a significant increase in nRT (148.0 ± 9.3 vs. 96.4 ± 6.0 ms at n = 4) compared with supine. Phenylephrine significantly reduced the HUT-induced increase in nRT in CFS to levels similar to supine (114.6 ± 7.1 vs. 114.6 ± 9.3 ms at n = 4). Compared with control subjects, CFS subjects are more sensitive both to orthostatic challenge and to baroreflex/chemoreflex-mediated interventions. Increasing blood pressure with phenylephrine can alter CBFv. In CFS subjects, mitigation of the HUT-induced CBFv decrease with phenylephrine has a beneficial effect on n-back outcome.

  7. G673 could be a novel mutational hot spot for intragenic suppressors of pheS5 lesion in Escherichia coli

    PubMed Central

    Ponmani, Thangaraj; Munavar, M Hussain

    2014-01-01

    The pheS5 Ts mutant of Escherichia coli defined by a G293 → A293 transition, which is responsible for thermosensitive Phenylalanyl-tRNA synthetase has been well studied at both biochemical and molecular level but genetic analyses pertaining to suppressors of pheS5 were hard to come by. Here we have systematically analyzed a spectrum of Temperature-insensitive derivatives isolated from pheS5 Ts mutant and identified two intragenic suppressors affecting the same base pair coordinate G673 (pheS19 defines G673 → T673; Gly225 → Cys225 and pheS28 defines G673 → C673; Gly225 → Arg225). In fact in the third derivative, the intragenic suppressor originally named pheS43 (G673 → C673transversion) is virtually same as pheS28. In the fourth case, the very pheS5 lesion itself has got changed from A293 → T293 (named pheS40). Cloning of pheS+, pheS5, pheS5-pheS19, pheS5-pheS28 alleles into pBR322 and introduction of these clones into pheS5 mutant revealed that excess of double mutant protein is not at all good for the survival of cells at 42°C. These results clearly indicate a pivotal role for Gly225 in the structural/functional integrity of alpha subunit of E. coli PheRS enzyme and it is proposed that G673 might define a hot spot for intragenic suppressors of pheS5. PMID:24811065

  8. Biosynthesis of wyosine derivatives in tRNA(Phe) of Archaea: role of a remarkable bifunctional tRNA(Phe):m1G/imG2 methyltransferase.

    PubMed

    Urbonavičius, Jaunius; Meškys, Rolandas; Grosjean, Henri

    2014-06-01

    The presence of tricyclic wyosine derivatives 3'-adjacent to anticodon is a hallmark of tRNA(Phe) in eukaryotes and archaea. In yeast, formation of wybutosine (yW) results from five enzymes acting in a strict sequential order. In archaea, the intermediate compound imG-14 (4-demethylwyosine) is a target of three different enzymes, leading to the formation of distinct wyosine derivatives (yW-86, imG, and imG2). We focus here on a peculiar methyltransferase (aTrm5a) that catalyzes two distinct reactions: N(1)-methylation of guanosine and C(7)-methylation of imG-14, whose function is to allow the production of isowyosine (imG2), an intermediate of the 7-methylwyosine (mimG) biosynthetic pathway. Based on the formation of mesomeric forms of imG-14, a rationale for such dual enzymatic activities is proposed. This bifunctional tRNA:m(1)G/imG2 methyltransferase, acting on two chemically distinct guanosine derivatives located at the same position of tRNA(Phe), is unique to certain archaea and has no homologs in eukaryotes. This enzyme here referred to as Taw22, probably played an important role in the emergence of the multistep biosynthetic pathway of wyosine derivatives in archaea and eukaryotes.

  9. The mu-opioid receptor antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP) [but not D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP)] produces a nonopioid receptor-mediated increase in K+ conductance of rat locus ceruleus neurons.

    PubMed

    Chieng, B; Connor, M; Christie, M J

    1996-09-01

    The somatostatin analogues D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP) and D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH2 (CTAP) have been used widely as selective antagonists of mu-opioid receptors. Actions of CTOP and CTAP on the membrane properties of rat locus ceruleus neurons were studied using intracellular recordings of membrane currents in superfused brain slices. CTOP increased a K+ conductance with an EC50 of 560 nM. The maximal conductance increase produced by CTOP (10 microM) was similar to that produced by high concentrations of the mu-opioid agonists D-Ala-Met-enkephalinglyol (1 microM) and Met-enkephalin (10 microM), as well as an alpha 2-adrenoceptor agonist (UK14304, 3 microM) and somatostatin (1 microM). The K+ current produced by CTOP was not antagonized by naloxone (1 microM), suggesting it was not mediated by mu-opioid receptors. The K+ currents induced by high concentrations of CTOP desensitized to 42% of the initial maximum after prolonged superfusion (t1/2 = 247 sec). In the presence of fully desensitized CTOP responses, somatostatin (1 microM) still produced near-maximal K+ currents; i.e., there was no cross-desensitization, which suggests that CTOP might act on a receptor distinct from somatostatin receptors. However, the converse did not apply; high concentrations of CTOP (30 microM) did not produce any additional current in the presence of desensitized somatostatin responses. No cross-desensitization was observed between CTOP (10-30 microM) and Met-enkephalin (30 microM) or nociceptin (3 microM) regardless of the order of drug application. Cyclo-(7-aminoheptanoyl-Phe-D-Trp-Lys-Thr[Bzl], antagonized both somatostatin-(KD = 10 microM) and CTOP-(KD = 8 microM) induced K+ currents with similar potency. Concentrations of CTOP (100 nM) that produced a small K+ current partially antagonized the actions of Met-enkephalin (10 microM) on mu-opioid receptors. In contrast to CTOP, CTAP produced no K+ current at concentrations of 300 nM and 1 microM and

  10. Lumacaftor/ivacaftor combination for cystic fibrosis patients homozygous for Phe508del-CFTR.

    PubMed

    Zhang, W; Zhang, X; Zhang, Y H; Strokes, D C; Naren, A P

    2016-04-01

    Cystic fibrosis (CF) is a life-shortening inherited disease caused by the loss or dysfunction of the CF transmembrane conductance regulator (CFTR) channel activity resulting from mutations in the CFTR gene. Phe508del is the most prevalent mutation, with approximately 90% of all CF patients carrying it on at least one allele. Over the past two or three decades, significant progress has been made in understanding the pathogenesis of CF, and in the development of effective CF therapies. The approval of Orkambi® (lumacaftor/ivacaftor) marks another milestone in CF therapeutics development, which, with the advent of personalized medicine, could potentially revolutionize CF care and management. This article reviews the rationale, progress and future direction in the development of lumacaftor/ivacaftor combination to treat CF patients homozygous for the Phe508del-CFTR mutation.

  11. Side chain and backbone contributions of Phe508 to CFTR folding

    SciTech Connect

    Thibodeau, Patrick H.; Brautigam, Chad A.; Machius, Mischa; Thomas, Philip J.

    2010-12-07

    Mutations in the cystic fibrosis transmembrane conductance regulator (CFTR), an integral membrane protein, cause cystic fibrosis (CF). The most common CF-causing mutant, deletion of Phe508, fails to properly fold. To elucidate the role Phe508 plays in the folding of CFTR, missense mutations at this position were generated. Only one missense mutation had a pronounced effect on the stability and folding of the isolated domain in vitro. In contrast, many substitutions, including those of charged and bulky residues, disrupted folding of full-length CFTR in cells. Structures of two mutant nucleotide-binding domains (NBDs) reveal only local alterations of the surface near position 508. These results suggest that the peptide backbone plays a role in the proper folding of the domain, whereas the side chain plays a role in defining a surface of NBD1 that potentially interacts with other domains during the maturation of intact CFTR.

  12. The Roles of Hemagglutinin Phe-95 in Receptor Binding and Pathogenicity of Influenza B Virus

    PubMed Central

    Ni, Fengyun; Mbawuike, Innocent Nnadi; Kondrashkina, Elena; Wang, Qinghua

    2014-01-01

    Diverged ~4,000 years ago, influenza B virus has several important differences from influenza A virus, including lower receptor-binding affinity and highly restricted host range. Based on our prior structural studies, we hypothesized that a single-residue difference in the receptor-binding site of hemagglutinin (HA), Phe-95 in influenza B virus versus Tyr-98 in influenza A/H1~H15, is possibly a key determinant for the low receptor-binding affinity. Here we demonstrate that the mutation Phe95→Tyr in influenza B virus HA restores all three hydrogen bonds made by Tyr-98 in influenza A/H3 HA and has the potential to enhance receptor binding. However, the full realization of this potential is influenced by the local environment into which the mutation is introduced. The binding and replication of the recombinant viruses correlate well with the receptor-binding capabilities of HA. These results are discussed in relation to the roles of Phe-95 in receptor binding and pathogenicity of influenza B virus. PMID:24503069

  13. 3,4-Phenylenedioxythiophene (PheDOT) Based Hole-Transporting Materials for Perovskite Solar Cells.

    PubMed

    Chen, Jian; Chen, Bai-Xue; Zhang, Fang-Shuai; Yu, Hui-Juan; Ma, Shuang; Kuang, Dai-Bin; Shao, Guang; Su, Cheng-Yong

    2016-04-05

    Two new electron-rich molecules based on 3,4-phenylenedioxythiophene (PheDOT) were synthesized and successfully adopted as hole-transporting materials (HTMs) in perovskite solar cells (PSCs). X-ray diffraction, absorption spectra, photoluminescence spectra, electrochemical properties, thermal stabilities, hole mobilities, conductivities, and photovoltaic parameters of PSCs based on these two HTMs were compared with each other. By introducing methoxy substituents into the main skeleton, the energy levels of PheDOT-core HTM were tuned to match with the perovskite, and its hole mobility was also improved (1.33×10(-4)  cm(2)  V(-1)  s(-1) , being higher than that of spiro-OMeTAD, 2.34×10(-5)  cm(2)  V(-1)  s(-1)). The PSC based on MeO-PheDOT as HTM exhibits a short-circuit current density (Jsc) of 18.31 mA cm(-2) , an open-circuit potential (Voc ) of 0.914 V, and a fill factor (FF) of 0.636, yielding an encouraging power conversion efficiency (PCE) of 10.64 % under AM 1.5G illumination. These results give some insight into how the molecular structures of HTMs affect their performances and pave the way for developing high-efficiency and low-cost HTMs for PSCs.

  14. The roles of hemagglutinin Phe-95 in receptor binding and pathogenicity of influenza B virus.

    PubMed

    Ni, Fengyun; Mbawuike, Innocent Nnadi; Kondrashkina, Elena; Wang, Qinghua

    2014-02-01

    Diverged ~4000 years ago, influenza B virus has several important differences from influenza A virus, including lower receptor-binding affinity and highly restricted host range. Based on our prior structural studies, we hypothesized that a single-residue difference in the receptor-binding site of hemagglutinin (HA), Phe-95 in influenza B virus versus Tyr-98 in influenza A/H1-H15, is possibly a key determinant for the low receptor-binding affinity. Here we demonstrate that the mutation Phe95→Tyr in influenza B virus HA restores all three hydrogen bonds made by Tyr-98 in influenza A/H1-15 HA and has the potential to enhance receptor binding. However, the full realization of this potential is influenced by the local environment into which the mutation is introduced. The binding and replication of the recombinant viruses correlate well with the receptor-binding capabilities of HA. These results are discussed in relation to the roles of Phe-95 in receptor binding and pathogenicity of influenza B virus.

  15. A mathematical model of tumour and blood pHe regulation: The HCO3-/CO2 buffering system.

    PubMed

    Martin, Natasha K; Gaffney, Eamonn A; Gatenby, Robert A; Gillies, Robert J; Robey, Ian F; Maini, Philip K

    2011-03-01

    Malignant tumours are characterised by a low, acidic extracellular pH (pHe) which facilitates invasion and metastasis. Previous research has proposed the potential benefits of manipulating systemic pHe, and recent experiments have highlighted the potential for buffer therapy to raise tumour pHe, prevent metastases, and prolong survival in laboratory mice. To examine the physiological regulation of tumour buffering and investigate how perturbations of the buffering system (via metabolic/respiratory disorders or changes in parameters) can alter tumour and blood pHe, we develop a simple compartmentalised ordinary differential equation model of pHe regulation by the HCO3-/CO2 buffering system. An approximate analytical solution is constructed and used to carry out a sensitivity analysis, where we identify key parameters that regulate tumour pHe in both humans and mice. From this analysis, we suggest promising alternative and combination therapies, and identify specific patient groups which may show an enhanced response to buffer therapy. In addition, numerical simulations are performed, validating the model against well-known metabolic/respiratory disorders and predicting how these disorders could change tumour pHe.

  16. Use of hollow microneedles for targeted delivery of phenylephrine to treat fecal incontinence.

    PubMed

    Jun, Hyesun; Han, Mee-Ree; Kang, Nae-Gyu; Park, Jung-Hwan; Park, Jung Ho

    2015-06-10

    A hollow microneedle (HM) was prepared to deliver a phenylephrine (PE) solution into the anal sphincter muscle as a method for treating fecal incontinence. The goal of this study was the local targeted delivery of PE into the sphincter muscle through the perianal skin with minimal pain using hollow microneedles, resulting in the increase of resting anal sphincter pressure. PE was administered on the left and the right sides of the anus of a rat through the perianal skin using 1.5mm long HM. An in vivo imaging system study was conducted after injection of Rhodamine B, and a histological study was performed after injection of gentian violet. The resting anal sphincter pressure in response to various drug doses was measured by using an air-charged catheter. Anal pressure change produced by HM administration was compared with change produced by intravenous injection (IV), subcutaneous (SC) injection and intramuscular (IM) injection. The change in mean blood pressure produced by HM administration as a function of PE dose was compared with change produced by PBS injection. A pharmacokinetic study of the new HM administration method was performed. A model drug solution was localized in the muscle layer under the perianal skin at the injection site and then diffused out over time. HM administration of PE induced significant contraction of internal anal sphincter pressure over 12h after injection, and the maximum anal pressure was obtained between 5 and 6h. Compared to IV, SC and IM treatments, HM treatment produced greater anal pressure. There was no increase in blood pressure after HM administration of PE within the range of predetermined concentration. Administration of 800μg/kg of PE using HM produced 0.81±0.38h of tmax. Our study suggests that HM administration enables local delivery of a therapeutic dose of PE to the anal sphincter muscle layer with less pain. This new treatment has great potential as a clinical application because of the ease of the procedure

  17. CaMKIIδ meditates phenylephrine induced cardiomyocyte hypertrophy through store-operated Ca(2+) entry.

    PubMed

    Ji, Yawei; Guo, Xin; Zhang, Zhe; Huang, Zhuyun; Zhu, Jianghua; Chen, Qing-Hui; Gui, Le

    Evidence suggests that store-operated Ca2+ entry (SOCE) is involved in the hypertrophy of cardiomyocytes. The signaling mechanisms of SOCE contributing to cardiac hypertrophy following phenylephrine (PE) stimulation are not fully understood. Ca(2+)/calmodulin-dependent protein kinase II δ (CaMKIIδ) plays an important role in regulating intracellular Ca(2+) hemostasis and function in the cardimyocytes. This study is aimed to determine the role of CaMKIIδ in regulating the PE-induced myocardial hypertrophy and the associated molecular signaling mechanisms. We used primary cultures of neonatal cardimyocytes isolated from the left ventricle of Sprague Dawley rats to investigate the effects of CaMKIIδ on myocardial hypertrophy and intracellular Ca(2+) mobilization. We found that the expression of CaMKIIδ was enhanced in PE-induced hypertrophic cardiomyocytes. CaMKIIδ siRNA, CaMKII inhibitor KN93, and SOCE blocker BTP2 attenuated the increase in the expression of CaMKIIδ and normalized the hypertrophic markers, atrial natriuretic peptide and brain natriuretic peptide, and size of cardiomyocytes induced by PE stimulation. The protein level of stromal interaction molecule 1 and Orai1, the essential components of the SOCE, is also enhanced in hypertrophic cardiomyocytes, which were normalized by CaMKIIδ siRNA and KN93 treatment. Hypertrophic cardiomyocytes showed an increase in the peak of Ca(2+) transient following store depletion, which was inhibited by SOCE blocker BTP2, CaMKIIδ siRNA, and KN93. The Ca(2+) currents through Ca(2+) release-activated Ca(2+) channels were increased in PE-treated cardiomyocytes and were attenuated by CaMKIIδ siRNA and KN93. These data indicate that PE-induced myocardial hypertrophy requires a complex signaling pathway that involves activation of both CaMKIIδ and SOCE. In conclusion, these studies reveal that up-regulation of CaMKIIδ may contribute to the PE-induced myocardial hypertrophy through the activation of SOCE expressed in

  18. Yeast tRNA(Phe) expressed in human cells can be selected by HIV-1 for use as a reverse transcription primer.

    PubMed

    Kelly, Nathan J; Morrow, Casey D

    2003-09-01

    All naturally occurring human immune deficiency viruses (HIV-1) select and use tRNA(Lys,3) as the primer for reverse transcription. Studies to elucidate the mechanism of tRNA selection from the intracellular milieu have been hampered due to the difficulties in manipulating the endogenous levels of tRNA(Lys,3). We have previously described a mutant HIV-1 with a primer binding site (PBS) complementary to yeast tRNA(Phe) (psHIV-Phe) that relies on transfection of yeast tRNA(Phe) for infectivity. To more accurately recapitulate the selection process, a cDNA was designed for the intracellular expression of the yeast tRNA(Phe). Increasing amounts of the plasmid encoding tRNA(Phe) resulted in a corresponding increase in levels of yeast tRNA(Phe) in the cell. The yeast tRNA(Phe) isolated from cells transfected with the cDNA for yeast tRNA(Phe), or in the cell lines expressing yeast tRNA(Phe), were aminoacylated, indicating that the expressed yeast tRNA(Phe) was incorporated into tRNA biogenesis pathways and translation. Increasing the cytoplasmic levels of tRNA(Phe) resulted in increased encapsidation of tRNA(Phe) in viruses with a PBS complementary to tRNA(Phe) (psHIV-Phe) or tRNA(Lys,3) (wild-type HIV-1). Production of infectious psHIV-Phe was dependent on the amount of cotransfected tRNA(Phe) cDNA. Increasing amounts of plasmids encoding yeast tRNA(Phe) produced an increase of infectious psHIV-Phe that plateaued at a level lower than that from the transfection of the wild-type genome, which uses tRNA(Lys,3) as the primer for reverse transcription. Cell lines were generated that expressed yeast tRNA(Phe) at levels approximately 0.1% of that for tRNA(Lys,3). Even with this reduced level of yeast tRNA(Phe), the cell lines complemented psHIV-Phe over background levels. The results of these studies demonstrate that intracellular levels of primer tRNA can have a direct effect on HIV-1 infectivity and further support the role for PBS-tRNA complementarity in the primer

  19. The effect of urapidil, an alpha-1 adrenoceptor antagonist and a 5-HT1A agonist, on the vascular tone of the porcine coronary and pulmonary arteries, the rat aorta and the human pulmonary artery.

    PubMed

    Bopp, Claire; Auger, Cyril; Diemunsch, Pierre; Schini-Kerth, Valérie

    2016-05-15

    Urapidil (Eupressyl(®)) an antihypertensive drug acting as an α1 antagonist and a 5-HT1A agonist, may be of special interest in the treatment of hypertension associated with preeclamptic toxaemia and hypoxia-induced pulmonary arterial vasoconstriction. However, the effect of urapidil on vascular tone has been poorly investigated. Vascular reactivity was evaluated using pulmonary and coronary arteries from 36 pigs, aortae from 22 rats and 9 human pulmonary artery samples suspended in organ chambers. Concentration-relaxation curves either to urapidil, 5-HT, or the 5-HT1A receptor agonist 8-OH-DPAT were constructed after pre-contraction of rings. Pig pulmonary and coronary artery rings were contracted with U46619, a thromboxane mimetic, rat aortic rings with either endothelin-1 or phenylephrine, and human pulmonary artery rings with U46619 or phenylephrine. Urapidil markedly inhibited phenylephrine-induced contractions in rat aortic rings with and without endothelium with a more pronounced effect observed in rings without endothelium. Both 5-HT and 8-OH-DPAT failed to induce relaxation in rat aortic rings with an intact endothelium. 5-HT, but not urapidil and 8-OH-DPAT, induced a concentration-dependent relaxation in the porcine coronary and pulmonary artery rings with an intact endothelium (P<0.05). 5-HT and phenylephrine but not urapidil caused concentration-dependent contractions in human pulmonary artery rings. The present findings, while confirming that urapidil is a potent inhibitor of α1-adrenoceptor-induced contraction, do not support the role of 5-HT1A receptor activation in the control of the vascular tone of the different types of arteries tested in response to urapidil. In addition, they indicate that urapidil seems to preferentially target arteries with endothelial dysfunction.

  20. Vascular Dysfunction in a Transgenic Model of Alzheimer's Disease: Effects of CB1R and CB2R Cannabinoid Agonists

    PubMed Central

    Navarro-Dorado, Jorge; Villalba, Nuria; Prieto, Dolores; Brera, Begoña; Martín-Moreno, Ana M.; Tejerina, Teresa; de Ceballos, María L.

    2016-01-01

    There is evidence of altered vascular function, including cerebrovascular, in Alzheimer's disease (AD) and transgenic models of the disease. Indeed vasoconstrictor responses are increased, while vasodilation is reduced in both conditions. β-Amyloid (Aβ) appears to be responsible, at least in part, of alterations in vascular function. Cannabinoids, neuroprotective and anti-inflammatory agents, induce vasodilation both in vivo and in vitro. We have demonstrated a beneficial effect of cannabinoids in models of AD by preventing glial activation. In this work we have studied the effects of these compounds on vessel density in amyloid precursor protein (APP) transgenic mice, line 2576, and on altered vascular responses in aortae isolated ring. First we showed increased collagen IV positive vessels in AD brain compared to control subjects, with a similar increase in TgAPP mice, which was normalized by prolonged oral treatment with the CB1/CB2 mixed agonist WIN 55,212-2 (WIN) and the CB2 selective agonist JWH-133 (JWH). In Tg APP mice the vasoconstriction induced by phenylephrine and the thromboxane agonist U46619 was significantly increased, and no change in the vasodilation to acetylcholine (ACh) was observed. Tg APP displayed decreased vasodilation to both cannabinoid agonists, which were able to prevent decreased ACh relaxation in the presence of Aβ. In summary, we have confirmed and extended the existence of altered vascular responses in Tg APP mice. Moreover, our results suggest that treatment with cannabinoids may ameliorate the vascular responses in AD-type pathology. PMID:27695396

  1. Novel Agonist Bioisosteres and Common Structure-Activity Relationships for The Orphan G Protein-Coupled Receptor GPR139

    PubMed Central

    Shehata, Mohamed A.; Nøhr, Anne C.; Lissa, Delphine; Bisig, Christoph; Isberg, Vignir; Andersen, Kirsten B.; Harpsøe, Kasper; Björkling, Fredrik; Bräuner-Osborne, Hans; Gloriam, David E.

    2016-01-01

    GPR139 is an orphan class A G protein-coupled receptor found mainly in the central nervous system. It has its highest expression levels in the hypothalamus and striatum, regions regulating metabolism and locomotion, respectively, and has therefore been suggested as a potential target for obesity and Parkinson’s disease. The two aromatic amino acids L-Trp and L-Phe have been proposed as putative endogenous agonists, and three structurally related benzohydrazide, glycine benzamide, and benzotriazine surrogate agonist series have been published. Herein, we assayed 158 new analogues selected from a pharmacophore model, and identified 12 new GPR139 agonists, containing previously untested bioisosteres. Furthermore, we present the first combined structure-activity relationships, and a refined pharmacophore model to serve as a rationale for future ligand identification and optimization. PMID:27830715

  2. [Dmt(1)]DALDA analogues with enhanced μ opioid agonist potency and with a mixed μ/κ opioid activity profile.

    PubMed

    Bai, Longxiang; Li, Ziyuan; Chen, Jiajia; Chung, Nga N; Wilkes, Brian C; Li, Tingyou; Schiller, Peter W

    2014-04-01

    Analogues of [Dmt(1)]DALDA (H-Dmt-d-Arg-Phe-Lys-NH2; Dmt=2',6'-dimethyltyrosine), a potent μ opioid agonist peptide with mitochondria-targeted antioxidant activity, were prepared by replacing Phe(3) with various 2',6'-dialkylated Phe analogues, including 2',6'-dimethylphenylalanine (Dmp), 2',4',6'-trimethylphenylalanine (Tmp), 2'-isopropyl-6'-methylphenylalanine (Imp) and 2'-ethyl-6'-methylphenylalanine (Emp), or with the bulky amino acids 3'-(1-naphthyl)alanine (1-Nal), 3'-(2-naphthyl)alanine (2-Nal) or Trp. Several compounds showed significantly increased μ agonist potency, retained μ receptor selectivity and are of interest as drug candidates for neuropathic pain treatment. Surprisingly, the Dmp(3)-, Imp(3)-, Emp(3)- and 1-Nal(3)-containing analogues showed much increased κ receptor binding affinity and had mixed μ/κ properties. In these cases, molecular dynamics studies indicated conformational preorganization of the unbound peptide ligands due to rotational restriction around the C(β)C(γ) bond of the Xxx(3) residue, in correlation with the observed κ receptor binding enhancement. Compounds with a mixed μ/κ opioid activity profile are known to have therapeutic potential for treatment of cocaine abuse.

  3. (/sup 3/H)(D-Ala2,NMePhe4,Gly-ol5)-enkephalin (mu-opioid) binding in beige-J mice

    SciTech Connect

    Raffa, R.B.; Baldy, W.J. Jr.; Shank, R.P.; Mathiasen, J.R.; Vaught, J.L.

    1988-05-01

    Tritiated (D-Ala2,NMePhe4,Gly-ol5)-enkephalin ((3H)DAGO) was used to examine mu-opioid receptor number and mu-ligand binding in brain synaptic membranes (P2 fraction) from C57BL/6J-bgJ/bgJ (beige-J) mice, a strain with combined deficiencies in immunological function (resembling Chediak-Higashi syndrome) and analgesic response to mu-opioid agonists such as morphine and DAGO. As controls, white mice, beige-J littermates (normally responsive to mu-opioid agonists), and a known mu-deficient strain (CXBK) were also examined. Neither the KD (0.47 to 0.49 nM) nor the Bmax (153 to 168 fmol/mg protein) determined for beige-J mice was significantly different from values determined for littermates or white mice. In contrast, the Bmax of CXBK mice (66 fmol/mg protein) was clearly less than that of the other strains. The analgesic defect of beige-J mice, therefore, is not likely due to an insufficient number of mu-opioid receptors, as it presumably is in CXBK mice. Carbachol (200 micrograms/ml), which partly corrects the analgesic defect of beige-J mice, had no effect on (3H)DAGO binding either acutely in vitro or chronically ex vivo after administration to beige-J mice for three weeks. Hence, the analgesic defect of beige-J mice appears to be due to some defect in the mu-opioid receptor-effector coupling mechanism or to some endogenous substance that inhibits binding of mu-opioid ligands to otherwise functional receptors.

  4. A close hidden stellar companion to the SX Phe-type variable star DW Psc

    SciTech Connect

    Qian, S.-B.; Li, L.-J.; Wang, S.-M.; He, J.-J.; Zhou, X.; Jiang, L.-Q.

    2015-01-01

    DW Psc is a high-amplitude SX Phe-type variable with a period of pulsation of 0.05875 days. Using a few newly determined times of maximum light together with those collected from the literature, the changes in the observed-calculated (O-C) diagram are analyzed. It is discovered that the O-C curve of DW Psc shows a cyclic variation with a period of 6.08 years and a semi-amplitude of 0.0066 days. The periodic variation is analyzed for the light travel time effect, which is due to the presence of a stellar companion (M{sub 2}sini∼0.45(±0.03) M{sub ⊙}). The two-component stars in the binary system are orbiting each other in an eccentric orbit (e ∼ 0.4) at an orbital separation of about 2.7(±0.3) AU. The detection of a close stellar companion to an SX Phe-type star supports the idea that SX Phe-type pulsating stars are blue stragglers that were formed from the merging of close binaries. The stellar companion has played an important role in the merging of the original binary by removing angular momentum from the central binary during early dynamical interaction or/and late dynamical evolution. After the more massive component in DW Psc evolves into a red giant, the cool close companion should help to remove the giant envelope via possible critical Roche-lobe overflow, and the system may be a progenitor of a cataclysmic variable. The detection of a close stellar companion to DW Psc makes it a very interesting system to study in the future.

  5. Agonist-activated ion channels

    PubMed Central

    Colquhoun, David

    2006-01-01

    This paper looks at ion channels as an example of the pharmacologist's stock in trade, the action of an agonist on a receptor to produce a response. Looked at in this way, ion channels have been helpful because they are still the only system which is simple enough for quantitative investigation of transduction mechanisms. A short history is given of attempts to elucidate what happens between the time when agonist first binds, and the time when the channel opens. PMID:16402101

  6. Alterations in phenylephrine-induced contractions and the vascular expression of Na+,K+-ATPase in ouabain-induced hypertension

    PubMed Central

    Rossoni, Luciana V; Salaices, Mercedes; Marín, Jesús; Vassallo, Dalton V; Alonso, María J

    2002-01-01

    Hypertension development, phenylephrine-induced contraction and Na+,K+-ATPase functional activity and protein expression in aorta (AO), tail (TA) and superior mesenteric (SMA) arteries from ouabain- (25 μg day−1, s.c., 5 weeks) and vehicle-treated rats were evaluated.Ouabain treatment increased systolic blood pressure (127±1 vs 160±2 mmHg, n=24, 35; P<0.001) while the maximum response to phenylephrine was reduced (P<0.01) in AO (102.8±3.9 vs 67.1±10.1% of KCl response, n=12, 9) and SMA (82.5±7.5 vs 52.2±5.8%, n=12, 9).Endothelium removal potentiated the phenylephrine response to a greater extent in segments from ouabain-treated rats. Thus, differences of area under the concentration-response curves (dAUC) in endothelium-denuded and intact segments for control and ouabain-treated rats were, respectively: AO, 56.6±9.6 vs 198.3±18.3 (n=9, 7); SMA, 85.5±15.4 vs 165.4±24.8 (n=6, 6); TA, 13.0±6.1 vs 39.5±10.4% of the corresponding control AUC (n=6, 6); P<0.05.The relaxation to KCl (1 – 10 mM) was similar in segments from both groups. Compared to controls, the inhibition of 0.1 mM ouabain on KCl relaxation was greater in AO (dAUC: 64.8±4.6 vs 84.0±5.1%, n=11, 14; P<0.05), similar in SMA (dAUC: 39.1±3.9 vs 43.3±7.8%, n=6, 7; P>0.05) and smaller in TA (dAUC: 62.1±5.5 vs 41.4±8.2%, n=12, 13; P<0.05) in ouabain-treated rats.Protein expression of both α1 and α2 isoforms of Na+,K+-ATPase was augmented in AO, unmodified in SMA and reduced in TA from ouabain-treated rats.These results suggest that chronic administration of ouabain induces hypertension and regional vascular alterations, the latter possibly as a consequence of the hypertension. PMID:11834625

  7. Oxidation of Phe454 in the Gating Segment Inactivates Trametes multicolor Pyranose Oxidase during Substrate Turnover

    PubMed Central

    Volc, Jindrich; Peterbauer, Clemens K.; Leitner, Christian; Haltrich, Dietmar

    2016-01-01

    The flavin-dependent enzyme pyranose oxidase catalyses the oxidation of several pyranose sugars at position C-2. In a second reaction step, oxygen is reduced to hydrogen peroxide. POx is of interest for biocatalytic carbohydrate oxidations, yet it was found that the enzyme is rapidly inactivated under turnover conditions. We studied pyranose oxidase from Trametes multicolor (TmPOx) inactivated either during glucose oxidation or by exogenous hydrogen peroxide using mass spectrometry. MALDI-MS experiments of proteolytic fragments of inactivated TmPOx showed several peptides with a mass increase of 16 or 32 Da indicating oxidation of certain amino acids. Most of these fragments contain at least one methionine residue, which most likely is oxidised by hydrogen peroxide. One peptide fragment that did not contain any amino acid residue that is likely to be oxidised by hydrogen peroxide (DAFSYGAVQQSIDSR) was studied in detail by LC-ESI-MS/MS, which showed a +16 Da mass increase for Phe454. We propose that oxidation of Phe454, which is located at the flexible active-site loop of TmPOx, is the first and main step in the inactivation of TmPOx by hydrogen peroxide. Oxidation of methionine residues might then further contribute to the complete inactivation of the enzyme. PMID:26828796

  8. Conformational studies of Phe-rich foldamers by VCD spectroscopy and ab initio calculations.

    PubMed

    Longhi, Giovanna; Abbate, Sergio; Lebon, France; Castellucci, Nicola; Sabatino, Piera; Tomasini, Claudia

    2012-07-20

    Employing VCD spectroscopy, we demonstrate that the structural behavior of the oligomers Boc-(L-Phe-L-Oxd)(n)-OBn is similar from n = 2 to n = 6; ab initio calculations for the n = 1 case provide physical insight into the conformational properties. Further information is gained by IR, (1)H NMR, and ECD spectroscopies. ECD spectra suggest the presence of different conformations between n = 1 on one side and longer chain foldamers on the other side. VCD and absorption IR spectra in methanol solutions can be interpreted as indicative of a PPII structure. In the case of Boc-L-Phe-L-Oxd-OBn, VCD spectra in CCl(4) and detailed DFT computational analysis allow one to demonstrate that the most populated conformers exhibit backbone dihedral angles similar to those of a PPII geometry. This is a remarkable outcome, as we had previously demonstrated that the Boc-(L-Ala-D-Oxd)(n)-OBn series folds in a β-band ribbon spiral that is a subtype of the 3(10) helix.

  9. Contribution of Gln9 and Phe80 to substrate binding in ribonuclease MC1 from bitter gourd seeds.

    PubMed

    Numata, T; Kimura, M

    2001-11-01

    Ribonuclease MC1 (RNase MC1) isolated from bitter gourd (Momordica charantia) seeds specifically cleaves phosphodiester bonds on the 5'-side of uridine. The crystal structures of RNase MC1 in complex with 2'-UMP or 3'-UMP reveal that Gln9, Asn71, Leu73, and Phe80 are involved in uridine binding by hydrogen bonding and hydrophobic interactions [Suzuki et al. (2000) Biochem. Biophys. Res. Commun. 275, 572-576]. To evaluate the contribution of Gln9 and Phe80 to uridine binding, Gln9 was replaced with Ala, Phe, Glu, or His, and Phe80 with Ala by site-directed mutagenesis. The kinetic properties of the resulting mutant enzymes were characterized using cytidylyl-3',5'-uridine (CpU) as a substrate. The mutant Q9A exhibited a 3.7-fold increased K(m) and 27.6-fold decreased k(cat), while three other mutations, Q9F, Q9E, and Q9H, predominantly affected the k(cat) value. Replacing Phe80 with Ala drastically reduced the catalytic efficiency (k(cat)/K(m)) with a minimum K(m) value equal to 8 mM. It was further found that the hydrolytic activities of the mutants toward cytidine-2',3'-cyclic monophosphate (cCMP) were reduced. These results demonstrate that Gln9 and Phe80 play essential roles not only in uridine binding but also in hydrolytic activity. Moreover, we produced double Ala substituted mutants at Gln9, Asn71, Leu73, and Phe80, and compared their kinetic properties with those of the corresponding single mutants. The results suggest that these four residues may contribute to uridine binding in a mutually independent manner.

  10. Pharmacological properties of novel cyclic pentapeptides with µ-opioid receptor agonist activity.

    PubMed

    Perlikowska, Renata; Piekielna, Justyna; Fichna, Jakub; do-Rego, Jean Claude; Toth, Geza; Janecki, Tomasz; Janecka, Anna

    2014-03-01

    In our previous paper we have reported the synthesis and biological activity of a cyclic analog, Tyr-c(D-Lys- Phe-Phe-Asp)-NH2, based on endomorphin-2 (EM-2) structure. This analog displayed high affinity for the µ-opioid receptor, was much more stable than EM-2 in rat brain homogenate and showed remarkable antinociceptive activity after intracerebroventricular (i.c.v.) injection. Even more importantly, the cyclic analog elicited weak analgesia also after peripheral administration, giving evidence that it was able to cross, at least to some extent, the blood-brain barrier (BBB). Here we describe further modifications of this analog aimed at enhancing brain delivery by increasing lipophilicity. Two new cyclic pentapeptides, Tyr-c(D-Lys-D-1-Nal-Phe-Asp)-NH2 and Tyr-c(D-Lys-D-2-Nal-Phe-Asp)-NH2 (where 1-Nal=1- naphthyl-3-alanine, 2-Nal=2-naphthyl-3-alanine) were synthesized and evaluated in biological assays. Both analogs showed high µ-opioid receptor affinity and agonist activity and were stable in the rat brain homogenates. Unfortunately, the increase of lipophilicity was achieved at the expense of water solubility. The analog with D-2-Nal residue showed strong analgesic effect when given i.c.v. but could not be tested after intravenous (i.v.) administration where higher concentrations of the compound are required. However, this analog showed inhibitory effect on gastrointestinal (GI) motility in vivo, providing an interesting approach to the development of peripherally restricted agents that could be useful for studying gastrointestinal disorders in animal models.

  11. Simultaneous spectrophotometric-multivariate calibration determination of several components of ophthalmic solutions: phenylephrine, chloramphenicol, antipyrine, methylparaben and thimerosal.

    PubMed

    Collado, M S; Mantovani, V E; Goicoechea, H C; Olivieri, A C

    2000-08-16

    The use of multivariate spectrophotometric calibration for the simultaneous determination of several active components and excipients in ophthalmic solutions is presented. The resolution of five-component mixtures of phenylephrine, chloramphenicol, antipyrine, methylparaben and thimerosal has been accomplished by using partial least-squares (PLS-1) and a variant of the so-called hybrid linear analysis (HLA). Notwithstanding the presence of a large number of components and their high degree of spectral overlap, they have been determined simultaneously with high accuracy and precision, with no interference, rapidly and without resorting to extraction procedures using non aqueous solvents. A simple and fast method for wavelength selection in the calibration step is presented, based on the minimisation of the predicted error sum of squares (PRESS) calculated as a function of a moving spectral window.

  12. Simultaneous high-performance liquid chromatographic determination of paracetamol, phenylephrine HCl, and chlorpheniramine maleate in pharmaceutical dosage forms.

    PubMed

    Senyuva, Hamide; Ozden, Tuncel

    2002-02-01

    A rapid, precise, and specific high-performance liquid chromatographic method is described for the simultaneous determination of paracetamol, phenylephrine HCI, and chlorpheniramine maleate in combined pharmaceutical dosage forms. The method involves the use of a microBondapak CN RP analytical column (125 A, 10 microm, 3.9 x 150 mm) at 22 degrees C as the stationary phase with the mixture of acetonitrile and phosphate buffer (pH 6.22, 78:22) as the mobile phase. Derivatization of the drugs is not required. The method is applied to commercial pediatric cough-cold syrups, tablets, and capsules marketed in Turkey. The relative standard deviation for 10 replicate measurements of each drug in the medicaments is always less than 2%.

  13. Denatonium and 6-n-Propyl-2-thiouracil, Agonists of Bitter Taste Receptor, Inhibit Contraction of Various Types of Smooth Muscles in the Rat and Mouse.

    PubMed

    Sakai, Hiroyasu; Sato, Ken; Kai, Yuki; Chiba, Yoshihiko; Narita, Minoru

    2016-01-01

    Recently the global expression of taste 2 receptors (TAS2Rs) on smooth muscle cells in human airways was demonstrated. Here, the effects of agonists of taste receptor, type 2, denatonium and 6-n-propyl-2-thiouracil, on smooth-muscle contraction were examined in the rat and mouse. Contractions induced by carbachol (CCh), high K(+), and sodium fluoride, but not calyculin-A, were inhibited significantly in the presence of a TAS2R agonist in the bronchial smooth muscle of mice. The contraction induced by CCh was inhibited by TAS2R agonists in ileal smooth muscle. Phenylephrine-induced contraction was also inhibited by TAS2R agonists in aortic smooth muscle. Gastrointestinal motility and blood pressure were attenuated by administration of TAS2R agonists in vivo. These findings suggest that TAS2R may be receptor for endogenous biologically active substances as well as for bitter tastes on the tongue. TAS2R signaling could be employed in the development of anti-asthmatic, anti-spasmodic, and anti-hypertensive drugs.

  14. Denatonium and 6-n-Propyl-2-thiouracil, Agonists of Bitter Taste Receptor, Inhibit Contraction of Various Types of Smooth Muscles in the Rat and Mouse.

    PubMed

    Sakai, Hiroyasu; Sato, Ken; Kai, Yuki; Chiba, Yoshihiko; Narita, Minoru

    2016-01-01

    Recently the global expression of taste 2 receptors (TAS2Rs) on smooth muscle cells in human airways was demonstrated. Here, the effects of agonists of taste receptor, type 2, denatonium and 6-n-propyl-2-thiouracil, on smooth-muscle contraction were examined in the rat and mouse. Contractions induced by carbachol (CCh), high K, and sodium fluoride, but not calyculin-A, were inhibited significantly in the presence of a TAS2R agonist in the bronchial smooth muscle of mice. The contraction induced by CCh was inhibited by TAS2R agonists in ileal smooth muscle. Phenylephrine-induced contraction was also inhibited by TAS2R agonists in aortic smooth muscle. Gastrointestinal motility and blood pressure were attenuated by administration of TAS2R agonists in vivo. These findings suggest that TAS2R may be receptor for endogenous biologically active substances as well as for bitter tastes on the tongue. TAS2R signaling could be employed in the development of anti-asthmatic, anti-spasmodic, and anti-hypertensive drugs.

  15. Cyclo(D-Tyr-D-Phe): a new antibacterial, anticancer, and antioxidant cyclic dipeptide from Bacillus sp. N strain associated with a rhabditid entomopathogenic nematode.

    PubMed

    Nishanth Kumar, S; Dileep, C; Mohandas, C; Nambisan, Bala; Ca, Jayaprakas

    2014-03-01

    A new microbial cyclic dipeptide (diketopiperazine), cyclo(D-Tyr-D-Phe) was isolated for the first time from the ethyl acetate extract of fermented modified nutrient broth of Bacillus sp. N strain associated with rhabditid Entomopathogenic nematode. Antibacterial activity of the compound was determined by minimum inhibitory concentration and agar disc diffusion method against medically important bacteria and the compound recorded significant antibacterial against test bacteria. Highest activity was recorded against Staphylococcus epidermis (1 µg/ml) followed by Proteus mirabilis (2 µg/ml). The activity of cyclo(D-Tyr-D-Phe) against S. epidermis is better than chloramphenicol, the standard antibiotics. Cyclo(D-Tyr-D-Phe) recorded significant antitumor activity against A549 cells (IC50 value: 10 μM) and this compound recorded no cytotoxicity against factor signaling normal fibroblast cells up to 100 μM. Cyclo(D-Tyr-D-Phe) induced significant morphological changes and DNA fragmentation associated with apoptosis in A549 cells. Acridine orange/ethidium bromide stained cells indicated apoptosis induction by cyclo(D-Tyr-D-Phe). Flow cytometry analysis showed that the cyclo(D-Tyr-D-Phe) did not induce cell cycle arrest. Effector molecule of apoptosis such as caspase-3 was found activated in treated cells, suggesting apoptosis as the main mode of cell death. Antioxidant activity was evaluated by free radical scavenging and reducing power activity, and the compound recorded significant antioxidant activity. The free radical scavenging activity of cyclo(D-Tyr-D-Phe) is almost equal to that of butylated hydroxyanisole, the standard antioxidant agent. We also compared the biological activity of natural cyclo(D-Tyr-D-Phe) with synthetic cyclo(D-Tyr-D-Phe) and cyclo(L-Tyr-L-Phe). Natural and synthetic cyclo(D-Tyr-D-Phe) recorded similar pattern of activity. Although synthetic cyclo(L-Tyr-L-Phe) recorded lower activity. But in the case of reducing power activity

  16. Adenosine-A1 receptor agonist induced hyperalgesic priming type II.

    PubMed

    Araldi, Dioneia; Ferrari, Luiz F; Levine, Jon D

    2016-03-01

    We have recently shown that repeated exposure of the peripheral terminal of the primary afferent nociceptor to the mu-opioid receptor (MOR) agonist DAMGO ([D-Ala, N-Me-Phe, Gly-ol]-enkephalin acetate salt) induces a model of transition to chronic pain that we have termed type II hyperalgesic priming. Similar to type I hyperalgesic priming, there is a markedly prolonged response to subsequent administration of proalgesic cytokines, prototypically prostaglandin E2 (PGE2). However, type II hyperalgesic priming differs from type I in being rapidly induced, protein kinase A (PKA), rather than PKCε dependent, not reversed by a protein translation inhibitor, occurring in female as well as in male rats, and isolectin B4-negative neuron dependent. We report that, as with the repeated injection of a MOR agonist, the repeated administration of an agonist at the A1-adenosine receptor, also a Gi-protein coupled receptor, N-cyclopentyladenosine (CPA), also produces priming similar to DAMGO-induced type II hyperalgesic priming. In this study, we demonstrate that priming induced by repeated exposure to this A1-adenosine receptor agonist shares the same mechanisms, as MOR-agonist induced priming. However, the prolongation of PGE2 hyperalgesia induced by repeated administration of CPA depends on G-protein αi subunit activation, differently from DAMGO-induced type II priming, in which it depends on the β/γ subunit. These data implicate a novel form of Gi-protein signaling pathway in the type II hyperalgesic priming induced by repeated administration of an agonist at A1-adenosine receptor to the peripheral terminal of the nociceptor.

  17. Adenosine-A1 Receptor Agonist Induced Hyperalgesic Priming Type II

    PubMed Central

    Araldi, Dioneia; Ferrari, Luiz F.; Levine, Jon D.

    2016-01-01

    We have recently shown that repeated exposure of the peripheral terminal of the primary afferent nociceptor to the mu-opioid receptor (MOR) agonist DAMGO ([D-Ala2, N-Me-Phe4, Gly5-ol]-Enkephalin acetate salt) induces a model of the transition to chronic pain that we have termed Type II hyperalgesic priming. Similar to Type I hyperalgesic priming, there is a markedly prolonged response to subsequent administration of proalgesic cytokines, prototypically prostaglandin E2 (PGE2). However, Type II hyperalgesic priming differs from Type I in being rapidly induced, protein kinase A (PKA), rather than PKCε dependent, not reversed by a protein translation inhibitor, occurring in female as well as in male rats, and isolectin B4-negative neuron dependent. We report that as with the repeated injection of a MOR agonist, the repeated administration of an agonist at the A1-adenosine receptor, also a Gi-protein coupled receptor, N6-Cyclopentyladenosine (CPA), also produces priming similar to DAMGO-induced Type II hyperalgesic priming. In this study we demonstrate that priming induced by repeated exposure to this A1-adenosine receptor agonist shares the same mechanisms as MOR-agonist induced priming. However, the prolongation of PGE2 hyperalgesia induced by repeated administration of CPA depends on G-protein αi subunit activation, differently from DAMGO-induced Type II priming, in which it depends on the β/γ subunit. These data implicate a novel form of Gi-protein signaling pathway in the Type II hyperalgesic priming induced by repeated administration of an agonist at A1-adenosine receptor to the peripheral terminal of the nociceptor. PMID:26588695

  18. Endomorphin 1[psi] and endomorphin 2[psi], endomorphins analogues containing a reduced (CH2NH) amide bond between Tyr1 and Pro2, display partial agonist potency but significant antinociception.

    PubMed

    Zhao, Qian-Yu; Chen, Qiang; Yang, Ding-Jian; Feng, Yun; Long, Yuan; Wang, Peng; Wang, Rui

    2005-07-22

    Endomorphin 1 (EM1) and endomorphin 2 (EM2) are highly potent and selective mu-opioid receptor agonists and have significant antinociceptive action. In the mu-selective pocket of endomorphins (EMs), Pro2 residue is a spacer and directs the Tyr1 and Trp3/Phe3 side chains into the required orientation. The present work was designed to substitute the peptide bond between Tyr1 and Pro2 of EMs with a reduced (CH2NH) bond and study the agonist potency and antinociception of EM1[psi] (Tyr[psi(CH2NH)]Pro-Trp-Phe-NH2) and EM2[psi] (Tyr[psi(CH2NH)]Pro-Phe-Phe-NH2). Both EM1[psi] and EM2[psi] are partial mu opioid receptor agonists showing significant loss of agonist potency in GPI assay. However, EMs[psi] exhibited potent supraspinal antinociceptive action in vivo. In the mice tail-flick test, EMs[psi] (1, 5, 10 nmol/mouse, i.c.v.) produced potent and short-lasting antinociception in a dose-dependent and naloxone (1 mg/kg) reversed manner. At the highest dose of 10 nmol, the effect of EM2[psi] was prolonged and more significant than that of EM2. In the rat model of formalin injection induced inflammatory pain, EMs[psi] (0.1, 1, 10 nmol/rat, i.c.v.), like EMs, exerted transient but not dose-dependent antinociception. These results suggested that in the mu-selective pocket of EMs, the rigid conformation induced by the peptide bond between Tyr1 and Pro2 is essential to regulate their agonist properties at the mu opioid receptors. However, the increased conformational flexibility induced by the reduced (CH2NH) bond made less influence on their antinociception.

  19. Hydrolysis of tRNA(sup Phe) on Suspensions of Amino Acids

    NASA Technical Reports Server (NTRS)

    Gao, Kui; Orgel, Leslie E.

    2001-01-01

    RNA is adsorbed strongly on suspensions of many moderately soluble organic solids. In some cases, the hydrolysis of tRNA(sup Phe) is greatly accelerated by adsorption, and the major sites of hydrolysis are changed from those that are important in homogeneous solution. Here we show that the hydrolysis is greatly accelerated by suspensions of aspartic acid and beta-glutamic acid but not by suspensions of alpha-glutamic acid, asparagine, or glutamine. The non-enzymatic hydrolysis of RNA has been studied extensively, especially because of its relevance to the mechanisms of action of ribozymes and to biotechnology and therapy. Many ribonucleases, ribozymes, and non-biological catalysts function via acid-base catalysis of an intramolecular transesterification mechanism in which the 2'-OH group attacks the adjacent phosphate group. The pentacoordinated phosphorane intermediate may collapse back to starting material, or yield isomerized or cleaved products.

  20. Molecular cloning and sequencing of pheU, a gene for Escherichia coli tRNAPhe.

    PubMed Central

    Schwartz, I; Klotsky, R A; Elseviers, D; Gallagher, P J; Krauskopf, M; Siddiqui, M A; Wong, J F; Roe, B A

    1983-01-01

    A recombinant plasmid (designated pID2) carrying the E. coli gene for tRNAPhe has been isolated from a plasmid bank constructed by the ligation of a total EcoRI digest of E. coli K12 DNA into the EcoRI site of pACYC184 DNA. The plasmid was selected by virtue of its ability to complement a temperature-sensitive lesion in the gene (PheS) for the alpha-subunit of phenylalanyl-tRNA synthetase. Crude tRNA isolated from such transformants exhibited elevated levels of phenylalanine acceptor activity. The tRNAPhe gene has been localized within the first 300 base pairs of a 3.6 kb SalI fragment of pID2. The sequence of the gene and its flanking regions is presented. Images PMID:6306588

  1. Decavanadate possesses alpha-adrenergic agonist activity and a structural motif common with trans-beta form of noradrenaline.

    PubMed

    Venkataraman, B V; Ravishankar, H N; Rao, A V; Kalyani, P; Sharada, G; Namboodiri, K; Gabor, B; Ramasarma, T

    1997-04-01

    Decavanadate, an inorganic polymer of vanadate, produced contraction of rat aortic rings at a relatively high concentration compared to phenylephrine, an agonist of alpha-adrenergic receptor. This effect was blocked by two known alpha-adrenergic receptor antagonists, prazosin and phenoxybenzamine. Decavanadate, formed by possible dimerization of V5 under acid conditions, possessed a structural feature of two pairs of unshared oxygen atoms at a distance of 3.12 A, not found in its constituents of V4 or V5. A structural motif of O..O..O using such oxygen atoms is recognized in decavanadate. This matches with a similar motif of N..O..O that uses the essential amino and hydroxyl groups of the side-chain and the m-hydroxyl group in trans-beta form of noradrenaline. The interaction of such a structural motif with the membrane receptor is likely to be the basis of the unusual noradrenaline-mimic action of decavanadate.

  2. Contribution of Phe-7 to Tat-dependent export of β-lactamase in Xanthomonas campestris.

    PubMed

    Lee, Chen-Wei; Tseng, Yi-Hsuan; Deng, Fu-Seng; Lin, Juey-Wen; Tseng, Yi-Hsiung; Weng, Shu-Fen

    2012-07-01

    Strains of Xanthomonas campestris pv. campestris isolated in Taiwan are commonly resistant to ampicillin owing to the constitutive expression of a chromosomally encoded β-lactamase that is secreted into the periplasm. In this study, we found that levels of β-lactamase vary among X. campestris pv. campestris strains, a difference that can be attributed to amino acid substitutions at least at positions 7 and 206, with the former having the major impact. Bioinformatic and PCR analyses indicated that X. campestris pv. campestris possesses tatABC genes and that the signal peptide of X. campestris pv. campestris pre-Bla contains the typical twin-arginine motif (N-R-R-Q-F-L at amino acid residues 3 to 8 in strain X. campestris pv. campestris strain 11), suggesting that Bla is secreted via the Tat pathway. To assess the importance of Phe(7) in the efficient export of X. campestris pv. campestris Bla, we prepared mutant constructs containing amino acid substitutions and monitored their expression by measuring enzyme activity and detecting Bla protein by Western blotting. The results indicate that replacement of Phe(7) with Leu severely inhibited Bla export whereas replacement with Pro almost abolished it. Although a change to Arg caused moderate inhibition of export, replacement with Tyr had no effect. These results suggest that for efficient export of Bla by X. campestris pv. campestris, the aromatic-aromatic interactions and stability of protein structure around the twin-arginine motif are important, since only proteins that can attain a folded state in the cytoplasm are competent for export via the Tat pathway.

  3. Effects of intracellular alkalinization on resting and agonist-induced vascular tone.

    PubMed

    Danthuluri, N R; Deth, R C

    1989-03-01

    To evaluate the influence of intracellular alkalinization on basal and agonist-induced vascular tone, we studied the effect of NH4Cl on rat aorta. NH4Cl induced a gradually developing contraction in a dose-dependent manner. Although the contractile response to 20 mM NH4Cl was associated with a latent period (LP) of 23.4 +/- 2.8 min, intracellular pH (pHi) measurements in cultured rat aortic smooth muscle cells showed that NH4Cl-induced intracellular alkalinization was immediate and transient, returning to basal pHi levels in about 30-35 min. Agents that elevate Ca2+, such as A23187 and high KCl, significantly reduced the LP associated with 20 mM NH4Cl-induced contraction. NH4Cl-induced contractions were sensitive to extracellular Ca2+ removal and to the addition of forskolin (1 microM); however, NH4Cl by itself did not cause Ca2+-influx as shown by 45Ca-uptake studies. Addition of 20 mM NH4Cl to precontracted tissues resulted in a transient relaxation, which was complete in approximately 10 min, followed by a contraction above the original level of tone. NH4Cl pretreatment caused time-dependent alterations in both the rapid and slow phases of phenylephrine and angiotensin II contractions. Rapid-phase of phenylephrine and angiotensin II contractions. Rapid-phase responses were diminished at shorter NH4Cl incubation times (10 min), whereas slow-phase response was augmented after a longer incubation (20 min). Overall, the vasorelaxant and vasoconstrictor effects induced by NH4Cl suggest a complex relationship between intracellular alkalinization and arterial contractility.

  4. cDNA and deduced amino acid sequence of human pulmonary surfactant-associated proteolipid SPL(Phe)

    SciTech Connect

    Glasser, S.W.; Korfhagen, T.R.; Weaver, T.; Pilot-Matias, T.; Fox, J.L.; Whitsett, J.A.

    1987-06-01

    Hydrophobic surfactant-associated protein of M/sub r/ 6000-14,000 was isolated from either/ethanol or chloroform/methanol extracts of mammalian pulmonary surfactant. Automated Edman degradation in a gas-phase sequencer showed the major N-terminus of the human low molecular weight protein to be Phe-Pro-Ile-Pro-Leu-Pro-Try-Cys-Trp-Leu-Cys-Arg-Ala-Leu-. Because of the N-terminal phenylalanine, the surfactant protein was designated SPL(Phe). Antiserum generated against hydrophobic surfactant protein(s) from bovine pulmonary surfactant recognized protein of M/sub r/ 6000-14,000 in immunoblot analysis and was used to screen a lambdagt11 expression library constructed from adult human lung poly(A)/sup +/ RNA. This resulted in identification of a 1.4-kilobase cDNA clone that was shown to encode the N-terminus of the surfactant polypeptide SPL(Phe) (Phe-Pro-Ile-Pro-Leu-Pro-) within an open reading frame for a larger protein. Expression of a fused ..beta..-galactosidase-SPL (Phe) gene in Escherichia coli yielded an immunoreactive M/sub r/ 34,000 fusion peptide. Hybrid-arrested translation with the cDNA and immunoprecipitation of (/sup 35/S)methionine-labeled in vitro translation products of human poly(A)/sup +/ RNA with a surfactant polyclonal antibody resulted in identification of a M/sub r/ 40,000 precursor protein. Blot hybridization analysis of electrophoretically fractionated RNA from human lung detected a 2.0-kilobase RNA that was more abundant in adult lung than in fetal lung. These proteins, and specifically SPL(Phe), may therefore be useful for synthesis of replacement surfactants for treatment of hyaline membrane disease in newborn infants or of other surfactant-deficient states.

  5. Accurate long-range coefficients for two excited like isotope He atoms: He(2 {sup 1}P)-He(2 {sup 1}P), He(2 {sup 1}P)-He(2 {sup 3}P), and He(2 {sup 3}P)-He(2 {sup 3}P)

    SciTech Connect

    Zhang, J.-Y.; Yan, Z.-C.; Vrinceanu, D.; Babb, J. F.; Sadeghpour, H. R.

    2007-07-15

    A general formalism is used to express the long-range potential energies in inverse powers of the separation distance between two like atomic or molecular systems with P symmetries. The long-range molecular interaction coefficients are calculated for the molecular symmetries {delta}, {pi}, and {sigma}, arising from the following interactions: He(2 {sup 1}P)-He(2 {sup 1}P), He(2 {sup 1}P)-He(2 {sup 3}P), and He(2 {sup 3}P)-He(2 {sup 3}P). The electric quadrupole-quadrupole term C{sub 5}, the van der Waals (dispersion) term C{sub 6}, and higher-order terms C{sub 8} and C{sub 10} are calculated ab initio using accurate variational wave functions in Hylleraas coordinates with finite nuclear mass effects. A comparison is made with previously published results where available.

  6. Crosslinking of elongation factor Tu to tRNA(Phe) by trans-diamminedichloroplatinum (II). Characterization of two crosslinking sites in the tRNA.

    PubMed Central

    Wikman, F P; Romby, P; Metz, M H; Reinbolt, J; Clark, B F; Ebel, J P; Ehresmann, C; Ehresmann, B

    1987-01-01

    Trans-diamminedichloroplatinum (II) was used to induce reversible crosslinks between EF-Tu and Phe-tRNA(Phe) within the ternary EF-Tu/GTP/Phe-tRNA(Phe) complex. Up to 40% of the complex was specifically converted into crosslinked species. Two crosslinking sites have been unambiguously identified. The major one encompassing nucleotides 58 to 65 is located in the 3'-part of the T-stem, and the minor one encompassing nucleotides 31 to 42 includes the anticodon loop and part of the 3'-strand of the anticodon stem. Images PMID:3302946

  7. Differential opioid agonist regulation of the mouse mu opioid receptor.

    PubMed

    Blake, A D; Bot, G; Freeman, J C; Reisine, T

    1997-01-10

    Mu opioid receptors mediate the analgesia induced by morphine. Prolonged use of morphine causes tolerance development and dependence. To investigate the molecular basis of tolerance and dependence, the cloned mouse mu opioid receptor with an amino-terminal epitope tag was stably expressed in human embryonic kidney (HEK) 293 cells, and the effects of prolonged opioid agonist treatment on receptor regulation were examined. In HEK 293 cells the expressed mu receptor showed high affinity, specific, saturable binding of radioligands and a pertussis toxin-sensitive inhibition of adenylyl cyclase. Pretreatment (1 h, 3 h, or overnight) of cells with 1 microM morphine or [D-Ala2MePhe4,Gly(ol)5]enkephalin (DAMGO) resulted in no apparent receptor desensitization, as assessed by opioid inhibition of forskolin-stimulated cAMP levels. In contrast, the morphine and DAMGO pretreatments (3 h) resulted in a 3-4-fold compensatory increase in forskolin-stimulated cAMP accumulation. The opioid agonists methadone and buprenorphine are used in the treatment of addiction because of a markedly lower abuse potential. Pretreatment of mu receptor-expressing HEK 293 cells with methadone or buprenorphine abolished the ability of opioids to inhibit adenylyl cyclase. No compensatory increase in forskolin-stimulated cAMP accumulation was found with methadone or buprenorphine; these opioids blocked the compensatory effects observed with morphine and DAMGO. Taken together, these results indicate that methadone and buprenorphine interact differently with the mouse mu receptor than either morphine or DAMGO. The ability of methadone and buprenorphine to desensitize the mu receptor and block the compensatory rise in forskolin-stimulated cAMP accumulation may be an underlying mechanism by which these agents are effective in the treatment of morphine addiction.

  8. Dopamine agonist therapy in hyperprolactinemia.

    PubMed

    Webster, J

    1999-12-01

    Introduction of the dopamine agonist bromocriptine heralded a major advance in the management of hyperprolactinemic disorders. Although its side effects of nausea, dizziness and headache and its short elimination half-life are limiting factors, its efficacy established it as a reference compound against the activity of which several dopamine agonists, like pergolide, lysuride, metergoline, terguride and dihydroergocristine, fell by the wayside. More recently, two new agents, cabergoline and quinagolide, have been introduced and appear to offer considerable advantages over bromocriptine. Cabergoline, an ergoline D2 agonist, has a long plasma half-life that enables once- or twice-weekly administration. Quinagolide, in contrast, is a nonergot D2 agonist with an elimination half-life intermediate between those of bromocriptine and cabergoline, allowing the drug to be administered once daily. Comparative studies indicate that cabergoline is clearly superior to bromocriptine in efficacy (prolactin suppression, restoration of gonadal function) and in tolerability. In similar studies, quinagolide appeared to have similar efficacy and superior tolerability to that of bromocriptine. Results of a small crossover study indicate that cabergoline is better tolerated, with a trend toward activity superior to that of quinagolide. In hyperprolactinemic men and in women not seeking to become pregnant, cabergoline may be regarded as the treatment of choice.

  9. N-formyl peptide receptors in human neutrophils display distinct membrane distribution and lateral mobility when labeled with agonist and antagonist

    PubMed Central

    1993-01-01

    Receptors for bacterial N-formyl peptides are instrumental for neutrophil chemotactic locomotion and activation at sites of infection. As regulatory mechanisms for signal transduction, both rapid coupling of the occupied receptor to cytoskeletal components, and receptor lateral redistribution, have been suggested (Jesaitis et al., 1986, 1989). To compare the distribution and lateral diffusion of the nonactivated and activated neutrophil N-formyl-peptide receptor, before internalization, we used a new fluorescent N-formyl-peptide receptor antagonist, tertbutyloxycarbonyl-Phe(D)-Leu-Phe(D)-Leu-Phe-OH (Boc- FLFLF, 0.1-1 microM), and the fluorescent receptor agonist formyl-Nle- Leu-Phe-Nle-Tyr-Lys (fnLLFnLYK, 0.1-1 microM). Fluorescent Boc-FLFLF did not elicit an oxidative burst in the neutrophil at 37 degrees C, as assessed by chemiluminescence and reduction of p-nitroblue tetrazolium chloride, but competed efficiently both with formyl-methionyl-leucyl- phenylalanine (fMLF) and fnLLFnLYK. It was not internalized, as evidenced by confocal microscopy and acid elution of surface bound ligand. The lateral mobility characteristics of the neutrophil fMLF receptor were investigated with the technique of FRAP. The diffusion coefficient (D) was similar for antagonist- and agonist-labeled receptors (D approximately 5 x 10(-10) cm2/s), but the fraction of mobile receptors was significantly lower in agonist- compared to antagonist-labeled cells, approximately 40% in contrast to approximately 60%. This reduction in receptor mobile fraction was slightly counteracted, albeit not significantly, by dihydrocytochalasin B (dhcB, 5 microM). To block internalization of agonist-labeled receptors, receptor mobility measurements were done at 14 degrees C. At this temperature, confocal microscopy revealed clustering of receptors in response to agonist binding, compared to a more uniform receptor distribution in antagonist-labeled cells. The pattern of agonist- induced receptor clustering was

  10. Influence of the dopamine receptor agonists fenoldopam and quinpirole in the rat superior mesenteric vascular bed.

    PubMed Central

    Dupont, A. G.; Lefebvre, R. A.; Vanderniepen, P.

    1987-01-01

    The effect of local administration of the dopamine 2 (DA2)-receptor agonist quinpirole and of the DA1-receptor agonist fenoldopam was studied in the in situ, constant flow autoperfused, superior mesenteric vascular bed of the rat. Local infusion of quinpirole (30 micrograms kg-1 min-1 for 5 min) had no effect on baseline perfusion pressure; it reduced the pressor responses to electrical stimulation (4 Hz, 1 ms, supramaximal voltage) of the periarterial sympathetic nerves to 45.6 +/- 2.1% of its original value but did not modify similar pressor responses produced by locally administered noradrenaline. The inhibitory effect of quinpirole was antagonized by the selective DA2-receptor antagonist domperidone (10 micrograms kg-1) but not by the selective DA1-receptor antagonist SCH 23390 (50 micrograms kg-1). Local infusion of fenoldopam (30 micrograms kg-1 min-1 for 5 min) reduced baseline perfusion pressure to 89.9 +/- 1.9%, increased the pressor response to electrical stimulation (4 Hz, 1 ms, supramaximal voltage) of the periarterial nerves to 134.7 +/- 14.0%, but reduced the pressor response to locally administered noradrenaline to 37.2 +/- 8.2%. Similar pressor responses induced by the selective alpha 1-adrenoceptor agonist phenylephrine were also reduced by fenoldopam (to 38.4 +/- 6.4%), but responses to locally administered angiotensin II were not modified. Pretreatment with SCH 23390 (50 micrograms kg-1) antagonized the effect of fenoldopam on baseline perfusion pressure, but had no influence on the effect of fenoldopam on responses to electrical stimulation or to noradrenaline. Pretreatment with the selective alpha 2-adrenoceptor antagonist rauwolscine (100 micrograms kg-1) had no effect on the reduction in baseline perfusion pressure induced by fenoldopam nor on its inhibitory effect on the response to noradrenaline, but it antagonized the stimulatory effect of fenoldopam on the response to electrical stimulation.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2886174

  11. Draft Genome Sequence of Comamonas thiooxydans Strain PHE2-6 (NBRC 110656), a Chlorinated-Ethene-Degrading Bacterium

    PubMed Central

    Shimodaira, Jun; Yonezuka, Kenta; Tabata, Michiro; Nagase, Shun; Kasai, Daisuke; Hosoyama, Akira; Yamazoe, Atsushi; Fujita, Nobuyuki

    2016-01-01

    Comamonas thiooxydans strain PHE2-6 (NBRC 110656), which was isolated from a trichloroethene-contaminated site in Japan, utilizes phenol as a sole source of carbon and cometabolizes cis- and trans-dichloroethenes. We report here the draft genome sequence of this strain, containing 5,309,680 bp, with 60.6% G+C content. PMID:27340052

  12. 40 CFR 721.7620 - Alkyl(heterocyclicyl) phe-nyl-azohetero monocyclic polyone, ((alkylimidazolyl) methyl) derivative...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-azohetero monocyclic polyone, ((alkylimidazolyl) methyl) derivative (generic name). 721.7620 Section 721... Alkyl(heterocyclicyl) phe-nyl-azohetero monocyclic polyone, ((alkylimidazolyl) methyl) derivative...) derivative (PMN P-86-136) is subject to reporting under this section for the significant new uses...

  13. 40 CFR 721.7620 - Alkyl(heterocyclicyl) phe-nyl-azohetero monocyclic polyone, ((alkylimidazolyl) methyl) derivative...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-azohetero monocyclic polyone, ((alkylimidazolyl) methyl) derivative (generic name). 721.7620 Section 721... Alkyl(heterocyclicyl) phe-nyl-azohetero monocyclic polyone, ((alkylimidazolyl) methyl) derivative...) derivative (PMN P-86-136) is subject to reporting under this section for the significant new uses...

  14. Description of two new alpha variants: Hb Canuts [alpha85(F6)Asp-->His (alpha1)] and Hb Ambroise Pare [alpha117(GH5)Phe-->Ile (alpha2)]; two new beta variants: Hb Beaujolais [beta84(EF8)Thr-->Asn] and Hb Monplaisir [beta147 (Tyr-Lys-Leu-Ala-Phe-Phe-Leu-Leu-Ser-Asn-Phe-Tyr-158-COOH)] and one new delta variant: Hb (A2)North Africa [delta59(E3)Lys-->Met].

    PubMed

    Joly, Philippe; Lacan, Philippe; Bererd, Martine; Garcia, Caroline; Zanella-Cleon, Isabelle; Becchi, Michel; Aubry, Martine; Couprie, Nicole; Francina, Alain

    2009-01-01

    We present here five new hemoglobin (Hb) variants which have been identified during routine Hb analysis before their genotypic characterization. Four of these result from a classical missense mutation: Hb Canuts [alpha85(F6)Asp-->His (alpha1)], Hb Ambroise Pare [alpha117(GH5)Phe-->Ile (alpha2)], Hb Beaujolais [beta84(EF8)Thr-->Asn] and HbA(2)-North Africa [delta59(E3)Lys-->Met]. The last one, Hb Monplaisir [beta147 (Tyr-Lys-Leu-Ala-Phe-Phe-Leu-Leu-Ser-Asn-Phe-Tyr-158-COOH)], results from a frameshift mutation at the stop codon of the beta-globin gene which leads to a modified C-terminal sequence in the beta-globin chain. None of these variants seem to have a particular clinical expression in the heterozygous state. The circumstances of the discovery of these five new Hb variants emphasize the fact that an association of techniques is necessary for a complete screening of Hb variants during routine Hb analysis. Globin chain separation by reversed phase liquid chromatography (RP-LC) appears to be the most relevant method.

  15. Crystallization and preliminary crystallographic analysis of the catechol 2,3-dioxygenase PheB from Bacillus stearothermophilus BR219

    SciTech Connect

    Sugimoto, Keisuke; Matsufuzi, Kazuki; Ohnuma, Hiroaki; Senda, Miki; Fukuda, Masao; Senda, Toshiya

    2006-02-01

    PheB, an extradiol-cleaving catecholic dioxygenase, was crystallized by the hanging-drop vapour-diffusion method using PEG 4000 as a precipitant. The crystal belongs to the orthorhombic system, space group P2{sub 1}2{sub 1}2{sub 1}, and diffracts to 2.3 Å resolution. Class II extradiol-cleaving catecholic dioxygenase, a key enzyme of aromatic compound degradation in bacteria, cleaves the aromatic ring of catechol by adding two O atoms. PheB is one of the class II extradiol-cleaving catecholic dioxygenases and shows a high substrate specificity for catechol derivatives, which have one aromatic ring. In order to reveal the mechanism of the substrate specificity of PheB, PheB has been crystallized by the hanging-drop vapour-diffusion method using PEG 4000 as a precipitant. The space group of the obtained crystal was P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 65.5, b = 119.2, c = 158.7 Å. The crystal diffracted to 2.3 Å resolution.

  16. PHENOME-WIDE INTERACTION STUDY (PheWIS) IN AIDS CLINICAL TRIALS GROUP DATA (ACTG)

    PubMed Central

    Verma, Shefali S.; Frase, Alex T.; Verma, Anurag; Pendergrass, Sarah A.; Mahony, Shaun; Haas, David W.; Ritchie, Marylyn D.

    2015-01-01

    Association studies have shown and continue to show a substantial amount of success in identifying links between multiple single nucleotide polymorphisms (SNPs) and phenotypes. These studies are also believed to provide insights toward identification of new drug targets and therapies. Albeit of all the success, challenges still remain for applying and prioritizing these associations based on available biological knowledge. Along with single variant association analysis, genetic interactions also play an important role in uncovering the etiology and progression of complex traits. For gene-gene interaction analysis, selection of the variants to test for associations still poses a challenge in identifying epistatic interactions among the large list of variants available in high-throughput, genome-wide datasets. Therefore in this study, we propose a pipeline to identify interactions among genetic variants that are associated with multiple phenotypes by prioritizing previously published results from main effect association analysis (genome-wide and phenome-wide association analysis) based on a-priori biological knowledge in AIDS Clinical Trials Group (ACTG) data. We approached the prioritization and filtration of variants by using the results of a previously published single variant PheWAS and then utilizing biological information from the Roadmap Epigenome project. We removed variants in low functional activity regions based on chromatin states annotation and then conducted an exhaustive pairwise interaction search using linear regression analysis. We performed this analysis in two independent pre-treatment clinical trial datasets from ACTG to allow for both discovery and replication. Using a regression framework, we observed 50,798 associations that replicate at p-value 0.01 for 26 phenotypes, among which 2,176 associations for 212 unique SNPs for fasting blood glucose phenotype reach Bonferroni significance and an additional 9,970 interactions for high

  17. Modulation of A10 dopamine neurons by gamma-aminobutyric acid agonists.

    PubMed

    Kalivas, P W; Duffy, P; Eberhardt, H

    1990-05-01

    Microinjection of the gamma-aminobutyric acidA agonist, muscimol, into the A10 region of the rat produced a dose-dependent increase in motor activity. This effect was antagonized by intra-A10 administration of the gamma-aminobutyric acidA antagonist, bicuculline, and by peripheral administration of haloperidol, and was associated with an increase in extracellular levels of dopamine metabolites in the nucleus accumbens. Although microinjection of the gamma-aminobutyric acidB agonist, baclofen, into the A10 region did not alter motor activity, it abolished the capacity of intra-A10 injection of mu opioid agonist, Tyr-D-Ala-Gly-MePhe-Gly(ol), or muscimol to increase motor activity. Baclofen also prevented the motor stimulant response to peripheral injection of cocaine or amphetamine, but was ineffective in blocking caffeine-induced behavioral activity. Pretreatment with baclofen prevented the capacity of a mu opioid agonist to elevate dopamine metabolite levels in the nucleus accumbens and prefrontal cortex in postmortem tissue. Baclofen also prevented the elevation of extracellular dopamine content in the nucleus accumbens produced by injection of a mu opioid agonist into the A10 region, as measured in the conscious rat with in vivo dialysis. Finally, when dopamine metabolite levels were elevated in the prefrontal cortex by mild footshock, it was shown that pretreatment with baclofen in the A10 region abolished this response. These data support electrophysiological studies suggesting that activation of gamma-aminobutyric acidB receptors on dopamine perikarya inhibits dopaminergic activity, while activation of gamma-aminobutyric acidA receptors results in an indirect disinhibition of dopaminergic function.

  18. Candida glabrata binds to glycosylated and lectinic receptors on the coronary endothelial luminal membrane and inhibits flow sense and cardiac responses to agonists.

    PubMed

    Torres-Tirado, David; Knabb, Maureen; Castaño, Irene; Patrón-Soberano, Araceli; De Las Peñas, Alejandro; Rubio, Rafael

    2016-01-01

    Candida glabrata (CG) is an opportunistic fungal pathogen that initiates infection by binding to host cells via specific lectin-like adhesin proteins. We have previously shown the importance of lectin-oligosaccharide binding in cardiac responses to flow and agonists. Because of the lectinic-oligosaccharide nature of CG binding, we tested the ability of CG to alter the agonist- and flow-induced changes in cardiac function in isolated perfused guinea pig hearts. Both transmission and scanning electron microscopy showed strong attachment of CG to the coronary endothelium, even after extensive washing. CG shifted the coronary flow vs. auricular-ventricular (AV) delay relationship upward, indicating that greater flow was required to achieve the same AV delay. This effect was completely reversed with mannose, partially reversed with galactose and N-acetylgalactosamine, but hyaluronan had no effect. Western blot analysis was used to determine binding of CG to isolated coronary endothelial luminal membrane (CELM) receptors, and the results indicate that flow-sensitive CELM receptors, ANG II type I, α-adrenergic 1A receptor, endothelin-2, and VCAM-1 bind to CG. In addition, CG inhibited agonist-induced effects of bradykinin, angiotensin, and phenylephrine on AV delay, coronary perfusion pressure, and left ventricular pressure. Mannose reversed the inhibitory effects of CG on the agonist responses. These results suggest that CG directly binds to flow-sensitive CELM receptors via lectinic-oligosaccharide interactions with mannose and disrupts the lectin-oligosaccharide binding necessary for flow-induced cardiac responses.

  19. Molecular docking of opiates and opioid peptides, a tool for the design of selective agonists and antagonists, and for the investigation of atypical ligand-receptor interactions.

    PubMed

    Gentilucci, L; Tolomelli, A; De Marco, R; Artali, R

    2012-01-01

    In the last years, molecular docking emerged as a powerful tool to investigate the interactions between opioid ligands and their receptors, thus driving the design and development of new selective agonists or antagonists of therapeutic interest. This review especially covers the most representative and recent comparative molecular docking analyses of structurally related compounds, as well as of agonists and antagonists within the active and inactive states of the receptors. The comparative analyses gave important information on the structural determinants responsible for the affinity and selectivity of the ligands, and defined the features responsible for the activation of the receptors. A special section is dedicated to the analyses of recently discovered, unusual agonists lacking of the tyramine pharmacophore, such as Salvinorin A, and the cyclopeptides which comprise the D-Trp-Phe pharmacophoric motif. For the atypical structure of these compounds, the docking proved to be essential to disclose how they interact with and activate the receptors.

  20. Efficient Activation of Pathogenic ΔPhe501 Mutation in Monocarboxylate Transporter 8 by Chemical and Pharmacological Chaperones.

    PubMed

    Braun, Doreen; Schweizer, Ulrich

    2015-12-01

    Monocarboxylate transporter 8 (MCT8) is a thyroid hormone transmembrane transporter expressed in many cell types, including neurons. Mutations that inactivate transport activity of MCT8 cause severe X-linked psychomotor retardation in male patients, a syndrome originally described as the Allan-Herndon-Dudley syndrome. Treatment options currently explored the focus on finding thyroid hormone-like compounds that bypass MCT8 and enter cells through different transporters. Because MCT8 is a multipass transmembrane protein, some pathogenic mutations affect membrane trafficking while potentially retaining some transporter activity. We explore here the effects of chemical and pharmacological chaperones on the expression and transport activity of the MCT8 mutant ΔPhe501. Dimethylsulfoxide, 4-phenylbutyric acid as well as its sodium salt, and the isoflavone genistein increase T3 uptake into MDCK1 cells stably transfected with mutant MCT8-ΔPhe501. We show that ΔPhe501 represents a temperature-sensitive mutant protein that is stabilized by the proteasome inhibitor MG132. 4-Phenylbutyrate has been used to stabilize ΔPhe508 mutant cystic fibrosis transmembrane conductance regulator protein and is in clinical use in patients with urea cycle defects. Genistein is enriched in soy and available as a nutritional supplement. It is effective in stabilizing MCT8-ΔPhe501 at 100 nM concentration. Expression of the L471P mutant is increased in response to phenylbutyrate, but T3 uptake activity is not induced, supporting the notion that the chaperone specifically increases membrane expression. Our findings suggest that certain pathogenic MCT8 mutants may be responsive to (co-)treatment with readily available compounds, which increase endogenous protein function.

  1. Enhanced bioconversion rate and released substrate inhibition in (R)-phenylephrine whole-cell bioconversion via partial acetone treatment.

    PubMed

    Kan, Shu-Chen; Zang, Chi-Zong; Yeh, Chiung-Wen; Chang, Wei-Feng; Lin, Chia-Chi; Hung, Tzu-Hsiang; Shieh, Chwen-Jen; Liu, Yung-Chuan

    2016-05-01

    An approach was developed to enhance the efficiency for the bioconversion of 1-(3-hydroxyphenyl)-2-(methyamino)-ethanone to (R)-phenylephrine. The strain Serratia marcescens N10612, giving the benefit of 99% enantiomeric excess in (R)-PE conversion, was used. The fermentation was devised to harvest cells with high hydrophobic prodigiosin content inside the cells. Then, the partial acetone extraction was applied to remove prodigiosin from the cells. The treatment was found to increase the cells conversion rate without loss of the cells NADPH redox system. When using 50% (v/v) acetone for 5min, the processed cells can give a specific conversion rate of 16.03μmol/h/g-cells. As compared the treated cells with cells under the basal medium, the maximum reaction rate (Vmax) increased from 6.69 to 10.27 (μmol/h/g-cells), the dissociation constant (Km) decreased from 0.236 to 0.167mM and the substrate inhibition constant (KSi) increased from 0.073 to 1.521mM. The 20-fold increase in substrate inhibition constant referred to a great release from the substrate inhibition for the use of S. marcescens N10612 in the bioconversion, which would greatly benefit the bioconversion to be industrialized.

  2. Early NADPH oxidase-2 activation is crucial in phenylephrine-induced hypertrophy of H9c2 cells.

    PubMed

    Hahn, Nynke E; Musters, René J P; Fritz, Jan M; Pagano, Patrick J; Vonk, Alexander B A; Paulus, Walter J; van Rossum, Albert C; Meischl, Christof; Niessen, Hans W M; Krijnen, Paul A J

    2014-09-01

    Reactive oxygen species (ROS) produced by different NADPH oxidases (NOX) play a role in cardiomyocyte hypertrophy induced by different stimuli, such as angiotensin II and pressure overload. However, the role of the specific NOX isoforms in phenylephrine (PE)-induced cardiomyocyte hypertrophy is unknown. Therefore we aimed to determine the involvement of the NOX isoforms NOX1, NOX2 and NOX4 in PE-induced cardiomyocyte hypertrophy. Hereto rat neonatal cardiomyoblasts (H9c2 cells) were incubated with 100 μM PE to induce hypertrophy after 24 and 48h as determined via cell and nuclear size measurements using digital imaging microscopy, electron microscopy and an automated cell counter. Digital-imaging microscopy further revealed that in contrast to NOX1 and NOX4, NOX2 expression increased significantly up to 4h after PE stimulation, coinciding and co-localizing with ROS production in the cytoplasm as well as the nucleus. Furthermore, inhibition of NOX-mediated ROS production with apocynin, diphenylene iodonium (DPI) or NOX2 docking sequence (Nox2ds)-tat peptide during these first 4h of PE stimulation significantly inhibited PE-induced hypertrophy of H9c2 cells, both after 24 and 48h of PE stimulation. These data show that early NOX2-mediated ROS production is crucial in PE-induced hypertrophy of H9c2 cells.

  3. Quantitative analysis of chlorpheniramine maleate and phenylephrine hydrochloride in nasal drops by differential-derivative spectrophotometric, zero-crossing first derivative UV spectrophotometric and absorbance ratio methods.

    PubMed

    Erk, N

    2000-11-01

    Three simple, rapid and accurate methods are described for the simultaneous determination of chlorpheniramine maleate and phenylephrine hydrochloride in two component mixtures. The first method comprised of measurement of difference absorptivities derivatized in first order of a nasal drops in 0.1 N NaOH relative to that of an equimolar solution in methanol at wavelengths of 271.6 and 250.2 nm, respectively. The second method, zero-crossing derivative spectrophotometry, is based on recording the first derivative curves and determining each component using the zero-crossing technique. Using first derivative spectrophotometry, the amplitudes in the first derivative spectra at 246.5 and 238.6 nm were selected to simultaneously determine chlorpheniramine maleate and phenylephrine hydrochloride in the mixture. The presence of identical zero-crossing points for pure drugs and nasal drop solutions established the non-interference of the excipients in the absorption at these wavelengths. Absorbance ratio method was also developed for a comparison method. The proposed procedures were successfully applied to the determination of chlorpheniramine maleate and phenylephrine hydrochloride in nasal drops, with a high percentage of recovery, good accuracy and precision.

  4. Nonpeptidic Lysosomal Modulators Derived from Z-Phe-Ala-Diazomethylketone for Treating Protein Accumulation Diseases

    PubMed Central

    2012-01-01

    Lysosomes are involved in protein turnover and removing misfolded species, and their enzymes have the potential to offset the defect in proteolytic clearance that contributes to the age-related dementia Alzheimer's disease (AD). The weak cathepsin B and L inhibitor Z-Phe-Ala-diazomethylketone (PADK) enhances lysosomal cathepsin levels at low concentrations, thereby eliciting protective clearance of PHF-τ and Aβ42 in the hippocampus and other brain regions. Here, a class of positive modulators is established with compounds decoupled from the cathepsin inhibitory properties. We utilized PADK as a departure point to develop nonpeptidic structures with the hydroxyethyl isostere. The first-in-class modulators SD1002 and SD1003 exhibit improved levels of cathepsin up-regulation but almost complete removal of cathepsin inhibitory properties as compared to PADK. Isomers of the lead compound SD1002 were synthesized, and the modulatory activity was determined to be stereoselective. In addition, the lead compound was tested in transgenic mice with results indicating protection against AD-type protein accumulation pathology. PMID:24900408

  5. Ligand Promiscuity of Aryl Hydrocarbon Receptor Agonists and Antagonists Revealed by Site-Directed Mutagenesis

    PubMed Central

    Soshilov, Anatoly A.

    2014-01-01

    The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that can be activated by structurally diverse chemicals. To examine the mechanisms responsible for the promiscuity in AhR ligand binding, we determined the effects of mutations within the AhR ligand-binding domain (LBD) on the activity of diverse AhR ligands. Site-directed mutagenesis identified Ile319 of the mouse AhR and, to a lesser extent, Phe318 as residues involved in ligand-selective modulation of AhR transformation using a panel of 12 AhR ligands. These ligands could be categorized into four distinct structurally related groups based on their ability to activate AhR mutants at position 319 in vitro. The mutation I319K was selectively activated by FICZ and not by other examined ligands in vitro and in cell culture. F318L and F318A mutations resulted in the conversion of AhR agonists β-naphthoflavone and 3-methylcholanthrene, respectively, into partial agonists/antagonists. Hsp90 binding to the AhR was decreased with several mutations and was inversely correlated with AhR ligand-binding promiscuity. Together, these data define overlapping amino acid residues within the AhR LBD involved in the selectivity of ligand binding, the agonist or antagonist mode of ligand binding, and hsp90 binding and provide insights into the ligand diversity of AhR activators. PMID:24591650

  6. Potential of Endophytic Bacterium Paenibacillus sp. PHE-3 Isolated from Plantago asiatica L. for Reduction of PAH Contamination in Plant Tissues

    PubMed Central

    Zhu, Xuezhu; Jin, Li; Sun, Kai; Li, Shuang; Ling, Wanting; Li, Xuelin

    2016-01-01

    Endophytes are ubiquitous in plants, and they may have a natural capacity to biodegrade polycyclic aromatic hydrocarbons (PAHs). In our study, a phenanthrene-degrading endophytic Paenibacillus sp. PHE-3 was isolated from P. asiatica L. grown in a PAH-contaminated site. The effects of environmental variables on phenanthrene biodegradation by strain PHE-3 were studied, and the ability of strain PHE-3 to use high molecular weight PAH (HMW-PAH) as a sole carbon source was also evaluated. Our results indicated that pH value of 4.0–8.0, temperature of 30 °C–42 °C, initial phenanthrene concentration less than 100 mg·L−1, and some additional nutrients are favorable for the biodegradation of phenanthrene by strain PHE-3. The maximum biodegradation efficiency of phenanthrene was achieved at 99.9% after 84 h cultivation with additional glutamate. Moreover, the phenanthrene biodegradation by strain PHE-3 was positively correlated with the catechol 2,3-dioxygenase activity (ρ = 0.981, p < 0.05), suggesting that strain PHE-3 had the capability of degrading HMW-PAHs. In the presence of other 2-, 3-ringed PAHs, strain PHE-3 effectively degraded HMW-PAHs through co-metabolism. The results of this study are beneficial in that the re-colonization potential and PAH degradation performance of endophytic Paenibacillus sp. PHE-3 may be applied towards reducing PAH contamination in plants. PMID:27347988

  7. Potential of Endophytic Bacterium Paenibacillus sp. PHE-3 Isolated from Plantago asiatica L. for Reduction of PAH Contamination in Plant Tissues.

    PubMed

    Zhu, Xuezhu; Jin, Li; Sun, Kai; Li, Shuang; Ling, Wanting; Li, Xuelin

    2016-06-24

    Endophytes are ubiquitous in plants, and they may have a natural capacity to biodegrade polycyclic aromatic hydrocarbons (PAHs). In our study, a phenanthrene-degrading endophytic Paenibacillus sp. PHE-3 was isolated from P. asiatica L. grown in a PAH-contaminated site. The effects of environmental variables on phenanthrene biodegradation by strain PHE-3 were studied, and the ability of strain PHE-3 to use high molecular weight PAH (HMW-PAH) as a sole carbon source was also evaluated. Our results indicated that pH value of 4.0-8.0, temperature of 30 °C-42 °C, initial phenanthrene concentration less than 100 mg·L(-1), and some additional nutrients are favorable for the biodegradation of phenanthrene by strain PHE-3. The maximum biodegradation efficiency of phenanthrene was achieved at 99.9% after 84 h cultivation with additional glutamate. Moreover, the phenanthrene biodegradation by strain PHE-3 was positively correlated with the catechol 2,3-dioxygenase activity (ρ = 0.981, p < 0.05), suggesting that strain PHE-3 had the capability of degrading HMW-PAHs. In the presence of other 2-, 3-ringed PAHs, strain PHE-3 effectively degraded HMW-PAHs through co-metabolism. The results of this study are beneficial in that the re-colonization potential and PAH degradation performance of endophytic Paenibacillus sp. PHE-3 may be applied towards reducing PAH contamination in plants.

  8. Novel diazabicycloalkane delta opioid agonists.

    PubMed

    Loriga, Giovanni; Lazzari, Paolo; Manca, Ilaria; Ruiu, Stefania; Falzoi, Matteo; Murineddu, Gabriele; Bottazzi, Mirko Emilio Heiner; Pinna, Giovanni; Pinna, Gérard Aimè

    2015-09-01

    Here we report the investigation of diazabicycloalkane cores as potential new scaffolds for the development of novel analogues of the previously reported diazatricyclodecane selective delta (δ) opioid agonists, as conformationally constrained homologues of the reference δ agonist (+)-4-[(αR)-α((2S,5R)-4-allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide (SNC80). In particular, we have simplified the diazatricyclodecane motif of δ opioid agonist prototype 1a with bridged bicyclic cores. 3,6-diazabicyclo[3.1.1]heptane, 3,8-diazabicyclo[3.2.1]octane, 3,9-diazabicyclo[3.3.1]nonane, 3,9-diazabicyclo[4.2.1]nonane, and 3,10-diazabicyclo[4.3.1]decane were adopted as core motifs of the novel derivatives. The compounds were synthesized and biologically assayed as racemic (3-5) or diastereoisomeric (6,7) mixtures. All the novel compounds 3-7 showed δ agonism behaviour and remarkable affinity to δ receptors. Amongst the novel derivatives, 3,8-diazabicyclo[3.2.1]octane based compound 4 evidenced improved δ affinity and selectivity relative to SNC80.

  9. Idiosyncrasy and identity in the prokaryotic phe-system: Crystal structure of E. coli phenylalanyl-tRNA synthetase complexed with phenylalanine and AMP

    PubMed Central

    Mermershtain, Inbal; Finarov, Igal; Klipcan, Liron; Kessler, Naama; Rozenberg, Haim; Safro, Mark G

    2011-01-01

    The crystal structure of Phenylalanyl-tRNA synthetase from E. coli (EcPheRS), a class II aminoacyl-tRNA synthetase, complexed with phenylalanine and AMP was determined at 3.05 Å resolution. EcPheRS is a (αβ)2 heterotetramer: the αβ heterodimer of EcPheRS consists of 11 structural domains. Three of them: the N-terminus, A1 and A2 belong to the α-subunit and B1-B8 domains to the β subunit. The structure of EcPheRS revealed that architecture of four helix-bundle interface, characteristic of class IIc heterotetrameric aaRSs, is changed: each of the two long helices belonging to CLM transformed into the coil-short helix structural fragments. The N-terminal domain of the α-subunit in EcPheRS forms compact triple helix domain. This observation is contradictory to the structure of the apo form of TtPheRS, where N-terminal domain was not detected in the electron density map. Comparison of EcPheRS structure with TtPheRS has uncovered significant rearrangements of the structural domains involved in tRNAPhe binding/translocation. As it follows from modeling experiments, to achieve a tighter fit with anticodon loop of tRNA, a shift of ∼5 Å is required for C-terminal domain B8, and of ∼6 to 7 Å for the whole N terminus. EcPheRSs have emerged as an important target for the incorporation of novel amino acids into genetic code. Further progress in design of novel compounds is anticipated based on the structural data of EcPheRS. PMID:21082706

  10. Structural and thermodynamic analysis of the binding of tRNA(phe) by the putative anticancer alkaloid chelerythrine: Spectroscopy, calorimetry and molecular docking studies.

    PubMed

    Basu, Pritha; Payghan, Pavan V; Ghoshal, Nanda; Suresh Kumar, Gopinatha

    2016-08-01

    The interaction of the putative anticancer alkaloid chelerythrine with tRNA(phe) was characterized by spectroscopy, calorimetry and molecular docking studies. The charged iminium form of chelerythrine binds with tRNA(phe) in a cooperative mode with a binding affinity value of (4.06±0.01)×10(5)M(-1). The neutral alkanolamine form does not bind to tRNA(phe) but in the presence of high concentration of tRNA(phe) this form gets converted to the iminium form and then binds with tRNA(phe). The partial intercalative mode of binding of chelerythrine to the tRNA(phe) was characterized from the steady state anisotropy, iodide ion-induced fluorescence quenching and viscosity measurements. Chelerythrine binding induced conformational perturbations in tRNA(phe) as observed from the circular dichroism spectroscopy. The strong binding was also supported by the ethidium bromide displacement assay. The binding was favoured by both enthalpy and entropy contributions. Although the binding was dependent on the [Na(+)], non-electrostatic forces contributed predominantly to the Gibbs energy change. The negative value of the heat capacity change proposed the involvement of hydrophobic forces in the binding. Molecular docking study was carried out to decipher the details of the recognition of tRNA(phe) by chelerythrine. The study provided insights about the chelerythrine binding pockets on tRNA(phe) and marked the necessary interactions for binding of chelerythrine molecule. Partially intercalative mode of the alkaloid binding was supported by docking studies. In total, docking studies corroborated well with our experiential observations. The structural and thermodynamic results of chelerythrine binding to tRNA(phe) may be helpful to develop new RNA therapeutic agents.

  11. Design and synthesis of potent bradykinin agonists containing a benzothiazepine moiety.

    PubMed

    Amblard, M; Daffix, I; Bedos, P; Bergé, G; Pruneau, D; Paquet, J L; Luccarini, J M; Bélichard, P; Dodey, P; Martinez, J

    1999-10-07

    A bradykinin analogue (H-Arg-Pro-Pro-Gly-Phe-Ser-D-BT-Arg-OH, 3) in which the Pro-Phe dipeptide was replaced by the (3S)[amino]-5-(carbonylmethyl)-2,3-dihydro-1, 5-benzothiazepin-4(5H)-one (D-BT) moiety has been synthesized. The same modification was performed on the potent bradykinin B(2) receptor antagonist HOE 140 (H-D-Arg-Arg-Pro-Hyp-Gly-Thi-Ser-D-Tic-Oic-Arg-OH), in which the -D-Tic-Oic- moiety was replaced by D-BT to yield H-D-Arg-Arg-Pro-Hyp-Gly-Thi-Ser-D-BT-Arg-OH, 1 (JMV1116). These compounds were examined in vitro for their binding affinity toward bradykinin B(1) and B(2) receptors as well as for their ability to interfere with bradykinin-induced contraction of both human umbilical vein and rat uterus. The two compounds 3 and 1 competed with [(3)H]bradykinin binding to the human cloned B(2) receptor giving K(i) values of 13 +/- 2 and 0.7 +/- 0.1 nM, respectively. Unexpectedly, both compounds were full bradykinin B(2) receptor agonists on the human umbilical vein (pD(2) = 6.60 +/- 0.07 for 3 and 6.80 +/- 0.08 for 1) and rat uterus (pD(2) = 7.20 +/- 0.09 for 3 and 7.50 +/- 0.09 for 1) preparations with the same efficacy as bradykinin. In addition 1 induced a concentration-dependent phosphoinositide production in CHO cells expressing the human cloned B(2) receptor. These data provide evidence for a bioactive conformation of bradykinin constrained at the dipeptide Pro-Phe.

  12. Regulation of membrane cholecystokinin-2 receptor by agonists enables classification of partial agonists as biased agonists.

    PubMed

    Magnan, Rémi; Masri, Bernard; Escrieut, Chantal; Foucaud, Magali; Cordelier, Pierre; Fourmy, Daniel

    2011-02-25

    Given the importance of G-protein-coupled receptors as pharmacological targets in medicine, efforts directed at understanding the molecular mechanism by which pharmacological compounds regulate their presence at the cell surface is of paramount importance. In this context, using confocal microscopy and bioluminescence resonance energy transfer, we have investigated internalization and intracellular trafficking of the cholecystokinin-2 receptor (CCK2R) in response to both natural and synthetic ligands with different pharmacological features. We found that CCK and gastrin, which are full agonists on CCK2R-induced inositol phosphate production, rapidly and abundantly stimulate internalization. Internalized CCK2R did not rapidly recycle to plasma membrane but instead was directed to late endosomes/lysosomes. CCK2R endocytosis involves clathrin-coated pits and dynamin and high affinity and prolonged binding of β-arrestin1 or -2. Partial agonists and antagonists on CCK2R-induced inositol phosphate formation and ERK1/2 phosphorylation did not stimulate CCK2R internalization or β-arrestin recruitment to the CCK2R but blocked full agonist-induced internalization and β-arrestin recruitment. The extreme C-terminal region of the CCK2R (and more precisely phosphorylatable residues Ser(437)-Xaa(438)-Thr(439)-Thr(440)-Xaa(441)-Ser(442)-Thr(443)) were critical for β-arrestin recruitment. However, this region and β-arrestins were dispensable for CCK2R internalization. In conclusion, this study allowed us to classify the human CCK2R as a member of class B G-protein-coupled receptors with regard to its endocytosis features and identified biased agonists of the CCK2R. These new important insights will allow us to investigate the role of internalized CCK2R·β-arrestin complexes in cancers expressing this receptor and to develop new diagnosis and therapeutic strategies targeting this receptor.

  13. "PHE in Action": Development and Modeling of an Intervention to Improve Patient Engagement among Older Adults.

    PubMed

    Menichetti, Julia; Graffigna, Guendalina

    2016-01-01

    The increasing prevalence of chronic conditions among older adults constitutes a major public health problem. Thus, changes in lifestyles are required to prevent secondary conditions and sustain good care practices. While patient engagement received great attention in the last years as key strategy to solve this issue, to date no interventions exist to sustain the engagement of older chronic patients toward their health management. This study describes the design, development, and optimization of PHEinAction, a theoretically-driven intervention program to increase patient engagement in older chronic populations and consequently to foster healthy changes that can help reduce risks of health problems. The development process followed the UK Medical Research Council's (MRC) guidelines and involved selecting the theoretical base for the intervention, identifying the relevant evidence-based literature, and conducting exploratory research to qualitatively evaluate program's feasibility, acceptability, and comprehension. The result was a user-endorsed intervention designed to improve older patients' engagement in health management based on the theoretical framework of the Patient Health Engagement (PHE) model. The intervention program, which emerged from this process, consisted of 2 monthly face-to-face 1-h sessions delivered by a trained facilitator and one brief telephonic consultation, and aimed to facilitate a range of changes for patient engagement (e.g., motivation to change, health information seeking and use, emotional adjustment, health behaviors planning). PHEinAction is the first example of a theoretically-based patient engagement intervention designed for older chronic targets. The intervention program is based on psychological theory and evidence; it facilitates emotional, psychological, and behavioral processes to support patient engagement and lifestyle change and maintenance. It provides estimates of the extent to which it could help high-risk groups

  14. Vasodilation in response to the GPR30 agonist G-1 is not different from estradiol in the mRen2.Lewis female rat.

    PubMed

    Lindsey, Sarah H; Carver, Kyle A; Prossnitz, Eric R; Chappell, Mark C

    2011-05-01

    Our studies in the mRen2.Lewis female rat, an angiotensin II- and estrogen-dependent model of hypertension, revealed that chronic activation of estrogen receptor GPR30 markedly reduces blood pressure in ovariectomized females. The present studies measured acute vasodilation to the selective GPR30 agonist G-1 and 17-β-estradiol (10(-9)-10(-5.5) M) in isolated aortic rings and mesenteric arteries from intact mRen2.Lewis females. Maximal relaxation was greater in mesenteric vessels versus the aorta for both G-1 (47% ± 8% vs 80% ± 5% of phenylephrine preconstriction, P < 0.001) and estradiol (42% ± 7% vs 83% ± 4% of phenylephrine preconstriction, P < 0.001). The GPR30 antagonist G15 attenuated the response to both estradiol and G-1. Removal of the endothelium or pretreatment with Nitro-L-arginine methyl ester (L-NAME) partially attenuated vasorelaxation. Responses were not altered in mesenteric vessels from ovariectomized females. Immunohistochemical analysis revealed GPR30 expression in mesenteric endothelial and smooth muscle cells, and smooth muscle expression was confirmed in cultured cells. We conclude that estradiol-induced relaxation in conduit and resistance vessels from mRen2.Lewis females may be mediated by the novel estrogen receptor GPR30. The direct vasodilatory response of G-1 in resistance vessels presents one mechanism for the reduction in blood pressure induced by chronic G-1 administration.

  15. Chemical synthesis and crystallization of the dipeptide AcPheIleNH(2) in TTAB/heptane/octanol reversed micelles.

    PubMed

    Dias, A I; Feliciano, A S; Cabral, J M S; Prazeres, D M F

    2007-01-01

    The chemical synthesis of the dipeptide acetyl phenyl iso-leucin-amide (AcPheIleNH(2)) in tetradecyl trimethyl ammonium bromide (TTAB)/ heptane/octanol/carbonate buffer reversed micelles is described. The co-existence of the surfactant bounded minute water pools within the bulk organic solvent enables the simultaneous solubilization of the polar (IleNH(2)) and apolar (AcPheOEt) substrates, thus enabling the synthesis to take place at the micellar interface. The synthesis was favored by increasing the micellar interface via an increase in water content and surfactant concentration. The best dipeptide yield (87%) was obtained at 32 degrees C, with the largest concentrations of TTAB (200 mM) and water (1100 mM) tested. The low solubility of the dipeptide in the micellar media further led to the formation and growth of needle-like crystals during synthesis, thus enabling the removal of product from solution.

  16. Phenotype-Genotype Integrator (PheGenI): synthesizing genome-wide association study (GWAS) data with existing genomic resources.

    PubMed

    Ramos, Erin M; Hoffman, Douglas; Junkins, Heather A; Maglott, Donna; Phan, Lon; Sherry, Stephen T; Feolo, Mike; Hindorff, Lucia A

    2014-01-01

    Rapidly accumulating data from genome-wide association studies (GWASs) and other large-scale studies are most useful when synthesized with existing databases. To address this opportunity, we developed the Phenotype-Genotype Integrator (PheGenI), a user-friendly web interface that integrates various National Center for Biotechnology Information (NCBI) genomic databases with association data from the National Human Genome Research Institute GWAS Catalog and supports downloads of search results. Here, we describe the rationale for and development of this resource. Integrating over 66,000 association records with extensive single nucleotide polymorphism (SNP), gene, and expression quantitative trait loci data already available from the NCBI, PheGenI enables deeper investigation and interrogation of SNPs associated with a wide range of traits, facilitating the examination of the relationships between genetic variation and human diseases.

  17. HB Hillingdon [alpha46(CE4)Phe-->Val (alpha1 Or alpha2)]: a new alpha chain hemoglobin variant.

    PubMed

    Babb, Anna; Solaiman, Susannah; Green, Brian N; Mantio, Debbie; Patel, Ketan

    2009-01-01

    Routine antenatal hemoglobinopathy screening detected a new alpha chain variant that eluted with Hb A(2) on cation exchange high performance liquid chromatography (HPLC) in a lady of Sri Lankan origin who had normal hematological indices. The mutation was identified by electrospray ionization mass spectrometry (ESI-MS) as alpha46(CE4)Phe-->Val, inferring that the variant was due to a single base change at codon 46 (TTC>GTC) of the alpha1- or alpha2-globin genes.

  18. The μ-and δ-opioid pharmacophore conformations of cyclic β-casomorphin analogues indicate docking of the Phe3 residue to different domains of the opioid receptors

    NASA Astrophysics Data System (ADS)

    Brandt, Wolfgang; Stoldt, Matthias; Schinke, Heiko

    1996-06-01

    Cyclic β-casomorphin analogues with a d-configured amino acid residue in position 2, such as Tyr-c[-Xaa-Phe-Pro-Gly-] and Tyr-c[-Xaa-Phe- d-Pro-Gly-] (Xaa= d-A2bu, d-Orn, d-Lys) were found to bind to the μ-opioid receptor as well as to the δ-opioid receptor, whereas the corresponding l-Xaa2 derivatives are nearly inactive at both. Low-energy conformers of both active and nearly inactive derivatives have been determined in a systematic conformational search or by molecular dynamics simulations using the TRIPOS force field. The obatained conformations were compared with regard to a model for μ-selective opiates developed by Brandt et al. [Drug Des. Discov., 10 (1993) 257]. Superpositions as well as electrostatic, lipophilic and hydrogen bonding similarities with the δ-opioid receptor pharmacophore conformation of t-Hpp-JOM-13 proposed by Mosberg et al. [J. Med. Chem., 37 (1994) 4371, 4384] were used to establish the probable δ-pharmacophoric cyclic β-casomorphin conformations. These conformations were also compared with a δ-opioid agonist (SNC 80) and the highly potent antagonist naltrindole. These investigations led to a prediction of the μ-and δ-pharmacophore structures for the cyclic β-casomorphins. Interestingly, for the inactive compounds such conformations could not be detected. The comparison between the μ-and δ-pharmacophore conformations of the cyclic β-casomorphins demonstrates not only differences in spatial orientation of both aromatic groups, but also in the backbone conformations of the ring part. In particular, the differences in Φ2 and Ψ2 (μ≈70°,-80°; δ≈165°,55°) cause a completely different spatial arrangement of the cyclized peptide rings when all compounds are matched with regard to maximal spatial overlap of the tyrosine residue. Assuming that both the μ-and δ-pharmacophore conformations bind with the tyrosine residue in a similar orientation at the same transmembrane domain X of their receptors, the side chain of Phe3

  19. The aromatic residues Trp and Phe have different effects on the positioning of a transmembrane helix in the microsomal membrane.

    PubMed

    Braun, P; von Heijne, G

    1999-07-27

    We have examined the effect of Trp and Phe residues on the positioning of a poly-Leu transmembrane helix relative to the microsomal membrane by employing a previously described "glycosylation mapping" technique [Nilsson, I. M., Sääf, A., Whitley, P., Gafvelin, G., Waller, C., and von Heijne, G. (1998) J. Mol. Biol. 284, 1165-1175]. Both Trp and Phe tend to push the transmembrane helix into the membrane when inserted in positions flanking the poly-Leu stretch, and Trp (but not Phe) pulls the transmembrane helix toward the lipid-water interface when inserted inside the poly-Leu segment. Thus, the preference of Trp for the lipid-water interface previously suggested on the basis of biophysical studies of model peptides can also be observed for a bona fide transmembrane helix in a biological membrane. We further show that a sufficiently long poly-Trp segment functions as an efficient stop-transfer sequence during protein translocation across the microsomal membrane, despite the preference of Trp residues for the lipid-water interface region.

  20. A Mathematical Model of Tumour and Blood pHe Regulation: The HCO3−∕CO2 Buffering System

    PubMed Central

    Martin, Natasha K.; Gaffney, Eamonn A.; Gatenby, Robert A.; Gillies, Robert J.; Robey, Ian F.; Maini, Philip K.

    2011-01-01

    Malignant tumours are characterised by a low, acidic extracellular pH (pHe) which facilitates invasion and metastasis. Previous research has proposed the potential benefits of manipulating systemic pHe, and recent experiments have highlighted the potential for buffer therapy to raise tumour pHe, prevent metastases, and prolong survival in laboratory mice. To examine the physiological regulation of tumour buffering and investigate how perturbations of the buffering system (via metabolic/respiratory disorders or changes in parameters) can alter tumour and blood pHe, we develop a simple compartmentalised ordinary differential equation model of pHe regulation by the HCO3−∕CO2 buffering system. An approximate analytical solution is constructed and used to carry out a sensitivity analysis, where we identify key parameters that regulate tumour pHe in both humans and mice. From this analysis, we suggest promising alternative and combination therapies, and identify specific patient groups which may show an enhanced response to buffer therapy. In addition, numerical simulations are performed, validating the model against well-known metabolic/respiratory disorders and predicting how these disorders could change tumour pHe. PMID:21167185

  1. ( sup 111 In-DTPA-D-Phe sup 1 )-octreotide, a potential radiopharmaceutical for imaging of somatostatin receptor-positive tumors: Synthesis, radiolabeling and in vitro validation

    SciTech Connect

    Bakker, W.H.; Albert, R.; Bruns, C.; Breeman, W.A.P.; Hofland, L.J.; Marbach, P.; Pless, J.; Pralet, D.; Stolz, B.; Koper, J.W.; Lamberts, S.W.J.; Visser, T.J.; Krenning, E.P. Sandoz Pharma AG, Basel )

    1991-01-01

    As starting material for a potentially convenient radiopharmaceutical, a diethylenetriaminopentaacetic acid (DTPA) conjugated derivative of octreotide (SMS 201-995) was prepared. This peptide, (DTPA-D-Phe{sup 1})-octreotide (SDZ 215-811) binds more than 95% of added {sup 111}In in an easy, single-step labeling procedure without necessity of further purification. The specific somatostatin-like biologic effect of these analogues was proven by the inhibition of growth hormone secretion by cultured rat pituitary cells in a dose-dependent fashion by octreotide, (DTPA-D-Phe{sup 1})-octreotide and non-radioactive ({sup 115}In-DTPA-D-Phe{sup 1})-octreotide. The binding of ({sup 111}In-DTPA-D-Phe{sup 1})-octreotide to rat brain cortex membranes proved to be displaced similarly by natural somatosatin as well as by octreotide, suggesting specific binding of ({sup 111}In-DTPA-D-Phe{sup 1})-octreotide to somatostatin receptors. The binding of the indium-labeled compound showed a somewhat lower affinity when compared with the iodinated (Tyr{sup 3})-octreotide, but indium-labeled (DTPA-D-Phe{sup 1})-octreotide still binds with nanomolar affinity. In conjunction with in vivo studies, these results suggest that ({sup 111}In-DTPA-D-Phe{sup 1})-octreotide is a promising radiopharmaceutical for scintigraphic imaging of somatostatin receptor-positive tumors.

  2. Coarse-grained/molecular mechanics of the TAS2R38 bitter taste receptor: experimentally-validated detailed structural prediction of agonist binding.

    PubMed

    Marchiori, Alessandro; Capece, Luciana; Giorgetti, Alejandro; Gasparini, Paolo; Behrens, Maik; Carloni, Paolo; Meyerhof, Wolfgang

    2013-01-01

    Bitter molecules in humans are detected by ∼25 G protein-coupled receptors (GPCRs). The lack of atomic resolution structure for any of them is complicating an in depth understanding of the molecular mechanisms underlying bitter taste perception. Here, we investigate the molecular determinants of the interaction of the TAS2R38 bitter taste receptor with its agonists phenylthiocarbamide (PTC) and propylthiouracil (PROP). We use the recently developed hybrid Molecular Mechanics/Coarse Grained (MM/CG) method tailored specifically for GPCRs. The method, through an extensive exploration of the conformational space in the binding pocket, allows the identification of several residues important for agonist binding that would have been very difficult to capture from the standard bioinformatics/docking approach. Our calculations suggest that both agonists bind to Asn103, Phe197, Phe264 and Trp201, whilst they do not interact with the so-called extra cellular loop 2, involved in cis-retinal binding in the GPCR rhodopsin. These predictions are consistent with data sets based on more than 20 site-directed mutagenesis and functional calcium imaging experiments of TAS2R38. The method could be readily used for other GPCRs for which experimental information is currently lacking.

  3. Kappa Opioid Receptor Agonist and Brain Ischemia

    PubMed Central

    Chunhua, Chen; Chunhua, Xi; Megumi, Sugita; Renyu, Liu

    2014-01-01

    Opioid receptors, especially Kappa opioid receptor (KOR) play an important role in the pathophysiological process of cerebral ischemia reperfusion injury. Previously accepted KOR agonists activity has included anti-nociception, cardiovascular, anti-pruritic, diuretic, and antitussive effects, while compelling evidence from various ischemic animal models indicate that KOR agonist have neuroprotective effects through various mechanisms. In this review, we aimed to demonstrate the property of KOR agonist and its role in global and focal cerebral ischemia. Based on current preclinical research, the KOR agonists may be useful as a neuroprotective agent. The recent discovery of salvinorin A, highly selective non-opioid KOR agonist, offers a new tool to study the role of KOR in brain HI injury and the protective effects of KOR agonist. The unique pharmacological profile of salvinorin A along with the long history of human usage provides its high candidacy as a potential alternative medication for brain HI injury. PMID:25574482

  4. Molecular modeling of the human vasopressin V2 receptor/agonist complex

    NASA Astrophysics Data System (ADS)

    Czaplewski, Cezary; Kaźmierkiewicz, Rajmund; Ciarkowski, Jerzy

    1998-05-01

    The V2 vasopressin renal receptor (V2R), which controls antidiuresis in mammals, is a member of the large family of heptahelical transmembrane (7TM) G protein-coupled receptors (GPCRs). Using the automated GPCR modeling facility available via Internet (http://expasy.hcuge.ch/swissmod/SWISS-MODEL.html) for construction of the 7TM domain in accord with the bovine rhodopsin (RD) footprint, and the SYBYL software for addition of the intra- and extracellular domains, the human V2R was modeled. The structure was further refined and its conformational variability tested by the use of a version of the Constrained Simulated Annealing (CSA) protocol developed in this laboratory. An inspection of the resulting structure reveals that the V2R (likewise any GPCR modeled this way) is much thicker and accordingly forms a more spacious TM cavity than most of the hitherto modeled GPCR constructs do, typically based on the structure of bacteriorhodopsin (BRD). Moreover, in this model the 7TM helices are arranged differently than they are in any BRD-based model. Thus, the topology and geometry of the TM cavity, potentially capable of receiving ligands, is in this model quite different than it is in the earlier models. In the subsequent step, two ligands, the native [arginine8]vasopressin (AVP) and the selective agonist [d-arginine8]vasopressin (DAVP) were inserted, each in two topologically non-equivalent ways, into the TM cavity and the resulting structures were equilibrated and their conformational variabilities tested using CSA as above. The best docking was selected and justified upon consideration of ligand-receptor interactions and structure-activity data. Finally, the amino acid residues were indicated, mainly in TM helices 3-7, as potentially important in both AVP and DAVP docking. Among those Cys112, Val115-Lys116, Gln119, Met123 in helix 3; Glu174 in helix 4; Val206, Ala210, Val213-Phe214 in helix 5; Trp284, Phe287-Phe288, Gln291 in helix 6; and Phe307, Leu310, Ala314 and

  5. Molecular modeling of the human vasopressin V2 receptor/agonist complex.

    PubMed

    Czaplewski, C; Kaźmierkiewicz, R; Ciarkowski, J

    1998-05-01

    The V2 vasopressin renal receptor (V2R), which controls antidiuresis in mammals, is a member of the large family of heptahelical transmembrane (7TM) G protein-coupled receptors (GPCRs). Using the automated GPCR modeling facility available via Internet (http:/(/)expasy.hcuge.ch/swissmod/SWISS-MODEL.+ ++html) for construction of the 7TM domain in accord with the bovine rhodopsin (RD) footprint, and the SYBYL software for addition of the intra- and extracellular domains, the human V2R was modeled. The structure was further refined and its conformational variability tested by the use of a version of the Constrained Simulated Annealing (CSA) protocol developed in this laboratory. An inspection of the resulting structure reveals that the V2R (likewise any GPCR modeled this way) is much thicker and accordingly forms a more spacious TM cavity than most of the hitherto modeled GPCR constructs do, typically based on the structure of bacteriorhodopsin (BRD). Moreover, in this model the 7TM helices are arranged differently than they are in any BRD-based model. Thus, the topology and geometry of the TM cavity, potentially capable of receiving ligands, is in this model quite different than it is in the earlier models. In the subsequent step, two ligands, the native [arginine8]vasopressin (AVP) and the selective agonist [D-arginine8]vasopressin (DAVP) were inserted, each in two topologically non-equivalent ways, into the TM cavity and the resulting structures were equilibrated and their conformational variabilities tested using CSA as above. The best docking was selected and justified upon consideration of ligand-receptor interactions and structure-activity data. Finally, the amino acid residues were indicated, mainly in TM helices 3-7, as potentially important in both AVP and DAVP docking. Among those Cys112, Val115-Lys116, Gln119, Met123 in helix 3; Glu174 in helix 4; Val206, Ala210, Val213-Phe214 in helix 5; Trp284, Phe287-Phe288, Gln291 in helix 6; and Phe307, Leu310, Ala314

  6. Dopamine receptor agonists, partial agonists and psychostimulant addiction.

    PubMed

    Pulvirenti, L; Koob, G F

    1994-10-01

    Despite the epidemic growth of psychostimulant addiction over the past years, few pharmacological means of intervention are available to date for clinical treatment. This is of importance since the withdrawal syndrome that follows abstinence from drugs such as cocaine and the amphetamines is characterized, among other symptoms, by intense craving for the abused drug, and this is considered a critical factor leading into relapse of drug use. In this article, Luigi Pulvirenti and George Koob focus on the modulatory role shown by drugs acting at the dopamine receptor on the various phases of psychostimulant dependence in preclinical models and in human studies, and suggest that a class of compounds with partial agonist properties at the dopamine receptor may have therapeutic potential.

  7. Potent μ-Opioid Receptor Agonists from Cyclic Peptides Tyr-c[D-Lys-Xxx-Tyr-Gly]: Synthesis, Biological, and Structural Evaluation.

    PubMed

    Li, Yangmei; Cazares, Margret; Wu, Jinhua; Houghten, Richard A; Toll, Laurence; Dooley, Colette

    2016-02-11

    To optimize the structure of a μ-opioid receptor ligand, analogs H-Tyr-c[D-Lys-Xxx-Tyr-Gly] were synthesized and their biological activity was tested. The analog containing a Phe(3) was identified as not only exhibiting binding affinity 14-fold higher than the original hit but also producing agonist activity 3-fold more potent than morphine. NMR study suggested that a trans conformation at D-Lys(2)-Xxx(3) is crucial for these cyclic peptides to maintain high affinity, selectivity, and functional activity toward the μ-opioid receptor.

  8. Beta-agonists and animal welfare

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of beta-agonists in animal feed is a high profile topic within the U.S. as consumers and activist groups continue to question its safety. The only beta-agonist currently available for use in swine is ractopamine hydrochloride (RAC). This is available as Paylean™ (Elanco Animal Health – FDA a...

  9. Small molecule fluoride toxicity agonists.

    PubMed

    Nelson, James W; Plummer, Mark S; Blount, Kenneth F; Ames, Tyler D; Breaker, Ronald R

    2015-04-23

    Fluoride is a ubiquitous anion that inhibits a wide variety of metabolic processes. Here, we report the identification of a series of compounds that enhance fluoride toxicity in Escherichia coli and Streptococcus mutans. These molecules were isolated by using a high-throughput screen (HTS) for compounds that increase intracellular fluoride levels as determined via a fluoride riboswitch reporter fusion construct. A series of derivatives were synthesized to examine structure-activity relationships, leading to the identification of compounds with improved activity. Thus, we demonstrate that small molecule fluoride toxicity agonists can be identified by HTS from existing chemical libraries by exploiting a natural fluoride riboswitch. In addition, our findings suggest that some molecules might be further optimized to function as binary antibacterial agents when combined with fluoride.

  10. Small Molecule Fluoride Toxicity Agonists

    PubMed Central

    Nelson1, James W.; Plummer, Mark S.; Blount, Kenneth F.; Ames, Tyler D.; Breaker, Ronald R.

    2015-01-01

    SUMMARY Fluoride is a ubiquitous anion that inhibits a wide variety of metabolic processes. Here we report the identification of a series of compounds that enhance fluoride toxicity in Escherichia coli and Streptococcus mutans. These molecules were isolated by using a high-throughput screen (HTS) for compounds that increase intracellular fluoride levels as determined via a fluoride riboswitch-reporter fusion construct. A series of derivatives were synthesized to examine structure-activity relationships, leading to the identification of compounds with improved activity. Thus, we demonstrate that small molecule fluoride toxicity agonists can be identified by HTS from existing chemical libraries by exploiting a natural fluoride riboswitch. In addition, our findings suggest that some molecules might be further optimized to function as binary antibacterial agents when combined with fluoride. PMID:25910244

  11. Protease activity at invadopodial focal digestive areas is dependent on NHE1-driven acidic pHe.

    PubMed

    Greco, Maria Raffaella; Antelmi, Ester; Busco, Giovanni; Guerra, Lorenzo; Rubino, Rosa; Casavola, Valeria; Reshkin, Stephan Joel; Cardone, Rosa Angela

    2014-02-01

    Degradation of the extracellular matrix (ECM) is a critical step of tumor cell invasion and requires protease-dependent proteolysis focalized at the invadopodia where the proteolysis of the ECM occurs. Most of the extracellular proteases belong to serine- or metallo-proteases and the invadopodia is where protease activity is regulated. While recent data looking at global protease activity in the growth medium reported that their activity and role in invasion is dependent on Na+/H+ exchanger 1 (NHE1)-driven extracellular acidification, there is no data on this aspect at the invadopodia, and an open question remains whether this acid extracellular pH (pHe) activation of proteases in tumor cells occurs preferentially at invadopodia. We previously reported that the NHE1 is expressed in breast cancer invadopodia and that the NHE1‑dependent acidification of the peri-invadopodial space is critical for ECM proteolysis. In the present study, using, for the first time, in situ zymography analysis, we demonstrated a concordance between NHE1 activity, extracellular acidification and protease activity at invadopodia to finely regulate ECM digestion. We demonstrated that: (i) ECM proteolysis taking place at invadopodia is driven by acidification of the peri-invadopodia microenvironment; (ii) that the proteases have a functional pHe optimum that is acidic; (iii) more than one protease is functioning to digest the ECM at these invadopodial sites of ECM proteolysis; and (iv) lowering pHe or inhibiting the NHE1 increases protease secretion while blocking protease activity changes NHE1 expression at the invadopodia.

  12. Direct detection of phenylephrine 3-O-sulfate in LS180 human intestinal cells using a novel hydrophilic interaction liquid chromatography (HILIC) assay.

    PubMed

    Shah, Heta N; Halquist, Matthew T; Gerk, Phillip M

    2017-01-01

    The efficacy of phenylephrine (PE) is controversial due to its extensive pre-systemic metabolism through sulfation to form phenylephrine-3-O-sulfate (PES). Hence quantitation of PES is important in order to study the metabolism of PE. There are no published methods available for direction detection of PES. We have developed and validated a hydrophilic interaction liquid chromatography (HILIC) method for the direct detection of PES and simultaneous detection of PE to study the enzyme kinetics and metabolism of PE to enable approaches to reduce the presystemic metabolism of PE. This is the first method which facilitates direct detection of PES and simultaneous detection of PE using a zwitterionic HILIC column with improved sensitivity in a single short run. The observed quantitative ranges of our method for PE and PES were 0.39-200μM and 0.0625-32μM (respectively) with a run time of 6.0min. The method was applied to the determination of PE and PES in LS180 human intestinal cell line, recombinant enzymes and human intestinal cytosol (HIC).

  13. Third place--Resident Clinical Science Award 1990. The in vivo and in vitro effect of phenylephrine (Neo Synephrine) on nasal ciliary beat frequency and mucociliary transport.

    PubMed

    Phillips, P P; McCaffrey, T V; Kern, E B

    1990-10-01

    Twenty volunteers with normal noses were studied to determine the effect of phenylephrine on nasal ciliary function. In vivo study of this drug was performed in 15 patients and revealed a significant increase in their ciliary beat frequency from a control of 11 Hz to 12.03 Hz (p = 0.001). Mucociliary transit times in these volunteers were also studied, revealing a mean of 9.9 minutes prestimulation and 10.2 minutes poststimulation, which was not statistically significant (p = 0.77). Five additional subjects donated ciliated mucosal samples for in vitro analysis of varying concentrations of this agent that showed a significant ciliostimulatory effect at lower concentrations (0.01%), with a progressive cilioinhibitory effect at higher concentrations (0.25%, 0.5%). The 0.05% concentration showed no significant change in ciliary activity compared to control measurements. These data demonstrate that phenylephrine has a ciliostimulatory effect in vivo, as well as in appropriate concentrations in vitro, and should be safe and relatively nontoxic to the mucociliary apparatus for short-term use.

  14. A conformation-selective IR-UV study of the dipeptides Ac-Phe-Ser-NH2 and Ac-Phe-Cys-NH2: probing the SH···O and OH···O hydrogen bond interactions.

    PubMed

    Yan, Bin; Jaeqx, Sander; van der Zande, Wim J; Rijs, Anouk M

    2014-06-14

    The conformational preferences of peptides are mainly controlled by the stabilizing effect of intramolecular interactions. In peptides with polar side chains, not only the backbone but also the side chain interactions determine the resulting conformations. In this paper, the conformational preferences of the capped dipeptides Ac-Phe-Ser-NH2 (FS) and Ac-Phe-Cys-NH2 (FC) are resolved under laser-desorbed jet cooling conditions using IR-UV ion dip spectroscopy and density functional theory (DFT) quantum chemistry calculations. As serine (Ser) and cysteine (Cys) only differ in an OH (Ser) or SH (Cys) moiety; this subtle alteration allows us to study the effect of the difference in hydrogen bonding for an OH and SH group in detail, and its effect on the secondary structure. IR absorption spectra are recorded in the NH stretching region (3200-3600 cm(-1)). In combination with quantum chemical calculations the spectra provide a direct view of intramolecular interactions. Here, we show that both FS as FC share a singly γ-folded backbone conformation as the most stable conformer. The hydrogen bond strength of OH···O (FS) is stronger than that of SH···O (FC), resulting in a more compact gamma turn structure. A second conformer is found for FC, showing a β turn interaction.

  15. Opiate agonist-induced re-distribution of Wntless, a mu-opioid receptor interacting protein, in rat striatal neurons.

    PubMed

    Reyes, B A S; Vakharia, K; Ferraro, T N; Levenson, R; Berrettini, W H; Van Bockstaele, E J

    2012-01-01

    Wntless (WLS), a mu-opioid receptor (MOR) interacting protein, mediates Wnt protein secretion that is critical for neuronal development. We investigated whether MOR agonists induce re-distribution of WLS within rat striatal neurons. Adult male rats received either saline, morphine or [d-Ala2, N-Me-Phe4, Gly-ol5]-enkephalin (DAMGO) directly into the lateral ventricles. Following thirty minutes, brains were extracted and tissue sections were processed for immunogold silver detection of WLS. In saline-treated rats, WLS was distributed along the plasma membrane and within the cytoplasmic compartment of striatal dendrites as previously described. The ratio of cytoplasmic to total dendritic WLS labeling was 0.70±0.03 in saline-treated striatal tissue. Morphine treatment decreased this ratio to 0.48±0.03 indicating a shift of WLS from the intracellular compartment to the plasma membrane. However, following DAMGO treatment, the ratio was 0.85±0.05 indicating a greater distribution of WLS intracellularly. The difference in the re-distribution of the WLS following different agonist exposure may be related to DAMGO's well known ability to induce internalization of MOR in contrast to morphine, which is less effective in producing receptor internalization. Furthermore, these data are consistent with our hypothesis that MOR agonists promote dimerization of WLS and MOR, thereby preventing WLS from mediating Wnt secretion. In summary, our findings indicate differential agonist-induced trafficking of WLS in striatal neurons following distinct agonist exposure. Adaptations in WLS trafficking may represent a novel pharmacological target in the treatment of opiate addiction and/or pain.

  16. The bifunctional μ opioid agonist/antioxidant [Dmt(1)]DALDA is a superior analgesic in an animal model of complex regional pain syndrome-type i.

    PubMed

    Schiller, Peter W; Nguyen, Thi M-D; Saray, Amy; Poon, Annie Wing Hoi; Laferrière, André; Coderre, Terence J

    2015-11-18

    Reactive oxygen species (ROS) play an important role in the development of complex regional pain syndrome-Type I (CRPS-I), as also demonstrated with the chronic post ischemia pain (CPIP) animal model of CRPS-I. We show that morphine and the antioxidant N-acetylcysteine (NAC) act synergistically to reduce mechanical allodynia in CPIP rats. The tetrapeptide amide [Dmt(1)]DALDA (H-Dmt-d-Arg-Phe-Lys-NH2) is a potent and selective μ opioid receptor (MOR) agonist with favorable pharmacokinetic properties and with antioxidant activity due to its N-terminal Dmt (2',6'-dimethyltyrosine) residue. In the CPIP model, [Dmt(1)]DALDA was 15-fold more potent than morphine in reversing mechanical allodynia and 4.5-fold more potent as analgesic in the heat algesia test. The results indicate that bifunctional compounds with MOR agonist/antioxidant activity have therapeutic potential for the treatment of CRPS-I.

  17. Investigation of the mechanism of agonist and inverse agonist action at D2 dopamine receptors.

    PubMed

    Roberts, David J; Lin, Hong; Strange, Philip G

    2004-05-01

    This study investigated, for the D2 dopamine receptor, the relation between the ability of agonists and inverse agonists to stabilise different states of the receptor and their relative efficacies. Ki values for agonists were determined in competition versus the binding of the antagonist [3H]spiperone. Competition data were fitted best by a two-binding site model (with the exception of bromocriptine, for which a one-binding site model provided the best fit) and agonist affinities for the higher (Kh) (G protein-coupled) and lower affinity (Kl) (G protein-uncoupled) sites determined. Ki values for agonists were also determined in competition versus the binding of the agonist [3H]N-propylnorapomorphine (NPA) to provide a second estimate of Kh. Maximal agonist effects (Emax) and their potencies (EC50) were determined from concentration-response curves for agonist stimulation of guanosine-5'-O-(3-[32S]thiotriphosphate) ([35S]GTPgammaS) binding. The ability of agonists to stabilise the G protein-coupled state of the receptor (Kl/Kh determined from ligand-binding assays) did not correlate with either of two measures of relative efficacy (relative Emax, Kl/EC50) of agonists determined in [35S]GTPgammaS-binding assays, when the data for all of the compounds tested were analysed. For a subset of compounds, however, there was a relation between Kl/Kh and Emax. Competition-binding data versus [3H]spiperone and [3H]NPA for a range of inverse agonists were fitted best by a one-binding site model. Ki values for the inverse agonists tested were slightly lower in competition versus [3H]NPA compared to [3H]spiperone. These data do not provide support for the idea that inverse agonists act by binding preferentially to the ground state of the receptor.

  18. The Phe105 Loop of Alix Bro1 Domain Plays a Key Role in HIV-1 Release

    SciTech Connect

    Sette, Paola; Mu, Ruiling; Dussupt, Vincent; Jiang, Jiansheng; Snyder, Greg; Smith, Patrick; Xiao, Tsan Sam; Bouamr, Fadila

    2011-12-07

    Alix and cellular paralogs HD-PTP and Brox contain N-terminal Bro1 domains that bind ESCRT-III CHMP4. In contrast to HD-PTP and Brox, expression of the Bro1 domain of Alix alleviates HIV-1 release defects that result from interrupted access to ESCRT. In an attempt to elucidate this functional discrepancy, we solved the crystal structures of the Bro1 domains of HD-PTP and Brox. They revealed typical 'boomerang' folds they share with the Bro1 Alix domain. However, they each contain unique structural features that may be relevant to their specific function(s). In particular, phenylalanine residue in position 105 (Phe105) of Alix belongs to a long loop that is unique to its Bro1 domain. Concurrently, mutation of Phe105 and surrounding residues at the tip of the loop compromise the function of Alix in HIV-1 budding without affecting its interactions with Gag or CHMP4. These studies identify a new functional determinant in the Bro1 domain of Alix.

  19. Heparin and penicillamine-hypotaurine-epinephrine (PHE) solution during bovine in vitro fertilization procedures impair the quality of spermatozoa but improve normal oocyte fecundation and early embryonic development.

    PubMed

    Gonçalves, F S; Barretto, L S S; Arruda, R P; Perri, S H V; Mingoti, G Z

    2014-01-01

    The presence of heparin and a mixture of penicillamine, hypotaurine, and epinephrine (PHE) solution in the in vitro fertilization (IVF) media seem to be a prerequisite when bovine spermatozoa are capacitated in vitro, in order to stimulate sperm motility and acrosome reaction. The present study was designed to determine the effect of the addition of heparin and PHE during IVF on the quality and penetrability of spermatozoa into bovine oocytes and on subsequent embryo development. Sperm quality, evaluated by the integrity of plasma and acrosomal membranes and mitochondrial function, was diminished (P<0.05) in the presence of heparin and PHE. Oocyte penetration and normal pronuclear formation rates, as well as the percentage of zygotes presenting more than two pronuclei, was higher (P<0.05) in the presence of heparin and PHE. No differences were observed in cleavage rates between treatment and control (P>0.05). However, the developmental rate to the blastocyst stage was increased in the presence of heparin and PHE (P>0.05). The quality of embryos that reached the blastocyst stage was evaluated by counting the inner cell mass (ICM) and trophectoderm (TE) cell numbers and total number of cells; the percentage of ICM and TE cells was unaffected (P>0.05) in the presence of heparin and PHE (P<0.05). In conclusion, this study demonstrated that while the supplementation of IVF media with heparin and PHE solution impairs spermatozoa quality, it plays an important role in sperm capacitation, improving pronuclear formation, and early embryonic development.

  20. Conformational analysis of the ΜΒΡ83-99 (Phe91) and ΜΒΡ83-99 (Tyr91) peptide analogues and study of their interactions with the HLA-DR2 and human TCR receptors by using Molecular Dynamics

    NASA Astrophysics Data System (ADS)

    Potamitis, C.; Matsoukas, M.-T.; Tselios, T.; Mavromoustakos, T.; Golič Grdadolnik, S.

    2011-09-01

    The two new synthetic analogues of the MBP83-99 epitope substituted at Lys91 (primary TCR contact) with Phe [MBP83-99 (Phe91)] or Tyr [MBP83-99 (Tyr91)], have been structurally elucidated using 1D and 2D high resolution NMR studies. The conformational analysis of the two altered peptide ligands (APLs) has been performed and showed that they adopt a linear and extended conformation which is in agreement with the structural requirements of the peptides that interact with the HLA-DR2 and TCR receptors. In addition, Molecular Dynamics (MD) simulations of the two analogues in complex with HLA-DR2 (DRA, DRB1*1501) and TCR were performed. Similarities and differences of the binding motif of the two analogues were observed which provide a possible explanation of their biological activity. Their differences in the binding mode in comparison with the MBP83-99 epitope may also explain their antagonistic versus agonistic activity. The obtained results clearly indicate that substitutions in crucial amino acids (TCR contacts) in combination with the specific conformational characteristics of the MBP83-99 immunodominant epitope lead to an alteration of their biological activity. These results make the rational drug design intriguing since the biological activity is very sensitive to the substitution and conformation of the mutated MBP epitopes.

  1. Synthesis, biological evaluation, and automated docking of constrained analogues of the opioid peptide H-Dmt-D-Ala-Phe-Gly-NH₂ using the 4- or 5-methyl substituted 4-amino-1,2,4,5-tetrahydro-2-benzazepin-3-one scaffold.

    PubMed

    De Wachter, Rien; de Graaf, Chris; Keresztes, Atilla; Vandormael, Bart; Ballet, Steven; Tóth, Géza; Rognan, Didier; Tourwé, Dirk

    2011-10-13

    The Phe(3) residue of the N-terminal tetrapeptide of dermorphin (H-Dmt-d-Ala-Phe-Gly-NH(2)) was conformationally constrained using 4- or 5-methyl-substituted 4-amino-1,2,4,5-tetrahydro-2-benzazepin-3-one (Aba) stereoisomeric scaffolds. Several of the synthesized peptides were determined to be high affinity agonists for the μ opioid receptor (OPRM) with selectivity over the δ opioid receptor (OPRD). Interesting effects of the Aba configuration on ligand binding affinity were observed. H-Dmt-d-Ala-erythro-(4S,5S)-5-Me-Aba-Gly-NH(2)9 and H-Dmt-threo-(4R,5S)-5-Me-Aba-Gly-NH(2)12 exhibited subnanomolar affinity for OPRM, while they possess an opposite absolute configuration at position 4 of the Aba ring. However, in the 4-methyl substituted analogues, H-Dmt-d-Ala-(4R)-Me-Aba-Gly-NH(2)14 was significantly more potent than the (4S)-derivative 13. These unexpected results were rationalized using the binding poses predicted by molecular docking simulations. Interestingly, H-Dmt-d-Ala-(4R)-Me-Aba-Gly-NH(2)14 is proposed to bind in a different mode compared with the other analogues. Moreover, in contrast to Ac-4-Me-Aba-NH-Me, which adopts a β-turn in solution and in the crystal structure, the binding mode of this analogue suggests an alternative receptor-bound conformation.

  2. [Safety of beta-agonists in asthma].

    PubMed

    Oscanoa, Teodoro J

    2014-01-01

    Beta 2 agonist bronchodilators (β2A) are very important part in the pharmacotherapy of bronchial asthma, a disease that progresses in the world in an epidemic way. The β2A are prescribed to millions of people around the world, therefore the safety aspects is of public interest. Short-Acting β2 Agonists (SABAs), such as albuterol inhaler, according to current evidence, confirming its safety when used as a quick-relief or rescue medication. The long-acting β2 agonists (LABAs) The long-acting bronchodilators β2A (Long acting β2 Agonists or LABAs) are used associated with inhaled corticosteroids as controller drugs for asthma exacerbationsaccess, for safety reasons LABAs are not recommended for use as monotherapy.

  3. Design of peptides with α,β-dehydro-residues: syntheses, crystal structures and molecular conformations of two ΔPhe-Trp containing peptides

    NASA Astrophysics Data System (ADS)

    Vijayaraghavan, R.; Makker, J.; Kumar, P.; Dey, S.; Singh, T. P.

    2003-06-01

    The ΔPhe-Trp is a newly designed moiety that was found inducing a unique conformation in peptides. The peptides Boc-L-Val-ΔPhe-L-Trp-OCH 3 (I) and Boc-L-Leu-ΔPhe-L-Trp-OCH 3 (II) were synthesized by azlactone method in solution phase. The peptide (I) was crystallized from its solution in ethanol-water mixture in orthorhombic space group P2 12 12 1 with a=10.663(3) Å, b=11.204(3) Å, c=26.516(10) Å and peptide (II) was crystallized from its solution in acetone in a monoclinic space group P2 1 with a=9.354(1)Å, b=11.218(4)Å, c=15.633(1)Å and β=101.83(1)°. The structures were determined by direct methods. Peptide (I) was refined to an R value of 0.059 for 1554 observed reflections [ I≥2 σ (I)] and peptide (II) was refined to an R value of 0.043 for 2920 observed reflections [ I≥2 σ (I)]. The structures of peptides (I) and (II) were found to be identical. They formed an unusual type VIa β-turn conformation which is observed for the first time with a ΔPhe residue at ( i+2) position indicating a unique influence of ΔPhe-Trp moiety in inducing a reproducible new structure in peptides.

  4. PPAR Agonists and Cardiovascular Disease in Diabetes

    PubMed Central

    Calkin, Anna C.; Thomas, Merlin C.

    2008-01-01

    Peroxisome proliferators activated receptors (PPARs) are ligand-activated nuclear transcription factors that play important roles in lipid and glucose homeostasis. To the extent that PPAR agonists improve diabetic dyslipidaemia and insulin resistance, these agents have been considered to reduce cardiovascular risk. However, data from murine models suggests that PPAR agonists also have independent anti-atherosclerotic actions, including the suppression of vascular inflammation, oxidative stress, and activation of the renin angiotensin system. Many of these potentially anti-atherosclerotic effects are thought to be mediated by transrepression of nuclear factor-kB, STAT, and activator protein-1 dependent pathways. In recent clinical trials, PPARα agonists have been shown to be effective in the primary prevention of cardiovascular events, while their cardiovascular benefit in patients with established cardiovascular disease remains equivocal. However, the use of PPARγ agonists, and more recently dual PPARα/γ coagonists, has been associated with an excess in cardiovascular events, possibly reflecting unrecognised fluid retention with potent agonists of the PPARγ receptor. Newer pan agonists, which retain their anti-atherosclerotic activity without weight gain, may provide one solution to this problem. However, the complex biologic effects of the PPARs may mean that only vascular targeted agents or pure transrepressors will realise the goal of preventing atherosclerotic vascular disease. PMID:18288280

  5. Long-term studies of dopamine agonists.

    PubMed

    Hubble, Jean P

    2002-02-26

    Dopamine agonists have long been used as adjunctive therapy for the treatment of Parkinson's disease (PD). In more recent years these drugs have also been proved safe and effective as initial therapy in lieu of levodopa in the treatment of PD. Long-term levodopa therapy is associated with motor complications, including fluctuating response patterns and dyskinesia. By initially introducing a dopamine agonist as symptomatic drug therapy, it may be possible to postpone the use of levodopa and delay or prevent the development of motor complications. Recently, four clinical trials have explored this hypothesis by comparing the long-term response and side effects of levodopa with dopamine agonist therapy. The drugs studied have included ropinirole, pramipexole, cabergoline, and pergolide. In each of these projects, the occurrence of motor complications, such as wearing off and dyskinesia, was significantly less in the subjects assigned to initiation of therapy with a dopamine agonist. The addition of levodopa could be postponed by many months or even several years. Therefore, these long-term studies of dopamine agonists support the initiation of a dopamine agonist instead of levodopa in an effort to postpone levodopa-related motor complications. This therapeutic approach may be particularly appropriate in PD patients with a long treatment horizon on the basis of age and general good health. The extension phase of the long-term study comparing pramipexole with levodopa is ongoing, and follow-up information may help to establish the value of this treatment strategy.

  6. Molecular Modeling of the Human P2Y2 Receptor and Design of a Selective Agonist, 2′-Amino-2′-deoxy-2-thio-UTP

    PubMed Central

    Ivanov, Andrei A.; Ko, Hyojin; Cosyn, Liesbet; Maddileti, Savitri; Besada, Pedro; Fricks, Ingrid; Costanzi, Stefano; Harden, T. Kendall; Van Calenbergh, Serge; Jacobson, Kenneth A.

    2012-01-01

    A rhodopsin-based homology model of the nucleotide-activated human P2Y2 receptor, including loops, termini, and phospholipids, was optimized with Monte Carlo Multiple Minimum. Docked UTP formed a nucleobase π–π complex with conserved Phe3.32. Selectivity-enhancing 2′-amino-2′-deoxy substitution interacted through π-hydrogen bonding with aromatic Phe6.51 and Tyr3.33. A “sequential ligand composition” approach for docking the flexible dinucleotide agonist Up4U demonstrated a shift of conserved cationic Arg3.29 from the UTP γ position to δ position of Up4U and Up4ribose. Sysnthesized nucleotides were tested as agonists at human P2Y receptors expressed in 1321N1 astrocytoma cells. 2′-Amino and 2-thio modifications synergized to enhance potency and selectivity; compound 8 (8 nM EC50) was 300-fold P2Y2-selective versus P2Y4. 2′-Amine acetylation reduced potency, and trifluoroacetylation produced intermediate potency. 5-Amino nucleobase substitution did not enhance potency through a predicted hydrophilic interaction, possibly because of destabilization of the receptor-favored (N)-ribose conformation. This detailed view of P2Y2 receptor recognition suggests mutations for model validation. PMID:17302398

  7. Development and Validation of Chemometric-Assisted Spectrophotometric Methods for Simultaneous Determination of Phenylephrine Hydrochloride and Ketorolac Tromethamine in Binary Combinations.

    PubMed

    Elfatatry, Hamed M; Mabrouk, Mokhtar M; Hammad, Sherin F; Mansour, Fotouh R; Kamal, Amira H; Alahmad, Shoeb

    2016-09-01

    The present work describes new spectrophotometric methods for the simultaneous determination of phenylephrine hydrochloride and ketorolac tromethamine in their synthetic mixtures. The applied chemometric techniques are multivariate methods including classical least squares, principal component regression, and partial least squares. In these techniques, the concentration data matrix was prepared by using the synthetic mixtures containing these drugs dissolved in distilled water. The absorbance data matrix corresponding to the concentration data was obtained by measuring the absorbances at 16 wavelengths in the range 244-274 nm at 2 nm intervals in the zero-order spectra. The spectrophotometric procedures do not require any separation steps. The accuracy, precision, and linearity ranges of the methods have been determined, and analyzing synthetic mixtures containing the studied drugs has validated them. The developed methods were successfully applied to the synthetic mixtures and the results were compared to those obtained by a reported HPLC method.

  8. Teaghrelins, unique acylated flavonoid tetraglycosides in Chin-shin oolong tea, are putative oral agonists of the ghrelin receptor.

    PubMed

    Lo, Yuan-Hao; Chen, Ying-Jie; Chang, Chi-I; Lin, Yi-Wen; Chen, Chung-Yu; Lee, Maw-Rong; Lee, Viola S Y; Tzen, Jason T C

    2014-06-04

    Chin-shin oolong tea, a popular tea in Taiwan, was empirically perceived to induce hunger and accelerate gastric emptying in a manner similar to the physiological effects of ghrelin, an endogenous acylated peptide known as the hunger hormone. Two unique acylated flavonoid tetraglycosides previously identified in Chin-shin oolong tea were demonstrated to induce hunger of rats in a food intake assay and, thus, named teaghrelin-1 and teaghrelin-2. Similar to GHRP-6, a synthetic analogue of ghrelin, teaghrelin-1 stimulated growth hormone secretion of rat primary anterior pituitary cells in a dose-dependent manner, and the stimulation was inhibited by [D-Arg(1),D-Phe(5),D-Trp(7,9),Leu(11)]-substance P, an antagonist of the ghrelin receptor. While teaghrelin-2 remained unmodified, a meta-O-methylated metabolite of teaghrelin-1 was detected in bile of rats after intravenous injection. Presumably, teaghrelins are promising oral agonists of the ghrelin receptor.

  9. Disagreement between standard transthoracic impedance cardiography and the automated transthoracic electrical bioimpedance method in estimating the cardiovascular responses to phenylephrine and isoprenaline in healthy man.

    PubMed Central

    De Mey, C; Enterling, D

    1993-01-01

    1. Impedance cardiography is a well-established noninvasive method to assess within-subject changes of cardiovascular function. We compared the standard approach (ZCG) which requires tedious signal analysis with an automated approach (TEB: NCCOM 3) with its own specific equipment, algorithms and equations in order to assess agreement of the method-specific measurements and calculations. 2. Ten healthy men were studied on two occasions with either ZCG or TEB, at rest and at the end of 5 min i.v.-infusions with 1 microgram min-1 isoprenaline and 100 micrograms min-1 phenylephrine. 3. There was good agreement for the method-independent changes (HR, SBP/DBP), but there were large differences for method-specific measurements: dZ/dtmax [TEB-ZCG] = -0.68, CI: -0.83 to -0.53 ohm s-1, PEP [TEB-ZCG] = -22.1, CI: -35.0 to -9.2 ms and QS2c [TEB-ZCG] = -16.5, CI: -32.4 to -0.6 ms and for the calculated stroke volume SV [TEB-ZCG] = 30.3, CI: 15.5 to 45.2 ml. The responses of dZ/dtmax and SV to isoprenaline and phenylephrine, although qualitatively similar, reached no quantitative agreement either. A substantial disagreement was evident for the STI responses to isoprenaline where TEB failed to detect the expected reduction of VETc and thus grossly underestimated the shortening of QS2c. 4. It is concluded that TEB-measurements and -calculations did not agree with standard ZCG, that the methods, albeit related, cannot be considered as interchangeable and that suspicion is justified that TEB might yield erroneous results under specific circumstances. PMID:8485014

  10. Western-style diet modulates contractile responses to phenylephrine differently in mesenteric arteries from senescence-accelerated prone (SAMP8) and resistant (SAMR1) mice.

    PubMed

    Jiménez-Altayó, Francesc; Onetti, Yara; Heras, Magda; Dantas, Ana P; Vila, Elisabet

    2013-08-01

    The influence of two known cardiovascular risk factors, aging and consumption of a high-fat diet, on vascular mesenteric artery reactivity was examined in a mouse model of accelerated senescence (SAM). Five-month-old SAM prone (SAMP8) and resistant (SAMR1) female mice were fed a Western-type high-fat diet (WD; 8 weeks). Mesenteric arteries were dissected, and vascular reactivity, protein and messenger RNA expression, superoxide anion (O 2 (·-) ) and hydrogen peroxide formation were evaluated by wire myography, immunofluorescence, RT-qPCR, ethidium fluorescence and ferric-xylenol orange, respectively. Contraction to KCl and relaxation to acetylcholine remained unchanged irrespective of senescence and diet. Although similar contractions to phenylephrine were observed in SAMR1 and SAMP8, accelerated senescence was associated with decreased eNOS and nNOS and increased O 2 (·-) synthesis. Senescence-related alterations were compensated, at least partly, by the contribution of NO derived from iNOS and the enhanced endogenous antioxidant capacity of superoxide dismutase 1 to maintain vasoconstriction. Administration of a WD induced qualitatively different alterations in phenylephrine contractions of mesenteric arteries from SAMR1 and SAMP8. SAMR1 showed increased contractions partly as a result of decreased NO availability generated by decreased eNOS and nNOS and enhanced O 2 (·-) formation. In contrast, WD feeding in SAMP8 resulted in reduced contractions due to, at least in part, the increased functional participation of iNOS-derived NO. In conclusion, senescence-dependent intrinsic alterations during early stages of vascular senescence may promote vascular adaptation and predispose to further changes in response to high-fat intake, which may lead to the progression of aging-related cardiovascular disease, whereas young subjects lack the capacity for this adaptation.

  11. Biased μ-opioid receptor agonists diversely regulate lateral mobility and functional coupling of the receptor to its cognate G proteins.

    PubMed

    Melkes, Barbora; Hejnova, Lucie; Novotny, Jiri

    2016-12-01

    There are some indications that biased μ-opioid ligands may diversely affect μ-opioid receptor (MOR) properties. Here, we used confocal fluorescence recovery after photobleaching (FRAP) to study the regulation by different MOR agonists of receptor movement within the plasma membrane of HEK293 cells stably expressing a functional yellow fluorescent protein (YFP)-tagged μ-opioid receptor (MOR-YFP). We found that the lateral mobility of MOR-YFP was increased by (D-Ala(2),N-MePhe(4),Gly(5)-ol)-enkephalin (DAMGO) and to a lesser extent also by morphine but decreased by endomorphin-2. Interestingly, cholesterol depletion strongly enhanced the ability of morphine to elevate receptor mobility but significantly reduced or even eliminated the effect of DAMGO and endomorphin-2, respectively. Moreover, the ability of DAMGO and endomorphin-2 to influence MOR-YFP movement was diminished by pertussis toxin treatment. The results obtained by agonist-stimulated [(35)S]GTPγS binding assays indicated that DAMGO exhibited higher efficacy than morphine and endomorphin-2 did and that the efficacy of DAMGO, contrary to the latter agonists, was enhanced by cholesterol depletion. Overall, our study provides clear evidence that biased MOR agonists diversely affect receptor mobility in plasma membranes as well as MOR/G protein coupling and that the regulatory effect of different ligands depends on the membrane cholesterol content. These findings help to delineate the fundamental properties of MOR regarding their interaction with biased MOR ligands and cognate G proteins.

  12. Function of Phe-259 and Thr-314 within the Substrate Binding Pocket of the Juvenile Hormone Esterase of Manduca sexta†

    PubMed Central

    Kamita, Shizuo G.; Wogulis, Mark D.; Law, Christopher S.; Morisseau, Christophe; Tanaka, Hiromasa; Huang, Huazhang; Wilson, David K.; Hammock, Bruce D.

    2013-01-01

    Juvenile hormone (JH) is a key insect developmental hormone that is found at low nanomolar levels in larval insects. The methyl ester of JH is hydrolyzed in many insects by an esterase that shows high specificity for JH. We have previously determined a crystal structure of the JH esterase (JHE) of the tobacco hornworm Manduca sexta (MsJHE) [Wogulis, M., Wheelock, C. E., Kamita, S. G., Hinton, A. C., Whetstone, P. A., Hammock, B. D., and Wilson, D. K. (2006) Biochemistry 45, 4045-4057]. Our molecular modeling indicates that JH fits very tightly within the substrate binding pocket of MsJHE. This tight fit places two non-catalytic amino acid residues, Phe-259 and Thr-314, within the appropriate distance and geometry to potentially interact with the α,β-unsaturated ester and epoxide, respectively, of JH. These residues are highly conserved in numerous biologically active JHEs. Kinetic analyses of mutants of Phe-259 or Thr-314 indicate that these residues contribute to the low KM that MsJHE shows for JH. This low KM, however, comes at the cost of reduced substrate turnover. Neither nucleophilic attack of the resonance stabilized ester by the catalytic serine nor the availability of a water molecule for attack of the acyl-enzyme intermediate appear to be a rate-determining step in the hydrolysis of JH by MsJHE. We hypothesize that the release of the JH acid metabolite from the substrate binding pocket limits the catalytic cycle. Our findings also demonstrate that chemical bond strength does not necessarily correlate with how reactive the bond will be to metabolism. PMID:20307057

  13. Potent and selective agonists of human melanocortin receptor 5: cyclic analogues of alpha-melanocyte-stimulating hormone.

    PubMed

    Bednarek, Maria A; MacNeil, Tanya; Tang, Rui; Fong, Tung M; Cabello, M Angeles; Maroto, Marta; Teran, Ana

    2007-05-17

    The physiological role of melanocortin receptor 5 (MC5R) in humans is not clear despite its broad presence in various peripheral sites and in the brain, cortex, and cerebellum. To differentiate between functions of this receptor and those of the other melanocortin receptors (hMC1,3,4R), peptides with improved receptor subtype selectivity are needed. The endogenous ligands, melanocortins, and their various synthetic analogues are not particularly selective for hMC5R. In this study, cyclic peptides derived from MTII, Ac-Nle-cyclo(Asp-His6-D-Phe7-Arg8-Trp-Lys)-NH2 (a pan-agonist at the melanocortin receptors) were prepared and tested in binding and functional assays on CHO cells expressing hMC1b,3-5R. The analogues included in their structures sterically constrained hydrophobic amino acids in positions 6 (His) and 8 (Arg), and the D-4,4'-biphenyl residue in position 7 (D-Phe). Several of the new compounds were selective potent agonists at hMC5R. They are exemplified by peptide 29, Ac-Nle-cyclo(Asp-Oic6-D-4,4'-Bip7-Pip8-Trp-Lys)-NH2 (Oic=octahydroindole-2-COOH; 4,4'-Bip=4,4'-biphenylalanine; Pip=pipecolic acid) of IC50=0.95 nM and EC50=0.99 nM at hMC5R and selectivity for this receptor with respect to the other melanocortin receptors greater than 5000-fold.

  14. A new therapeutic approach to erectile dysfunction: urotensin-II receptor high affinity agonist ligands.

    PubMed

    di Villa Bianca, Roberta d'Emmanuele; Mitidieri, Emma; Donnarumma, Erminia; Fusco, Ferdinando; Longo, Nicola; Rosa, Giuseppe De; Novellino, Ettore; Grieco, Paolo; Mirone, Vincenzo; Cirino, Giuseppe; Sorrentino, Raffaella

    2015-01-01

    Urotensin-II (U-II) is a cyclic peptide that acts through a G protein-coupled receptor (urotensin-II receptor [UTR]) mainly involved in cardiovascular function in humans. The urotensinergic system is also implicated in the urogenital tract. Indeed, U-II relaxes human corpus cavernosum strips and causes an increase in intracavernous pressure (ICP) in rats. In light of this, the U-II/UTR pathway can be considered a new target for the treatment of erectile dysfunction. On this hypothesis, herein we report on two new UTR high affinity-agonists, P5U (H-Asp-c[Pen-Phe-Trp-Lys-Tyr-Cys]-Val-OH) and UPG84(H-Asp-c[Pen-Phe-DTrp-Orn-(pNH 2 ) Phe-Cys]-Val-OH). The effects of P5U and UPG84 were each compared separately with U-II by monitoring the ICP in anesthetized rats. Intracavernous injection of U-II (0.03-1 nmol), P5U (0.03-1 nmol) or UPG84 (0.03-1 nmol) caused an increase in ICP. P5U, in particular, elicited a significant increase in ICP as compared to U-II. The observed effect by using P5U at a dose of 0.1 nmol per rat was comparable to the effect elicited by U-II at a dose of 0.3 nmol. Moreover, UPG84 at the lowest dose (0.03 nmol) showed an effect similar to the highest dose of U-II (1 nmol). Furthermore, UPG84 was found to be more effective than P5U. Indeed, while the lowest dose of P5U (0.03 nmol) did not affect the ICP, UPG84, at the same dose, induced a prominent penile erection in rat. These compounds did not modify the blood pressure, which indicates a good safety profile. In conclusion, UPG84 and P5U may open new perspectives for the management of erectile dysfunction.

  15. Ocular hypotensive effects of melatonin receptor agonists in the rabbit: further evidence for an MT3 receptor.

    PubMed

    Pintor, Jesus; Peláez, Teresa; Hoyle, Charles H V; Peral, Assumpta

    2003-03-01

    (1) Melatonin is involved in the control of intraocular pressure during the night and day photoperiod. We have investigated the receptor that regulates intraocular pressure in New Zealand white rabbits by means of agonists and antagonists of melatonin receptors. (2) Melatonin and its analogues: 2-Phe-melatonin, 6-Cl-melatonin, 2-I-melatonin, 5- methoxycarbonylamino-N-acetyltryptamine (5-MCA-NAT) and N-acetyltryptamine all produced a reduction in intraocular pressure. Dose-response analysis for these compounds gave pD(2) values of 9.3+/-0.24 for melatonin; 9.0+/-0.09 for 6-Cl-melatonin; 9.0+/-0.84 for 2-I-melatonin; 8.9+/-0.07 for 5-MCA-NAT; 8.7+/-0.18 for 2-Phe-melatonin and 9.4+/-0.30 for N-acetyltryptamine (all n=8). (3) At a dose of 0.5 nmol (in 10 micro l) melatonin and the selective melatonin MT(3) agonist 5-MCA-NAT, induced greater reductions of intraocular pressure (22.8+/-2.3% and 32.5+/-1.4%, respectively) than the other compounds. (4) The melatonin-receptor antagonists, prazosin, DH-97 and 4-P-PDOT, reversed the effect of 5-MCA-NAT in a dose-dependent manner, with pA(2) values of 13.5+/-0.17 for prazosin, 10.6+/-0.16 for DH-97 and 9.4+/-0.20 for 4-P-PDOT (n=8). (5) Cholinoceptor antagonists (hexamethonium and atropine) and alpha(2)- and beta(2)-adrenoceptor antagonists (yohimbine and ICI 118,551) partially reversed the effects produced by melatonin and 5-MCA-NAT, suggesting the possible involvement of cholinergic and noradrenergic systems in the hypotensive actions mediated by melatonin agonists. The alpha(1)-adrenoceptor antagonist, corynanthine, had no significant effect. (6) The strong hypotensive effect of the MT(3) agonist, 5-MCA-NAT, suggests that this compound may be a useful agent for treating those pathologies where intraocular pressure is abnormally elevated.

  16. Design of peptides with α,β-dehydro-residues: synthesis, crystal structure and molecular conformation of a tetrapeptide Z-ΔVal-Val-ΔPhe-Ile-Ome

    NASA Astrophysics Data System (ADS)

    Makker, J.; Dey, S.; Mukherjee, S.; Vijayaraghavan, R.; Kumar, P.; Singh, T. P.

    2003-06-01

    This is the first designed peptide with a combination of a branched β-carbon ΔVal and a ΔPhe residues. The peptide Z-ΔVal-Val-ΔPhe-Ile-Ome was synthesized in solution phase. Single crystals were grown by slow evaporation from its solution in acetone-water mixture at 25 °C. The crystals belong to an orthorhombic space group P2 12 12 1 with a=12.513(2) Å, b=15.904(5) Å, c=17.686(2) Å and Z=4. The structure was determined by direct methods and refined by least-squares procedure to an R factor of 0.082. The peptide adopts a 3 10-helical conformation with two intramolecular hydrogen bonds ( i+3→ i) involving carbonyl oxygen atoms of carbobenzoxy group and ΔVal and NH groups of ΔPhe and Ile with distances of 2.764(6) and 3.047(7) Å, respectively. The structure determination has revealed that a tetrapeptide with ΔVal at ( i+1) and ΔPhe at ( i+3) positions adopts a folded conformation despite the presence of unfavorable branched β-carbon residues Val and Ile at ( i+2) and ( i+4) positions, respectively. The packing of the molecules in the unit cell is stabilized by two intermolecular hydrogen bonds involving NH groups of ΔVal and Val residues with carbonyl oxygen atoms of Val and ΔPhe residues belonging to a symmetry related molecule. The side chains of Val, ΔPhe and Ile form infinite chains of van der Waals interactions.

  17. Addition of D-penicillamine, hypotaurine, and epinephrine (PHE) mixture to IVF medium maintains motility and longevity of bovine sperm and enhances stable production of blastocysts in vitro.

    PubMed

    Kang, Sung-Sik; Koyama, Keisuke; Huang, Weiping; Yang, Yinghua; Yanagawa, Yojiro; Takahashi, Yoshiyuki; Nagano, Masashi

    2015-01-01

    The present study aimed to establish an efficient system for bovine embryo production by in vitro fertilization (IVF) that can achieve stable normal fertilization and blastocyst developmental rates in any bull without optimization of the sperm concentration in IVF medium. We examined the effects of a PHE mixture (20 μM D-penicillamine, 10 μM hypotaurine and 1 μM epinephrine), theophylline (2.5 mM), and sperm concentration (1, 2 or 5 × 10(6) cells/ml) on fertilization and blastocyst developmental rates. High cleavage rates (78.3 to 92.4%) and blastocyst developmental rates (31.9 to 62.0%) at day 7 were obtained in the presence of PHE and theophylline in IVF medium with a sperm concentration of 2 × 10(6) cells/ml using sperm from 9 bulls. In addition, the synergistic effect of PHE and theophylline on normal fertilization (2 pronuclei) was clarified at 12 h after IVF with a sperm concentration of 1 × 10(6) cells/ml. Moreover, high linearity, high flagellar beat cross frequency, and low amplitude of lateral head of motile sperm were found by computer-assisted sperm analysis. In conclusion, the combination of the PHE mixture and theophylline synergistically accelerates sperm motility and sperm penetration of bovine oocytes. Theophylline activates sperm motility with increasing intracellular cAMP. However, PHE prevents an excessive increase of cAMP and maintains sperm motility without hyperactivation. When the combination of PHE and theophylline is added to IVF medium at a sperm concentration of 2 × 10(6) cells/ml, we can achieve stable normal fertilization and blastocyst development in any bull.

  18. Addition of D-penicillamine, hypotaurine, and epinephrine (PHE) mixture to IVF medium maintains motility and longevity of bovine sperm and enhances stable production of blastocysts in vitro

    PubMed Central

    KANG, Sung-Sik; KOYAMA, Keisuke; HUANG, Weiping; YANG, Yinghua; YANAGAWA, Yojiro; TAKAHASHI, Yoshiyuki; NAGANO, Masashi

    2014-01-01

    The present study aimed to establish an efficient system for bovine embryo production by in vitro fertilization (IVF) that can achieve stable normal fertilization and blastocyst developmental rates in any bull without optimization of the sperm concentration in IVF medium. We examined the effects of a PHE mixture (20 μM D-penicillamine, 10 μM hypotaurine and 1 μM epinephrine), theophylline (2.5 mM), and sperm concentration (1, 2 or 5 × 106 cells/ml) on fertilization and blastocyst developmental rates. High cleavage rates (78.3 to 92.4%) and blastocyst developmental rates (31.9 to 62.0%) at day 7 were obtained in the presence of PHE and theophylline in IVF medium with a sperm concentration of 2 × 106 cells/ml using sperm from 9 bulls. In addition, the synergistic effect of PHE and theophylline on normal fertilization (2 pronuclei) was clarified at 12 h after IVF with a sperm concentration of 1 × 106 cells/ml. Moreover, high linearity, high flagellar beat cross frequency, and low amplitude of lateral head of motile sperm were found by computer-assisted sperm analysis. In conclusion, the combination of the PHE mixture and theophylline synergistically accelerates sperm motility and sperm penetration of bovine oocytes. Theophylline activates sperm motility with increasing intracellular cAMP. However, PHE prevents an excessive increase of cAMP and maintains sperm motility without hyperactivation. When the combination of PHE and theophylline is added to IVF medium at a sperm concentration of 2 × 106 cells/ml, we can achieve stable normal fertilization and blastocyst development in any bull. PMID:25501343

  19. The structural basis for agonist and partial agonist action on a β(1)-adrenergic receptor.

    PubMed

    Warne, Tony; Moukhametzianov, Rouslan; Baker, Jillian G; Nehmé, Rony; Edwards, Patricia C; Leslie, Andrew G W; Schertler, Gebhard F X; Tate, Christopher G

    2011-01-13

    β-adrenergic receptors (βARs) are G-protein-coupled receptors (GPCRs) that activate intracellular G proteins upon binding catecholamine agonist ligands such as adrenaline and noradrenaline. Synthetic ligands have been developed that either activate or inhibit βARs for the treatment of asthma, hypertension or cardiac dysfunction. These ligands are classified as either full agonists, partial agonists or antagonists, depending on whether the cellular response is similar to that of the native ligand, reduced or inhibited, respectively. However, the structural basis for these different ligand efficacies is unknown. Here we present four crystal structures of the thermostabilized turkey (Meleagris gallopavo) β(1)-adrenergic receptor (β(1)AR-m23) bound to the full agonists carmoterol and isoprenaline and the partial agonists salbutamol and dobutamine. In each case, agonist binding induces a 1 Å contraction of the catecholamine-binding pocket relative to the antagonist bound receptor. Full agonists can form hydrogen bonds with two conserved serine residues in transmembrane helix 5 (Ser(5.42) and Ser(5.46)), but partial agonists only interact with Ser(5.42) (superscripts refer to Ballesteros-Weinstein numbering). The structures provide an understanding of the pharmacological differences between different ligand classes, illuminating how GPCRs function and providing a solid foundation for the structure-based design of novel ligands with predictable efficacies.

  20. Muscimol as an ionotropic GABA receptor agonist.

    PubMed

    Johnston, Graham A R

    2014-10-01

    Muscimol, a psychoactive isoxazole from Amanita muscaria and related mushrooms, has proved to be a remarkably selective agonist at ionotropic receptors for the inhibitory neurotransmitter GABA. This historic overview highlights the discovery and development of muscimol and related compounds as a GABA agonist by Danish and Australian neurochemists. Muscimol is widely used as a ligand to probe GABA receptors and was the lead compound in the development of a range of GABAergic agents including nipecotic acid, tiagabine, 4,5,6,7-tetrahydroisoxazolo(5,4-c)pyridin-3-ol, (Gaboxadol(®)) and 4-PIOL.

  1. Fluorescence Spectroscopy of tRNA[superscript Phe] Y Base in the Presence of Mg[superscript 2+] and Small Molecule Ligands

    ERIC Educational Resources Information Center

    Kirk, Sarah R.; Silverstein, Todd P.; McFarlane Holman, Karen L.

    2008-01-01

    This laboratory project is one component of a semester-long advanced biochemistry laboratory course that uses several complementary techniques to study tRNA[superscript Phe] conformational changes induced by ligand binding. In this article we describe a set of experiments in which students use fluorescence spectroscopy to study tRNA[superscript…

  2. A novel mutation in DNAJB6, p.(Phe91Leu), in childhood-onset LGMD1D with a severe phenotype.

    PubMed

    Nam, Tai-Seung; Li, Wenting; Heo, Suk-Hee; Lee, Kyung-Hwa; Cho, Anna; Shin, Jin-Hong; Kim, Young Ok; Chae, Jong-Hee; Kim, Dae-Seong; Kim, Myeong-Kyu; Choi, Seok-Yong

    2015-11-01

    To identify and characterize genetic mutation in a Korean family with limb-girdle muscular dystrophy 1 (LGMD1), we analyzed in the affected family members clinical features, DNAJB6 by Sanger sequencing, muscle structures by magnetic resonance imaging (MRI), and functional consequences of the identified mutation using a zebrafish model. The clinical phenotypes along with identification of a novel c.271T > C (p.(Phe91Leu)) mutation in DNAJB6 led to the diagnosis of LGMD1D in the affected family members. This mutation presents unique clinical and radiological features compared with other DNAJB6 mutants. All affected members examined showed reduced pulmonary function, and had nasal voice and dysphagia except the two members who were thirteen and twelve years of age at the time of examination. Muscle phenotypes developed between 8 and 11 years of age and were more severe as compared to previously reported LGMD1D patients with mutant DNAJB6. Patients' MRI scans exhibited early involvement of the lateral head of gastrocnemius, in contrast to its late involvement in reported LGMD1D cases. Functional study using zebrafish embryos demonstrated that p.Phe91Leu elicits more severe muscle defects than the reported p.Phe93Leu and p.Pro96Arg mutations. We conclude that a novel p.(Phe91Leu) mutation in DNAJB6 is associated with severe childhood-onset LGMD1D.

  3. Distribution and dissemination of the Val1016Ile and Phe1534Cys Kdr mutations in Aedes aegypti Brazilian natural populations

    PubMed Central

    2014-01-01

    Background The chemical control of the mosquito Aedes aegypti, the major vector of dengue, is being seriously threatened due to the development of pyrethroid resistance. Substitutions in the 1016 and 1534 sites of the voltage gated sodium channel (AaNaV), commonly known as kdr mutations, confer the mosquito with knockdown resistance. Our aim was to evaluate the allelic composition of natural populations of Brazilian Ae. aegypti at both kdr sites. Methods The AaNaV IIIS6 region was cloned and sequenced from three Brazilian populations. Additionally, individual mosquitoes from 30 populations throughout the country were genotyped for 1016 and 1534 sites, based in allele-specific PCR. For individual genotypes both sites were considered as a single locus. Results The 350 bp sequence spanning the IIIS6 region of the AaNa V gene revealed the occurrence of the kdr mutation Phe1534Cys in Brazil. Concerning the individual genotyping, beyond the susceptible wild-type (NaVS), two kdr alleles were identified: substitutions restricted to the 1534 position (NaVR1) or simultaneous substitutions in both 1016 and 1534 sites (NaVR2). A clear regional distribution pattern of these alleles was observed. The NaVR1kdr allele occurred in all localities, while NaVR2 was more frequent in the Central and Southeastern localities. Locations that were sampled multiple times in the course of a decade revealed an increase in frequency of the kdr mutations, mainly the double mutant allele NaVR2. Recent samples also indicate that NaVR2 is spreading towards the Northern region. Conclusions We have found that in addition to the previously reported Val1016Ile kdr mutation, the Phe1534Cys mutation also occurs in Brazil. Allelic composition at both sites was important to elucidate the actual distribution of kdr mutations throughout the country. Studies to determine gene flow and the fitness costs of these kdr alleles are underway and will be important to better understand the dynamics of Ae. aegypti

  4. Corepressors of agonist-bound nuclear receptors

    SciTech Connect

    Gurevich, Igor; Aneskievich, Brian J.

    2007-09-15

    Nuclear receptors (NRs) rely on coregulator proteins to modulate transcription of target genes. NR coregulators can be broadly subdivided into coactivators which potentiate transcription and corepressors which silence gene expression. The prevailing view of coregulator action holds that in the absence of agonist the receptor interacts with a corepressor via the corepressor nuclear receptor (CoRNR, 'corner') box motifs within the corepressor. Upon agonist binding, a conformational change in the receptor causes the shedding of corepressor and the binding of a coactivator which interacts with the receptor via NR boxes within the coregulator. This view was challenged with the discovery of RIP140 which acts as a NR corepressor in the presence of agonist and utilizes NR boxes. Since then a number of other corepressors of agonist-bound NRs have been discovered. Among them are LCoR, PRAME, REA, MTA1, NSD1, and COPR1 Although they exhibit a great diversity of structure, mechanism of repression and pathophysiological function, these corepressors frequently have one or more NR boxes and often recruit histone deacetylases to exert their repressive effects. This review highlights these more recently discovered corepressors and addresses their potential functions in transcription regulation, disease pharmacologic responses and xenobiotic metabolism.

  5. Multiple tyrosine metabolites are GPR35 agonists

    PubMed Central

    Deng, Huayun; Hu, Haibei; Fang, Ye

    2012-01-01

    Both kynurenic acid and 2-acyl lysophosphatidic acid have been postulated to be the endogenous agonists of GPR35. However, controversy remains whether alternative endogenous agonists exist. The molecular targets accounted for many nongenomic actions of thyroid hormones are mostly unknown. Here we report the agonist activity of multiple tyrosine metabolites at the GPR35. Tyrosine metabolism intermediates that contain carboxylic acid and/or catechol functional groups were first selected. Whole cell dynamic mass redistribution (DMR) assays enabled by label-free optical biosensor were then used to characterize their agonist activity in native HT-29. Molecular assays including β-arrestin translocation, ERK phosphorylation and receptor internalization confirmed that GPR35 functions as a receptor for 5,6-dihydroxyindole-2-carboxylic acid, 3,3′,5′-triiodothyronine, 3,3′,5-triiodothyronine, gentisate, rosmarinate, and 3-nitrotyrosine. These results suggest that multiple tyrosine metabolites are alternative endogenous ligands of GPR35, and GPR35 may represent a druggable target for treating certain diseases associated with abnormality of tyrosine metabolism. PMID:22523636

  6. The fibroblast growth factor receptor 2 p.Ala172Phe mutation in Pfeiffer syndrome--history repeating itself.

    PubMed

    Jay, Sally; Wiberg, Akira; Swan, Marc; Lester, Tracy; Williams, Louise J; Taylor, Indira B; Johnson, David; Wilkie, Andrew O M

    2013-05-01

    Pfeiffer syndrome is an autosomal dominant condition classically combining craniosynostosis with digital anomalies of the hands and feet. The majority of cases are caused by heterozygous mutations in the third immunoglobulin-like domain (IgIII) of FGFR2, whilst a small number of cases can be attributed to mutations outside this region of the protein. A mild form of Pfeiffer syndrome can rarely be caused by a specific mutation in FGFR1. We report on the clinical and genetic findings in a three generation British family with Pfeiffer syndrome caused by a heterozygous missense mutation, p.Ala172Phe, located in the IgII domain of FGFR2. This is the first reported case of this particular mutation since Pfeiffer's index case, originally described in a German family in 1964, on which basis the syndrome was eponymously named. Genetic analysis demonstrated the two families to be unrelated. Similarities in phenotypes between the two families are discussed. Independent genetic origins, but phenotypic similarities in the two families add to the evidence supporting the theory of selfish spermatogonial selective advantage for this rare gain-of-function FGFR2 mutation.

  7. Rapid Brownian Motion Primes Ultrafast Reconstruction of Intrinsically Disordered Phe-Gly Repeats Inside the Nuclear Pore Complex

    PubMed Central

    Moussavi-Baygi, R.; Mofrad, M. R. K.

    2016-01-01

    Conformational behavior of intrinsically disordered proteins, such as Phe-Gly repeat domains, alters drastically when they are confined in, and tethered to, nan channels. This has challenged our understanding of how they serve to selectively facilitate translocation of nuclear transport receptor (NTR)-bearing macromolecules. Heterogeneous FG-repeats, tethered to the NPC interior, nonuniformly fill the channel in a diameter-dependent manner and adopt a rapid Brownian motion, thereby forming a porous and highly dynamic polymeric meshwork that percolates in radial and axial directions and features two distinguishable zones: a dense hydrophobic rod-like zone located in the center, and a peripheral low-density shell-like zone. The FG-meshwork is locally disrupted upon interacting with NTR-bearing macromolecules, but immediately reconstructs itself between 0.44 μs and 7.0 μs, depending on cargo size and shape. This confers a perpetually-sealed state to the NPC, and is solely due to rapid Brownian motion of FG-repeats, not FG-repeat hydrophobic bonds. Elongated-shaped macromolecules, both in the presence and absence of NTRs, penetrate more readily into the FG-meshwork compared to their globular counterparts of identical volume and surface chemistry, highlighting the importance of the shape effects in nucleocytoplasmic transport. These results can help our understanding of geometrical effects in, and the design of, intelligent and responsive biopolymer-based materials in nanofiltration and artificial nanopores. PMID:27470900

  8. Adsorbents with high selectivity for uremic middle molecular peptides containing the Asp-Phe-Leu-Ala-Glu sequence.

    PubMed

    Qiao, Yitao; Zhao, Jianxin; Li, Pinglin; Wang, Jun; Feng, Jing; Wang, Wei; Sun, Hongwei; Ma, Yi; Yuan, Zhi

    2010-05-18

    Asp-Phe-Leu-Ala-Glu (DE5) is a frequent sequence of many toxic middle molecular peptides that accumulate in uremic patients. To eliminate these peptides by hemoperfusion, three adsorbents (CP1-Zn(2+), CP2-Zn(2+), and CP3-Zn(2+)) were designed on the basis of coordination and hydrophobic interactions. Adsorption experiments indicated that CP2-Zn(2+) had the highest affinity for DE5 among these three adsorbents. Also, the adsorption capacity of CP2-Zn(2+) in DE5 and DE5-containing peptides was about 2-6 times higher than that of peptides without the DE5 sequence. Linear polymers bearing the same functional groups of the adsorbents were used as models to study the adsorption mechanism via isothermal titration calorimetry (ITC) and computer-aided analyses. The results indicated that coordination and hydrophobic interactions played the most important roles in their affinity. When two carboxyl moieties on Asp and Glu residues coordinated to CP2-Zn(2+), the hydrophobic interaction took place by the aggregation of the hydrophobic amino acid residues with phenyl group on CP2-Zn(2+). The optimal collaboration of these interactions led to the tight binding and selective adsorption of DE5-containing peptides onto CP2-Zn(2+). These results may provide new insight into the design of affinity adsorbents for peptides containing DE5-like sequences.

  9. Serotonergic agonists behave as partial agonists at the dopamine D2 receptor.

    PubMed

    Rinken, A; Ferré, S; Terasmaa, A; Owman, C; Fuxe, K

    1999-02-25

    RAT dopamine D2short receptors expressed in CHO cells were characterized by activation of [35S]GTPgammaS binding. There were no significant differences between the maximal effects seen in activation of [35S]GTPgammaS binding caused by dopaminergic agonists, but the effects of 5-HT, 8OH-DPAT and 5-methoxytryptamine amounted to 47 +/- 7%, 43 +/- 5% and 70 +/- 7% of the dopamine effect, respectively. The dopaminergic antagonist (+)butaclamol inhibited activations of both types of ligands with equal potency (pA2 = 8.9 +/- 0.1), indicating that only one type of receptor is involved. In competition with [3H]raclopride binding, dopaminergic agonists showed 53 +/- 2% of the binding sites in the GTP-dependent high-affinity state, whereas 5-HT showed only 20 +/- 3%. Taken together, the results indicate that serotonergic agonists behave as typical partial agonists for D2 receptors with potential antiparkinsonian activity.

  10. Mu opioid receptor agonist DAMGO-induced suppression of saccharin intake in Lewis and Fischer rats.

    PubMed

    Liu, Chuang; Sue Grigson, Patricia

    2005-12-07

    Rats suppress intake of a saccharin cue when paired with a drug of abuse such as morphine or cocaine. Relative to Lewis rats, Fischer rats exhibit greater avoidance of a saccharin cue following saccharin-morphine pairings. The present study used the mu agonist, [D-Ala2,N-MePhe4,Gly-ol5]enkephalin (DAMGO), to test whether strain differences in sensitivity of the mu receptor contribute to this effect. Water-deprived Lewis and Fischer rats were given 5 min access to 0.15% saccharin followed by an icv injection of either DAMGO (0.5 microg/1 microl/rat) or an equal volume of saline. There were six taste-drug pairings occurring at 48 h intervals. The results showed that, relative to the saline treated controls, all rats reduced intake of the saccharin cue following saccharin-DAMGO pairings. No differences occurred between strains. These data suggest that greater morphine-induced suppression of saccharin intake by the Fischer rats is not likely mediated by differences in sensitivity of the mu receptor. Other mechanisms are implicated.

  11. Wheel running reduces high-fat diet intake, preference and mu-opioid agonist stimulated intake.

    PubMed

    Liang, Nu-Chu; Bello, Nicholas T; Moran, Timothy H

    2015-05-01

    The ranges of mechanisms by which exercise affects energy balance remain unclear. One potential mechanism may be that exercise reduces intake and preference for highly palatable, energy dense fatty foods. The current study used a rodent wheel running model to determine whether and how physical activity affects HF diet intake/preference and reward signaling. Experiment 1 examined whether wheel running affected the ability of intracerebroventricular (ICV) μ opioid receptor agonist D-Ala2, NMe-Phe4, Glyol5-enkephalin (DAMGO) to increase HF diet intake. Experiment 2 examined the effects of wheel running on the intake of and preference for a previously preferred HF diet. We also assessed the effects of wheel running and diet choice on mesolimbic dopaminergic and opioidergic gene expression. Experiment 1 revealed that wheel running decreased the ability of ICV DAMGO administration to stimulate HF diet intake. Experiment 2 showed that wheel running suppressed weight gain and reduced intake and preference for a previously preferred HF diet. Furthermore, the mesolimbic gene expression profile of wheel running rats was different from that of their sedentary paired-fed controls but similar to that of sedentary rats with large HF diet consumption. These data suggest that alterations in preference for palatable, energy dense foods play a role in the effects of exercise on energy homeostasis. The gene expression results also suggest that the hedonic effects of exercise may substitute for food reward to limit food intake and suppress weight gain.

  12. Determination of phenylephrine hydrochloride, chlorpheniramine maleate, and methscopolamine nitrate in tablets or capsules by liquid chromatography with two UV absorbance detectors in series.

    PubMed

    Cieri, Uco R

    2006-01-01

    A procedure is presented for the simultaneous determination of phenylephrine HCI (PE), chlorpheniramine maleate (CM), and methscopolamine nitrate in commercial tablets or capsules by liquid chromatography (LC) with 2 UV absorbance detectors in series. Reference and sample solutions are prepared in methanol. LC separations are performed on a 7.5 cm Novapak silica column. The mobile phase is prepared by mixing 930 mL methanol with 70 mL of a 0.5% aqueous solution of 1-pentanesulfonic acid, sodium salt. The injection volume is 20 microL; the flow rate is approximately 1 mL/min. Retention times are approximately 1.5 min for PE, 3 min for CM, and 6 min for methscopolamine nitrate. One detector determines the first 2 compounds at 265 nm, but the third compound does not produce a detectable peak. The other detector set at 210 nm generates peaks for all 3 compounds, but only methscopolamine is within the recorder range; the other 2 compounds are exceedingly off scale. If it is not feasible or desirable to arrange 2 UV absorbance detectors in series, separate determinations can be made, one for the first 2 compounds and the other for the third component of the mixture. Two commercial samples of tablets and 2 commercial samples of capsules were analyzed by the proposed method. Recovery studies were also conducted with amounts of the 3 compounds ranging from 80 to 120% of the quantities present in the sample solutions.

  13. Clinical assessment of the warming sensation accompanying flavor 316282 in a cold and cough syrup containing paracetamol, phenylephrine hydrochloride, and guaifenesin

    PubMed Central

    Monnet, Joëlle

    2014-01-01

    Objective: The primary objective was to assess the warming sensation caused by flavor 316282 in a cold and cough product in the target population. Methods: A single-cohort, single-treatment arm, open-label study. Subjects received one 30-mL dose of syrup containing flavor 316282, paracetamol, phenylephrine hydrochloride, and guaifenesin and recorded onset and disappearance of any warming sensation in the mouth/throat. Subjects’ assessment of strength and appeal of the sensation, taste, texture, and acceptability of the product as a cold and cough remedy was investigated using questionnaires. Results: A total of 51 subjects were included; 47 (92.1%) experienced a warming sensation. The median duration of the warming sensation was 100 s (95% confidence interval = 82 s, 112 s). The majority of subjects rated the syrup as excellent, good, or fair for treatment of cough and cold symptoms (96.1%), taste (80.4%), and texture (98.0%). There were no safety concerns, and the syrup was well tolerated. Most subjects liked the warming sensation. Conclusions: Flavor 316282 in a cold and cough syrup is associated with a warming sensation. The syrup is well tolerated, safe, and palatable. PMID:26770699

  14. Kinetic properties of C-11 phenylephrine in isolated rat heart: Effects of di-deuterium substitution, age, MAO inhibition, and reserpine

    SciTech Connect

    Raffel, D.M.; Rosario, R.B. del; Tluczek, L.

    1995-05-01

    Elimination of the {alpha}-carbon CH{sub 3} group from C-11 hydroxyephedrine (HED) yields a new radiotracer for cardiac sympathetic neurons: C-11 phenylephrine (PHEN). This small structural change has profound effects on the tracer kinetics - HED is not metabolized by neuronal monoamine oxidase (MAO), while PHEN is an excellent MAO substrate. To assess the influence of MAO metabolism and vesicular storage on PHEN kinetics a series of constant infusion studies were performed. Isolated working rat hearts were perfused under control conditions for 25 min, then switched to a second perfusate circuit containing PHEN at tracer concentrations. PHEN was infused for 10 min then the heart switched back to normal perfusate to effect washout of PHEN. The amount of PHEN in the heart was externally measured using coinsidence detection. The data between 1 and 4 min were used to estimate an uptake constant, K{sub up} (ml/min/g wet). Washout data were fit to multiple exponentials. Several studies were done: (1) To slow MAO metabolism, the dideuterium substituted analog C-11 D{sub 2-}PHEN was made and studied as described above. (2) For both tracers, the effect of age on washout kinetics was studied as rat heart MAO levels steadily increase throughout the animal`s life. (3) The effect of MAO inhibition was studied using 100 {mu}M pargyline throughout the experiment. (4) Reserpine pretreated rats were used to assess the influence of vesicular storage on tracer kinetics.

  15. Development and validation of RP-HPLC method for simultaneous estimation of nimesulide, phenylephrine hydrochloride, chlorpheniramine maleate and caffeine anhydrous in pharmaceutical dosage form.

    PubMed

    Kumar, Ashok; Sharma, Rishbha; Nair, Anroop; Saini, Gautam

    2012-01-01

    In this study, a simple, specific and accurate reverse phase high performance liquid chromatographic method was developed for the simultaneous determination of nimesulide (NS), phenylephrine hydrochloride (PE), chlorpheniramine maleate (CPM) and caffeine anhydrous (CF) in pharmaceutical dosage forms. A reversed phase Hypersil phenyl column (4.6 mm x 25 cm) with mobile phase having pH 5.5 consisting of methanol and buffer (55:45, v/v) was used. The flow rate was 1.0 mL per minute and the effluents were monitored at 214 nm. The retention times of all the drugs were found to be 7.47 min (NS), 3.944 min (PE), 4.55 min (CF) and 17.15 min (CPM), respectively. The linearity for all the drugs was obtained in the range of 300-800 microg/mL (NS), 15-32 microg/mL (PE), 16-32 microg/mL (CPM) and 30-180 microg/mL (CF), respectively. The results of analysis have been well validated according to guidelines of International Conference of Harmonisation of technical requirements for registration of pharmaceuticals for human use. The method was found to be simple, precise, economical, less time consuming and reproducible. Hence, the suggested procedure could be used for the determination of all the four drugs in commercial preparations.

  16. Reduction in renal blood flow following administration of norepinephrine and phenylephrine in septic rats treated with Kir6.1 ATP-sensitive and KCa1.1 calcium-activated K+ channel blockers.

    PubMed

    da Rosa Maggi Sant'Helena, Bruna; Guarido, Karla L; de Souza, Priscila; Crestani, Sandra; da Silva-Santos, J Eduardo

    2015-10-15

    We evaluated the effects of K+ channel blockers in the vascular reactivity of in vitro perfused kidneys, as well as on the influence of vasoactive agents in the renal blood flow of rats subjected to the cecal ligation and puncture (CLP) model of sepsis. Both norepinephrine and phenylephrine had the ability to increase the vascular perfusion pressure reduced in kidneys of rats subjected to CLP at 18 h and 36 h before the experiments. The non-selective K+ channel blocker tetraethylammonium, but not the Kir6.1 blocker glibenclamide, normalized the effects of phenylephrine in kidneys from the CLP 18 h group. Systemic administration of tetraethylammonium, glibenclamide, or the KCa1.1 blocker iberiotoxin, did not change the renal blood flow in control or septic rats. Norepinephrine or phenylephrine also had no influence on the renal blood flow of septic animals, but its injection in rats from the CLP 18 h group previously treated with either glibenclamide or iberiotoxin resulted in an exacerbated reduction in the renal blood flow. These results suggest an abnormal functionality of K+ channels in the renal vascular bed in sepsis, and that the blockage of different subtypes of K+ channels may be deleterious for blood perfusion in kidneys, mainly when associated with vasoactive drugs.

  17. Development of Spexin-based Human Galanin Receptor Type II-Specific Agonists with Increased Stability in Serum and Anxiolytic Effect in Mice

    PubMed Central

    Reyes-Alcaraz, Arfaxad; Lee, Yoo-Na; Son, Gi Hoon; Kim, Nam Hoon; Kim, Dong-Kyu; Yun, Seongsik; Kim, Dong-Hoon; Hwang, Jong-Ik; Seong, Jae Young

    2016-01-01

    The novel neuropeptide spexin (SPX) was discovered to activate galanin receptor 2 (GALR2) and 3 (GALR3) but not galanin receptor 1 (GALR1). Although GALR2 is known to display a function, particularly in anxiety, depression, and appetite regulation, the further determination of its function would benefit from a more stable and selective agonist that acts only at GALR2. In the present study, we developed a GALR2-specific agonist with increased stability in serum. As galanin (GAL) showed a low affinity to GALR3, the residues in SPX were replaced with those in GAL, revealing that particular mutations such as Gln5 → Asn, Met7 → Ala, Lys11 → Phe, and Ala13 → Pro significantly decreased potencies toward GALR3 but not toward GALR2. Quadruple (Qu) mutation of these residues still retained potency to GALR2 but totally abolished the potency to both GALR3 and GALR1. The first amino acid modifications or D-Asn1 substitution significantly increased the stability when they are incubated in 100% fetal bovine serum. Intracerebroventricular administration of the mutant peptide with D-Asn1 and quadruple substitution (dN1-Qu) exhibited an anxiolytic effect in mice. Taken together, the GALR2-specific agonist with increased stability can greatly help delineation of GALR2-mediated functions and be very useful for treatments of anxiety disorder. PMID:26907960

  18. PHE in Action”: Development and Modeling of an Intervention to Improve Patient Engagement among Older Adults

    PubMed Central

    Menichetti, Julia; Graffigna, Guendalina

    2016-01-01

    The increasing prevalence of chronic conditions among older adults constitutes a major public health problem. Thus, changes in lifestyles are required to prevent secondary conditions and sustain good care practices. While patient engagement received great attention in the last years as key strategy to solve this issue, to date no interventions exist to sustain the engagement of older chronic patients toward their health management. This study describes the design, development, and optimization of PHEinAction, a theoretically-driven intervention program to increase patient engagement in older chronic populations and consequently to foster healthy changes that can help reduce risks of health problems. The development process followed the UK Medical Research Council's (MRC) guidelines and involved selecting the theoretical base for the intervention, identifying the relevant evidence-based literature, and conducting exploratory research to qualitatively evaluate program's feasibility, acceptability, and comprehension. The result was a user-endorsed intervention designed to improve older patients' engagement in health management based on the theoretical framework of the Patient Health Engagement (PHE) model. The intervention program, which emerged from this process, consisted of 2 monthly face-to-face 1-h sessions delivered by a trained facilitator and one brief telephonic consultation, and aimed to facilitate a range of changes for patient engagement (e.g., motivation to change, health information seeking and use, emotional adjustment, health behaviors planning). PHEinAction is the first example of a theoretically-based patient engagement intervention designed for older chronic targets. The intervention program is based on psychological theory and evidence; it facilitates emotional, psychological, and behavioral processes to support patient engagement and lifestyle change and maintenance. It provides estimates of the extent to which it could help high-risk groups

  19. The structure of the genomic Bacillus subtilis dUTPase: novel features in the Phe-lid.

    PubMed

    García-Nafría, Javier; Burchell, Lynn; Takezawa, Mine; Rzechorzek, Neil J; Fogg, Mark J; Wilson, Keith S

    2010-09-01

    dUTPases are a ubiquitous family of enzymes that are essential for all organisms and catalyse the breakdown of 2-deoxyuridine triphosphate (dUTP). In Bacillus subtilis there are two homotrimeric dUTPases: a genomic and a prophage form. Here, the structures of the genomic dUTPase and of its complex with the substrate analogue dUpNHpp and calcium are described, both at 1.85 A resolution. The overall fold resembles that of previously solved trimeric dUTPases. The C-terminus, which contains one of the conserved sequence motifs, is disordered in both structures. The crystal of the complex contains six independent protomers which accommodate six dUpNHpp molecules, with three triphosphates in the trans conformation and the other three in the active gauche conformation. The structure of the complex confirms the role of several key residues that are involved in ligand binding and the position of the catalytic water. Asp82, which has previously been proposed to act as a general base, points away from the active site. In the complex Ser64 reorients in order to hydrogen bond the phosphate chain of the substrate. A novel feature has been identified: the position in the sequence of the ;Phe-lid', which packs against the uracil moiety, is adjacent to motif III, whereas in all other dUTPase structures the lid is in a conserved position in motif V of the flexible C-terminal arm. This requires a reconsideration of some aspects of the accepted mechanism.

  20. Agonistic and reproductive interactions in Betta splendens.

    PubMed

    Bronstein, P M

    1984-12-01

    Reproductive and agonistic behaviors in Siamese fighting fish were investigated in eight experiments, and some consequences and determinants of these sequences were isolated. First, fights and the formation of dominance-subordinancy relations were studied. Second, it was determined that large body size as well as males' prior residency in a tank produced an agonistic advantage; the magnitude of this advantage was positively related to the duration of residency. Third, the prior-residency effect in Bettas was determined by males' familiarity with visual and/or tactile cues in their home tanks. Fourth, dominant males had greater access to living space and were more likely to display at a mirror, build nests, and approach females than were subordinates. Finally, it was discovered that chemical cues associated with presumedly inert plastic tank dividers influence Bettas' social behavior.

  1. Agonists block currents through acetylcholine receptor channels.

    PubMed Central

    Sine, S M; Steinbach, J H

    1984-01-01

    We have examined the effects of high concentrations of cholinergic agonists on currents through single acetylcholine receptor (AChR) channels on clonal BC3H1 cells. We find that raised concentrations of acetylcholine (ACh; above 300 microM) or carbamylcholine (Carb; above 1,000 microM) produce a voltage- and concentration-dependent reduction in the mean single-channel current. Raised concentrations of suberyldicholine (Sub; above 3 microM) produce a voltage- and concentration-dependent increase in the number of brief duration low-conductance interruptions of open-channel currents. These observations can be quantitatively described by a model in which agonist molecules enter and transiently occlude the ion-channel of the AChR. PMID:6478036

  2. Ropinirole, a non-ergoline dopamine agonist.

    PubMed

    Jost, Wolfgang H; Angersbach, Dieter

    2005-01-01

    Dopamine agonists have become indispensable in the treatment of Parkinson's disease. In every-day practice, however, the decision to select the best compound for an individual patient is rendered difficult because of the large number of substances available on the market. This review article provides a closer look at the experimental and clinical studies with ropinirole published so far. Ropinirole is a non-ergoline dopamine agonist which has been proven to be effective in both, monotherapy and combination therapy of idiopathic Parkinson's disease. In addition to ameliorating bradykinesia, rigor, and tremor, ropinirole facilitates the daily life and improves depressive moods of patients with Parkinson's disease. The long-term complications of levodopa are avoided, and problems commonly associated with levodopa treatment are reduced. Ropinirole appears to have a neuroprotective effect. In addition to Parkinson's disease, ropinirole has also been used successfully in the treatment of restless legs syndrome.

  3. The identification of orally bioavailable thrombopoietin agonists.

    PubMed

    Munchhof, Michael J; Antipas, Amy S; Blumberg, Laura C; Brissette, William H; Brown, Matthew F; Casavant, Jeffrey M; Doty, Jonathan L; Driscoll, James; Harris, Thomas M; Wolf-Gouveia, Lilli A; Jones, Christopher S; Li, Qifang; Linde, Robert G; Lira, Paul D; Marfat, Anthony; McElroy, Eric; Mitton-Fry, Mark; McCurdy, Sandra P; Reiter, Lawrence A; Ripp, Sharon L; Shavnya, Andrei; Thomasco, Lisa M; Trevena, Kristen A

    2009-03-01

    Recently, we disclosed a series of potent pyrimidine benzamide-based thrombopoietin receptor agonists. Unfortunately, the structural features required for the desired activity conferred physicochemical properties that were not favorable for the development of an oral agent. The physical properties of the series were improved by replacing the aminopyrimidinyl group with a piperidine-4-carboxylic acid moiety. The resulting compounds possessed favorable in vivo pharmacokinetic properties, including good bioavailability.

  4. A new alpha-globin variant with increased oxygen affinity in a Swiss family: Hb Frauenfeld [alpha 138(H21)Ser-->Phe, TCC>TTC (alpha 2)].

    PubMed

    Hochuli, Michel; Zurbriggen, Karin; Schmid, Marlis; Speer, Oliver; Rochat, Philippe; Frauchiger, Beat; Kleinert, Peter; Schmugge, Markus; Troxler, Heinz

    2009-01-01

    A new alpha-globin mutation [alpha 138(H21)Ser-->Phe] was found in a 55-year-old male proband with an erythrocytosis known since his youth. Cation exchange high performance liquid chromatography (HPLC) revealed an additional peak eluting slightly before Hb A indicating the presence of a variant. The peak area of the variant was approximately one-third that of Hb A suggesting an alpha-globin variant. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry analysis confirmed the mutation at the protein level. The variant is also detectable with isoelectric focusing and reversed phase HPLC. DNA analysis revealed a heterozygous sequence mutation at codon 138 of the alpha2 gene. A C>T transition at the second nucleotide of the codon indicated a Ser-->Phe exchange. The variant showed increased oxygen affinity and was named Hb Frauenfeld.

  5. Signal Use by Octopuses in Agonistic Interactions.

    PubMed

    Scheel, David; Godfrey-Smith, Peter; Lawrence, Matthew

    2016-02-08

    Cephalopods show behavioral parallels to birds and mammals despite considerable evolutionary distance [1, 2]. Many cephalopods produce complex body patterns and visual signals, documented especially in cuttlefish and squid, where they are used both in camouflage and a range of interspecific interactions [1, 3-5]. Octopuses, in contrast, are usually seen as solitary and asocial [6, 7]; their body patterns and color changes have primarily been interpreted as camouflage and anti-predator tactics [8-12], though the familiar view of the solitary octopus faces a growing list of exceptions. Here, we show by field observation that in a shallow-water octopus, Octopus tetricus, a range of visible displays are produced during agonistic interactions, and these displays correlate with the outcome of those interactions. Interactions in which dark body color by an approaching octopus was matched by similar color in the reacting octopus were more likely to escalate to grappling. Darkness in an approaching octopus met by paler color in the reacting octopus accompanied retreat of the paler octopus. Octopuses also displayed on high ground and stood with spread web and elevated mantle, often producing these behaviors in combinations. This study is the first to document the systematic use of signals during agonistic interactions among octopuses. We show prima facie conformity of our results to an influential model of agonistic signaling [13]. These results suggest that interactions have a greater influence on octopus evolution than has been recognized and show the importance of convergent evolution in behavioral traits.

  6. Dipeptide Phe-Cys derived from in silico thermolysin-hydrolysed RuBisCO large subunit suppresses oxidative stress in cultured human hepatocytes.

    PubMed

    Je, Jae-Young; Cho, Young-Sook; Gong, Min; Udenigwe, Chibuike C

    2015-03-15

    A dipeptide (Phe-Cys) was predicted to be bioactive following bioinformatics analysis of the large subunit of plant and microalgae ribulose-1,5-bisphosphate carboxylase (RuBisCO), which was hydrolysed in silico with thermolysin. The peptide was synthesised and found to possess in vitro reducing potential and inhibitory activity against lipid peroxidation, comparable to the activity of glutathione. In cultured Chang human hepatocytes, 2.5-10 μM Phe-Cys was found to induce the suppression of reactive oxygen species formation and membrane lipid peroxidation in oxidative stressed cells. Intracellular glutathione levels were found to increase in the peptide-treated cells under normal condition, which can potentially contribute in protecting the cells from oxidative damage. Furthermore, Western blot analysis showed that the levels of antioxidant enzymes, catalase and superoxide dismutase-1, increased in the hepatic cells when treated with Phe-Cys in the presence of the oxidant. The results show that this peptide has great potential to be used against oxidative stress-induced health conditions.

  7. Isomerization and epimerization of the aspartyl tetrapeptide Ala-Phe-Asp-GlyOH at pH 10-A CE study.

    PubMed

    Brückner, Christin; Bunz, Svenja-Catharina; Imhof, Diana; Neusüss, Christian; Scriba, Gerhard K E

    2013-09-01

    Isomerization and enantiomerization of Asp in the tetrapeptide Ala-Phe-Asp-GlyOH are studied at pH 10 and 80°C as well as 25°C. CE-MS allowed the distinction between α-Asp and β-Asp linkages in degradation products based on the ratio of the b and y fragment ions. Besides isomerization and enantiomerization of Asp, enantiomerization of Ala and Phe was also observed at both temperatures by chiral amino acid HPLC analysis using Marfey's reagent for derivatization. The rate of enantiomerization of the amino acids proceeded in the order Asp > Ala > Phe. The CE assay was validated with respect to linearity, LOQ, LOD, and precision and employed to characterize the time course of the degradation of the tetrapeptide upon incubation in borate buffer, pH 10. Isomerization to β-Asp peptides was identified as the major degradation reaction. The configuration of Asp or Ala affected the half-life of the starting peptide to a minor extent but did not influence the distribution of the individual products under equilibrium conditions at 80°C. Degradation at 25°C proceeded very slowly so that the equilibrium was not reached after 245 days.

  8. Partial tandem duplication of mtDNA-tRNA(Phe) impairs mtDNA translation in late-onset mitochondrial myopathy.

    PubMed

    Arzuffi, Paola; Lamperti, Costanza; Fernandez-Vizarra, Erika; Tonin, Paola; Morandi, Lucia; Zeviani, Massimo

    2012-01-01

    An 80-year-old woman (PI) has been suffering of late onset progressive weakness and wasting of lower-limb muscles, accompanied by high creatine kinase levels in blood. A muscle biopsy, performed at 63 years, showed myopathic features with partial deficiency of cytochrome c oxidase. A second biopsy taken 7 years later confirmed the presence of a mitochondrial myopathy but also of vacuolar degeneration and other morphological features resembling inclusion body myopathy. Her 46-year-old daughter (PII) and 50-year-old son (PIII) are clinically normal, but the creatine kinase levels were moderately elevated and the EMG was consistently myopathic in both. Analysis of mitochondrial DNA sequence revealed in all three patients a novel, homoplasmic 15 bp tandem duplication adjacent to the 5' end of mitochondrial tRNA(Phe) gene, encompassing the first 11 nucleotides of this gene and the four terminal nucleotides of the adjacent D-loop region. Both mutant fibroblasts and cybrids showed low oxygen consumption rate, reduced mitochondrial protein synthesis, and decreased mitochondrial tRNA(Phe) amount. These findings are consistent with an unconventional pathogenic mechanism causing the tandem duplication to interfere with the maturation of the mitochondrial tRNA(Phe) transcript.

  9. Influence of the Envelope gp120 Phe 43 Cavity on HIV-1 Sensitivity to Antibody-Dependent Cell-Mediated Cytotoxicity Responses.

    PubMed

    Prévost, Jérémie; Zoubchenok, Daria; Richard, Jonathan; Veillette, Maxime; Pacheco, Beatriz; Coutu, Mathieu; Brassard, Nathalie; Parsons, Matthew S; Ruxrungtham, Kiat; Bunupuradah, Torsak; Tovanabutra, Sodsai; Hwang, Kwan-Ki; Moody, M Anthony; Haynes, Barton F; Bonsignori, Mattia; Sodroski, Joseph; Kaufmann, Daniel E; Shaw, George M; Chenine, Agnès L; Finzi, Andrés

    2017-04-01

    HIV-1-infected cells presenting envelope glycoproteins (Env) in the CD4-bound conformation on their surface are preferentially targeted by antibody-dependent cellular-mediated cytotoxicity (ADCC). HIV-1 has evolved sophisticated mechanisms to avoid the exposure of Env ADCC epitopes by downregulating CD4 and by limiting the overall amount of Env on the cell surface. In HIV-1, substitution of large residues such as histidine or tryptophan for serine 375 (S375H/W) in the gp120 Phe 43 cavity, where Phe 43 of CD4 contacts gp120, results in the spontaneous sampling of an Env conformation closer to the CD4-bound state. While residue S375 is well conserved in the majority of group M HIV-1 isolates, CRF01_AE strains have a naturally occurring histidine at this position (H375). Interestingly, CRF01_AE is the predominant circulating strain in Thailand, where the RV144 trial took place. In this trial, which resulted in a modest degree of protection, ADCC responses were identified as being part of the correlate of protection. Here we investigate the influence of the Phe 43 cavity on ADCC responses. Filling this cavity with a histidine or tryptophan residue in Env with a natural serine residue at this position (S375H/W) increased the susceptibility of HIV-1-infected cells to ADCC. Conversely, the replacement of His 375 by a serine residue (H375S) within HIV-1 CRF01_AE decreased the efficiency of the ADCC response. Our results raise the intriguing possibility that the presence of His 375 in the circulating strain where the RV144 trial was held contributed to the observed vaccine efficacy.IMPORTANCE HIV-1-infected cells presenting Env in the CD4-bound conformation on their surface are preferentially targeted by ADCC mediated by HIV-positive (HIV(+)) sera. Here we show that the gp120 Phe 43 cavity modulates the propensity of Env to sample this conformation and therefore affects the susceptibility of infected cells to ADCC. CRF01_AE HIV-1 strains have an unusual Phe 43 cavity

  10. Analogs of alpha-melanocyte stimulating hormone with high agonist potency and selectivity at human melanocortin receptor 1b: the role of Trp(9) in molecular recognition.

    PubMed

    Bednarek, Maria A; Macneil, Tanya; Tang, Rui; Fong, Tung M; Angeles Cabello, M; Maroto, Marta; Teran, Ana

    2008-05-01

    alpha-Melanocyte stimulating hormone (alphaMSH), Ac-Ser(1)-Tyr(2)-Ser(3)-Met(4)-Glu(5)-His(6)-Phe(7)-Arg(8)-Trp(9)-Gly(10)-Lys(11)-Pro(12)-Val(13)-NH(2), is an endogenous agonist for the melanocortin receptor 1 (MC1R), the receptor found in the skin, several types of immune cells, and other peripheral sites. Three-dimensional models of complexes of this receptor with alphaMSH and its synthetic analog NDP-alphaMSH, Ac-Ser(1)-Tyr(2)-Ser(3)-Nle(4)-Glu(5)-His(6)-D-Phe(7)-Arg(8)-Trp(9)-Gly(10)-Lys(11)-Pro(12)-Val(13)-NH(2), have been previously proposed. In those models, the 6-9 segment of the ligand was considered essential for the ligand-receptor interactions. In this study, we probed the role of Trp(9) of NDP-alphaMSH in interactions with hMC1bR. Analogs of NDP-alphaMSH with various amino acids in place of Trp(9) were synthesized and tested in vitro in receptor affinity binding and cAMP functional assays at human melanocortin receptors 1b, 3, 4, and 5 (hMC1b,3-5R). Several new compounds displayed high agonist potency at hMC1bR (EC(50) = 0.5-5 nM) and receptor subtype selectivity greater than 2000-fold versus hMC3-5R. The Trp(9) residue of NDP-alphaMSH was determined to be not essential for molecular recognition at hMC1bR.

  11. Potent and selective agonists of alpha-melanotropin (alphaMSH) action at human melanocortin receptor 5; linear analogs of alpha-melanotropin.

    PubMed

    Bednarek, Maria A; MacNeil, Tanya; Tang, Rui; Fong, Tung M; Cabello, M Angeles; Maroto, Marta; Teran, Ana

    2007-05-01

    Alpha-melanotropin, Ac-Ser(1)-Tyr-Ser-Met-Glu-His(6)-Phe(7)-Arg(8)-Trp(9)-Gly-Lys-Pro-Val(13)-NH(2)(1), is a non-selective endogenous agonist for the melanocortin receptor 5; the receptor present in various peripheral tissues and in the brain, cortex and cerebellum. Most of the synthetic analogs of alphaMSH, including a broadly used and more potent the NDP-alphaMSH peptide, Ac-Ser(1)-Tyr-Ser-Nle(4)-Glu-His(6)-D-Phe(7)-Arg(8)-Trp(9)-Gly-Lys-Pro-Val(13)-NH(2), are also not particularly selective for MC5R. To elucidate physiological functions of the melanocortin receptor 5 in rodents and humans, the receptor subtype selective research tools are needed. We report herein syntheses and pharmacological evaluation in vitro of several analogs of NDP-alphaMSH which are highly potent and specific agonists for the human MC5R. The new linear peptides, of structures and solubility properties similar to those of the endogenous ligand alphaMSH, are exemplified by compound 7, Ac-Ser(1)-Tyr-Ser-Met-Glu-Oic(6)-D-4,4'-Bip(7)-Pip(8)-Trp(9)-Gly-Lys-Pro-Val(13)-NH(2) (Oic: octahydroindole-2-COOH, 4,4'-Bip: 4,4'-biphenylalanine, Pip: pipecolic acid), shortly NODBP-alphaMSH, which has an IC(50)=0.74 nM (binding assay) and EC(50)=0.41 (cAMP production assay) at hMC5R nM and greater than 3500-fold selectivity with respect to the melanocortin receptors 1b, 3 and 4. A shorter peptide derived from NODBP-alphaMSH: Ac-Nle-Glu-Oic(6)-D-4,4'-Bip(7)-Pip(8)-Trp(9) -NH(2) (17) was measured to be an agonist only 10-fold less potent at hMC5R than the full length parent peptide. In the structure of this smaller analog, the Nle-Glu-Oic(6)-D-4,4'-Bip(7)-Pip(8) segment was found to be critical for high agonist potency, while the C-terminal Trp(9) residue was shown to be required for high hMC5R selectivity versus hMC1b,3,4R.

  12. Discovery of G Protein-Biased EP2 Receptor Agonists

    PubMed Central

    2016-01-01

    To identify G protein-biased and highly subtype-selective EP2 receptor agonists, a series of bicyclic prostaglandin analogues were designed and synthesized. Structural hybridization of EP2/4 dual agonist 5 and prostacyclin analogue 6, followed by simplification of the ω chain enabled us to discover novel EP2 agonists with a unique prostacyclin-like scaffold. Further optimization of the ω chain was performed to improve EP2 agonist activity and subtype selectivity. Phenoxy derivative 18a showed potent agonist activity and excellent subtype selectivity. Furthermore, a series of compounds were identified as G protein-biased EP2 receptor agonists. These are the first examples of biased ligands of prostanoid receptors. PMID:26985320

  13. Sports doping: emerging designer and therapeutic β2-agonists.

    PubMed

    Fragkaki, A G; Georgakopoulos, C; Sterk, S; Nielen, M W F

    2013-10-21

    Beta2-adrenergic agonists, or β2-agonists, are considered essential bronchodilator drugs in the treatment of bronchial asthma, both as symptom-relievers and, in combination with inhaled corticosteroids, as disease-controllers. The use of β2-agonists is prohibited in sports by the World Anti-Doping Agency (WADA) due to claimed anabolic effects, and also, is prohibited as growth promoters in cattle fattening in the European Union. This paper reviews the last seven-year (2006-2012) literature concerning the development of novel β2-agonists molecules either by modifying the molecule of known β2-agonists or by introducing moieties producing indole-, adamantyl- or phenyl urea derivatives. New emerging β2-agonists molecules for future therapeutic use are also presented, intending to emphasize their potential use for doping purposes or as growth promoters in the near future.

  14. Agonist-receptor-arrestin, an alternative ternary complex with high agonist affinity.

    PubMed

    Gurevich, V V; Pals-Rylaarsdam, R; Benovic, J L; Hosey, M M; Onorato, J J

    1997-11-14

    The rapid decrease of a response to a persistent stimulus, often termed desensitization, is a widespread biological phenomenon. Signal transduction by numerous G protein-coupled receptors appears to be terminated by a strikingly uniform two-step mechanism, most extensively characterized for the beta2-adrenergic receptor (beta2AR), m2 muscarinic cholinergic receptor (m2 mAChR), and rhodopsin. The model predicts that activated receptor is initially phosphorylated and then tightly binds an arrestin protein that effectively blocks further G protein interaction. Here we report that complexes of beta2AR-arrestin and m2 mAChR-arrestin have a higher affinity for agonists (but not antagonists) than do receptors not complexed with arrestin. The percentage of phosphorylated beta2AR in this high affinity state in the presence of full agonists varied with different arrestins and was enhanced by selective mutations in arrestins. The percentage of high affinity sites also was proportional to the intrinsic activity of an agonist, and the coefficient of proportionality varies for different arrestin proteins. Certain mutant arrestins can form these high affinity complexes with unphosphorylated receptors. Mutations that enhance formation of the agonist-receptor-arrestin complexes should provide useful tools for manipulating both the efficiency of signaling and rate and specificity of receptor internalization.

  15. Agonistic behavior in food animals: review of research and techniques.

    PubMed

    McGlone, J J

    1986-04-01

    One type of social behavior--agonistic behavior--is commonly observed among food animals. Agonistic behaviors are those behaviors which cause, threaten to cause or seek to reduce physical damage. Agonistic behavior is comprised of threats, aggression and submission. While any one of these divisions of agonistic behavior may be observed alone, they usually are found, in sequence, from the start to the end of an interaction. Food animals may show interspecific or intraspecific agonistic behaviors. Interspecific agonistic behavior has not been extensively studied but it is agriculturally important because farm workers may become injured or killed by aggressive food animals. Types of intraspecific agonistic behavior are: when animals are brought together, intermale fighting, resource defense, inter-gender fighting and aberrant aggression. Common pitfalls in research on agonistic behavior among food animals include too few replicates to detect a biological difference, the assumptions of the analysis are not met, only aggression and not submission or other agonistic behavior components are measured, incomplete description of the behaviors are reported and a complete, quantitive ethogram did not form the basis for selecting behavioral measures.

  16. Computational modeling toward understanding agonist binding on dopamine 3.

    PubMed

    Zhao, Yaxue; Lu, Xuefeng; Yang, Chao-Yie; Huang, Zhimin; Fu, Wei; Hou, Tingjun; Zhang, Jian

    2010-09-27

    The dopamine 3 (D3) receptor is a promising therapeutic target for the treatment of nervous system disorders, such as Parkinson's disease, and current research interests primarily focus on the discovery/design of potent D3 agonists. Herein, a well-designed computational protocol, which combines pharmacophore identification, homology modeling, molecular docking, and molecular dynamics (MD) simulations, was employed to understand the agonist binding on D3 aiming to provide insights into the development of novel potent D3 agonists. We (1) identified the chemical features required in effective D3 agonists by pharmacophore modeling based upon 18 known diverse D3 agonists; (2) constructed the three-dimensional (3D) structure of D3 based on homology modeling and the pharmacophore hypothesis; (3) identified the binding modes of the agonists to D3 by the correlation between the predicted binding free energies and the experimental values; and (4) investigated the induced fit of D3 upon agonist binding through MD simulations. The pharmacophore models of the D3 agonists and the 3D structure of D3 can be used for either ligand- or receptor-based drug design. Furthermore, the MD simulations further give the insight that the long and flexible EL2 acts as a "door" for agonist binding, and the "ionic lock" at the bottom of TM3 and TM6 is essential to transduce the activation signal.

  17. The M1 muscarinic receptor allosteric agonists AC-42 and 1-[1'-(2-methylbenzyl)-1,4'-bipiperidin-4-yl]-1,3-dihydro-2H-benzimidazol-2-one bind to a unique site distinct from the acetylcholine orthosteric site.

    PubMed

    Jacobson, Marlene A; Kreatsoulas, Constantine; Pascarella, Danette M; O'Brien, Julie A; Sur, Cyrille

    2010-10-01

    Activation of M1 muscarinic receptors occurs through orthosteric and allosteric binding sites. To identify critical residues, site-directed mutagenesis and chimeric receptors were evaluated in functional calcium mobilization assays to compare orthosteric agonists, acetylcholine and xanomeline, M1 allosteric agonists AC-42 (4-n-butyl-1-[4-(2-methylphenyl)-4-oxo-1-butyl]-piperidine hydrogen chloride), TBPB (1-[1'-(2-methylbenzyl)-1,4'-bipiperidin-4-yl]-1,3-dihydro-2H-benzimidazol-2-one), and the clozapine metabolite N-desmethylclozapine. A minimal epitope has been defined for AC-42 that comprises the first 45 amino acids, the third extracellular loop, and seventh transmembrane domain (Mol Pharmacol 61:1297-1302, 2002). Using chimeric M1 and M3 receptor constructs, the AC-42 minimal epitope has been extended to also include transmembrane II. Phe77 was identified as a critical residue for maintenance of AC-42 and TBPB agonist activity. In contrast, the functional activity of N-desmethylclozapine did not require Phe77. To further map the binding site of AC-42, TBPB, and N-desmethylclozapine, point mutations previously reported to affect activities of M1 orthosteric agonists and antagonists were studied. Docking into an M1 receptor homology model revealed that AC-42 and TBPB share a similar binding pocket adjacent to the orthosteric binding site at the opposite face of Trp101. In contrast, the activity of N-desmethylclozapine was generally unaffected by the point mutations studied, and the docking indicated that N-desmethylclozapine bound to a site distinct from AC-42 and TBPB overlapping with the orthosteric site. These results suggest that structurally diverse allosteric agonists AC-42, TBPB, and N-desmethylclozapine may interact with different subsets of residues, supporting the hypothesis that M1 receptor activation can occur through at least three different binding domains.

  18. D-Cycloserine: Agonist turned antagonist.

    PubMed

    Lanthorn, T H

    1994-10-01

    D-Cycloserine can enhance activation of the NMDA receptor complex and could enhance the induction of long-term potentiation (LTP). In animals and humans, D-cycloserine can enhance performance in learning and memory tasks. This enhancing effect can disappear during repeated administration. The enhancing effects are also lost when higher doses are used, and replaced by behavioral and biochemical effects like those produced by NMDA antagonists. It has been reported that NMDA agonists, applied before or after tetanic stimulation, can block the induction of LTP. This may be the result of feedback inhibition of second messenger pathways stimulated by receptor activation. This may explain the antagonist-like effects of glycine partial agonists like D-cycloserine. In clinical trials of D-cycloserine in age-associated memory impairment (AAMI) and Alzheimer's disease, chronic treatment provided few positive effects on learning and memory. This may be due to inhibition of second messenger pathways following chronic stimulation of the receptor complex.

  19. Inverse agonist properties of atypical antipsychotic drugs.

    PubMed

    Akam, Elizabeth; Strange, Philip G

    2004-06-01

    Mechanisms of action of several atypical antipsychotic drugs have been examined at the D(2) dopamine receptor expressed in CHO cells. The drugs tested were found to exhibit inverse agonist activity at the D(2) dopamine receptor based on their effects to potentiate forskolin-stimulated cyclic AMP (cAMP) accumulation. Each of the antipsychotic drugs tested (clozapine, olanzapine, quetiapine and risperidone) increased cAMP accumulation to the same extent. The increase in cAMP was also similar to that seen with typical antipsychotic drugs. Inverse agonism at the D(2) dopamine receptor seems, therefore, to be a property common to all classes of antipsychotic drugs. The effect of sodium ions on the binding of the drugs to the receptor was also assessed. Each of the atypical antipsychotic drugs tested here bound with higher affinity in the absence of sodium ions. Previous studies have shown that some antipsychotic drugs are insensitive to sodium ions and some bind with higher affinity in the presence of sodium ions. Given that all of these antipsychotic drugs are inverse agonists, it may be concluded that this sodium ion sensitivity is unrelated to mechanisms of inverse agonism.

  20. Cyclic analogs of alpha-melanocyte-stimulating hormone (alphaMSH) with high agonist potency and selectivity at human melanocortin receptor 1b.

    PubMed

    Bednarek, Maria A; MacNeil, Tanya; Tang, Rui; Fong, Tung M; Cabello, M Angeles; Maroto, Marta; Teran, Ana

    2008-06-01

    Alpha-melanotropin (alphaMSH), Ac-Ser1-Tyr2-Ser3-Met4-Glu5-His6-Phe7-Arg8-Trp9-Gly10-Lys11-Pro12-Val13-NH2,(1) has been long recognized as an important physiological regulator of skin and hair pigmentation in mammals. Binding of this peptide to the melanocortin receptor 1 (MC1R) leads to activation of tyrosinase, the key enzyme of the melanin biosynthesis pathway. In this study, interactions of the human MC1bR (an isoform of the receptor 1a) with the synthetic cyclic analogs of alphaMSH were studied. These ligands were analogs of MTII, Ac-Nle4-cyclo-(Asp5-His6-D-Phe7-Arg8-Trp9-Lys10)-NH2, a potent pan-agonist at the human melanocortin receptors (hMC1,3-5R). In the structure of MTII, the His6-D-Phe7-Arg8-Trp9 segment has been recognized as "essential" for molecular recognition at the human melanocortin receptors (hMC1,3-5R). Herein, the role of the Trp9 in the ligand interactions with the hMC1b,3-5R has been reevaluated. Analogs with various amino acids in place of Trp9 were synthesized and tested in vitro in receptor affinity binding and cAMP functional assays at human melanocortin receptors 1b, 3, 4 and 5 (hMC1b,3-5R). Several of the new peptides were high potency agonists (partial) at hMC1bR (EC50 from 0.5 to 20 nM) and largely inactive at hMC3-5R. The bulky aromatic side chain in position 9, such as that in Trp, was found not to be essential to agonism (partial) of the studied peptides at hMC1bR.

  1. afa-8 Gene cluster is carried by a pathogenicity island inserted into the tRNA(Phe) of human and bovine pathogenic Escherichia coli isolates.

    PubMed

    Lalioui, L; Le Bouguénec, C

    2001-02-01

    We recently described a new afimbrial adhesin, AfaE-VIII, produced by animal strains associated with diarrhea and septicemia and by human isolates associated with extraintestinal infections. Here, we report that the afa-8 operon, encoding AfaE-VIII adhesin, from the human blood isolate Escherichia coli AL862 is carried by a 61-kb genomic region with characteristics typical of a pathogenicity island (PAI), including a size larger than 10 kb, the presence of an integrase-encoding gene, the insertion into a tRNA locus (pheR), and the presence of a small direct repeat at each extremity. Moreover, the G+C content of the afa-8 operon (46.4%) is lower than that of the E. coli K-12/MG1655 chromosome (50.8%). Within this PAI, designated PAI I(AL862), we identified open reading frames able to code for products similar to proteins involved in sugar utilization. Four probes spanning these sequences hybridized with 74.3% of pathogenic afa-8-positive E. coli strains isolated from humans and animals, 25% of human pathogenic afa-8-negative E. coli strains, and only 8% of fecal strains (P = 0.05), indicating that these sequences are strongly associated with the afa-8 operon and that this genetic association may define a PAI widely distributed among human and animal afa-8-positive strains. One of the distinctive features of this study is that E. coli AL862 also carries another afa-8-containing PAI (PAI II(AL862)), which appeared to be similar in size and genetic organization to PAI I(AL862) and was inserted into the pheV gene. We investigated the insertion sites of afa-8-containing PAI in human and bovine pathogenic E. coli strains and found that this PAI preferentially inserted into the pheV gene.

  2. The role of active-site Phe87 in modulating the organic co-solvent tolerance of cytochrome P450 BM3 monooxygenase

    PubMed Central

    Kuper, Jochen; Tee, Kang Lan; Wilmanns, Matthias; Roccatano, Danilo; Schwaneberg, Ulrich; Wong, Tuck Seng

    2012-01-01

    Understanding the effects of organic co-solvents on protein structure and function is pivotal to engineering enzymes for biotransformation in non-aqueous solvents. The effects of DMSO on the catalytic activity of cytochrome P450 BM3 have previously been investigated and the importance of Phe87 in its organic co-solvent tolerance was identified. To probe the DMSO inactivation mechanism and the functional role of Phe87 in modulating the organic co-solvent tolerance of P450 BM3, the haem domain (Thr1–Leu455) of the F87A variant was cocrystallized in the presence of 14%(v/v) and 28%(v/v) DMSO. At both DMSO concentrations the protein retained the canonical structure of the P450 haem domain without any sign of partial or global unfolding. Interestingly, a DMSO molecule was found in the active site of both structures, with its O atom pointing towards the haem iron. The orientation of the DMSO molecule indicated a dynamic coordination process that was in competition with the active-site water molecule. The ability of the DMSO molecule to coordinate the haem iron is plausibly the main reason why P450 BM3 is inactivated at elevated DMSO concentrations. The data allowed an interesting comparison with the wild-type structures reported previously. A DMSO molecule was found when the wild-type protein was placed in 28%(v/v) DMSO, in which the DMSO molecule coordinated the haem iron directly via its S atom. Intriguingly, no DMSO molecule was observed at 14%(v/v) DMSO for the wild-type structure. These results suggested that the bulky phenyl side chain of Phe87 protects the haem from being accessed by the DMSO molecule and explains the higher tolerance of the wild-type enzyme towards organic co-solvents compared with its F87A variant. PMID:22949185

  3. Adsorption behavior of the three species of the biprotic peptide Phe-Ala onto an end-capped C18-bonded organic/inorganic hybrid stationary phase.

    PubMed

    Gritti, Fabrice; Guiochon, Georges

    2009-12-15

    We recorded the overloaded elution band profiles of the dipeptide phenylalanine-alanine (Phe-Ala) on a column packed with C18-bonded organic (ethyl)/inorganic (silica) hybrid porous particles (BEH), eluted with a series of buffered methanol-water mobile phases (20/80, v/v). The (W)(S)pHs of the mobile phases were successively adjusted with addition of suitable buffers to values of 1.67, 2.44, 3.83, 4.94, 7.41, and 10.71 (where the notation (W)(S)pH means that the pH of the solution is directly measured in the solution (S) after the electrode was calibrated in pure water (W)). The ionic strength of the eluent was kept constant at 20 mM. The injected samples had different sizes and concentrations. The retention of the low-concentration samples was minimum at an intermediate (W)(S)pH (k' approximately 0.5) and maximum for the lowest (k' approximately 1.3) and highest (k' approximately 3.5) (W)(S)pHs showing that the zwitterion (+Phe-Ala-) is less strongly adsorbed than the positively (+Phe-Ala) and negatively (Phe-Ala-) charged species of the dipeptide onto BEH-C18. The elution profiles of the concentrated samples demonstrated that the adsorption isotherm of the zwitterionic species is an anti-Langmuirian Moreau isotherm due to significant adsorbate-adsorbate interactions, whereas the isotherms of the charged species are more conventional Langmuir isotherms. A simple ternary isotherm for the coadsorption of the three dipeptide species is proposed. It accounts well for the complex band profiles observed when large concentrated samples of the peptide are injected under controlled pH conditions. The slight departure between the calculated and the experimental band profiles obtained under uncontrolled pH conditions suggests the possible adsorption of the buffer components onto the packing material and the possible influence of microenvironment effects near the stationary phase surface, which would affect the local pH along the column. Preparative chromatography of

  4. Estrogen receptor agonists for attenuation of neuroinflammation and neurodegeneration

    PubMed Central

    Chakrabarti, Mrinmay; Haque, Azizul; Banik, Naren L.; Nagarkatti, Prakash; Nagarkatti, Mitzi; Ray, Swapan K.

    2014-01-01

    Recent results from laboratory investigations and clinical trials indicate important roles for estrogen receptor (ER) agonists in protecting the central nervous system (CNS) from noxious consequences of neuroinflammation and neurodegeneration. Neurodegenerative processes in several CNS disorders including spinal cord injury (SCI), multiple sclerosis (MS), Parkinson's disease (PD), and Alzheimer's disease (AD) are associated with activation of microglia and astrocytes, which drive the resident neuroinflammatory response. During neurodegenerative processes, activated microglia and astrocytes cause deleterious effects on surrounding neurons. The inhibitory activity of ER agonists on microglia activation might be a beneficial therapeutic option for delaying the onset or progression of neurodegenerative injuries and diseases. Recent studies suggest that ER agonists can provide neuroprotection by modulation of cell survival mechanisms, synaptic reorganization, regenerative responses to axonal injury, and neurogenesis process. The anti-inflammatory and neuroprotective actions of ER agonists are mediated mainly via two ERs known as ERα and ERβ. Although some studies have suggested that ER agonists may be deleterious to some neuronal populations, the potential clinical benefits of ER agonists for augmenting cognitive function may triumph over the associated side effects. Also, understanding the modulatory activities of ER agonists on inflammatory pathways will possibly lead to the development of selective anti-inflammatory molecules with neuroprotective roles in different CNS disorders such as SCI, MS, PD, and AD in humans. Future studies should be concentrated on finding the most plausible molecular pathways for enhancing protective functions of ER agonists in treating neuroinflammatory and neurodegenerative injuries and diseases in the CNS. PMID:25245209

  5. TOXICITY OF AHR AGONISTS TO FISH EARLY LIFE STAGES

    EPA Science Inventory

    Fish early life stages are exceptionally sensitive to the lethal toxicity of chemicals that act as arylhydrocarbon receptor (AhR) agonists. Toxicity characterizations based on 2,3,7,8-tetrachlorodibenzo-p-dioxin, generally the most potent AhR agonist, support the toxicity equiva...

  6. Physical Chemistry to the Rescue: Differentiating Nicotinic and Cholinergic Agonists

    ERIC Educational Resources Information Center

    King, Angela G.

    2005-01-01

    Researches suggest that two agonists can bind to the same binding site of an important transmembrane protein and elicit a biological response through strikingly different binding interactions. Evidence is provided which suggests two possible types of nicotinic acetylcholine receptor agonist binding like acetlycholine (cholinergic) or like nicotine…

  7. Neuroprotection by Alpha 2-Adrenergic Agonists in Cerebral Ischemia

    PubMed Central

    Zhang, Yonghua; Kimelberg, Harold K.

    2005-01-01

    Ischemic brain injury is implicated in the pathophysiology of stroke and brain trauma, which are among the top killers worldwide, and intensive studies have been performed to reduce neural cell death after cerebral ischemia. Alpha 2-adrenergic agonists have been shown to improve the histomorphological and neurological outcome after cerebral ischemic injury when administered during ischemia, and recent studies have provided considerable evidence that alpha 2-adrenergic agonists can protect the brain from ischemia/reperfusion injury. Thus, alpha 2-adrenergic agonists are promising potential drugs in preventing cerebral ischemic injury, but the mechanisms by which alpha 2-adrenergic agonists exert their neuroprotective effect are unclear. Activation of both the alpha 2-adrenergic receptor and imidazoline receptor may be involved. This mini review examines the recent progress in alpha 2-adrenergic agonists - induced neuroprotection and its proposed mechanisms in cerebral ischemic injury. PMID:18369397

  8. Characterization of melanocortin NDP-MSH agonist peptide fragments at the mouse central and peripheral melanocortin receptors.

    PubMed

    Haskell-Luevano, C; Holder, J R; Monck, E K; Bauzo, R M

    2001-06-21

    The central melanocortin receptors, melanocortin-4 (MC4R) and melanocortin-3 (MC3R), are involved in the regulation of satiety and energy homeostasis. The MC4R in particular has become a pharmaceutical industry drug target due to its direct involvement in the regulation of food intake and its potential therapeutic application for the treatment of obesity-related diseases. The melanocortin receptors are stimulated by the native ligand, alpha-melanocyte stimulating hormone (alpha-MSH). The potent and enzymatically stable analogue NDP-MSH (Ac-Ser-Tyr-Ser-Nle-Glu-His-DPhe-Arg-Trp-Gly-Lys-Pro-Val-NH(2)) is a lead peptide for the identification of melanocortin amino acids important for receptor molecular recognition and stimulation. We have synthesized nine peptide fragments of NDP-MSH, deleting N- and C-terminal amino acids to determine the "minimally active" sequence of NDP-MSH. Additionally, five peptides were synthesized to study stereochemical inversion at the Phe 7 and Trp 9 positions in attempts to increase tetra- and tripeptide potencies. These peptide analogues were pharmacologically characterized at the mouse melanocortin MC1, MC3, MC4, and MC5 receptors. This study has identified the Ac-His-DPhe-Arg-Trp-NH(2) tetrapeptide as possessing 10 nM agonist activity at the brain MC4R. The tripeptide Ac-DPhe-Arg-Trp-NH(2) possessed micromolar agonist activities at the MC1R, MC4R, and MC5R but only slight stimulatory activity was observed at the MC3R (at up to 100 microM concentration). This study has also examined to importance of both N- and C-terminal NDP-MSH amino acids at the different melanocortin receptors, providing information for drug design and identification of putative ligand-receptor interactions.

  9. In vivo application of ( sup 111 In-DTPA-D-Phe sup 1 )-octreotide for detection of somatostatin receptor-positive tumors in rats

    SciTech Connect

    Bakker, W.H.; Krenning, E.P.; Reubi, J.C.; Breeman, W.A.P.; Setyono-Han, B.; de Jong, M.; Kooij, P.P.M.; Bruns, C.; van Hagen, P.M.; Marbach, P.; Visser, T.J.; Pless, J.; Lamberts, S.W.J. Sandoz Research Inst., Berne Dr. Daniel den Hoed Cancer Centre, Rotterdam Sandoz Pharma AG, Basel )

    1991-01-01

    In this study the authors investigated its in vivo application in the visualization of somatostatin receptor-positive tumors in rats. The distribution of the radiopharmaceutical was investigated after intravenous injection in normal rats and in rats bearing the somatostatin receptor-positive rat pancreatic carcinoma CA 20948. Ex vivo autoradiographic studies showed that specific accumulation of radioactivity occurred in somatostatin receptor-containing tissue (anterior pituitary gland). However, in contrast to the adrenals and pituitary, the tracer accumulation in the kidneys was not mediated by somatostatin receptors. Increasing radioactivity over the somatostatin receptor-positive tumors was measured rapidly after injection and the tumors were clearly visualized by gamma camera scintigraphy. In rats pretreated with 1 mg octreotide accumulation of ({sup 111}In-DPTA-D-Phe{sup 1})-octreotide in the tumors was prevented. Because of its relatively long effective half-life, ({sup 111}In-DTPA-D-Phe{sup 1})-octreotide is a radionuclide-coupled somatostatin analogue which can be used to visualize somatostatin receptor-bearing tumors efficiently after 24 hr, when interfering background radioactivity is minimized by renal clearance.

  10. Capillary electrophoretic study of the degradation pathways and kinetics of the aspartyl model tetrapeptide Gly-Phe-Asp-GlyOH in alkaline solution.

    PubMed

    Brückner, Christin; Imhof, Diana; Scriba, Gerhard K E

    2013-03-25

    The aim of the present study was the investigation of the isomerization and epimerization kinetics of the aspartyl tetrapeptide Gly-Phe-Asp-GlyOH at alkaline conditions. Incubations of the model tetrapeptide in sodium borate buffer, pH 10 and ionic strength 0.2M, at 25°C and 80°C were analyzed by a validated CE-UV assay and fitted according to a pharmacokinetic model. CE-ESI-MS was used for peptide identification. Enantiomerization and isomerization of the aspartyl residue of the model tetrapeptide was observed under all experimental conditions applied. Differences in the velocity and the ratios of the rates of the degradation reactions indicated different effects of temperature on the individual reactions. At 80°C, a rapid formation of β-Asp and d-Asp containing isomers from Gly-l-Phe-α-l-Asp-GlyOH was monitored. Rate constants of the hydrolysis of the succinimide (Asu) intermediate generally exceeded the formation of the intermediate from α/β-Asp peptides. A higher rate constant was observed for the enantiomerization from l-configured Asu compared to d-Asu. At 25°C, epimerization and isomerization equilibrium was not reached within 5208h. Compared to 80°C different ratios of the individual reaction rates were noted. Moreover, inversion of the sequence of the first 2 amino acids was noted as a minor side reaction at 80°C.

  11. Superpotent [Dmt¹] dermorphin tetrapeptides containing the 4-aminotetrahydro-2-benzazepin-3-one scaffold with mixed μ/δ opioid receptor agonistic properties.

    PubMed

    Vandormael, Bart; Fourla, Danai-Dionysia; Gramowski-Voss, Alexandra; Kosson, Piotr; Weiss, Dieter G; Schröder, Olaf H-U; Lipkowski, Andrzej; Georgoussi, Zafiroula; Tourwé, Dirk

    2011-11-24

    Novel dermorphin tetrapeptides are described in which Tyr(1) is replaced by Dmt(1), where d-Ala(2) and Gly(4) are N-methylated, and where Phe(3)-Gly(4) residue is substituted by the constrained Aba(3)-Gly(4) peptidomimetic. Most of these peptidic ligands displayed binding affinities in the nanomolar range for both μ- and δ-opioid receptors but no detectable affinity for the κ-opioid receptor. Measurements of cAMP accumulation, phosphorylation of extracellular signal-regulated kinase (ERK1/2) in HEK293 cells stably expressing each of these receptors individually, and functional screening in primary neuronal cultures confirmed the potent agonistic properties of these peptides. The most potent ligand H-Dmt-NMe-d-Ala-Aba-Gly-NH(2) (BVD03) displayed mixed μ/δ opioid agonist properties with picomolar functional potencies. Functional electrophysiological in vitro assays using primary cortical and spinal cord networks showed that this analogue possessed electrophysiological similarity toward gabapentin and sufentanil, which makes it an interesting candidate for further study as an analgesic for neuropathic pain.

  12. Nuclear Magnetic Resonance Structure Revealed that the Human Polyomavirus JC Virus Agnoprotein Contains an α-Helix Encompassing the Leu/Ile/Phe-Rich Domain

    PubMed Central

    Coric, Pascale; Saribas, A. Sami; Abou-Gharbia, Magid; Childers, Wayne; White, Martyn K.

    2014-01-01

    ABSTRACT Agnoprotein is a small multifunctional regulatory protein required for sustaining the productive replication of JC virus (JCV). It is a mostly cytoplasmic protein localizing in the perinuclear area and forms highly stable dimers/oligomers through a Leu/Ile/Phe-rich domain. There have been no three-dimensional structural data available for agnoprotein due to difficulties associated with the dynamic conversion from monomers to oligomers. Here, we report the first nuclear magnetic resonance (NMR) structure of a synthetic agnoprotein peptide spanning amino acids Thr17 to Glu55 where Lys23 to Phe39 encompassing the Leu/Ile/Phe-rich domain forms an amphipathic α-helix. On the basis of these structural data, a number of Ala substitution mutations were made to investigate the role of the α-helix in the structure and function of agnoprotein. Single L29A and L36A mutations exhibited a significant negative effect on both protein stability and viral replication, whereas the L32A mutation did not. In addition, the L29A mutant displayed a highly nuclear localization pattern, in contrast to the pattern for the wild type (WT). Interestingly, a triple mutant, the L29A+L32A+L36A mutant, yielded no detectable agnoprotein expression, and the replication of this JCV mutant was significantly reduced, suggesting that Leu29 and Leu36 are located at the dimer interface, contributing to the structure and stability of agnoprotein. Two other single mutations, L33A and E34A, did not perturb agnoprotein stability as drastically as that observed with the L29A and L36A mutations, but they negatively affected viral replication, suggesting that the role of these residues is functional rather than structural. Thus, the agnoprotein dimerization domain can be targeted for the development of novel drugs active against JCV infection. IMPORTANCE Agnoprotein is a small regulatory protein of JC virus (JCV) and is required for the successful completion of the viral replication cycle. It forms

  13. Quantifying agonist activity at G protein-coupled receptors.

    PubMed

    Ehlert, Frederick J; Suga, Hinako; Griffin, Michael T

    2011-12-26

    When an agonist activates a population of G protein-coupled receptors (GPCRs), it elicits a signaling pathway that culminates in the response of the cell or tissue. This process can be analyzed at the level of a single receptor, a population of receptors, or a downstream response. Here we describe how to analyze the downstream response to obtain an estimate of the agonist affinity constant for the active state of single receptors. Receptors behave as quantal switches that alternate between active and inactive states (Figure 1). The active state interacts with specific G proteins or other signaling partners. In the absence of ligands, the inactive state predominates. The binding of agonist increases the probability that the receptor will switch into the active state because its affinity constant for the active state (K(b)) is much greater than that for the inactive state (K(a)). The summation of the random outputs of all of the receptors in the population yields a constant level of receptor activation in time. The reciprocal of the concentration of agonist eliciting half-maximal receptor activation is equivalent to the observed affinity constant (K(obs)), and the fraction of agonist-receptor complexes in the active state is defined as efficacy (ε) (Figure 2). Methods for analyzing the downstream responses of GPCRs have been developed that enable the estimation of the K(obs) and relative efficacy of an agonist. In this report, we show how to modify this analysis to estimate the agonist K(b) value relative to that of another agonist. For assays that exhibit constitutive activity, we show how to estimate K(b) in absolute units of M(-1). Our method of analyzing agonist concentration-response curves consists of global nonlinear regression using the operational model. We describe a procedure using the software application, Prism (GraphPad Software, Inc., San Diego, CA). The analysis yields an estimate of the product of K(obs) and a parameter proportional to efficacy (

  14. Agonistic behavior in males and females: effects of an estrogen receptor beta agonist in gonadectomized and gonadally intact mice

    PubMed Central

    Allen, Amy E. Clipperton; Cragg, Cheryl L.; Wood, Alexis J.; Pfaff, Donald W.; Choleris, Elena

    2010-01-01

    Summary Affiliative and agonistic social interactions are mediated by gonadal hormones. Research with estrogen receptor alpha (ERα) or beta (ERβ) knockout (KO) mice show that long-term inactivation of ERα decreases, while inactivation of ERβ increases, male aggression. Opposite effects were found in female αERKO and βERKO mice. The role of acute activation of ERα or ERβ in the agonistic responses of adult non-KO mice is unknown. We report here the effects of the ERβ selective agonist WAY-200070 on agonistic and social behavior in gonadally intact and gonadectomized (gonadex) male and female CD-1 mice towards a gonadex, same-sex intruder. All 15 min resident-intruder tests were videotaped for comprehensive behavioral analysis. Separate analyses assessed: 1) effects of WAY-200070 on each sex and gonadal condition; 2) differences between sexes, and between gonadally intact and gonadex mice, in untreated animals. Results show that in gonadally intact male and female mice WAY-200070 increased agonistic behaviors such as pushing down and aggressive grooming, while leaving attacks unaffected. In untreated mice, males attacked more than females, and gonadex animals showed less agonistic behavior than same-sex, gonadally intact mice. Overall, our detailed behavioral analysis suggested that in gonadally intact male and female mice, ERβ mediates patterns of agonistic behavior that are not directly involved in attacks. This suggests that specific aspects of aggressive behavior are acutely mediated by ERβ in adult mice. Our results also showed that, in resident-intruder tests, female mice spend as much time in intrasexual agonistic interactions as males, but use agonistic behaviors that involve extremely low levels of direct attacks. This non-attack aggression in females is increased by acute activation of ERβ. Thus, acute activation of ERβ similarly mediates agonistic behavior in adult male and female CD-1 mice. PMID:20129736

  15. The cardiovascular effects of peroxisome proliferator-activated receptor agonists.

    PubMed

    Friedland, Sayuri N; Leong, Aaron; Filion, Kristian B; Genest, Jacques; Lega, Iliana C; Mottillo, Salvatore; Poirier, Paul; Reoch, Jennifer; Eisenberg, Mark J

    2012-02-01

    Although peroxisome proliferator-activated receptor agonists are prescribed to improve cardiovascular risk factors, their cardiovascular safety is controversial. We therefore reviewed the literature to identify landmark randomized controlled trials evaluating the effect of peroxisome proliferator-activated receptor gamma agonists (pioglitazone and rosiglitazone), alpha agonists (fenofibrate and gemfibrozil), and pan agonists (bezafibrate, muraglitazar, ragaglitazar, tesaglitazar, and aleglitazar) on cardiovascular outcomes. Pioglitazone may modestly reduce cardiovascular events but also may increase the risk of bladder cancer. Rosiglitazone increases the risk of myocardial infarction and has been withdrawn in European and restricted in the United States. Fibrates improve cardiovascular outcomes only in select subgroups: fenofibrate in diabetic patients with metabolic syndrome, gemfibrozil in patients with dyslipidemia, and bezafibrate in patients with diabetes or metabolic syndrome. The cardiovascular safety of the new pan agonist aleglitazar, currently in phase II trials, remains to be determined. The heterogenous effects of peroxisome proliferator-activated receptor agonists to date highlight the importance of postmarketing surveillance. The critical question of why peroxisome proliferator-activated receptor agonists seem to improve cardiovascular risk factors without significantly improving cardiovascular outcomes requires further investigation.

  16. Synthetic RORγ agonists regulate multiple pathways to enhance antitumor immunity

    PubMed Central

    Hu, Xiao; Liu, Xikui; Moisan, Jacques; Wang, Yahong; Lesch, Charles A.; Spooner, Chauncey; Morgan, Rodney W.; Zawidzka, Elizabeth M.; Mertz, David; Bousley, Dick; Majchrzak, Kinga; Kryczek, Ilona; Taylor, Clarke; Van Huis, Chad; Skalitzky, Don; Hurd, Alexander; Aicher, Thomas D.; Toogood, Peter L.; Glick, Gary D.; Paulos, Chrystal M.; Zou, Weiping; Carter, Laura L.

    2016-01-01

    ABSTRACT RORγt is the key transcription factor controlling the development and function of CD4+ Th17 and CD8+ Tc17 cells. Across a range of human tumors, about 15% of the CD4+ T cell fraction in tumor-infiltrating lymphocytes are RORγ+ cells. To evaluate the role of RORγ in antitumor immunity, we have identified synthetic, small molecule agonists that selectively activate RORγ to a greater extent than the endogenous agonist desmosterol. These RORγ agonists enhance effector function of Type 17 cells by increasing the production of cytokines/chemokines such as IL-17A and GM-CSF, augmenting expression of co-stimulatory receptors like CD137, CD226, and improving survival and cytotoxic activity. RORγ agonists also attenuate immunosuppressive mechanisms by curtailing Treg formation, diminishing CD39 and CD73 expression, and decreasing levels of co-inhibitory receptors including PD-1 and TIGIT on tumor-reactive lymphocytes. The effects of RORγ agonists were not observed in RORγ−/− T cells, underscoring the selective on-target activity of the compounds. In vitro treatment of tumor-specific T cells with RORγ agonists, followed by adoptive transfer to tumor-bearing mice is highly effective at controlling tumor growth while improving T cell survival and maintaining enhanced IL-17A and reduced PD-1 in vivo. The in vitro effects of RORγ agonists translate into single agent, immune system-dependent, antitumor efficacy when compounds are administered orally in syngeneic tumor models. RORγ agonists integrate multiple antitumor mechanisms into a single therapeutic that both increases immune activation and decreases immune suppression resulting in robust inhibition of tumor growth. Thus, RORγ agonists represent a novel immunotherapy approach for cancer. PMID:28123897

  17. [Histrelin acetate--the first once yearly LHRH agonist].

    PubMed

    Altarac, Silvio

    2011-01-01

    Long-acting synthetic luteinising hormone-releasing hormone agonists have become the mainstay for androgen-deprivation therapy, because they avoid the physical and psychological discomfort associated with orchidectomy and lack the potential cardiotoxicity associated with estrogens such as diethylstilbestrol. Currently available luteinising hormone-releasing hormone agonist analogues include leuprolide, goserelin, triptorelin, degarelix and buserelin were administered as either intramuscular or subcutaneous depot injections on a 1, 2, 3 or 6 months basis. Histrelin acetate is the first long-acting luteinising hormone-releasing hormone agonist available as a once-yearly subcutaneous implant.

  18. Toll-like receptor agonists in cancer therapy

    PubMed Central

    Adams, Sylvia

    2010-01-01

    Toll-like receptors (TLRs) are pattern-recognition receptors related to the Drosophila Toll protein. TLR activation alerts the immune system to microbial products and initiates innate and adaptive immune responses. The naturally powerful immunostimulatory property of TLR agonists can be exploited for active immunotherapy against cancer. Antitumor activity has been demonstrated in several cancers, and TLR agonists are now undergoing extensive clinical investigation. This review discusses recent advances in the field and highlights potential opportunities for the clinical development of TLR agonists as single agent immunomodulators, vaccine adjuvants and in combination with conventional cancer therapies. PMID:20563267

  19. Potentially harmful elements (PHEs) in scalp hair, soil and metallurgical wastes in Mitrovica, Kosovo: the role of oral bioaccessibility and mineralogy in human PHE exposure.

    PubMed

    Boisa, N; Bird, G; Brewer, P A; Dean, J R; Entwistle, J A; Kemp, S J; Macklin, M G

    2013-10-01

    Internationally publicized impacts upon human health associated with potentially harmful element (PHE) exposure have been reported amongst internally displaced populations (IDPs) in Mitrovica, Kosovo, following the Kosovan War. Particular concern has surrounded the exposure to Pb indicated by the presence of highly elevated concentrations of Pb in blood and hair samples. This study utilizes a physiologically-based in-vitro extraction method to assess the bioaccessibility of PHEs in surface soils and metallurgical waste in Mitrovica and assesses the potential daily intake of soil-bound PHEs. Maximum As (210mgkg(-1)), Cd (38mgkg(-1)), Cu (410mgkg(-1)), Pb (18790mgkg(-1)) and Zn (8500mgkg(-1)) concentrations in surface soils (0-10cm) are elevated above guideline values. Samples with high PHE concentrations (e.g. As >1000mgkg(-1); Pb >1500mgkg(-1)) exhibit a wide range of bioaccessibilities (5.40 - 92.20% in the gastric (G) phase and 10.00 - 55.80% in the gastric-intestinal (G-I) phase). Samples associated with lower bioaccessibilities typically contain a number of XRD-identifiable primary and secondary mineral phases, particularly As- and Pb-bearing arsenian pyrite, beudantite, galena and cerrusite. Quantification of the potential human exposure risk associated with the ingestion of soil-associated PHEs indicates that on average, 0.01μg Cd kg(-1) BW d(-1), 0.16μg Cu kg(-1) BW d(--1), 0.12μg As kg(-1) BW d(-1), 7.81μg Pb kg(-1) BW d(-1), and 2.68μg Zn kg(-1) BW d(-1) could be bioaccessible following ingestion of PHE-rich soils in the Mitrovica region, with Pb, and to a lesser extent As, indicating the likely possibility of local populations exceeding the recommended tolerable daily intake. Lead present within surface soils of the area could indeed have contributed to the human Pb burden due to the high bioaccessibility of Pb present within these soils (13.40 - 92.20% in the gastric phase). Data for Pb levels in scalp hair (≤120μgg(-1)) and blood (≥650μgdL(-1

  20. Characterization of a novel bivalent morphinan possessing kappa agonist and micro agonist/antagonist properties.

    PubMed

    Mathews, Jennifer L; Peng, Xuemei; Xiong, Wennan; Zhang, Ao; Negus, S Stevens; Neumeyer, John L; Bidlack, Jean M

    2005-11-01

    Previous research has shown that compounds with mixed kappa and mu activity may have utility for the treatment of cocaine abuse and dependence. The present study characterizes the pharmacological profile of a bivalent morphinan that was shown to be a kappa opioid receptor agonist and a mu opioid receptor agonist/antagonist. MCL-145 [bis(N-cyclobutylmethylmorphinan) fumarate] is related to the morphinan cyclorphan and its N-cyclobutylmethyl derivative MCL-101 [3-hydroxy-N-cyclobutylmethyl morphinan S-(+)-mandelate]. MCL-145 consists of two morphinans connected by a spacer at the 3-hydroxy position. This compound had K(i) values of 0.078 and 0.20 nM for the kappa and mu opioid receptors, respectively, using radioligand binding assays as shown by Neumeyer et al. in 2003. In the guanosine 5'-O -(3-[(35) S]thiotriphosphate) binding assay, MCL-145 produced an E(max) value of 80% for the kappa opioid receptor and 42% for the mu opioid receptor. The EC(50) values obtained for this compound were 4.3 and 3.1 nM for the kappa and mu opioid receptors, respectively. In vivo MCL-145 produced a full dose-response curve in the 55 degrees C warm water tail-flick test and was equipotent to morphine. The agonist properties of MCL-145 were antagonized by the mu-selective antagonist beta-funaltrexamine and the kappa-selective antagonist nor-binaltorphimine. MCL-145 also acted as a mu antagonist, as measured by the inhibition of morphine-induced antinociception.

  1. Effects of melanocortin-4 receptor agonists and antagonists on expression of genes related to reproduction in spotted scat, Scatophagus argus.

    PubMed

    Jiang, Dong-Neng; Li, Jian-Tao; Tao, Ya-Xiong; Chen, Hua-Pu; Deng, Si-Ping; Zhu, Chun-Hua; Li, Guang-Li

    2017-02-14

    Melanocortin-4 receptor (Mc4r) function related to reproduction in fish has not been extensively investigated. Here, we report on gene expression changes by real-time PCR following treatment with Mc4r agonists and antagonists in the spotted scat (Scatophagus argus). Using in vitro incubated hypothalamus, the Mc4r nonselective agonist NDP-MSH ([Nle(4), D-Phe(7)]-α-melanocyte stimulating hormone; 10(-6) M) and selective agonist THIQ (N-[(3R)-1, 2, 3, 4-Tetrahydroisoquinolinium-3-ylcarbonyl]- (1R)-1-(4-chlorobenzyl)-2-[4-cyclohexyl-4-(1H-1,2,4-triazol-1-ylmethyl) piperidin-1-yl]-2-oxoethylamine; 10(-7) M) significantly increased the expression of gnrh (Gonadotropin releasing hormone), while the Mc4r nonselective antagonist SHU9119 (Ac-Nle-[Asp-His-DPhe/DNal(2')-Arg-Trp-Lys]-NH2; 10(-6) M) and selective antagonist Ipsen 5i (compound 5i synthesized in Ipsen Research Laboratories; 10(-6) M) significantly inhibited gnrh expression after 3 h of incubation. In incubated pituitary tissue, NDP-MSH and THIQ significantly increased the expression of fshb (Follicle-stimulating hormone beta subunit) and lhb (Luteinizing hormone beta subunit), while SHU9119 and Ipsen 5i significantly decreased fshb and lhb expression after 3 h of incubation. During the in vivo experiment, THIQ (1 mg/kg bw) significantly increased gnrh expression in hypothalamic tissue, as well as the fshb and lhb expression in pituitary tissue 12 h after abdominal injection. Furthermore, Ipsen 5i (1 mg/kg bw) significantly inhibited gnrh expression in hypothalamic tissue, as well as fshb and lhb gene expression in pituitary tissue 12 h after abdominal injection. In summary, Mc4r singling appears to stimulate gnrh expression in the hypothalamus, thereby modulating the synthesis of Fsh and Lh in the pituitary. In addition, Mc4r also appears to directly regulate fshb and lhb levels in the pituitary in spotted scat. Our study suggests that Mc4r, through the hypothalamus and pituitary, participates in

  2. Selective involvement of kappa opioid and phencyclidine receptors in the analgesic and motor effects of dynorphin-A-(1-13)-Tyr-Leu-Phe-Asn-Gly-Pro.

    PubMed

    Shukla, V K; Bansinath, M; Dumont, M; Lemaire, S

    1992-09-18

    Dynorphin A-(1-13)-Tyr-Leu-Phe-Asn-Gly-Pro (Dyn Ia; 1-8 nmol) injected intracerebroventricularly in the mouse produces two independent behavioral effects: (1) a norbinaltorphimine (kappa opioid antagonist)-reversible analgesia in the acetic acid-induced writhing test and (2) motor dysfunction characterized by wild running, pop-corn jumping, hindlimb jerking and barrel rolling and antagonized by the irreversible phencyclidine (PCP) and sigma (sigma) receptor antagonist, metaphit and the non-competitive N-methyl-D-aspartate (NMDA) receptor antagonists, dextromethorphan and ketamine. The specific involvement of the PCP receptor in the motor effects of Dyn Ia is supported by the direct competitive interaction of the peptide with the binding of [3H]MK-801 (Ki: 0.63 microM) and [3H]TCP (Ki: 4.6 microM) to mouse brain membrane preparations.

  3. Benzyloxycarbonyl-D-Phe-Pro-methoxypropylboroglycine: a novel inhibitor of thrombin with high selectivity containing a neutral side chain at the P1 position.

    PubMed Central

    Claeson, G; Philipp, M; Agner, E; Scully, M F; Metternich, R; Kakkar, V V; DeSoyza, T; Niu, L H

    1993-01-01

    Thrombin, the blood-clotting enzyme, is a serine proteinase with trypsin-like specificity and is able to cleave Arg-Xaa peptide bonds but only in a very limited number of substrates (and sites therein). For the prevention and treatment of thrombosis the control of thrombin activity is a key target, and a variety of synthetic inhibitors have been introduced recently, all of which have a positive charge at the P1 site. We report the synthesis of the first example of a new class of inhibitor containing a neutral side chain at the P1 site, the peptide benzyloxycarbonyl-D-Phe-Pro- methoxypropylboroglycine. The peptide is a potent inhibitor of thrombin [Ki (limiting) = 7 nM] and is highly selective for its target enzyme in respect of other serine proteinases. This may be expected to confer considerable advantage in terms of specificity of action and reduced toxicity over conventional, positively charged, inhibitors. PMID:8452516

  4. Thermodynamic and kinetic analysis of the isolated FAD domain of rat neuronal nitric oxide synthase altered in the region of the FAD shielding residue Phe1395.

    PubMed

    Dunford, Adrian J; Marshall, Ker R; Munro, Andrew W; Scrutton, Nigel S

    2004-06-01

    In rat neuronal nitric oxide synthase, Phe1395 is positioned over the FAD isoalloxazine ring. This is replaced by Trp676 in human cytochrome P450 reductase, a tryptophan in related diflavin reductases (e.g. methionine synthase reductase and novel reductase 1), and tyrosine in plant ferredoxin-NADP(+) reductase. Trp676 in human cytochrome P450 reductase is conformationally mobile, and plays a key role in enzyme reduction. Mutagenesis of Trp676 to alanine results in a functional NADH-dependent reductase. Herein, we describe studies of rat neuronal nitric oxide synthase FAD domains, in which the aromatic shielding residue Phe1395 is replaced by tryptophan, alanine and serine. In steady-state assays the F1395A and F1395S domains have a greater preference for NADH compared with F1395W and wild-type. Stopped-flow studies indicate flavin reduction by NADH is significantly faster with F1395S and F1395A domains, suggesting that this contributes to altered preference in coenzyme specificity. Unlike cytochrome P450 reductase, the switch in coenzyme specificity is not attributed to differential binding of NADPH and NADH, but probably results from improved geometry for hydride transfer in the F1395S- and F1395A-NADH complexes. Potentiometry indicates that the substitutions do not significantly perturb thermodynamic properties of the FAD, although considerable changes in electronic absorption properties are observed in oxidized F1395A and F1395S, consistent with changes in hydrophobicity of the flavin environment. In wild-type and F1395W FAD domains, prolonged incubation with NADPH results in development of the neutral blue semiquinone FAD species. This reaction is suppressed in the mutant FAD domains lacking the shielding aromatic residue.

  5. Characterization of P-Rex1 for its role in fMet-Leu-Phe-induced superoxide production in reconstituted COS(phox) cells.

    PubMed

    Nie, Baoming; Cheng, Ni; Dinauer, Mary C; Ye, Richard D

    2010-05-01

    P-Rex1 (phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger 1) is a Rac-specific guanine nucleotide exchange factor activated by Gbetagamma subunits and by PtdIns((3,4,5))P(3). Recent studies indicate that P-Rex1 plays an important role in signaling downstream of neutrophil chemoattractant receptors. Here we report that heterologous expression of P-Rex1, but not Vav1, reconstitutes formyl peptide receptor 1 (FPR1)-mediated NADPH oxidase activation in the transgenic COS(phox) cells expressing gp91(phox), p22(phox), p67(phox) and p47(phox). A successful reconstitution requires the expression of a full-length P-Rex1 with intact DH and PH domains, and is accompanied by P-Rex1 membrane localization as well as Rac1 activation. P-Rex1-dependent superoxide generation in the reconstituted COS(phox) cells was further enhanced by expression of the novel PKC isoform PKCdelta and by overexpression of Akt. Heterologous expression of P-Rex1 in COS(phox) cells potentiated fMet-Leu-Phe-induced Akt phosphorylation, whereas expression of a constitutively active form of Akt enhanced Rac1 activation. In contrast, a dominant negative Akt mutant reduced the fMet-Leu-Phe stimulated superoxide generation as well as Rac1 activation. These results demonstrate that in COS(phox) cells, P-Rex1 is a critical component for FPR1-mediated signaling leading to NADPH oxidase activation, and there is a crosstalk between the P-Rex1-Rac pathway and Akt in superoxide generation.

  6. Octopaminergic agonists for the cockroach neuronal octopamine receptor.

    PubMed

    Hirashima, Akinori; Morimoto, Masako; Kuwano, Eiichi; Eto, Morifusa

    2003-01-01

    The compounds 1-(2,6-diethylphenyl)imidazolidine-2-thione and 2-(2,6-diethylphenyl)imidazolidine showed the almost same activity as octopamine in stimulating adenylate cyclase of cockroach thoracic nervous system among 70 octopamine agonists, suggesting that only these compounds are full octopamine agonists and other compounds are partial octopamine agonists. The quantitative structure-activity relationship of a set of 22 octopamine agonists against receptor 2 in cockroach nervous tissue, was analyzed using receptor surface modeling. Three-dimensional energetics descriptors were calculated from receptor surface model/ligand interaction and these three-dimensional descriptors were used in quantitative structure-activity relationship analysis. A receptor surface model was generated using some subset of the most active structures and the results provided useful information in the characterization and differentiation of octopaminergic receptor.

  7. (R)-(-)-10-methyl-11-hydroxyaporphine: a highly selective serotonergic agonist.

    PubMed

    Cannon, J G; Mohan, P; Bojarski, J; Long, J P; Bhatnagar, R K; Leonard, P A; Flynn, J R; Chatterjee, T K

    1988-02-01

    Prior work in these laboratories identified (+/-)-5-hydroxy-6-methyl-2- (di-n-propylamino)tetralin as a dopaminergic agonist prodrug. The ortho methyl hydroxy aromatic substitution pattern in this molecule has now been incorporated into the aporphine ring system to give a congener of the dopaminergic agonist apomorphine in which the position 10 OH group has been replaced by methyl. Preparation of the target compound involved acid-catalyzed rearrangement of the 3-(1-phenyltetrazolyl) ether of morphine and subsequent molecular modification of the product, the 10-(1-phenyltetrazolyl) ether of (R)-(-)-apomorphine. Surprisingly, the target compound elicited no responses in any assays for effects at dopamine receptors, but rather it displayed pharmacological properties consistent with its being a serotonergic agonist with a high degree of selectivity for 5-HT1A receptors similar to the serotonergic agonist 8-hydroxy-2-(di-n-propylamino)tetralin.

  8. Partial agonist therapy in schizophrenia: relevance to diminished criminal responsibility.

    PubMed

    Gavaudan, Gilles; Magalon, David; Cohen, Julien; Lançon, Christophe; Léonetti, Georges; Pélissier-Alicot, Anne-Laure

    2010-11-01

    Pathological gambling (PG), classified in the DSM-IV among impulse control disorders, is defined as inappropriate, persistent gaming for money with serious personal, family, and social consequences. Offenses are frequently committed to obtain money for gambling. Pathological gambling, a planned and structured behavioral disorder, has often been described as a complication of dopamine agonist treatment in patients with Parkinson's disease. It has never been described in patients with schizophrenia receiving dopamine agonists. We present two patients with schizophrenia, previously treated with antipsychotic drugs without any suggestion of PG, who a short time after starting aripiprazole, a dopamine partial agonist, developed PG and criminal behavior, which totally resolved when aripiprazole was discontinued. Based on recent advances in research on PG and adverse drug reactions to dopamine agonists in Parkinson's disease, we postulate a link between aripiprazole and PG in both our patients with schizophrenia and raise the question of criminal responsibility.

  9. Agonist Replacement for Stimulant Dependence: A Review of Clinical Research

    PubMed Central

    Stoops, William W.; Rush, Craig R.

    2013-01-01

    Stimulant use disorders are an unrelenting public health concern worldwide. Agonist replacement therapy is among the most effective strategies for managing substance use disorders including nicotine and opioid dependence. The present paper reviewed clinical data from human laboratory self-administration studies and clinical trials to determine whether agonist replacement therapy is a viable strategy for managing cocaine and/or amphetamine use disorders. The extant literature suggests that agonist replacement therapy may be effective for managing stimulant use disorders, however, the clinical selection of an agonist replacement medication likely needs to be based on the pharmacological mechanism of the medication and the stimulant abused by patients. Specifically, dopamine releasers appear most effective for reducing cocaine use whereas dopamine reuptake inhibitors appear most effective for reducing amphetamine use. PMID:23574440

  10. Selecting agonists from single cells infected with combinatorial antibody libraries.

    PubMed

    Zhang, Hongkai; Yea, Kyungmoo; Xie, Jia; Ruiz, Diana; Wilson, Ian A; Lerner, Richard A

    2013-05-23

    We describe a system for direct selection of antibodies that are receptor agonists. Combinatorial antibody libraries in lentiviruses are used to infect eukaryotic cells that contain a fluorescent reporter system coupled to the receptor for which receptor agonist antibodies are sought. In this embodiment of the method, very large numbers of candidate antibodies expressing lentivirus and eukaryotic reporter cells are packaged together in a format where each is capable of replication, thereby forging a direct link between genotype and phenotype. Following infection, cells that fluoresce are sorted and the integrated genes encoding the agonist antibodies recovered. We validated the system by illustrating its ability to generate rapidly potent antibody agonists that are complete thrombopoietin phenocopies. The system should be generalizable to any pathway where its activation can be linked to production of a selectable phenotype.

  11. Agonist pharmacology of two Drosophila GABA receptor splice variants.

    PubMed Central

    Hosie, A. M.; Sattelle, D. B.

    1996-01-01

    1. The Drosophila melanogaster gamma-aminobutyric acid (GABA) receptor subunits, RDLac and DRC 17-1-2, form functional homo-oligomeric receptors when heterologously expressed in Xenopus laevis oocytes. The subunits differ in only 17 amino acids, principally in regions of the N-terminal domain which determine agonist pharmacology in vertebrate ionotropic neurotransmitter receptors. A range of conformationally restricted GABA analogues were tested on the two homo-oligomers and their agonists pharmacology compared with that of insect and vertebrate iontropic GABA receptors. 2. The actions of GABA, isoguvacine and isonipecotic acid on RDLac and DRC 17-1-2 homo-oligomers were compared, by use of two-electrode voltage-clamp. All three compounds were full agonists of both receptors, but were 4-6 fold less potent agonists of DRC 17-1-2 homo-oligomers than of RDLac. However, the relative potencies of these agonists on each receptor were very similar. 3. A more complete agonist profile was established for RDLac homo-oligomers. The most potent agonists of these receptors were GABA, muscimol and trans-aminocrotonic acid (TACA), which were approximately equipotent. RDLac homo-oligomers were fully activated by a range of GABA analogues, with the order of potency: GABA > ZAPA ((Z)-3-[(aminoiminomethyl)thio]prop-2-enoic acid) > isoguvacine > imidazole-4-acetic acid > or = isonipecotic acid > or = cis-aminocrotonic acid (CACA) > beta-alanine. 3-Aminopropane sulphonic acid (3-APS), a partial agonist of RDLac homo-oligomers, was the weakest agonist tested and 100 fold less potent than GABA. 4. SR95531, an antagonist of vertebrate GABAA receptors, competitively inhibited the GABA responses of RDLac homo-oligomers, which have previously been found to insensitive to bicuculline. However, its potency (IC50 500 microM) was much reduced when compared to GABAA receptors. 5. The agonist pharmacology of Drosophila RDLac homo-oligomers exhibits aspects of the characteristic pharmacology of

  12. Beta2-agonists and exercise-induced asthma.

    PubMed

    Anderson, Sandra D; Caillaud, Corinne; Brannan, John D

    2006-01-01

    Beta2-agonists taken immediately before exercise provide significant protection against exercise- induced asthma (EIA) in most patients. However, when they are taken daily, there are some negative aspects regarding severity, control, and recovery from EIA. First, there is a significant minority (15-20%) of asthmatics whose EIA is not prevented by beta2-agonists, even when inhaled corticosteroids are used concomitantly. Second, with daily use, there is a decline in duration of the protective effect of long-acting beta2-agonists. Third, if breakthrough EIA occurs, recovery of lung function is slower in response to a beta2-agonist, and additional doses are often required to achieve pre-exercise values. If a person who takes a beta2-agonist daily experiences problems with exercise, then the physician should consider changing the treatment regimen to achieve better control of EIA. These problems likely result from desensitization of the beta2-receptor on the mast cell, which enhances mediator release, and on the bronchial smooth muscle, which enhances the bronchoconstrictor response and delays recovery from EIA. These effects are reversed within 72 h after cessation of a beta2-agonists. The important clinical question is: Are we actually compromising the beneficial effects of beta2-agonists on the prevention and recovery from EIA by prescribing them daily? Patients with EIA need to ensure that their doses of inhaled corticosteroid or other anti-inflammatory therapy are optimized so that, if necessary, a beta2-agonist can be used intermittently as prophylactic medication with greater confidence in the outcome.

  13. [Effects of GLP-1 receptor agonists on carbohydrate metabolism control].

    PubMed

    Fernández-García, José Carlos; Colomo, Natalia; Tinahones, Francisco José

    2014-09-01

    Glucagon-like peptide-1 (GLP-1) receptor agonists are a new group of drugs for the treatment of type 2 diabetes mellitus (DM2). In the present article, we review the available evidence on the efficacy of GLP-1 receptor agonists as glucose-lowering agents, their place in therapeutic algorithms, and the clinical factors associated with a favorable treatment response. Finally, we describe the clinical characteristics of patients who may benefit from these drugs.

  14. [Effects of GLP-1 receptor agonists on carbohydrate metabolism control].

    PubMed

    Fernández-García, José Carlos; Colomo, Natalia; Tinahones, Francisco José

    2014-01-01

    Glucagon-like peptide-1 (GLP-1) receptor agonists are a new group of drugs for the treatment of type 2 diabetes mellitus (DM2). In the present article, we review the available evidence on the efficacy of GLP-1 receptor agonists as glucose-lowering agents, their place in therapeutic algorithms, and the clinical factors associated with a favorable treatment response. Finally, we describe the clinical characteristics of patients who may benefit from these drugs.

  15. Identification of M-CSF agonists and antagonists

    DOEpatents

    Pandit, Jayvardhan; Jancarik, Jarmila; Kim, Sung-Hou; Koths, Kirston; Halenbeck, Robert; Fear, Anna Lisa; Taylor, Eric; Yamamoto, Ralph; Bohm, Andrew

    2000-02-15

    The present invention is directed to methods for crystallizing macrophage colony stimulating factor. The present invention is also directed to methods for designing and producing M-CSF agonists and antagonists using information derived from the crystallographic structure of M-CSF. The invention is also directed to methods for screening M-CSF agonists and antagonists. In addition, the present invention is directed to an isolated, purified, soluble and functional M-CSF receptor.

  16. Behavioural effects of selective tachykinin agonists in midbrain dopamine regions.

    PubMed

    Stoessl, A J; Szczutkowski, E; Glenn, B; Watson, I

    1991-11-29

    The effects of selective NK-1, NK-2 and NK-3 tachykinin agonists in midbrain dopamine cell containing regions were investigated in the rat. The NK-3 agonist senktide induced locomotion, rearing and sniffing following infusion into the substantia nigra pars compacta, and to a lesser extent in the ventral tegmental area. These behavioural responses were not seen following infusion of the selective NK-1 agonist [Sar9,Met (O2)11]SP or the NK-2 agonist [N1e10]NKA4-10. In contrast, grooming was induced only by the NK-1 agonist administered into the substantia nigra. Yawning, chewing mouth movements and wet dog shakes were all seen following infusion of senktide into the ventral tegmental area. These findings suggest that (i) dopamine-mediated behavioural responses seen following tachykinin administration into the midbrain are dependent upon stimulation of NK-3 tachykinin receptors, (ii) tachykinin-induced grooming is mediated by stimulation of NK-1 receptors and (iii) some of the previously described 5-HT mediated behaviours seen following administration of NK-3 tachykinin agonists are probably generated by stimulation of 5-HT cell bodies in the ventral tegmental area.

  17. Histamine H3-receptor inverse agonists as novel antipsychotics.

    PubMed

    Ito, Chihiro

    2009-06-01

    Schizophrenia (SZ) that is resistant to treatment with dopamine (DA) D2 antagonists may involve changes other than those in the dopaminergic system. Recently, histamine (HA), which regulates arousal and cognitive functions, has been suggested to act as a neurotransmitter in the central nervous system. Four HA receptors-H1, H2, H3, and H4-have been identified. Our recent basic and clinical studies revealed that brain HA improved the symptoms of SZ. The H3 receptor is primarily localized in the central nervous system, and it acts not only as a presynaptic autoreceptor that modulates the HA release but also as a presynaptic heteroreceptor that regulates the release of other neurotransmitters such as monoamines and amino acids. H3-receptor inverse agonists have been considered to improve cognitive functions. Many atypical antipsychotics are H3-receptor antagonists. Imidazole-containing H3-receptor inverse agonists inhibit not only cytochrome P450 but also hERG potassium channels (encoded by the human ether-a-go-go-related gene). Several imidazole H3-receptor inverse agonists also have high affinity for H4 receptors, which are expressed at high levels in mast cells and leukocytes. Clozapine is an H4-receptor agonist; this agonist activity may be related to the serious side effect of agranulocytosis caused by clozapine. Therefore, selective non-imidazole H3-receptor inverse agonists can be considered as novel antipsychotics that may improve refractory SZ.

  18. Characterization of the new AmpC β-lactamase FOX-8 reveals a single mutation, Phe313Leu, located in the R2 loop that affects ceftazidime hydrolysis.

    PubMed

    Pérez-Llarena, Francisco José; Kerff, Frédéric; Zamorano, Laura; Fernández, María Carmen; Nuñez, Maria Luz; Miró, Elisenda; Oliver, Antonio; Navarro, Ferran; Bou, Germán

    2013-10-01

    A novel class C β-lactamase (FOX-8) was isolated from a clinical strain of Escherichia coli. The FOX-8 enzyme possessed a unique substitution (Phe313Leu) compared to FOX-3. Isogenic E. coli strains carrying FOX-8 showed an 8-fold reduction in resistance to ceftazidime relative to FOX-3. In a kinetic analysis, FOX-8 displayed a 33-fold reduction in kcat/Km for ceftazidime compared to FOX-3. In the FOX family of β-lactamases, the Phe313 residue located in the R2 loop affects ceftazidime hydrolysis and alters the phenotype of E. coli strains carrying this variant.

  19. Multivariate optimization and validation of a capillary electrophoresis method for the simultaneous determination of dextromethorphan hydrobromur, phenylephrine hydrochloride, paracetamol and chlorpheniramine maleate in a pharmaceutical preparation using response surface methodology.

    PubMed

    Palabiyik, I Murat; Onur, Feyyaz

    2010-01-01

    A fast, accurate, precise and sensitive capillary electrophoresis method for the simultaneous determination of dextromethorphan hydrobromide, phenylephrine hydrochloride, paracetamol and chlorpheniramine maleate has been developed. Response surface methodology with a central composite design was used for optimization of the concentration of the buffer, pH of the buffer and applied voltage. Therefore, working with Na(2)HPO(4) buffer (pH 8.00, 0.01 M) at 20 kV as an applied voltage in the capillary electrophoresis method were found to be suitable; under these optimal conditions, these four active ingredients were separated in about 7 min. This developed method was validated and successfully applied to a pharmaceutical preparation, sugar-coated tablet, and the results were compared with a high-performance liquid chromatographic method developed by us.

  20. Identification of Determinants Required for Agonistic and Inverse Agonistic Ligand Properties at the ADP Receptor P2Y12

    PubMed Central

    Schmidt, Philipp; Ritscher, Lars; Dong, Elizabeth N.; Hermsdorf, Thomas; Cöster, Maxi; Wittkopf, Doreen; Meiler, Jens

    2013-01-01

    The ADP receptor P2Y12 belongs to the superfamily of G protein–coupled receptors (GPCRs), and its activation triggers platelet aggregation. Therefore, potent antagonists, such as clopidogrel, are of high clinical relevance in prophylaxis and treatment of thromboembolic events. P2Y12 displays an elevated basal activity in vitro, and as such, inverse agonists may be therapeutically beneficial compared with antagonists. Only a few inverse agonists of P2Y12 have been described. To expand this limited chemical space and improve understanding of structural determinants of inverse agonist-receptor interaction, this study screened a purine compound library for lead structures using wild-type (WT) human P2Y12 and 28 constitutively active mutants. Results showed that ATP and ATP derivatives are agonists at P2Y12. The potency at P2Y12 was 2-(methylthio)-ADP > 2-(methylthio)-ATP > ADP > ATP. Determinants required for agonistic ligand activity were identified. Molecular docking studies revealed a binding pocket for the ATP derivatives that is bordered by transmembrane helices 3, 5, 6, and 7 in human P2Y12, with Y105, E188, R256, Y259, and K280 playing a particularly important role in ligand interaction. N-Methyl-anthraniloyl modification at the 3′-OH of the 2′-deoxyribose leads to ligands (mant-deoxy-ATP [dATP], mant-deoxy-ADP) with inverse agonist activity. Inverse agonist activity of mant-dATP was found at the WT human P2Y12 and half of the constitutive active P2Y12 mutants. This study showed that, in addition to ADP and ATP, other ATP derivatives are not only ligands of P2Y12 but also agonists. Modification of the ribose within ATP can result in inverse activity of ATP-derived ligands. PMID:23093496

  1. Molecular basis of agonist docking in a human GPR103 homology model by site-directed mutagenesis and structure–activity relationship studies

    PubMed Central

    Neveu, C; Dulin, F; Lefranc, B; Galas, L; Calbrix, C; Bureau, R; Rault, S; Chuquet, J; Boutin, J A; Guilhaudis, L; Ségalas-Milazzo, I; Vaudry, D; Vaudry, H; Santos, J Sopkova-de Oliveira; Leprince, J

    2014-01-01

    Background and Purpose The neuropeptide 26RFa and its cognate receptor GPR103 are involved in the control of food intake and bone mineralization. Here, we have tested, experimentally, the predicted ligand-receptor interactions by site-directed mutagenesis of GPR103 and designed point-substituted 26RFa analogues. Experimental Approach Using the X-ray structure of the β2-adrenoceptor, a 3-D molecular model of GPR103 has been built. The bioactive C-terminal octapeptide 26RFa(19–26), KGGFSFRF-NH2, was docked in this GPR103 model and the ligand-receptor complex was submitted to energy minimization. Key Results In the most stable complex, the Phe-Arg-Phe-NH2 part was oriented inside the receptor cavity, whereas the N-terminal Lys residue remained outside. A strong intermolecular interaction was predicted between the Arg25 residue of 26RFa and the Gln125 residue located in the third transmembrane helix of GPR103. To confirm this interaction experimentally, we tested the ability of 26RFa and Arg-modified 26RFa analogues to activate the wild-type and the Q125A mutant receptors transiently expressed in CHO cells. 26RFa (10−6 M) enhanced [Ca2+]i in wild-type GPR103-transfected cells, but failed to increase [Ca2+]i in Q125A mutant receptor-expressing cells. Moreover, asymmetric dimethylation of the side chain of arginine led to a 26RFa analogue, [ADMA25]26RFa(20–26), that was unable to activate the wild-type GPR103, but antagonized 26RFa-evoked [Ca2+]i increase. Conclusion and Implications Altogether, these data provide strong evidence for a functional interaction between the Arg25 residue of 26RFa and the Gln125 residue of GPR103 upon ligand-receptor activation, which can be exploited for the rational design of potent GPR103 agonists and antagonists. PMID:24913445

  2. Dihydrocodeine/Agonists for Alcohol Dependents

    PubMed Central

    Ulmer, Albrecht; Müller, Markus; Frietsch, Bernhard

    2012-01-01

    Objective: Alcohol addiction too often remains insufficiently treated. It shows the same profile as severe chronic diseases, but no comparable, effective basic treatment has been established up to now. Especially patients with repeated relapses, despite all therapeutic approaches, and patients who are not able to attain an essential abstinence to alcohol, need a basic medication. It seems necessary to acknowledge that parts of them need any agonistic substance, for years, possibly lifelong. For >14 years, we have prescribed such substances with own addictive character for these patients. Methods: We present a documented best possible practice, no designed study. Since 1997, we prescribed Dihydrocodeine (DHC) to 102 heavily alcohol addicted patients, later, also Buprenorphine, Clomethiazole (>6 weeks), Baclofen, and in one case Amphetamine, each on individual indication. This paper focuses on the data with DHC, especially. The Clomethiazole-data has been submitted to a German journal. The number of treatments with the other substances is still low. Results: The 102 patients with the DHC treatment had 1367 medically assisted detoxifications and specialized therapies before! The 4 years-retention rate was 26.4%, including 2.8% successfully terminated treatments. In our 12-steps scale on clinical impression, we noticed a significant improvement from mean 3.7 to 8.4 after 2 years. The demand for medically assisted detoxifications in the 2 years remaining patients was reduced by 65.5%. Mean GGT improved from 206.6 U/l at baseline to 66.8 U/l after 2 years. Experiences with the other substances are similar but different in details. Conclusion: Similar to the Italian studies with GHB and Baclofen, we present a new approach, not only with new substances, but also with a new setting and much more trusting attitude. We observe a huge improvement, reaching an almost optimal, stable, long term status in around 1/4 of the patients already. Many further

  3. Anti-nociception mediated by a κ opioid receptor agonist is blocked by a δ receptor agonist

    PubMed Central

    Taylor, A M W; Roberts, K W; Pradhan, A A; Akbari, H A; Walwyn, W; Lutfy, K; Carroll, F I; Cahill, C M; Evans, C J

    2015-01-01

    BACKGROUND AND PURPOSE The opioid receptor family comprises four structurally homologous but functionally distinct sub-groups, the μ (MOP), δ (DOP), κ (KOP) and nociceptin (NOP) receptors. As most opioid agonists are selective but not specific, a broad spectrum of behaviours due to activation of different opioid receptors is expected. In this study, we examine whether other opioid receptor systems influenced KOP-mediated antinociception. EXPERIMENTAL APPROACH We used a tail withdrawal assay in C57Bl/6 mice to assay the antinociceptive effect of systemically administered opioid agonists with varying selectivity at KOP receptors. Pharmacological and genetic approaches were used to analyse the interactions of the other opioid receptors in modulating KOP-mediated antinociception. KEY RESULTS Etorphine, a potent agonist at all four opioid receptors, was not anti-nociceptive in MOP knockout (KO) mice, although etorphine is an efficacious KOP receptor agonist and specific KOP receptor agonists remain analgesic in MOP KO mice. As KOP receptor agonists are aversive, we considered KOP-mediated antinociception might be a form of stress-induced analgesia that is blocked by the anxiolytic effects of DOP receptor agonists. In support of this hypothesis, pretreatment with the DOP antagonist, naltrindole (10 mg·kg−1), unmasked etorphine (3 mg·kg−1) antinociception in MOP KO mice. Further, in wild-type mice, KOP-mediated antinociception by systemic U50,488H (10 mg·kg−1) was blocked by pretreatment with the DOP agonist SNC80 (5 mg·kg−1) and diazepam (1 mg·kg−1). CONCLUSIONS AND IMPLICATIONS Systemic DOP receptor agonists blocked systemic KOP antinociception, and these results identify DOP receptor agonists as potential agents for reversing stress-driven addictive and depressive behaviours mediated through KOP receptor activation. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles

  4. A new hemoglobin variant: Hb Meylan [β73(E17)Asp → Phe; HBB: c.220G>T; c.221A>T] with a double base mutation at the same codon.

    PubMed

    Renoux, Céline; Feray, Cécile; Joly, Philippe; Zanella-Cleon, Isabelle; Garcia, Caroline; Lacan, Philippe; Couprie, Nicole; Francina, Alain

    2015-01-01

    We report a new β-globin chain variant: Hb Meylan [β73(E17)Asp → Phe; HBB: c.220G>T; c.221A>T]. The new variant results from a double nucleotide mutation at the same codon. The possible molecular mechanisms are discussed.

  5. GABA receptor agonists: pharmacological spectrum and therapeutic actions.

    PubMed

    Bartholini, G

    1985-01-01

    From the data discussed in this review it appears that GABA receptor agonists exhibit a variety of actions in the central nervous system, some of which are therapeutically useful (Table V). GABA receptor agonists, by changing the firing rate of the corresponding neurons accelerate noradrenaline turnover without changes in postsynaptic receptor density and diminish serotonin liberation with an up-regulation of 5HT2 receptors. These effects differ from those of tricyclic antidepressants which primarily block monoamine re-uptake and cause down-regulation of beta-adrenergic and 5HT2 receptors. The GABA receptor agonist progabide has been shown to exert an antidepressant action which is indistinguishable from that of imipramine in patients with major affective disorders. The fact that: (a) GABA receptor agonists and tricyclic antidepressants affect noradrenergic and serotonergic transmission differently; and (b) tricyclic antidepressants alter GABA-related parameters challenges the classical monoamine hypothesis of depression and suggests that GABA-mediated mechanisms play a role in mood disorders. Decreases in cellular excitability produced by GABAergic stimulation leads to control of seizures in practically all animal models of epilepsy. GABA receptor agonists have a wide spectrum as they antagonize not only seizures which are dependent on decreased GABA synaptic activity but also convulsant states which are apparently independent of alterations in GABA-mediated events. These results in animals are confirmed in a wide range of human epileptic syndromes. GABA receptor agonists decrease dopamine turnover in the basal ganglia and antagonize neuroleptic-induced increase in dopamine release. On repeated treatment, progabide prevents or reverses the neuroleptic-induced up-regulation of dopamine receptors in the rat striatum and antagonizes the concomitant supersensitivity to dopaminomimetics. Behaviorally, GABA receptor agonists diminish the stereotypies induced by

  6. Benzodiazepine agonist and inverse agonist actions on GABAA receptor-operated chloride channels. II. Chronic effects of ethanol

    SciTech Connect

    Buck, K.J.; Harris, R.A. )

    1990-05-01

    Mice were made tolerant to and dependent on ethanol by administration of a liquid diet. Gamma-aminobutyric acid (GABA) receptor-dependent uptake of 36Cl- by mouse cortical microsacs was used to study the actions of benzodiazepine (BZ) agonists and inverse agonists. Chronic exposure to ethanol attenuated the ability of a BZ agonist, flunitrazepam, to augment muscimol-stimulated uptake of 36Cl- and enhanced the actions of BZ inverse agonists, Ro15-4513 (ethyl-8-azido-5,6-dihydro-5-methyl-6-oxo-4H-imidazo(1,4)-benzodiazepine - 3-carboxylate) and DMCM (methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate), to inhibit GABAA receptor-operated chloride channels. Augmentation of chloride flux by pentobarbital was not reduced by chronic ethanol exposure. Attenuation of flunitrazepam efficacy was transient and returned to control levels within 6 to 24 hr after withdrawal from ethanol, but increased sensitivity to Ro15-4513 was observed as long as 8 days after withdrawal. Chronic exposure to ethanol did not alter (3H)SR 95531 (2-(3'-carbethoxy-2'propyl)-3-amino-6-p-methoxyphenylpyridazinium bromide) binding to low-affinity GABAA receptors or muscimol stimulation of chloride flux; and did not alter (3H)Ro15-4513 or (3H)flunitrazepam binding to central BZ receptors or allosteric modulation of this binding by muscimol (i.e., muscimol-shift). These results suggest that chronic exposure to ethanol reduces coupling between BZ agonist sites and the chloride channel, and may be responsible for the development of cross-tolerance between ethanol and BZ agonists. In contrast, coupling between BZ inverse agonist sites and the chloride channel is increased.

  7. Intracerebroventricular administration of kappa-agonists induces convulsions in mice.

    PubMed

    Bansinath, M; Ramabadran, K; Turndorf, H; Shukla, V K

    1991-07-01

    Intracerebroventricular (ICV) administration of kappa-agonists (PD 117302, U-50488H and U-69593) induced convulsions in a dose-related manner in mice. The dose at which 50% of animals convulsed (CD50) was in nmol ranges for all opioids. Among the opioids used, PD 117302 was the most potent convulsant. ICV administration of either vehicle alone or U-53445E, a non-kappa-opioid (+) enantiomer of U-50488H did not induce convulsions. The convulsive response of kappa-agonists was differentially susceptible for antagonism by naloxone and/or MR 2266. Collectively, these findings support the view that convulsions induced by kappa-agonists in mice involve stereospecific opioid receptor mechanisms. Furthermore, the convulsant effect of kappa-agonists could not be modified by pretreatment with MK-801, ketamine, muscimol or baclofen. It is concluded that kappa-opioid but not NMDA or GABA receptor mechanisms are involved in convulsions induced by kappa-agonists. These results are the first experimental evidence implicating stereospecific kappa-receptor mechanisms in opioid-induced convulsions in mice.

  8. Modification of opiate agonist binding by pertussis toxin

    SciTech Connect

    Abood, M.E.; Lee, N.M.; Loh, H.H.

    1986-03-05

    Opiate agonist binding is decreased by GTP, suggesting the possible involvement of GTP binding proteins in regulation of opiate receptor binding. This possibility was addressed by asking whether pertussis toxin treatment, which results in ADP-ribosylation and modification of G proteins, would alter opiate agonist binding. The striatum was chosen for the initial brain area to be studied, since regulation of opiate action in this area had been shown to be modified by pertussis toxin. Treatment of striatal membranes with pertussis toxin results in up to a 55% decrease in /sup 3/(H)-DADLE binding as compared with membranes treated identically without toxin. This corresponds to a near complete ADP-ribosylation of both G proteins in the striatal membrane. The decrease in agonist binding appears to be due to an altered affinity of the receptor for agonist as opposed to a decrease in the number of sites. This effect of pertussis toxin on opiate agonist binding demonstrates the actual involvement of G proteins in regulation of opiate receptor binding.

  9. Impact on the replacement of Phe by Trp in a short fragment of Aβ amyloid peptide on the formation of fibrils.

    PubMed

    Chaudhary, Nitin; Nagaraj, Ramakrishnan

    2011-02-01

    Aβ(16-22) (Ac-KLVFFAE-NH(2) ) is one of the shortest amyloid fibril-forming sequences identified in β-amyloid peptide. At neutral pH, the peptide forms fibrils in the concentration range of 0.2-2.0 mM after ≥ 10 days of incubation. Structures of the fibrils proposed based on solid-state NMR and MD simulations studies suggest antiparallel arrangement of β-strands and aromatic interactions between the Phe residues. In an effort to examine the role of aromatic interactions between two Phe residues in Aβ(16-22) , we have studied the self-assembly of Aβ(16-22) (AβFF) and two of its variants, Ac-KLVFWAE-NH(2) (AβFW) and Ac-KLVWFAE-NH(2) (AβWF). The peptides were dissolved in methanol (MeOH) at a concentration of 1 mM and in water (AβFW and AβWF, 1 mM; AβFF, 330 µM). Peptide solutions (100 µM) were prepared in 50 mM sodium phosphate buffer at pH 7 by diluting from MeOH and water stock solutions. AβFW forms amyloid-like fibrils immediately from MeOH, as indicated by atomic force microscopy. Dilution of AβFW into phosphate buffer from stock solution prepared in MeOH results in fibrils, but with different morphology and dimensions. The secondary structure potentiated by MeOH seems to be important for the self-assembly of AβFW, as fibrils are not formed from water where the peptide is unordered. On the other hand, AβFF and AβWF do not form amyloid fibrils rapidly from any of the solvents used for dissolution. However, drying of AβWF from MeOH on mica surface gives rod-like and fibrous structures. Our study indicates that positioning of the aromatic residues F and W has an important role to play in promoting self-assembly of the Aβ(16-22) peptides.

  10. Novel nonsecosteroidal VDR agonists with phenyl-pyrrolyl pentane skeleton.

    PubMed

    Shen, Wei; Xue, Jingwei; Zhao, Zekai; Zhang, Can

    2013-11-01

    In order to find the vitamin D receptor (VDR) ligand whose VDR agonistic activity is separated from the calcemic activity sufficiently, novel nonsecosteroidal analogs with phenyl-pyrrolyl pentane skeleton were synthesized and evaluated for the VDR binding affinity, antiproliferative activity in vitro and serum calcium raising ability in vivo (tacalcitol used as control). Among them, several compounds showed varying degrees of VDR agonistic and growth inhibition activities of the tested cell lines. The most effective compound 2g (EC₅₀: 1.06 nM) exhibited stronger VDR agonistic activity than tacalcitol (EC₅₀: 7.05 nM), inhibited the proliferations of HaCaT and MCF-7 cells with IC₅₀ of 2.06 μM and 0.307 μM (tacalcitol: 2.07 μM and 0.057 μM) and showed no significant effect on serum calcium.

  11. Compulsive eating and weight gain related to dopamine agonist use.

    PubMed

    Nirenberg, Melissa J; Waters, Cheryl

    2006-04-01

    Dopamine agonists have been implicated in causing compulsive behaviors in patients with Parkinson's disease (PD). These have included gambling, hypersexuality, hobbyism, and other repetitive, purposeless behaviors ("punding"). In this report, we describe 7 patients in whom compulsive eating developed in the context of pramipexole use. All of the affected patients had significant, undesired weight gain; 4 had other comorbid compulsive behaviors. In the 5 patients who lowered the dose of pramipexole or discontinued dopamine agonist treatment, the behavior remitted and no further weight gain occurred. Physicians should be aware that compulsive eating resulting in significant weight gain may occur in PD as a side-effect of dopamine agonist medications such as pramipexole. Given the known risks of the associated weight gain and obesity, further investigation is warranted.

  12. Effect of bombesin receptor subtype-3 and its synthetic agonist on signaling, glucose transport and metabolism in myocytes from patients with obesity and type 2 diabetes

    PubMed Central

    GONZÁLEZ, NIEVES; MARTÍN-DUCE, ANTONIO; MARTÍNEZ-ARRIETA, FÉLIX; MORENO-VILLEGAS, ZAIDA; PORTAL-NÚÑEZ, SERGIO; SANZ, RAÚL; EGIDO, JESÚS

    2015-01-01

    Bombesin receptor subtype-3 (BRS-3) is an orphan G-protein-coupled receptor (GPCR) member of the bombesin receptor family. Several studies have suggested an association between obesity, alterations in glucose metabolism, diabetes and the BRS-3 receptor. In this study, we focused on patients simultaneously diagnosed with obesity and type 2 diabetes (OB/T2D). The analysis of BRS-3 expression in the skeletal muscle of these patients revealed a marked decrease in the expression of BRS-3 at the mRNA (23.6±1.3-fold downregulation, p<0.0001) and protein level (49±7% decrease, p<0.05) compared to the normal patients (no obesity and diabetes). Moreover, in cultured primary myocytes from patients with OB/T2D, the synthetic BRS-3 agonist, [D-Try6,β-Ala11,Phe13,Nle14]bombesin6–14, significantly increased the phosphorylation levels of mitogen-activated protein kinase (MAPK), p90RSK1, protein kinase B (PKB) and p70s6K. Specifically, the ligand at 10−11 M induced the maximal phosphorylation of MAPKs (p42, 159±15% of the control; p44, 166±11% of the control; p<0.0001) and p90RSK1 (148±2% of the control, p<0.0001). The basal phosphorylation levels of all kinases were reduced (p<0.05) in the patients with OB/T2D compared to the normal patients. Furthermore, the BRS-3 agonist stimulated glucose transport, which was already detected at 10−12 M (133±9% of the control), reached maximal levels at 10−11 M (160±9%, p<0.0001) and was maintained at up to 10−8 M (overall mean, 153±7%; p<0.007). This effect was less promiment than that attained with 10−8 M insulin (202±9%, p=0.009). The effect of the agonist on glycogen synthase a activity achieved the maximum effect at 10−11 M (165±16% of the control; p<0.0001), which did not differ from that observed with higher concentrations of the agonist. These results suggest that muscle cells isolated from patients with OB/T2D have extremely high sensitivity to the synthetic ligand, and the effects are particularly observed on

  13. Captive female gorilla agonistic relationships with clumped defendable food resources.

    PubMed

    Scott, Jennifer; Lockard, Joan S

    2006-07-01

    Minimal feeding competition among female mountain gorillas (Gorilla gorilla beringei) has resulted in egalitarian social relationships with poorly defined agonistic dominance hierarchies. Thus, gorillas are generally viewed as non-competitive egalitarian folivores that have had little need to develop effective competitive strategies to access food resources. However, this generalization is inconsistent with more recent research indicating that most gorillas are frugivorous, feeding on patchily distributed food resources. The current study at Howletts Wild Animal Park, Kent, England, explores the effects of clumped and defendable foods on female gorilla agonistic relationships among three groups of western lowland gorillas (G. g. gorilla), conditions that are predicted to lead to well-differentiated agonistic dominance hierarchies among female primates. The Howletts gorillas foraged all day on low-energy/-nutrient, high-fiber foods widely distributed around their enclosure by the keepers. However, they also had periodic access to high-energy foods (e.g., nuts, raisins, strawberries, etc.) that the keepers would spread in a clumped and defendable patch. Frequencies of agonistic and submissive behaviors between females and proximity data were gathered. High-status females were found to monopolize the food patch and kept the low-status females at bay with cough-grunt threat vocalizations or by chasing them away. Agonistic interactions were initiated mostly by females of high status; these were directed towards females of low status and were generally not reciprocal. In addition, females of low status engaged in submissive behaviors the most often, which they directed primarily at females of high status, especially in response to aggression by the latter. Agonistic interactions between high- and low-status females had decided outcomes more often than not, with low-status females the losers. Competition over highly desirable foods distributed in defendable clumps at

  14. Nodule de Sœur Marie-Josèphe révélateur de carcinomes digestif et ovarien: à propos de 4 cas

    PubMed Central

    Touré, Papa Souleymane; Tall, Cheikh Tidiane; Dioussé, Pauline; Berthé, Adama; Diop, Madoky Maguatte; Sarr, Mamadou Moustapha; Diop, Balla; Léye, Yakham Mohamed; Diop, Bernard Marcel; Ka, Mamadou Mourtalla

    2015-01-01

    Le nodule de Sœur Marie-Josèphe est une métastase ombilicale d'une tumeur le plus souvent intra-abdominale. C'est un signe clinique rare dont l'incidence est de 1-3% de toutes les néoplasies abdomino-pelviennes, avec un pronostic péjoratif du fait de son retard diagnostique. Nous rapportons quatre observations d'une métastase cutanée ombilicale révélatrice d'un adénocarcinome dont deux pancréatiques, un gastrique et un d'origine ovarienne. Le but de notre travail est de montrer à travers ces quatre cas cliniques, l'intérêt de l'imagerie (tomodensitométrie, échographie) et de la biopsie dans la démarche diagnostique. A travers ces quatre observations nous insistons aussi sur les difficultés diagnostiques et thérapeutiques que pose cette tumeur dans nos pays à ressources limitées. PMID:26958132

  15. N-(3-hydroxymethyl-β-carboline-1-yl-ethyl- 2-yl)-l-Phe: development toward a nanoscaled antitumor drug capable of treating complicated thrombosis and inflammation

    PubMed Central

    Wu, Jianhui; Zhao, Ming; Wang, Yuji; Wang, Yaonan; Zhu, Haimei; Zhao, Shurui; Gui, Lin; Zhang, Xiaoyi; Peng, Shiqi

    2017-01-01

    It is well documented that the surfaces of cancer cells, activated platelets and inflammatory cells are rich in P-selectin. N-(3-hydroxymethyl-β-carboline-1-yl-ethyl-2-yl)-l-Phe (HMCEF) is a P-selectin inhibitor capable of simultaneously inhibiting thrombosis and inflammation. Based on the knowledge that P-selectin is a common target for antithrombotic, anti-inflammatory and antitumor drugs, the aim of this study article was to estimate the possibility of HMCEF as a nanoscaled antitumor drug. Images of transmission electron micro scopy, scanning electron microscopy and atomic force microscopy proved that HMCEF forms nanoparticles with a diameter of <120 nm that promote delivery in blood circulation. In vitro HMCEF intercalates into calf thymus DNA, cuts off DNA pBR22 and inhibits the proliferation of cancer cells. In vivo HMCEF dose dependently (0.2, 2 and 200 nmol/kg per day) slows tumor growth in treated S180 mice, and has a minimal effective dose of 2 nmol/kg per day. At 200 nmol/kg per day, HMCEF does not affect the liver and the kidney of the treated S180 mice, and at 20,000 nmol/kg HMCEF does not affect the liver and the kidney of the treated healthy ICR mice. HMCEF is a promising antitumor drug, which is characterized by its high safety and efficacy in the prevention of the complications of thrombosis and inflammation in patients. PMID:28176928

  16. Crystal structure of N-(tert-but-oxy-carbon-yl)phenyl-alanylde-hydro-alanine isopropyl ester (Boc-Phe-ΔAla-OiPr).

    PubMed

    Lenartowicz, Paweł; Makowski, Maciej; Zarychta, Bartosz; Ejsmont, Krzysztof

    2014-12-01

    In the title compound, the de-hydro-dipeptide (Boc-Phe-ΔAla-OiPr, C20H28N2O5), the mol-ecule has a trans conformation of the N-methyl-amide group. The geometry of the de-hydro-alanine moiety is to some extent different from those usually found in simple peptides, indicating conjugation between the H2C=C group and the peptide bond. The bond angles around de-hydro-alanine have unusually high values due to the steric hindrance, the same inter-action influencing the slight distortion from planarity of the de-hydro-alanine. The mol-ecule is stabilized by intra-molecular inter-actions between the isopropyl group and the N atoms of the peptide main chain. In the crystal, an N-H⋯O hydrogen bond links the mol-ecules into ribbons, giving a herringbone head-to-head packing arrangement extending along the [100] direction. In the stacks, the mol-ecules are linked by weak C-H⋯O hydrogen-bonding associations.

  17. Altered postreceptor signal transduction of formyl-Met-Leu-Phe receptors in polymorphonuclear leukocytes of patients with non-insulin-dependent diabetes mellitus.

    PubMed

    Fóris, G; Paragh, G; Dezsõ, B; Keresztes, T; Balogh, Z; Szabó, J

    1998-01-01

    The signal transduction of the formyl-Met-Leu-Phe (FMLP) receptor in polymorphonuclear leukocytes (PMNLs) from patients with non-insulin-dependent diabetes mellitus (NIDDM) was compared to that of PMNLs obtained from healthy volunteers. According to our previous studies in this group of patients neither the decrease in insulin binding capacity nor the enhanced insulin-degrading enzyme activity was involved. In control PMNLs, 10 nM FMLP induced a pertussis toxin-sensitive increase in phosphatidyl inositol (PI) cleavage and a subsequent Ca2+ signaling from the intracellular pools. On the other hand, the FMLP-induced protein kinase C (PKC) activation and translocation into the membrane could not be detected in these cells via the measurement of 32P incorporation into histone. In contrast, in PMNLs of this special group of patients suffering from NIDDM the FMLP stimulus produced a significantly low increase in PI cleavage and Ca2+ signaling from the intracellular pools. Moreover, in resting PMNLs of these patients with NIDDM, not only the [Ca2+]i but also the membrane-bound PKC activity was found to be significantly increased. In addition, PKC translocation into the cell membrane of diabetic PMNLs could be further triggered with FMLP as judged by the measurement of 32P incorporation into histone. Based on these results, it appears that the signaling of FMLP receptors in PMNLs of some NIDDM patients may have an alternative pathway through Ca2+ influx from extracellular medium, arachidonic acid cascade, and PKC activation.

  18. Switching cannabinoid response from CB(2) agonists to FAAH inhibitors.

    PubMed

    Tourteau, Aurélien; Leleu-Chavain, Natascha; Body-Malapel, Mathilde; Andrzejak, Virginie; Barczyk, Amélie; Djouina, Madjid; Rigo, Benoit; Desreumaux, Pierre; Chavatte, Philippe; Millet, Régis

    2014-03-01

    A series of 3-carboxamido-5-aryl-isoxazoles designed as CB2 agonists were evaluated as FAAH inhibitors. The pharmacological results led to identify structure-activity relationships enabling to switch cannabinoid response from CB2 agonists to FAAH inhibitors. Two compounds were selected for their FAAH and/or CB2 activity, and evaluated in a colitis model for their anti-inflammatory activity. Results showed that compounds 10 and 11 inhibit the development of DSS-induced acute colitis in mice and then, are interesting leads to explore new drug candidates for IBD.

  19. Partial agonistic action of endomorphins in the mouse spinal cord.

    PubMed

    Mizoguchi, H; Wu, H E; Narita, M

    2001-09-07

    The partial agonistic properties of endogenous mu-opioid peptides endomorphin-1 and endomorphin-2 for G-protein activation were determined in the mouse spinal cord, monitoring the increases in guanosine-5'-o-(3-[35S]thio)triphosphate binding. The G-protein activation induced by endogenous opioid peptide beta-endorphin in the spinal cord was significantly, but partially, attenuated by co-incubation with endomorphin-1 or endomorphin-2. The data indicates that endomorphin-1 and endomorphin-2 are endogenous partial agonists for mu-opioid receptor in the mouse spinal cord.

  20. Synthesis and activity of small molecule GPR40 agonists.

    PubMed

    Garrido, Dulce M; Corbett, David F; Dwornik, Kate A; Goetz, Aaron S; Littleton, Thomas R; McKeown, Steve C; Mills, Wendy Y; Smalley, Terrence L; Briscoe, Celia P; Peat, Andrew J

    2006-04-01

    The first report on the identification and structure-activity relationships of a novel series of GPR40 agonists based on a 3-(4-{[N-alkyl]amino}phenyl)propanoic acid template is described. Structural modifications to the original screening hit yielded compounds with a 100-fold increase in potency at the human GPR40 receptor and pEC(50)s in the low nanomolar range. The carboxylic acid moiety is not critical for activity but typically elicits an agonistic response higher than those observed with carboxamide replacements. These compounds may prove useful in unraveling the therapeutic potential of this receptor for the treatment of Type 2 diabetes.

  1. Pyrrolo- and pyridomorphinans: non-selective opioid antagonists and delta opioid agonists/mu opioid partial agonists.

    PubMed

    Kumar, V; Clark, M J; Traynor, J R; Lewis, J W; Husbands, S M

    2014-08-01

    Opioid ligands have found use in a number of therapeutic areas, including for the treatment of pain and opiate addiction (using agonists) and alcohol addiction (using antagonists such as naltrexone and nalmefene). The reaction of imines, derived from the opioid ligands oxymorphone and naltrexone, with Michael acceptors leads to pyridomorphinans with structures similar to known pyrrolo- and indolomorphinans. One of the synthesized compounds, 5e, derived from oxymorphone had substantial agonist activity at delta opioid receptors but not at mu and/or kappa opioid receptors and in that sense profiled as a selective delta opioid receptor agonist. The pyridomorphinans derived from naltrexone and naloxone were all found to be non-selective potent antagonists and as such could have utility as treatments for alcohol abuse.

  2. Induction of selective blood-tumor barrier permeability and macromolecular transport by a biostable kinin B1 receptor agonist in a glioma rat model.

    PubMed

    Côté, Jérôme; Bovenzi, Veronica; Savard, Martin; Dubuc, Céléna; Fortier, Audrey; Neugebauer, Witold; Tremblay, Luc; Müller-Esterl, Werner; Tsanaclis, Ana-Maria; Lepage, Martin; Fortin, David; Gobeil, Fernand

    2012-01-01

    Treatment of malignant glioma with chemotherapy is limited mostly because of delivery impediment related to the blood-brain tumor barrier (BTB). B1 receptors (B1R), inducible prototypical G-protein coupled receptors (GPCR) can regulate permeability of vessels including possibly that of brain tumors. Here, we determine the extent of BTB permeability induced by the natural and synthetic peptide B1R agonists, LysdesArg(9)BK (LDBK) and SarLys[dPhe(8)]desArg(9)BK (NG29), in syngeneic F98 glioma-implanted Fischer rats. Ten days after tumor inoculation, we detected the presence of B1R on tumor cells and associated vasculature. NG29 infusion increased brain distribution volume and uptake profiles of paramagnetic probes (Magnevist and Gadomer) at tumoral sites (T(1)-weighted imaging). These effects were blocked by B1R antagonist and non-selective cyclooxygenase inhibitors, but not by B2R antagonist and non-selective nitric oxide synthase inhibitors. Consistent with MRI data, systemic co-administration of NG29 improved brain tumor delivery of Carboplatin chemotherapy (ICP-Mass spectrometry). We also detected elevated B1R expression in clinical samples of high-grade glioma. Our results documented a novel GPCR-signaling mechanism for promoting transient BTB disruption, involving activation of B1R and ensuing production of COX metabolites. They also underlined the potential value of synthetic biostable B1R agonists as selective BTB modulators for local delivery of different sized-therapeutics at (peri)tumoral sites.

  3. Induction of Selective Blood-Tumor Barrier Permeability and Macromolecular Transport by a Biostable Kinin B1 Receptor Agonist in a Glioma Rat Model

    PubMed Central

    Côté, Jérôme; Bovenzi, Veronica; Savard, Martin; Dubuc, Céléna; Fortier, Audrey; Neugebauer, Witold; Tremblay, Luc; Müller-Esterl, Werner; Tsanaclis, Ana-Maria; Lepage, Martin; Fortin, David; Gobeil, Fernand

    2012-01-01

    Treatment of malignant glioma with chemotherapy is limited mostly because of delivery impediment related to the blood-brain tumor barrier (BTB). B1 receptors (B1R), inducible prototypical G-protein coupled receptors (GPCR) can regulate permeability of vessels including possibly that of brain tumors. Here, we determine the extent of BTB permeability induced by the natural and synthetic peptide B1R agonists, LysdesArg9BK (LDBK) and SarLys[dPhe8]desArg9BK (NG29), in syngeneic F98 glioma-implanted Fischer rats. Ten days after tumor inoculation, we detected the presence of B1R on tumor cells and associated vasculature. NG29 infusion increased brain distribution volume and uptake profiles of paramagnetic probes (Magnevist and Gadomer) at tumoral sites (T1-weighted imaging). These effects were blocked by B1R antagonist and non-selective cyclooxygenase inhibitors, but not by B2R antagonist and non-selective nitric oxide synthase inhibitors. Consistent with MRI data, systemic co-administration of NG29 improved brain tumor delivery of Carboplatin chemotherapy (ICP-Mass spectrometry). We also detected elevated B1R expression in clinical samples of high-grade glioma. Our results documented a novel GPCR-signaling mechanism for promoting transient BTB disruption, involving activation of B1R and ensuing production of COX metabolites. They also underlined the potential value of synthetic biostable B1R agonists as selective BTB modulators for local delivery of different sized-therapeutics at (peri)tumoral sites. PMID:22629405

  4. The Agonistic Approach: Reframing Resistance in Qualitative Research

    ERIC Educational Resources Information Center

    Vitus, Kathrine

    2008-01-01

    The agonistic approach--aimed at embracing opposing perspectives as part of a qualitative research process and acknowledging that process as fundamentally political--sheds light on both the construction of and the resistance to research identities. This approach involves reflexively embedding interview situations into the ethnographic context as a…

  5. Once-weekly glucagon-like peptide 1 receptor agonists.

    PubMed

    Kalra, Sanjay; Gupta, Yashdeep

    2015-07-01

    The once-weekly glucagon-like peptide 1 receptor agonists (QW GLP1RA) represent a major advancement in diabetes pharmaco-therapeutics. This review describes the basic, clinical, and comparative pharmacology of this novel class of drugs. It highlights the clinical placement and posology of these drugs.

  6. Use of ß-adrenergic agonists in hybrid catfish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ractopamine hydrochloride (RH) is a potent ß-adrenergic agonist that has been used in some species of fish to improve growth performance and dress out characteristics. While this metabolic modifier has been shown to have positive effects on growth of fish, little research has focused on the mechani...

  7. Dopamine agonists in prevention of ovarian hyperstimulation syndrome.

    PubMed

    Kasum, Miro; Vrčić, Hrvoje; Stanić, Patrik; Ježek, Davor; Orešković, Slavko; Beketić-Orešković, Lidija; Pekez, Marijeta

    2014-01-01

    The aim of this review is to analyze the efficacy of different dopamine agonists in the prevention of ovarian hyperstimulation syndrome (OHSS). Cabergoline, quinagolide and bromocriptine are the most common dopamine agonists used. There are wide clinical variations among the trials in the starting time (from the day of human chorionic gonadotrophin (hCG) to the day following oocyte retrieval); the duration of the treatment (4-21 days), the dose of cabergoline (0.5 mg or 0.25 mg orally) and in the regimens used. At present, the best known effective regimen is 0.5 mg of cabergoline for 8 days or rectal bromocriptine at a daily dose of 2.5 mg for 16 days. Dopamine agonists have shown significant evidences of their efficacy in the prevention of moderate and early-onset OHSS (9.41%), compared with a placebo (21.45%), which cannot be confirmed for the treatment of late OHSS. It would be advisable to start with the treatment on the day of hCG injection or preferably a few hours earlier. The use of dopamine agonists should be indicated in patients at high risk of OHSS, as well as in patients with a history of previous OHSS even without evident signs of the syndrome.

  8. [Alpha 2-adrenoceptor agonists for the treatment of chronic pain].

    PubMed

    Kulka, P J

    1996-04-25

    The antinociceptive effect of alpha(2)-adrenoceptor agonists is mediated by activation of descending inhibiting noradrenergic systems, which modulates 'wide-dynamic-range' neurones. Furthermore, they inhibit the liberation of substance P and endorphines and activate serotoninergic neurones. Despite this variety of antinociceptive actions, there is still little experience with alpha(2)-adrenoceptor agonists as therapeutic agents for use in chronic pain syndromes. Studies in animals and patients have shown that the transdermal, epidural and intravenous administration of the alpha(2)-adrenoceptor agonist clonidine reduces pain intensity in neuropathic pain syndromes for periods varying from some hours up to 1 month. Patients suffering from lancinating or sharp pain respond best to this therapy. Topically applied clonidine (200-300 microg) relieves hyperalgesia in sympathetically maintained pain. Epidural administration of 300 microg clonidine dissolved in 5 ml NaCl 0.9 % has also been shown to be effective. In patients suffering from cancer pain tolerant to opioids, pain control has proved possible again with combinations of opioids and clonidine. In isolated cases clonidine has been administered epidurally at a dose of 1500 microg/day for almost 5 months without evidence for any histotoxic property of clonidine. Side effects often observed during administration of alpha(2)-adrenoceptor agonists are dry mouth, sedation, hypotension and bradycardia. Therapeutic interventions are usually not required.

  9. Role of nicotine receptor partial agonists in tobacco cessation

    PubMed Central

    Maity, Nivedita; Chand, Prabhat; Murthy, Pratima

    2014-01-01

    One in three adults in India uses tobacco, a highly addictive substance in one or other form. In addition to prevention of tobacco use, offering evidence-based cessation services to dependent tobacco users constitutes an important approach in addressing this serious public health problem. A combination of behavioral methods and pharmacotherapy has shown the most optimal results in tobacco dependence treatment. Among currently available pharmacological agents, drugs that preferentially act on the α4 β2-nicotinic acetyl choline receptor like varenicline and cytisine appear to have relatively better cessation outcomes. These drugs are in general well tolerated and have minimal drug interactions. The odds of quitting tobacco use are at the very least doubled with the use of partial agonists compared with placebo and the outcomes are also superior when compared to nicotine replacement therapy and bupropion. The poor availability of partial agonists and specifically the cost of varenicline, as well as the lack of safety data for cytisine has limited their use world over, particularly in developing countries. Evidence for the benefit of partial agonists is more robust for smoking rather than smokeless forms of tobacco. Although more studies are needed to demonstrate their effectiveness in different populations of tobacco users, present literature supports the use of partial agonists in addition to behavioral methods for optimal outcome in tobacco dependence. PMID:24574554

  10. Dopamine receptor agonists for protection and repair in Parkinson's disease.

    PubMed

    Ferrari-Toninelli, Giulia; Bonini, Sara A; Cenini, Giovanna; Maccarinelli, Giuseppina; Grilli, Mariagrazia; Uberti, Daniela; Memo, Maurizio

    2008-01-01

    Dopamine agonists have been usually used as adjunctive therapy for the cure of Parkinson's disease. It is generally believed that treatment with these drugs is symptomatic rather than curative and it does not stop or delay the progression of neuronal degeneration. However, several dopamine agonists of the D2-receptor family have recently been shown to possess neuroprotective properties in different in vitro and in vivo experimental Parkinson's disease models. Here we summarize some recent molecular evidences underlining the wide pharmacological spectrum of dopamine agonists currently used for treating Parkinson's disease patients. In particular, the mechanism of action of different dopamine agonists does not always appear to be restricted to the stimulation of selective dopamine receptor subtypes since at least some of these drugs are endowed with antioxidant, antiapoptotic or neurotrophic properties. These neuroprotective activities are molecule-specific and may contribute to the clinical efficacy of these drugs for the treatment of chronic and progressive neurodegenerative diseases in which oxidative injury and/or protein misfolding and aggregation exert a primary role.

  11. Amylin and Amylin Agonists for Treating Psychiatric Diseases and Disorders

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methods and compositions for treating psychiatric diseases and disorders are disclosed. The methods provided generally involve the administration of an amylin or an amylin agonist to a subject in order to treat psychiatric diseases and disorders, and conditions associated with psychiatric diseases a...

  12. Melatonin receptor agonists: new options for insomnia and depression treatment.

    PubMed

    Spadoni, Gilberto; Bedini, Annalida; Rivara, Silvia; Mor, Marco

    2011-12-01

    The circadian nature of melatonin (MLT) secretion, coupled with the localization of MLT receptors to the suprachiasmatic nucleus, has led to numerous studies of the role of MLT in modulation of the sleep-wake cycle and circadian rhythms in humans. Although much more needs to be understood about the various functions exerted by MLT and its mechanisms of action, three therapeutic agents (ramelteon, prolonged-release MLT, and agomelatine) are already in use, and MLT receptor agonists are now appearing as new promising treatment options for sleep and circadian-rhythm related disorders. In this review, emphasis has been placed on medicinal chemistry strategies leading to MLT receptor agonists, and on the evidence supporting therapeutic efficacy of compounds undergoing clinical evaluation. A wide range of clinical trials demonstrated that ramelteon, prolonged-release MLT and tasimelteon have sleep-promoting effects, providing an important treatment option for insomnia and transient insomnia, even if the improvements of sleep maintenance appear moderate. Well-documented effects of agomelatine suggest that this MLT agonist offers an attractive alternative for the treatment of depression, combining efficacy with a favorable side effect profile. Despite a large number of high affinity nonselective MLT receptor agonists, only limited data on MT₁ or MT₂ subtype-selective compounds are available up to now. Administration of the MT₂-selective agonist IIK7 to rats has proved to decrease NREM sleep onset latency, suggesting that MT₂ receptor subtype is involved in the acute sleep-promoting action of MLT; rigorous clinical studies are needed to demonstrate this hypothesis. Further clinical candidates based on selective activation of MT₁ or MT₂ receptors are expected in coming years.

  13. Identification of raloxifene as a novel CB2 inverse agonist.

    PubMed

    Kumar, Pritesh; Song, Zhao-Hui

    2013-05-24

    The purpose of the current study was to apply a high throughput assay to systematically screen a library of food and drug administration (FDA)-approved drugs as potential ligands for the cannabinoid receptor 2 (CB2). A cell-based, homogenous time resolved fluorescence (HTRF) method for measuring changes in intracellular cAMP levels was validated and found to be suitable for testing ligands that may act on CB2. Among the 640 FDA-approved drugs screened, raloxifene, a drug used to treat/prevent post-menopausal osteoporosis, was identified for the first time to be a novel CB2 inverse agonist. Our results demonstrated that by acting on CB2, raloxifene enhances forskolin-stimulated cAMP accumulation in a concentration-dependant manner. Furthermore, our data showed that raloxifene competes concentration-dependently for specific [(3)H]CP-55,940 binding to CB2. In addition, raloxifene pretreatment caused a rightward shift of the concentration-response curves of the cannabinoid agonists CP-55,940, HU-210, and WIN55,212-2. Raloxifene antagonism is most likely competitive in nature, as these rightward shifts were parallel and were not associated with any changes in the efficacy of cannabinoid agonists on CB2. Our discovery that raloxfiene is an inverse agonist for CB2 suggests that it might be possible to repurpose this FDA-approved drug for novel therapeutic indications for which CB2 is a target. Furthermore, identifying raloxifene as a CB2 inverse agonist also provides important novel mechanisms of actions to explain the known therapeutic effects of raloxifene.

  14. Human insulin B24 (Phe----Ser). Secretion and metabolic clearance of the abnormal insulin in man and in a dog model.

    PubMed Central

    Shoelson, S E; Polonsky, K S; Zeidler, A; Rubenstein, A H; Tager, H S

    1984-01-01

    We have already demonstrated that a hyperinsulinemic, diabetic subject secreted an abnormal insulin in which serine replaced phenylalanine B24 (Shoelson S., M. Fickova, M. Haneda, A. Nahum, G. Musso, E. T. Kaiser, A. H. Rubenstein, and H. Tager. 1983. Proc. Natl. Acad. Sci. USA. 80:7390-7394). High performance liquid chromatography analysis now shows that the circulating insulin in several other family members also consists of a mixture of the abnormal human insulin B24 (Phe----Ser) and normal human insulin in a ratio of approximately 9.5:1 during fasting. Although all affected subjects show fasting hyperinsulinemia, only the propositus and her father are overtly diabetic. Analysis of the serum insulin from two nondiabetic siblings revealed that normal insulin increased from approximately 2 to 15% of total serum insulin after the ingestion of glucose and that the proportion of the normal hormone plateaued or fell while the level of total insulin continued to rise. Animal studies involving the graded intraportal infusion of equimolar amounts of semisynthetic human [SerB24]-insulin and normal human insulin in pancreatectomized dogs (to simulate the secretion of insulin due to oral glucose in man) also showed both a rise in the fraction of normal insulin that reached the periphery and the attainment of a brief steady state in this fraction while total insulin levels continued to rise. Separate experiments documented a decreased hepatic extraction, a decreased metabolic clearance rate, and an increased plasma half-life of human [SerB24]-insulin within the same parameters as those determined for normal human insulin. These results form a basis for considering (a) the differential clearance of low activity abnormal insulins and normal insulin from the circulation in vivo, and (b) the causes of hyperinsulinemia in both diabetic and nondiabetic individuals who secrete abnormal human insulins. PMID:6371057

  15. Synthesis and SAR of potent LXR agonists containing an indole pharmacophore

    SciTech Connect

    Washburn, David G.; Hoang, Tram H.; Campobasso, Nino; Smallwood, Angela; Parks, Derek J.; Webb, Christine L.; Frank, Kelly A.; Nord, Melanie; Duraiswami, Chaya; Evans, Christopher; Jaye, Michael; Thompson, Scott K.

    2009-03-27

    A novel series of 1H-indol-1-yl tertiary amine LXR agonists has been designed. Compounds from this series were potent agonists with good rat pharmacokinetic parameters. In addition, the crystal structure of an LXR agonist bound to LXR{alpha} will be disclosed.

  16. Activation of α₁-adrenoceptors enhances excitatory synaptic transmission via a pre- and postsynaptic protein kinase C-dependent mechanism in the medial prefrontal cortex of rats.

    PubMed

    Luo, Fei; Tang, Hua; Li, Bao-ming; Li, Si-hai

    2014-04-01

    The physiological effects of α₁-adrenoceptors (α₁-ARs) have been examined in many brain regions. However, little is known about the mechanism of modulation on synaptic transmission by α₁-ARs in the medial prefrontal cortex (mPFC). The present study investigated how α₁-AR activation regulates glutamatergic synaptic transmission in layer V/VI pyramidal cells of the rat mPFC. We found that the α₁-AR agonist phenylephrine (Phe) induced a significant enhancement of the amplitude and frequency of miniature excitatory postsynaptic currents (mEPSCs). The facilitation effect of Phe on the frequency of mEPSCs involved a presynaptic protein kinase C-dependent pathway. Phe produced a significant enhancement on the amplitude of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-R)- and N-methyl-D-aspartic acid receptor (NMDA-R)-mediated evoked excitatory postsynaptic currents (eEPSCs). Phe enhanced inward currents evoked by puff application of glutamate or NMDA. The Phe-induced facilitation of AMPA-R- and NMDA-R-mediated eEPSCs required, in part, postsynaptic Gq , phospholipase C and PKC. These findings suggest that α₁-AR activation facilitates excitatory synaptic transmission in mPFC pyramidal cells via both pre- and post-synaptic PKC-dependent mechanisms.

  17. Capillary electrophoresis analysis of the degradation of the aspartyl tripeptide Phe-Asp-GlyOH at pH 2.0 and 7.4 under forced conditions.

    PubMed

    Conrad, Uwe; Taichrib, Angelina; Neusüss, Christian; Scriba, Gerhard K E

    2010-02-05

    The degradation of the tripeptide l-Phe-alpha-l-Asp-GlyOH was studied at 80 degrees C and pH 2.0 and 7.4 by capillary electrophoresis. Separation of most known as well as unknown degradation products was achieved in a 50mM sodium phosphate buffer, pH 3.0. The diastereomers l-Phe-alpha-l-Asp-GlyOH/l-Phe-alpha-d-Asp-GlyOH could only be separated upon addition of 16mg/ml carboxymethyl-beta-cyclodextrin and 5% acetonitrile to the background electrolyte. Compound identification was performed by capillary electrophoresis-electrospray ionization-mass spectrometry. In addition to Asp isomerization and epimerization products as well as hydrolysis products four diketopiperazine derivatives were identified. Moreover, two degradation products were observed containing the amino acids Asp, Gly and Phe but the unequivocal assignment could not be accomplished based on the mass spectra. Following validation with regard to linearity, range, limit of detection, limit of quantitation and precision the assay was applied to the analysis of the incubation solutions. While peptide backbone hydrolysis dominated at pH 2.0, isomerization and enantiomerization yielding beta-Asp and d-Asp peptides as well as cyclization to diketopiperazine derivatives were observed at pH 7.4. The diketopiperazines were the dominant reaction products amounting to about 85% of the compounds detected after the maximal incubation time of 240h. A kinetic model was used to fit the concentration versus time data.

  18. Effects of an intrathecally administered benzodiazepine receptor agonist, antagonist and inverse agonist on morphine-induced inhibition of a spinal nociceptive reflex.

    PubMed Central

    Moreau, J. L.; Pieri, L.

    1988-01-01

    1. The effects of an intrathecally administered benzodiazepine receptor (BZR) agonist (midazolam, up to 50 micrograms), antagonist (flumazenil, Ro 15-1788, 5 micrograms) and inverse agonist (Ro 19-4603, 15 micrograms) on nociception and on morphine-induced antinociception were studied in rats. 2. By themselves, none of these compounds significantly altered pain threshold. 3. The BZR agonist midazolam enhanced the morphine-induced antinociceptive effect whereas the antagonist flumazenil did not alter it. In contrast, the BZR inverse agonist Ro 19-4603 decreased the morphine-induced antinociceptive effect. 4. Naloxone (1 mg kg-1 i.p.) completely reversed all these effects. 5. These results demonstrate that BZR agonists and inverse agonists are able to affect, by allosteric up- or down-modulation of gamma-aminobutyric acidA (GABAA)-receptors, the transmission of nociceptive information at the spinal cord level, when this transmission is depressed by mu-opioid receptor activation. PMID:2898960

  19. A Potent and Site-Selective Agonist of TRPA1.

    PubMed

    Takaya, Junichiro; Mio, Kazuhiro; Shiraishi, Takuya; Kurokawa, Tatsuki; Otsuka, Shinya; Mori, Yasuo; Uesugi, Motonari

    2015-12-23

    TRPA1 is a member of the transient receptor potential (TRP) cation channel family that is expressed primarily on sensory neurons. This chemosensor is activated through covalent modification of multiple cysteine residues with a wide range of reactive compounds including allyl isothiocyanate (AITC), a spicy component of wasabi. The present study reports on potent and selective agonists of TRPA1, discovered through screening 1657 electrophilic molecules. In an effort to validate the mode of action of hit molecules, we noted a new TRPA1-selective agonist, JT010 (molecule 1), which opens the TRPA1 channel by covalently and site-selectively binding to Cys621 (EC50 = 0.65 nM). The results suggest that a single modification of Cys621 is sufficient to open the TRPA1 channel. The TRPA1-selective probe described herein might be useful for further mechanistic studies of TRPA1 activation.

  20. Agonist-antagonist combinations in opioid dependence: a translational approach

    PubMed Central

    Mannelli, P.

    2011-01-01

    Summary The potential therapeutic benefits of co-administering opiate agonist and antagonist agents remain largely to be investigated. This paper focuses on the mechanisms of very low doses of naltrexone that help modulate the effects of methadone withdrawal and review pharmacological properties of the buprenorphine/naltrexone combination that support its clinical investigation. The bench-to-bedside development of the very low dose naltrexone treatment can serve as a translational paradigm to investigate and treat drug addiction. Further research on putative mechanisms elicited by the use of opioid agonist-antagonist combinations may lead to effective pharmacological alternatives to the gold standard methadone treatment, also useful for the management of the abuse of non opioid drugs and alcohol. PMID:22448305

  1. β2-Adrenoceptor agonists in the regulation of mitochondrial biogenesis.

    PubMed

    Peterson, Yuri K; Cameron, Robert B; Wills, Lauren P; Trager, Richard E; Lindsey, Chris C; Beeson, Craig C; Schnellmann, Rick G

    2013-10-01

    The stimulation of mitochondrial biogenesis (MB) via cell surface G-protein coupled receptors is a promising strategy for cell repair and regeneration. Here we report the specificity and chemical rationale of a panel of β2-adrenoceptor agonists with regards to MB. Using primary cultures of renal cells, a diverse panel of β2-adrenoceptor agonists elicited three distinct phenotypes: full MB, partial MB, and non-MB. Full MB compounds had efficacy in the low nanomolar range and represent two chemical scaffolds containing three distinct chemical clusters. Interestingly, the MB phenotype did not correlate with reported receptor affinity or chemical similarity. Chemical clusters were then subjected to pharmacophore modeling creating two models with unique and distinct features, consisting of five conserved amongst full MB compounds were identified. The two discrete pharmacophore models were coalesced into a consensus pharmacophore with four unique features elucidating the spatial and chemical characteristics required to stimulate MB.

  2. Integrating costimulatory agonists to optimize immune-based cancer therapies.

    PubMed

    Pardee, Angela D; Wesa, Amy K; Storkus, Walter J

    2009-03-01

    While immunotherapy for cancer has become increasingly popular, clinical benefits for such approaches remain limited. This is likely due to tumor-associated immune suppression, particularly in the advanced-disease setting. Thus, a major goal of novel immunotherapeutic design has become the coordinate reversal of existing immune dysfunction and promotion of specific tumoricidal T-cell function. Costimulatory members of the TNF-receptor family are important regulators of T-cell-mediated immunity. Notably, agonist ligation of these receptors restores potent antitumor immunity in the tumor-bearing host. Current Phase I/II evaluation of TNF-receptor agonists as single-modality therapies will illuminate their safety, mechanism(s) of action, and best use in prospective combinational immunotherapy approaches capable of yielding superior benefits to cancer patients.

  3. Integrating costimulatory agonists to optimize immune-based cancer therapies

    PubMed Central

    Pardee, Angela D; Wesa, Amy K

    2009-01-01

    While immunotherapy for cancer has become increasingly popular, clinical benefits for such approaches remain limited. This is likely due to tumor-associated immune suppression, particularly in the advanced-disease setting. Thus, a major goal of novel immunotherapeutic design has become the coordinate reversal of existing immune dysfunction and promotion of specific tumoricidal T-cell function. Costimulatory members of the TNF-receptor family are important regulators of T-cell-mediated immunity. Notably, agonist ligation of these receptors restores potent antitumor immunity in the tumor-bearing host. Current Phase I/II evaluation of TNF-receptor agonists as single-modality therapies will illuminate their safety, mechanism(s) of action, and best use in prospective combinational immunotherapy approaches capable of yielding superior benefits to cancer patients. PMID:20046961

  4. Detection of Pleiotropy through a Phenome-Wide Association Study (PheWAS) of Epidemiologic Data as Part of the Environmental Architecture for Genes Linked to Environment (EAGLE) Study

    PubMed Central

    Hall, Molly A.; Verma, Anurag; Brown-Gentry, Kristin D.; Goodloe, Robert; Boston, Jonathan; Wilson, Sarah; McClellan, Bob; Sutcliffe, Cara; Dilks, Holly H.; Gillani, Nila B.; Jin, Hailing; Mayo, Ping; Allen, Melissa; Schnetz-Boutaud, Nathalie; Crawford, Dana C.; Ritchie, Marylyn D.; Pendergrass, Sarah A.

    2014-01-01

    We performed a Phenome-wide association study (PheWAS) utilizing diverse genotypic and phenotypic data existing across multiple populations in the National Health and Nutrition Examination Surveys (NHANES), conducted by the Centers for Disease Control and Prevention (CDC), and accessed by the Epidemiological Architecture for Genes Linked to Environment (EAGLE) study. We calculated comprehensive tests of association in Genetic NHANES using 80 SNPs and 1,008 phenotypes (grouped into 184 phenotype classes), stratified by race-ethnicity. Genetic NHANES includes three surveys (NHANES III, 1999–2000, and 2001–2002) and three race-ethnicities: non-Hispanic whites (n = 6,634), non-Hispanic blacks (n = 3,458), and Mexican Americans (n = 3,950). We identified 69 PheWAS associations replicating across surveys for the same SNP, phenotype-class, direction of effect, and race-ethnicity at p<0.01, allele frequency >0.01, and sample size >200. Of these 69 PheWAS associations, 39 replicated previously reported SNP-phenotype associations, 9 were related to previously reported associations, and 21 were novel associations. Fourteen results had the same direction of effect across more than one race-ethnicity: one result was novel, 11 replicated previously reported associations, and two were related to previously reported results. Thirteen SNPs showed evidence of pleiotropy. We further explored results with gene-based biological networks, contrasting the direction of effect for pleiotropic associations across phenotypes. One PheWAS result was ABCG2 missense SNP rs2231142, associated with uric acid levels in both non-Hispanic whites and Mexican Americans, protoporphyrin levels in non-Hispanic whites and Mexican Americans, and blood pressure levels in Mexican Americans. Another example was SNP rs1800588 near LIPC, significantly associated with the novel phenotypes of folate levels (Mexican Americans), vitamin E levels (non-Hispanic whites) and triglyceride levels (non

  5. Detection of pleiotropy through a Phenome-wide association study (PheWAS) of epidemiologic data as part of the Environmental Architecture for Genes Linked to Environment (EAGLE) study.

    PubMed

    Hall, Molly A; Verma, Anurag; Brown-Gentry, Kristin D; Goodloe, Robert; Boston, Jonathan; Wilson, Sarah; McClellan, Bob; Sutcliffe, Cara; Dilks, Holly H; Gillani, Nila B; Jin, Hailing; Mayo, Ping; Allen, Melissa; Schnetz-Boutaud, Nathalie; Crawford, Dana C; Ritchie, Marylyn D; Pendergrass, Sarah A

    2014-12-01

    We performed a Phenome-wide association study (PheWAS) utilizing diverse genotypic and phenotypic data existing across multiple populations in the National Health and Nutrition Examination Surveys (NHANES), conducted by the Centers for Disease Control and Prevention (CDC), and accessed by the Epidemiological Architecture for Genes Linked to Environment (EAGLE) study. We calculated comprehensive tests of association in Genetic NHANES using 80 SNPs and 1,008 phenotypes (grouped into 184 phenotype classes), stratified by race-ethnicity. Genetic NHANES includes three surveys (NHANES III, 1999-2000, and 2001-2002) and three race-ethnicities: non-Hispanic whites (n = 6,634), non-Hispanic blacks (n = 3,458), and Mexican Americans (n = 3,950). We identified 69 PheWAS associations replicating across surveys for the same SNP, phenotype-class, direction of effect, and race-ethnicity at p<0.01, allele frequency >0.01, and sample size >200. Of these 69 PheWAS associations, 39 replicated previously reported SNP-phenotype associations, 9 were related to previously reported associations, and 21 were novel associations. Fourteen results had the same direction of effect across more than one race-ethnicity: one result was novel, 11 replicated previously reported associations, and two were related to previously reported results. Thirteen SNPs showed evidence of pleiotropy. We further explored results with gene-based biological networks, contrasting the direction of effect for pleiotropic associations across phenotypes. One PheWAS result was ABCG2 missense SNP rs2231142, associated with uric acid levels in both non-Hispanic whites and Mexican Americans, protoporphyrin levels in non-Hispanic whites and Mexican Americans, and blood pressure levels in Mexican Americans. Another example was SNP rs1800588 near LIPC, significantly associated with the novel phenotypes of folate levels (Mexican Americans), vitamin E levels (non-Hispanic whites) and triglyceride levels (non-Hispanic whites

  6. The Arrhythmogenic Calmodulin p.Phe142Leu Mutation Impairs C-domain Ca2+ Binding but Not Calmodulin-dependent Inhibition of the Cardiac Ryanodine Receptor*

    PubMed Central

    Liu, Yingjie; Larsen, Kamilla Taunsig; Nani, Alma; Tian, Xixi; Holt, Christian; Wang, Ruiwu; Fill, Michael

    2017-01-01

    A number of point mutations in the intracellular Ca2+-sensing protein calmodulin (CaM) are arrhythmogenic, yet their underlying mechanisms are not clear. These mutations generally decrease Ca2+ binding to CaM and impair inhibition of CaM-regulated Ca2+ channels like the cardiac Ca2+ release channel (ryanodine receptor, RyR2), and it appears that attenuated CaM Ca2+ binding correlates with impaired CaM-dependent RyR2 inhibition. Here, we investigated the RyR2 inhibitory action of the CaM p.Phe142Leu mutation (F142L; numbered including the start-Met), which markedly reduces CaM Ca2+ binding. Surprisingly, CaM-F142L had little to no aberrant effect on RyR2-mediated store overload-induced Ca2+ release in HEK293 cells compared with CaM-WT. Furthermore, CaM-F142L enhanced CaM-dependent RyR2 inhibition at the single channel level compared with CaM-WT. This is in stark contrast to the actions of arrhythmogenic CaM mutations N54I, D96V, N98S, and D130G, which all diminish CaM-dependent RyR2 inhibition. Thermodynamic analysis showed that apoCaM-F142L converts an endothermal interaction between CaM and the CaM-binding domain (CaMBD) of RyR2 into an exothermal one. Moreover, NMR spectra revealed that the CaM-F142L-CaMBD interaction is structurally different from that of CaM-WT at low Ca2+. These data indicate a distinct interaction between CaM-F142L and the RyR2 CaMBD, which may explain the stronger CaM-dependent RyR2 inhibition by CaM-F142L, despite its reduced Ca2+ binding. Collectively, these results add to our understanding of CaM-dependent regulation of RyR2 as well as the mechanistic effects of arrhythmogenic CaM mutations. The unique properties of the CaM-F142L mutation may provide novel clues on how to suppress excessive RyR2 Ca2+ release by manipulating the CaM-RyR2 interaction. PMID:27927985

  7. Dopamine agonists and the suppression of impulsive motor actions in Parkinson disease.

    PubMed

    Wylie, Scott A; Claassen, Daniel O; Huizenga, Hilde M; Schewel, Kerilyn D; Ridderinkhof, K Richard; Bashore, Theodore R; van den Wildenberg, Wery P M

    2012-08-01

    The suppression of spontaneous motor impulses is an essential facet of cognitive control that is linked to frontal-BG circuitry. BG dysfunction caused by Parkinson disease (PD) disrupts the proficiency of action suppression, but how pharmacotherapy for PD impacts impulsive motor control is poorly understood. Dopamine agonists improve motor symptoms of PD but can also provoke impulsive-compulsive behaviors (ICB). We investigated whether dopamine agonist medication has a beneficial or detrimental effect on impulsive action control in 38 PD patients, half of whom had current ICB. Participants performed the Simon conflict task, which measures susceptibility to acting on spontaneous action impulses as well as the proficiency of suppressing these impulses. Compared with an off-agonist state, patients on their agonists were no more susceptible to reacting impulsively but were less proficient at suppressing the interference from the activation of impulsive actions. Importantly, agonist effects depended on baseline performance in the off-agonist state; more proficient suppressors off agonist experienced a reduction in suppression on agonist, whereas less-proficient suppressors off agonist showed improved suppression on agonist. Patients with active ICB were actually less susceptible to making fast, impulsive response errors than patients without ICB, suggesting that behavioral problems in this subset of patients may be less related to impulsivity in motor control. Our findings provide further evidence that dopamine agonist medication impacts specific cognitive control processes and that the direction of its effects depends on individual differences in performance off medication.

  8. Improving the developability profile of pyrrolidine progesterone receptor partial agonists

    SciTech Connect

    Kallander, Lara S.; Washburn, David G.; Hoang, Tram H.; Frazee, James S.; Stoy, Patrick; Johnson, Latisha; Lu, Qing; Hammond, Marlys; Barton, Linda S.; Patterson, Jaclyn R.; Azzarano, Leonard M.; Nagilla, Rakesh; Madauss, Kevin P.; Williams, Shawn P.; Stewart, Eugene L.; Duraiswami, Chaya; Grygielko, Eugene T.; Xu, Xiaoping; Laping, Nicholas J.; Bray, Jeffrey D.; Thompson, Scott K.

    2010-09-17

    The previously reported pyrrolidine class of progesterone receptor partial agonists demonstrated excellent potency but suffered from serious liabilities including hERG blockade and high volume of distribution in the rat. The basic pyrrolidine amine was intentionally converted to a sulfonamide, carbamate, or amide to address these liabilities. The evaluation of the degree of partial agonism for these non-basic pyrrolidine derivatives and demonstration of their efficacy in an in vivo model of endometriosis is disclosed herein.

  9. Newspapers and newspaper ink contain agonists for the ah receptor.

    PubMed

    Bohonowych, Jessica E S; Zhao, Bin; Timme-Laragy, Alicia; Jung, Dawoon; Di Giulio, Richard T; Denison, Michael S

    2008-04-01

    Ligand-dependent activation of the aryl hydrocarbon receptor (AhR) pathway leads to a diverse array of biological and toxicological effects. The best-studied ligands for the AhR include polycyclic and halogenated aromatic hydrocarbons, the most potent of which is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, as new AhR ligands are identified and characterized, their structural and physiochemical diversity continues to expand. Our identification of AhR agonists in crude extracts from diverse materials raises questions as to the magnitude and extent of human exposure to AhR ligands through normal daily activities. We have found that solvent extracts of newspapers from countries around the world stimulate the AhR signaling pathway. AhR agonist activity was observed for dimethyl sulfoxide (DMSO), ethanol, and water extracts of printed newspaper, unprinted virgin paper, and black printing ink, where activation of luciferase reporter gene expression was transient, suggesting that the AhR active chemical(s) was metabolically labile. DMSO and ethanol extracts also stimulated AhR transformation and DNA binding, and also competed with [(3)H]TCDD for binding to the AhR. In addition, DMSO extracts of printed newspaper induced cytochrome P450 1A associated 7-ethoxyresorufin-O-deethylase activity in zebrafish embryos in vivo. Although the responsible bioactive chemical(s) remain to be identified, our results demonstrate that newspapers and printing ink contain relatively potent metabolically labile agonists of the AhR. Given the large amount of recycling and reprocessing of newspapers throughout the world, release of these easily extractable AhR agonists into the environment should be examined and their potential effects on aquatic organisms assessed.

  10. Newspapers and Newspaper Ink Contain Agonists for the Ah Receptor

    PubMed Central

    Bohonowych, Jessica E. S.; Zhao, Bin; Timme-Laragy, Alicia; Jung, Dawoon; Di Giulio, Richard T.; Denison, Michael S.

    2010-01-01

    Ligand-dependent activation of the aryl hydrocarbon receptor (AhR) pathway leads to a diverse array of biological and toxicological effects. The best-studied ligands for the AhR include polycyclic and halogenated aromatic hydrocarbons, the most potent of which is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). However, as new AhR ligands are identified and characterized, their structural and physiochemical diversity continues to expand. Our identification of AhR agonists in crude extracts from diverse materials raises questions as to the magnitude and extent of human exposure to AhR ligands through normal daily activities. We have found that solvent extracts of newspapers from countries around the world stimulate the AhR signaling pathway. AhR agonist activity was observed for dimethyl sulfoxide (DMSO), ethanol, and water extracts of printed newspaper, unprinted virgin paper, and black printing ink, where activation of luciferase reporter gene expression was transient, suggesting that the AhR active chemical(s) was metabolically labile. DMSO and ethanol extracts also stimulated AhR transformation and DNA binding, and also competed with [3H]TCDD for binding to the AhR. In addition, DMSO extracts of printed newspaper induced cytochrome P450 1A associated 7-ethoxyresorufin-O-deethylase activity in zebrafish embryos in vivo. Although the responsible bioactive chemical(s) remain to be identified, our results demonstrate that newspapers and printing ink contain relatively potent metabolically labile agonists of the AhR. Given the large amount of recycling and reprocessing of newspapers throughout the world, release of these easily extractable AhR agonists into the environment should be examined and their potential effects on aquatic organisms assessed. PMID:18203687

  11. Antipsychotic Induced Symptomatic Hyperprolactinemia: Are Dopamine Agonists Safe?

    PubMed

    Lertxundi, Unax; Domingo-Echaburu, Saioa; Peral, Javier; García, Montserrat

    2011-09-15

    Published literature shows that dopamine agonists can reverse antipsychotic-induced hyperprolactinemia without worsening psychotic symptoms in the majority of schizophrenic patients. However, psychiatrists have been reluctant to use drugs with dopaminergic properties for fear of exacerbating psychiatric symptoms. There are reported cases of psychosis worsening published for both cabergoline and bromocriptine. Cabergoline has proven to be more effective and safe when used to treat hyperprolactinemia, but whether cabergoline is also safer than bromocriptine in antipsychotic induced hyperprolactinemia remains unproven.

  12. Antipsychotic Induced Symptomatic Hyperprolactinemia: Are Dopamine Agonists Safe?

    PubMed Central

    Lertxundi, Unax; Domingo-Echaburu, Saioa; Peral, Javier; García, Montserrat

    2011-01-01

    Published literature shows that dopamine agonists can reverse antipsychotic-induced hyperprolactinemia without worsening psychotic symptoms in the majority of schizophrenic patients. However, psychiatrists have been reluctant to use drugs with dopaminergic properties for fear of exacerbating psychiatric symptoms. There are reported cases of psychosis worsening published for both cabergoline and bromocriptine. Cabergoline has proven to be more effective and safe when used to treat hyperprolactinemia, but whether cabergoline is also safer than bromocriptine in antipsychotic induced hyperprolactinemia remains unproven. PMID:27738363

  13. Angiotensin receptor agonistic autoantibodies and hypertension: preeclampsia and beyond.

    PubMed

    Xia, Yang; Kellems, Rodney E

    2013-06-21

    Hypertensive disorders are life-threatening diseases with high morbidity and mortality, affecting billions of individuals worldwide. A multitude of underlying conditions may contribute to hypertension, thus the need for a plethora of treatment options to identify the approach that best meets the needs of individual patients. A growing body of evidence indicates that (1) autoantibodies that bind to and activate the major angiotensin II type I (AT₁) receptor exist in the circulation of patients with hypertensive disorders, (2) these autoantibodies contribute to disease pathophysiology, (3) antibody titers correlate to the severity of the disease, and (4) efforts to block or remove these pathogenic autoantibodies have therapeutic potential. These autoantibodies, termed AT₁ agonistic autoantibodies have been extensively characterized in preeclampsia, a life-threatening hypertensive condition of pregnancy. As reviewed here, these autoantibodies cause symptoms of preeclampsia when injected into pregnant mice. Somewhat surprisingly, these auto antibodies also appear in 3 animal models of preeclampsia. However, the occurrence of AT₁ agonistic autoantibodies is not restricted to pregnancy. These autoantibodies are prevalent among kidney transplant recipients who develop severe transplant rejection and malignant hypertension during the first week after transplantation. AT₁ agonistic autoantibodies are also highly abundant among a group of patients with essential hypertension that are refractory to standard therapy. More recently these autoantibodies have been seen in patients with the autoimmune disease, systemic sclerosis. These 3 examples extend the clinical impact of AT₁ agonistic autoantibodies beyond pregnancy. Research reviewed here raises the intriguing possibility that preeclampsia and other hypertensive conditions are autoimmune diseases characterized by the presence of pathogenic autoantibodies that activate the major angiotensin receptor, AT₁. These

  14. Glucagon-like peptide-1 receptors agonists (GLP1 RA).

    PubMed

    Kalra, Sanjay

    2013-10-01

    The glucagon-like peptide-1 receptors agonists (GLP1RA) are a relatively new class of drugs, used for management of type 2 diabetes. This review studies the characteristics of these drugs, focusing upon their mechanism of action, intra-class differences, and utility in clinical practice. It compares them with other incretin based therapies, the dipeptidyl peptidase-IV inhibitors, and predicts future developments in the use of these molecules, while highlighting the robust indications for the use of these drugs.

  15. Gonadotropin-releasing hormone agonist-induced pituitary apoplexy

    PubMed Central

    Keane, Fergus; Navin, Patrick; Brett, Francesca; Dennedy, Michael C

    2016-01-01

    Summary Pituitary apoplexy represents an uncommon endocrine emergency with potentially life-threatening consequences. Drug-induced pituitary apoplexy is a rare but important consideration when evaluating patients with this presentation. We describe an unusual case of a patient with a known pituitary macroadenoma presenting with acute-onset third nerve palsy and headache secondary to tumour enlargement and apoplexy. This followed gonadotropin-releasing hormone (GNRH) agonist therapy used to treat metastatic prostate carcinoma. Following acute management, the patient underwent transphenoidal debulking of his pituitary gland with resolution of his third nerve palsy. Subsequent retrospective data interpretation revealed that this had been a secretory gonadotropinoma and GNRH agonist therapy resulted in raised gonadotropins and testosterone. Hence, further management of his prostate carcinoma required GNRH antagonist therapy and external beam radiotherapy. This case demonstrates an uncommon complication of GNRH agonist therapy in the setting of a pituitary macroadenoma. It also highlights the importance of careful, serial data interpretation in patients with pituitary adenomas. Finally, this case presents a unique insight into the challenges of managing a hormonal-dependent prostate cancer in a patient with a secretory pituitary tumour. Learning points While non-functioning gonadotropinomas represent the most common form of pituitary macroadenoma, functioning gonadotropinomas are exceedingly rare. Acute tumour enlargement, with potential pituitary apoplexy, is a rare but important adverse effect arising from GNRH agonist therapy in the presence of both functioning and non-functioning pituitary gonadotropinomas. GNRH antagonist therapy represents an alternative treatment option for patients with hormonal therapy-requiring prostate cancer, who also have diagnosed with a pituitary gonadotropinoma. PMID:27284452

  16. Dehydroepiandrosterone Derivatives as Potent Antiandrogens with Marginal Agonist Activity

    DTIC Science & Technology

    2010-07-01

    or 9), although these compounds still showed anti-DHT effects (lanes 2 vs. 6, 8, or 10). Figure 4 . The effects of DHEA derivatives on PSA...2009 - 30 JUN 2010 4 . TITLE AND SUBTITLE Dehydroepiandrosterone Derivatives as Potent Antiandrogens 5a. CONTRACT NUMBER with Marginal Agonist...words) We hypothesized that dehydroepiandrosterone ( DHEA ) metabolites or their synthetic derivatives are able to bind to the androgen receptor with

  17. Thermodynamic analysis of antagonist and agonist interactions with dopamine receptors.

    PubMed

    Duarte, E P; Oliveira, C R; Carvalho, A P

    1988-03-01

    The binding of [3H]spiperone to dopamine D-2 receptors and its inhibition by antagonists and agonists were examined in microsomes derived from the sheep caudate nucleus, at temperatures between 37 and 1 degree C, and the thermodynamic parameters of the binding were evaluated. The affinity of the receptor for the antagonists, spiperone and (+)-butaclamol, decreased as the incubation temperature decreased; the affinity for haloperidol did not further decrease at temperatures below 15 degrees C. The binding of the antagonists was associated with very large increases in entropy, as expected for hydrophobic interactions. The enthalpy and entropy changes associated with haloperidol binding were dependent on temperature, in contrast to those associated with spiperone and (+)-butaclamol. The magnitude of the entropy increase associated with the specific binding of the antagonists did not correlate with the degree of lipophilicity of these drugs. The data suggest that, in addition to hydrophobic forces, other forces are also involved in the antagonist-dopamine receptor interactions, and that a conformational change of the receptor could occur when the antagonist binds. Agonist binding data are consistent with a two-state model of the receptor, a high-affinity state (RH) and a low-affinity state (RL). The affinity of dopamine binding to the RH decreased with decreasing temperatures below 20 degrees C, whereas the affinity for the RL increased at low temperatures. In contrast, the affinity of apomorphine for both states of receptor decreased as the temperature decreased from 30 to 8 degrees C. A clear distinction between the energetics of high-affinity and low-affinity agonist binding was observed. The formation of the high-affinity complex was associated with larger increases in enthalpy and entropy than the interaction with the low-affinity state was. The results suggest that the interaction of the receptor with the G-proteins, induced or stabilized by the binding of

  18. Neuroprotective effects mediated by dopamine receptor agonists against malonate-induced lesion in the rat striatum.

    PubMed

    Fancellu, R; Armentero, M-T; Nappi, G; Blandini, F

    2003-10-01

    In rats, intrastriatal injection of malonate, a reversible inhibitor of the mitochondrial enzyme succinate dehydrogenase, induces a lesion similar to that observed following focal ischemia or in Huntington's disease. In this study we used the malonate model to explore the neuroprotective potential of dopamine agonists. Rats were injected intraperitoneally with increasing concentrations of D1, D2, or mixed D1/D2 dopamine agonists prior to intrastriatal injection of malonate. Administration of increasing doses of the D2-specific agonist quinpirole resulted in increased protection against malonate toxicity. Conversely, the D1-specific agonist SKF-38393, as well as the mixed D1/D2 agonist apomorphine, conferred higher neuroprotection at lower than at higher drug concentrations. Our data suggest that malonate- induced striatal toxicity can be attenuated by systemic administration of dopamine agonists, with D1 and D2 agonists showing different profiles of efficacy.

  19. Agonistic sounds signal male quality in the Lusitanian toadfish.

    PubMed

    Amorim, M Clara P; Conti, Carlotta; Modesto, Teresa; Gonçalves, Amparo; Fonseca, Paulo J

    2015-10-01

    Acoustic communication during agonistic behaviour is widespread in fishes. Yet, compared to other taxa, little is known on the information content of fish agonistic calls and their effect on territorial defence. Lusitanian toadfish males (Halobatrachus didactylus) are highly territorial during the breeding season and use sounds (boatwhistles, BW) to defend nests from intruders. BW present most energy in either the fundamental frequency, set by the contraction rate of the sonic muscles attached to the swimbladder, or in the harmonics, which are multiples of the fundamental frequency. Here we investigated if temporal and spectral features of BW produced during territorial defence reflect aspects of male quality that may be important in resolving disputes. We found that higher mean pulse period (i.e. lower fundamental frequency) reflected higher levels of 11-ketotestosterone (11KT), the main teleost androgen which, in turn, was significantly related with male condition (relative body mass and glycogen content). BW dominant harmonic mean and variability decreased with sonic muscle lipid content. We found no association between BW duration and male quality. Taken together, these results suggest that the spectral content of fish agonistic sounds may signal male features that are key in fight outcome.

  20. Emerging strategies for exploiting cannabinoid receptor agonists as medicines.

    PubMed

    Pertwee, Roger G

    2009-02-01

    Medicines that activate cannabinoid CB(1) and CB(2) receptor are already in the clinic. These are Cesamet (nabilone), Marinol (dronabinol; Delta(9)-tetrahydrocannabinol) and Sativex (Delta(9)-tetrahydrocannabinol with cannabidiol). The first two of these medicines can be prescribed to reduce chemotherapy-induced nausea and vomiting. Marinol can also be prescribed to stimulate appetite, while Sativex is prescribed for the symptomatic relief of neuropathic pain in adults with multiple sclerosis and as an adjunctive analgesic treatment for adult patients with advanced cancer. One challenge now is to identify additional therapeutic targets for cannabinoid receptor agonists, and a number of potential clinical applications for such agonists are mentioned in this review. A second challenge is to develop strategies that will improve the efficacy and/or the benefit-to-risk ratio of a cannabinoid receptor agonist. This review focuses on five strategies that have the potential to meet either or both of these objectives. These are strategies that involve: (i) targeting cannabinoid receptors located outside the blood-brain barrier; (ii) targeting cannabinoid receptors expressed by a particular tissue; (iii) targeting up-regulated cannabinoid receptors; (iv) targeting cannabinoid CB(2) receptors; or (v) 'multi-targeting'. Preclinical data that justify additional research directed at evaluating the clinical importance of each of these strategies are also discussed.

  1. Contact- and agonist-regulated microvesiculation of human platelets.

    PubMed

    Zhang, Yanjun; Liu, Xiao; Liu, Li; Zaske, Ana-Maria; Zhou, Zhou; Fu, Yuanyuan; Yang, Xi; Conyers, Jodie L; Li, Min; Dong, Jing-fei; Zhang, Jianning

    2013-08-01

    After exposure to an agonist, platelets are activated and become aggregated. They also shed membrane microparticles that participate in the pathogenesis of thrombosis, hyper-coagulation and inflammation. However, microvesiculation can potentially disrupt the integrity of platelet aggregation by shedding the membrane receptors and phosphatidylserine critical for forming and stabilising a platelet clot. We tested the hypothesis that adhesion and microvesiculation are functions of different subsets of platelets at the time of haemostasis by real-time monitoring of agonist-induced morphological changes and microvesiculation of human platelets.We identified two types of platelets that are adherent to fibrinogen: a high density bubble shape (HDBS) and low-density spread shape (LDSS). Adenosine diphosphate (ADP) predominantly induced HDBS platelets to vesiculate, whereas LDSS platelets were highly resistant to such vesiculation. Thrombin-receptor activating peptide (TRAP) stabilised platelets against microvesiculation by promoting a rapid HDBS-to-LDSS morphological transition. These activities of ADP and TRAP were reversed for platelets in suspension, independent of an engagement integrin αIIbβ3. As the result of membrane contact, LDSS platelets inhibited the microvesiculation of HDBS platelets in response to ADP. Aspirin and clopidogrel inhibited ADP-induced microvesiculation through different mechanisms. These results suggest that platelet aggregation and microvesiculation occur in different subsets of platelets and are differently regulated by agonists, platelet-platelets and platelet-fibrinogen interactions.

  2. Pharmacophore-driven identification of PPARγ agonists from natural sources

    NASA Astrophysics Data System (ADS)

    Petersen, Rasmus K.; Christensen, Kathrine B.; Assimopoulou, Andreana N.; Fretté, Xavier; Papageorgiou, Vassilios P.; Kristiansen, Karsten; Kouskoumvekaki, Irene

    2011-02-01

    In a search for more effective and safe anti-diabetic compounds, we developed a pharmacophore model based on partial agonists of PPARγ. The model was used for the virtual screening of the Chinese Natural Product Database (CNPD), a library of plant-derived natural products primarily used in folk medicine. From the resulting hits, we selected methyl oleanonate, a compound found, among others, in Pistacia lentiscus var. Chia oleoresin (Chios mastic gum). The acid of methyl oleanonate, oleanonic acid, was identified as a PPARγ agonist through bioassay-guided chromatographic fractionations of Chios mastic gum fractions, whereas some other sub-fractions exhibited also biological activity towards PPARγ. The results from the present work are two-fold: on the one hand we demonstrate that the pharmacophore model we developed is able to select novel ligand scaffolds that act as PPARγ agonists; while at the same time it manifests that natural products are highly relevant for use in virtual screening-based drug discovery.

  3. Emerging strategies for exploiting cannabinoid receptor agonists as medicines

    PubMed Central

    Pertwee, Roger G

    2009-01-01

    Medicines that activate cannabinoid CB1 and CB2 receptor are already in the clinic. These are Cesamet® (nabilone), Marinol® (dronabinol; Δ9-tetrahydrocannabinol) and Sativex® (Δ9-tetrahydrocannabinol with cannabidiol). The first two of these medicines can be prescribed to reduce chemotherapy-induced nausea and vomiting. Marinol® can also be prescribed to stimulate appetite, while Sativex® is prescribed for the symptomatic relief of neuropathic pain in adults with multiple sclerosis and as an adjunctive analgesic treatment for adult patients with advanced cancer. One challenge now is to identify additional therapeutic targets for cannabinoid receptor agonists, and a number of potential clinical applications for such agonists are mentioned in this review. A second challenge is to develop strategies that will improve the efficacy and/or the benefit-to-risk ratio of a cannabinoid receptor agonist. This review focuses on five strategies that have the potential to meet either or both of these objectives. These are strategies that involve: (i) targeting cannabinoid receptors located outside the blood-brain barrier; (ii) targeting cannabinoid receptors expressed by a particular tissue; (iii) targeting up-regulated cannabinoid receptors; (iv) targeting cannabinoid CB2 receptors; or (v) ‘multi-targeting’. Preclinical data that justify additional research directed at evaluating the clinical importance of each of these strategies are also discussed. PMID:19226257

  4. LHRH Agonists for the Treatment of Prostate Cancer: 2012

    PubMed Central

    Lepor, Herbert; Shore, Neal D

    2012-01-01

    The most recent guidelines on prostate cancer screening from the American Urological Association (2009), the National Comprehensive Cancer Network (2011), and the European Association of Urology (2011), as well as treatment and advances in disease monitoring, have increased the androgen deprivation therapy (ADT) population and the duration of ADT usage as the first-line treatment for metastatic prostate cancer. According to the European Association of Urology, gonadotropin-releasing hormone (GnRH) agonists have become the leading therapeutic option for ADT because they avoid the physical and psychological discomforts associated with orchiectomy. However, GnRH agonists display several shortcomings, including testosterone (T) surge (“clinical flare”) and microsurges. T surge delays the intended serologic endpoint of T suppression and may exacerbate clinical symptoms. Furthermore, ADT manifests an adverse-event spectrum that can impact quality of life with its attendant well-documented morbidities. Strategies to improve ADT tolerability include a holistic management approach, improved diet and exercise, and more specific monitoring to detect and prevent T depletion toxicities. Intermittent ADT, which allows hormonal recovery between treatment periods, has become increasingly utilized as a methodology for improving quality of life while not diminishing chronic ADT efficacy, and may also provide healthcare cost savings. This review assesses the present and potential future role of GnRH agonists in prostate cancer and explores strategies to minimize the adverse-event profile for patients receiving ADT. PMID:23172994

  5. Covalent agonists for studying G protein-coupled receptor activation

    PubMed Central

    Weichert, Dietmar; Kruse, Andrew C.; Manglik, Aashish; Hiller, Christine; Zhang, Cheng; Hübner, Harald; Kobilka, Brian K.; Gmeiner, Peter

    2014-01-01

    Structural studies on G protein-coupled receptors (GPCRs) provide important insights into the architecture and function of these important drug targets. However, the crystallization of GPCRs in active states is particularly challenging, requiring the formation of stable and conformationally homogeneous ligand-receptor complexes. Native hormones, neurotransmitters, and synthetic agonists that bind with low affinity are ineffective at stabilizing an active state for crystallogenesis. To promote structural studies on the pharmacologically highly relevant class of aminergic GPCRs, we here present the development of covalently binding molecular tools activating Gs-, Gi-, and Gq-coupled receptors. The covalent agonists are derived from the monoamine neurotransmitters noradrenaline, dopamine, serotonin, and histamine, and they were accessed using a general and versatile synthetic strategy. We demonstrate that the tool compounds presented herein display an efficient covalent binding mode and that the respective covalent ligand-receptor complexes activate G proteins comparable to the natural neurotransmitters. A crystal structure of the β2-adrenoreceptor in complex with a covalent noradrenaline analog and a conformationally selective antibody (nanobody) verified that these agonists can be used to facilitate crystallogenesis. PMID:25006259

  6. PPARgamma agonists as therapeutics for the treatment of Alzheimer's disease.

    PubMed

    Landreth, Gary; Jiang, Qingguang; Mandrekar, Shweta; Heneka, Michael

    2008-07-01

    Alzheimer's disease (AD) is characterized by the deposition of beta-amyloid within the brain parenchyma and is accompanied by the impairment of neuronal metabolism and function, leading to extensive neuronal loss. The disease involves the perturbation of synaptic function, energy, and lipid metabolism. The development of amyloid plaques results in the induction of a microglial-mediated inflammatory response. The nuclear receptor peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-activated transcription factor whose biological actions are to regulate glucose and lipid metabolism and suppress inflammatory gene expression. Thus, agonists of this receptor represent an attractive therapeutic target for AD. There is now an extensive body of evidence that has demonstrated the efficacy of PPARgamma agonists in ameliorating disease-related pathology and improved learning and memory in animal models of AD. Recent clinical trials of the PPARgamma agonist rosiglitazone have shown significant improvement in memory and cognition in AD patients. Thus, PPARgamma represents an important new therapeutic target in treating AD.

  7. Molecular impact of juvenile hormone agonists on neonatal Daphnia magna.

    PubMed

    Toyota, Kenji; Kato, Yasuhiko; Miyakawa, Hitoshi; Yatsu, Ryohei; Mizutani, Takeshi; Ogino, Yukiko; Miyagawa, Shinichi; Watanabe, Hajime; Nishide, Hiroyo; Uchiyama, Ikuo; Tatarazako, Norihisa; Iguchi, Taisen

    2014-05-01

    Daphnia magna has been used extensively to evaluate organism- and population-level responses to pollutants in acute toxicity and reproductive toxicity tests. We have previously reported that exposure to juvenile hormone (JH) agonists results in a reduction of reproductive function and production of male offspring in a cyclic parthenogenesis, D. magna. Recent advances in molecular techniques have provided tools to understand better the responses to pollutants in aquatic organisms, including D. magna. DNA microarray was used to evaluate gene expression profiles of neonatal daphnids exposed to JH agonists: methoprene (125, 250 and 500 ppb), fenoxycarb (0.5, 1 and 2 ppb) and epofenonane (50, 100 and 200 ppb). Exposure to these JH analogs resulted in chemical-specific patterns of gene expression. The heat map analyses based on hierarchical clustering revealed a similar pattern between treatments with a high dose of methoprene and with epofenonane. In contrast, treatment with low to middle doses of methoprene resulted in similar profiles to fenoxycarb treatments. Hemoglobin and JH epoxide hydrolase genes were clustered as JH-responsive genes. These data suggest that fenoxycarb has high activity as a JH agonist, methoprene shows high toxicity and epofenonane works through a different mechanism compared with other JH analogs, agreeing with data of previously reported toxicity tests. In conclusion, D. magna DNA microarray is useful for the classification of JH analogs and identification of JH-responsive genes.

  8. Suppression of atherosclerosis by synthetic REV-ERB agonist

    SciTech Connect

    Sitaula, Sadichha; Billon, Cyrielle; Kamenecka, Theodore M.; Solt, Laura A.; Burris, Thomas P.

    2015-05-08

    The nuclear receptors for heme, REV-ERBα and REV-ERBβ, play important roles in the regulation of metabolism and inflammation. Recently it was demonstrated that reduced REV-ERBα expression in hematopoetic cells in LDL receptor null mice led to increased atherosclerosis. We sought to determine if synthetic REV-ERB agonists that we have developed might have the ability to suppress atherosclerosis in this model. A previously characterized synthetic REV-ERB agonist, SR9009, was used to determine if activation of REV-ERB activity would affect atherosclerosis in LDL receptor deficient mice. Atherosclerotic plaque size was significantly reduced (p < 0.05) in mice administered SR9009 (100 mg/kg) for seven weeks compared to control mice (n = 10 per group). SR9009 treatment of bone marrow-derived mouse macrophages (BMDM) reduced the polarization of BMDMs to proinflammatory M1 macrophage while increasing the polarization of BMDMs to anti-inflammatory M2 macrophages. Our results suggest that pharmacological targeting of REV-ERBs may be a viable therapeutic option for treatment of atherosclerosis. - Highlights: • Synthetic REV-ERB agonist treatment reduced atherosclerosis in a mouse model. • Pharmacological activation of REV-ERB decreased M1 macrophage polarization. • Pharmacological activation of REV-ERB increased M2 macrophage polarization.

  9. TLR agonists: our best frenemy in cancer immunotherapy

    PubMed Central

    Kaczanowska, Sabina; Joseph, Ann Mary; Davila, Eduardo

    2013-01-01

    Various TLR agonists are currently under investigation in clinical trials for their ability to orchestrate antitumor immunity. The antitumor responses are largely attributed to their aptitude to stimulate APCs such as DCs which in turn, activate tumor-specific T cell responses. However, there is a potential for TLR signaling to occur on cells other than professional APCs that could negate antitumor responses or even worse, promote tumor growth. The impetus for this review is twofold. First, there is accumulating data demonstrating that the engagement of TLRs on different T cell subsets and different cancer types could promote tumor growth or conversely, contribute to antitumor responses. Second, the efficacy of TLR agonists as monotherapies to treat cancer patients has been limited. In this review, we discuss how TLR signaling within different T cell subsets and cancer cells can potentially impact the generation of antitumor responses. Based on evidence from preclinical models and clinical trials, we draw attention to several criteria that we believe must be considered when selecting TLR agonists for developing effective immunotherapeutic strategies against cancer. PMID:23475577

  10. LHRH Agonists for the Treatment of Prostate Cancer: 2012.

    PubMed

    Lepor, Herbert; Shore, Neal D

    2012-01-01

    The most recent guidelines on prostate cancer screening from the American Urological Association (2009), the National Comprehensive Cancer Network (2011), and the European Association of Urology (2011), as well as treatment and advances in disease monitoring, have increased the androgen deprivation therapy (ADT) population and the duration of ADT usage as the first-line treatment for metastatic prostate cancer. According to the European Association of Urology, gonadotropin-releasing hormone (GnRH) agonists have become the leading therapeutic option for ADT because they avoid the physical and psychological discomforts associated with orchiectomy. However, GnRH agonists display several shortcomings, including testosterone (T) surge ("clinical flare") and microsurges. T surge delays the intended serologic endpoint of T suppression and may exacerbate clinical symptoms. Furthermore, ADT manifests an adverse-event spectrum that can impact quality of life with its attendant well-documented morbidities. Strategies to improve ADT tolerability include a holistic management approach, improved diet and exercise, and more specific monitoring to detect and prevent T depletion toxicities. Intermittent ADT, which allows hormonal recovery between treatment periods, has become increasingly utilized as a methodology for improving quality of life while not diminishing chronic ADT efficacy, and may also provide healthcare cost savings. This review assesses the present and potential future role of GnRH agonists in prostate cancer and explores strategies to minimize the adverse-event profile for patients receiving ADT.

  11. Pregnane X receptor agonists impair postprandial glucose tolerance.

    PubMed

    Rysä, J; Buler, M; Savolainen, M J; Ruskoaho, H; Hakkola, J; Hukkanen, J

    2013-06-01

    We conducted a randomized, open, placebo-controlled crossover trial to investigate the effects of the pregnane X receptor (PXR) agonist rifampin on an oral glucose tolerance test (OGTT) in 12 healthy volunteers. The subjects were administered 600 mg rifampin or placebo once daily for 7 days, and OGTT was performed on the eighth day. The mean incremental glucose and insulin areas under the plasma concentration-time curves (AUC(incr)) increased by 192% (P = 0.008) and 45% (P = 0.031), respectively. The fasting glucose, insulin, and C-peptide, and the homeostasis model assessment for insulin resistance, were not affected. The glucose AUC(incr) during OGTT was significantly increased in rats after 4-day treatment with pregnenolone 16α-carbonitrile (PCN), an agonist of the rat PXR. The hepatic level of glucose transporter 2 (Glut2) mRNA was downregulated by PCN. In conclusion, both human and rat PXR agonists elicited postprandial hyperglycemia, suggesting a detrimental role of PXR activation on glucose tolerance.

  12. Beta2-Agonist Doping Control and Optical Isomer Challenges.

    PubMed

    Jacobson, Glenn A; Fawcett, J Paul

    2016-12-01

    The World Anti-Doping Agency (WADA) currently allows therapeutic use of the beta2-agonists salbutamol, formoterol and salmeterol when delivered via inhalation despite some evidence suggesting these anti-asthma drugs may be performance enhancing. Beta2-agonists are usually administered as 50:50 racemic mixtures of two enantiomers (non-superimposable mirror images), one of which demonstrates significant beta2-adrenoceptor-mediated bronchodilation while the other appears to have little or no pharmacological activity. For salbutamol and formoterol, urine thresholds have been adopted to limit supratherapeutic dosing and to discriminate between inhaled (permitted) and oral (prohibited) use. However, chiral switches have led to the availability of enantiopure (active enantiomer only) preparations of salbutamol and formoterol, which effectively doubles their urine thresholds and provides a means for athletes to take supratherapeutic doses for doping purposes. Given the availability of these enantiopure beta2-agonists, the analysis of these drugs using enantioselective assays should now become routine. For salmeterol, there is currently only a therapeutic dose threshold and adoption of a urinary threshold should be a high priority for doping control.

  13. The β2-adrenoceptor agonist formoterol stimulates mitochondrial biogenesis.

    PubMed

    Wills, Lauren P; Trager, Richard E; Beeson, Gyda C; Lindsey, Christopher C; Peterson, Yuri K; Beeson, Craig C; Schnellmann, Rick G

    2012-07-01

    Mitochondrial dysfunction is a common mediator of disease and organ injury. Although recent studies show that inducing mitochondrial biogenesis (MB) stimulates cell repair and regeneration, only a limited number of chemicals are known to induce MB. To examine the impact of the β-adrenoceptor (β-AR) signaling pathway on MB, primary renal proximal tubule cells (RPTC) and adult feline cardiomyocytes were exposed for 24 h to multiple β-AR agonists: isoproterenol (nonselective β-AR agonist), (±)-(R*,R*)-[4-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]amino]propyl]phenoxy] acetic acid sodium hydrate (BRL 37344) (selective β(3)-AR agonist), and formoterol (selective β(2)-AR agonist). The Seahorse Biosciences (North Billerica, MA) extracellular flux analyzer was used to quantify carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP)-uncoupled oxygen consumption rate (OCR), a marker of maximal electron transport chain activity. Isoproterenol and BRL 37244 did not alter mitochondrial respiration at any of the concentrations examined. Formoterol exposure resulted in increases in both FCCP-uncoupled OCR and mitochondrial DNA (mtDNA) copy number. The effect of formoterol on OCR in RPTC was inhibited by the β-AR antagonist propranolol and the β(2)-AR inverse agonist 3-(isopropylamino)-1-[(7-methyl-4-indanyl)oxy]butan-2-ol hydrochloride (ICI-118,551). Mice exposed to formoterol for 24 or 72 h exhibited increases in kidney and heart mtDNA copy number, peroxisome proliferator-activated receptor γ coactivator 1α, and multiple genes involved in the mitochondrial electron transport chain (F0 subunit 6 of transmembrane F-type ATP synthase, NADH dehydrogenase subunit 1, NADH dehydrogenase subunit 6, and NADH dehydrogenase [ubiquinone] 1β subcomplex subunit 8). Cheminformatic modeling, virtual chemical library screening, and experimental validation identified nisoxetine from the Sigma Library of Pharmacologically Active Compounds and two compounds from the ChemBridge DIVERSet

  14. Different skeletal effects of the peroxisome proliferator activated receptor (PPAR)α agonist fenofibrate and the PPARγ agonist pioglitazone

    PubMed Central

    Syversen, Unni; Stunes, Astrid K; Gustafsson, Björn I; Obrant, Karl J; Nordsletten, Lars; Berge, Rolf; Thommesen, Liv; Reseland, Janne E

    2009-01-01

    Background All the peroxisome proliferator activated receptors (PPARs) are found to be expressed in bone cells. The PPARγ agonist rosiglitazone has been shown to decrease bone mass in mice and thiazolidinediones (TZDs) have recently been found to increase bone loss and fracture risk in humans treated for type 2 diabetes mellitus. The aim of the study was to examine the effect of the PPARα agonist fenofibrate (FENO) and the PPARγ agonist pioglitazone (PIO) on bone in intact female rats. Methods Rats were given methylcellulose (vehicle), fenofibrate or pioglitazone (35 mg/kg body weight/day) by gavage for 4 months. BMC, BMD, and body composition were measured by DXA. Histomorphometry and biomechanical testing of excised femurs were performed. Effects of the compounds on bone cells were studied. Results The FENO group had higher femoral BMD and smaller medullary area at the distal femur; while trabecular bone volume was similar to controls. Whole body BMD, BMC, and trabecular bone volume were lower, while medullary area was increased in PIO rats compared to controls. Ultimate bending moment and energy absorption of the femoral shafts were reduced in the PIO group, while similar to controls in the FENO group. Plasma osteocalcin was higher in the FENO group than in the other groups. FENO stimulated proliferation and differentiation of, and OPG release from, the preosteoblast cell line MC3T3-E1. Conclusion We show opposite skeletal effects of PPARα and γ agonists in intact female rats. FENO resulted in significantly higher femoral BMD and lower medullary area, while PIO induced bone loss and impairment of the mechanical strength. This represents a novel effect of PPARα activation. PMID:19331671

  15. Superagonist, Full Agonist, Partial Agonist, and Antagonist Actions of Arylguanidines at 5-Hydroxytryptamine-3 (5-HT3) Subunit A Receptors.

    PubMed

    Alix, Katie; Khatri, Shailesh; Mosier, Philip D; Casterlow, Samantha; Yan, Dong; Nyce, Heather L; White, Michael M; Schulte, Marvin K; Dukat, Małgorzata

    2016-11-16

    Introduction of minor variations to the substitution pattern of arylguanidine 5-hydroxytryptamine-3 (5-HT3) receptor ligands resulted in a broad spectrum of functionally-active ligands from antagonist to superagonist. For example, (i) introduction of an additional Cl-substituent(s) to our lead full agonist N-(3-chlorophenyl)guanidine (mCPG, 2; efficacy % = 106) yielded superagonists 7-9 (efficacy % = 186, 139, and 129, respectively), (ii) a positional isomer of 2, p-Cl analog 11, displayed partial agonist actions (efficacy % = 12), and (iii) replacing the halogen atom at the meta or para position with an electron donating OCH3 group or a stronger electron withdrawing (i.e., CF3) group resulted in antagonists 13-16. We posit based on combined mutagenesis, crystallographic, and computational analyses that for the 5-HT3 receptor, the arylguanidines that are better able to simultaneously engage the primary and complementary subunits, thus keeping them in close proximity, have greater agonist character while those that are deficient in this ability are antagonists.

  16. Virtual screening of CB(2) receptor agonists from bayesian network and high-throughput docking: structural insights into agonist-modulated GPCR features.

    PubMed

    Renault, Nicolas; Laurent, Xavier; Farce, Amaury; El Bakali, Jamal; Mansouri, Roxane; Gervois, Philippe; Millet, Régis; Desreumaux, Pierre; Furman, Christophe; Chavatte, Philippe

    2013-04-01

    The relevance of CB(2)-mediated therapeutics is well established in the treatment of pain, neurodegenerative and gastrointestinal tract disorders. Recent works such as the crystallization of class-A G-protein-coupled receptors in a range of active states and the identification of specific anchoring sites for CB(2) agonists challenged us to design a reliable agonist-bound homology model of CB(2) receptor. Docking-scoring enrichment tests of a high-throughput virtual screening of 140 compounds led to 13 hits within the micromolar affinity range. Most of these hits behaved as CB(2) agonists, among which two novel full agonists emerged. Although the main challenge was a high-throughput docking run targeting an agonist-bound state of a CB(2) model, a prior 2D ligand-based Bayesian network was computed to enrich the input commercial library for 3D screening. The exclusive discovery of agonists illustrates the reliability of this agonist-bound state model for the identification of polar and aromatic amino acids as new agonist-modulated CB(2) features to be integrated in the wide activation pathway of G-protein-coupled receptors.

  17. 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.

  18. PPARgamma agonist pioglitazone does not enhance performance in mice.

    PubMed

    Sanchis-Gomar, Fabian; Pareja-Galeano, Helios; Martinez-Bello, Vladimir E

    2014-09-01

    Peroxisome-proliferator-activated receptor (PPAR) delta and adenosine monophosphate (AMP)-activated protein kinases (AMPKs) regulate the metabolic and contractile characteristics of myofibres. PPAR proteins are nuclear receptors that function as transcription factors and regulate the expression of multiple genes. AMPK has been described as a master metabolic regulator which also controls gene expression through the direct phosphorylation of some nuclear proteins. Since it was discovered that both PPARdelta agonists (GW1516) and AMPK activators (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside, known as AICAR) are very effective performance-enhancing substances in sedentary mice, the World Anti-doping Agency (WADA) included AICAR and GW1516 in the prohibited list of substances as metabolic modulators in the class 'Hormone and metabolic modulators'. Thiazolidinediones are PPARgamma agonists that can induce similar biological effects to those of PPARdelta and PPARdelta-AMPK agonists. Thus in this study, the effects of pioglitazone on mitochondrial biogenesis and performance were evaluated. Blood glucose levels and the protein expression of the intermediates involved in the mitochondrial biogenesis pathway and the citrate synthase activity were determined in both gastrocnemius and soleus muscles. Maximal aerobic velocity (MAV), endurance capacity, and grip strength before and after the training period were also determined. The MAV endurance capacity and grip strength of trained animals significantly increased. We found that the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and the nuclear respiratory factor-1 (NRF-1) protein content and citrate synthase activity significantly increased in the soleus muscle of trained animals. No effect of treatment was found. Therefore in our study, pioglitazone administration did not affect mitochondrial biogenesis signaling pathway.

  19. Comparative endpoint sensitivity of in vitro estrogen agonist assays.

    PubMed

    Dreier, David A; Connors, Kristin A; Brooks, Bryan W

    2015-07-01

    Environmental and human health implications of endocrine disrupting chemicals (EDCs), particularly xenoestrogens, have received extensive study. In vitro assays are increasingly employed as diagnostic tools to comparatively evaluate chemicals, whole effluent toxicity and surface water quality, and to identify causative EDCs during toxicity identification evaluations. Recently, the U.S. Environmental Protection Agency (USEPA) initiated ToxCast under the Tox21 program to generate novel bioactivity data through high throughput screening. This information is useful for prioritizing chemicals requiring additional hazard information, including endocrine active chemicals. Though multiple in vitro and in vivo techniques have been developed to assess estrogen agonist activity, the relative endpoint sensitivity of these approaches and agreement of their conclusions remain unclear during environmental diagnostic applications. Probabilistic hazard assessment (PHA) approaches, including chemical toxicity distributions (CTD), are useful for understanding the relative sensitivity of endpoints associated with in vitro and in vivo toxicity assays by predicting the likelihood of chemicals eliciting undesirable outcomes at or above environmentally relevant concentrations. In the present study, PHAs were employed to examine the comparative endpoint sensitivity of 16 in vitro assays for estrogen agonist activity using a diverse group of compounds from the USEPA ToxCast dataset. Reporter gene assays were generally observed to possess greater endpoint sensitivity than other assay types, and the Tox21 ERa LUC BG1 Agonist assay was identified as the most sensitive in vitro endpoint for detecting an estrogenic response. When the sensitivity of this most sensitive ToxCast in vitro endpoint was compared to the human MCF-7 cell proliferation assay, a common in vitro model for biomedical and environmental monitoring applications, the ERa LUC BG1 assay was several orders of magnitude less

  20. Biased signaling by peptide agonists of protease activated receptor 2.

    PubMed

    Jiang, Yuhong; Yau, Mei-Kwan; Kok, W Mei; Lim, Junxian; Wu, Kai-Chen; Liu, Ligong; Hill, Timothy A; Suen, Jacky Y; Fairlie, David P

    2017-02-07

    Protease activated receptor 2 (PAR2) is associated with metabolism, obesity, inflammatory, respiratory and gastrointestinal disorders, pain, cancer and other diseases. The extracellular N-terminus of PAR2 is a common target for multiple proteases, which cleave it at different sites to generate different N-termini that activate different PAR2-mediated intracellular signaling pathways. There are no synthetic PAR2 ligands that reproduce the same signaling profiles and potencies as proteases. Structure-activity relationships here for 26 compounds spanned a signaling bias over 3 log units, culminating in three small ligands as biased agonist tools for interrogating PAR2 functions. DF253 (2f-LAAAAI-NH2) triggered PAR2-mediated calcium release (EC50 2 μM) but not ERK1/2 phosphorylation (EC50 > 100 μM) in CHO cells transfected with hPAR2. AY77 (Isox-Cha-Chg-NH2) was a more potent calcium-biased agonist (EC50 40 nM, Ca2+; EC50 2 μM, ERK1/2), while its analogue AY254 (Isox-Cha-Chg-A-R-NH2) was an ERK-biased agonist (EC50 2 nM, ERK1/2; EC50 80 nM, Ca2+). Signaling bias led to different functional responses in human colorectal carcinoma cells (HT29). AY254, but not AY77 or DF253, attenuated cytokine-induced caspase 3/8 activation, promoted scratch-wound healing and induced IL-8 secretion, all via PAR2-ERK1/2 signaling. Different ligand components were responsible for different PAR2 signaling and functions, clues that can potentially lead to drugs that modulate different pathway-selective cellular and physiological responses.

  1. Melatonin and Melatonin Agonists as Adjunctive Treatments in Bipolar Disorders.

    PubMed

    Geoffroy, Pierre Alexis; Etain, Bruno; Franchi, Jean-Arthur Micoulaud; Bellivier, Frank; Ritter, Philipp

    2015-01-01

    Bipolar disorders (BD) present with abnormalities of circadian rhythmicity and sleep homeostasis, even during phases of remission. These abnormalities are linked to the underlying neurobiology of genetic susceptibility to BD. Melatonin is a pineal gland secreted neurohormone that induces circadian-related and sleep-related responses. Exogenous melatonin has demonstrated efficacy in treating primary insomnia, delayed sleep phase disorder, improving sleep parameters and overall sleep quality, and some psychiatric disorders like autistic spectrum disorders. In order to evaluate the efficacy of melatonin among patients with BD, this comprehensive review emphasizes the abnormal melatonin function in BD, the rationale of melatonin action in BD, the available data about the exogenous administration of melatonin, and melatonin agonists (ramelteon and tasimelteon), and recommendations of use in patients with BD. There is a scientific rationale to propose melatonin-agonists as an adjunctive treatment of mood stabilizers in treating sleep disorders in BD and thus to possibly prevent relapses when administered during remission phases. We emphasized the need to treat insomnia, sleep delayed latencies and sleep abnormalities in BD that are prodromal markers of an emerging mood episode and possible targets to prevent future relapses. An additional interesting adjunctive therapeutic effect might be on preventing metabolic syndrome, particularly in patients treated with antipsychotics. Finally, melatonin is well tolerated and has little dependence potential in contrast to most available sleep medications. Further studies are expected to be able to produce stronger evidence-based therapeutic guidelines to confirm and delineate the routine use of melatonin-agonists in the treatment of BD.

  2. INSIGHT AGONISTES: A READING OF SOPHOCLES'S OEDIPUS THE KING.

    PubMed

    Mahon, Eugene J

    2015-07-01

    In this reading of Sophocles's Oedipus the King, the author suggests that insight can be thought of as the main protagonist of the tragedy. He personifies this depiction of insight, calling it Insight Agonistes, as if it were the sole conflicted character on the stage, albeit masquerading at times as several other characters, including gods, sphinxes, and oracles. This psychoanalytic reading of the text lends itself to an analogy between psychoanalytic process and Sophocles's tragic hero. The author views insight as always transgressing against, always at war with a conservative, societal, or intrapsychic chorus of structured elements. A clinical vignette is presented to illustrate this view of insight.

  3. Dehydroepiandrosterone Derivatives as Potent Antiandrogens with Marginal Agonist Activity

    DTIC Science & Technology

    2013-07-01

    DATES COVERED 01 July 2012 – 30 June 2013 4 . TITLE AND SUBTITLE Dehydroepiandrosterone Derivatives as Potent Antiandrogens with Marginal Agonist...Page Introduction…………………………………………………………….………..….. 1 Body………………………………………………………………………………….. 1- 4 Key Research...In addition, we previously found that androstenediol (Adiol), a physiological metabolite from dehydroepiandrosterone ( DHEA ) and a precursor of

  4. 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.

  5. Is there a justification for classifying GLP-1 receptor agonists as basal and prandial?

    PubMed

    Miñambres, Inka; Pérez, Antonio

    2017-01-01

    Several GLP-1 receptor agonists are currently available for treatment of type 2 diabetic patients. Based on their pharmacokinetic/pharmacodynamic profile, these drugs are classified as short-acting GLP-1 receptor agonists (exenatide and lixisenatide) or long-acting GLP-1 receptor agonists (exenatide-LAR, liraglutide, albiglutide, and dulaglutide). In clinical practice, they are also classified as basal or prandial GLP-1 receptor agonists to differentiate between patients who would benefit more from one or another based on characteristics such as previous treatment and the predominance of fasting or postprandial hyperglycemia. In the present article we examine available data on the pharmacokinetic characteristics of the various GLP-1 agonists and compare their effects with respect to the main parameters used to evaluate glycemic control. The article also analyzes whether the differences between the different GLP-1 agonists justify their classification as basal or prandial.

  6. Antidepressant-like Effects of δ Opioid Receptor Agonists in Animal Models

    PubMed Central

    Saitoh, Akiyoshi; Yamada, Mitsuhiko

    2012-01-01

    Recently, δ opioid receptor agonists have been proposed to be attractive targets for the development of novel antidepressants. Several studies revealed that single treatment of δ opioid receptor agonists produce antidepressant-like effects in the forced swimming test, which is one of the most popular animal models for screening antidepressants. In addition, subchronic treatment with δ opioid receptor agonists has been shown to completely attenuate the hyperemotional responses found in olfactory bulbectomized rats. This animal model exhibits hyperemotional behavior that may mimic the anxiety, aggression, and irritability found in depressed patients, suggesting that δ opioid receptor agonists could be effective in the treatment of these symptoms in depression. On the other hand, prototype δ opioid receptor agonists produce convulsive effects, which limit their therapeutic potential and clinical development. In this review, we presented the current knowledge regarding the antidepressant-like effects of δ opioid receptor agonists, which include some recently developed drugs lacking convulsive effects. PMID:23449756

  7. Biostable agonists that match or exceed activity of native insect kinins on recombinant arthropod GPCRs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The multifunctional arthropod insect kinins share the evolutionarily conserved C-terminal pentapeptide motif Phe-X1-X2-Trp-Gly-NH2, where X1 = His, Asn, Ser, or Tyr and X2 = Ser, Pro, or Ala. Insect kinins regulate diuresis in many species of insects. Compounds with similar biological activity cou...

  8. Mechanisms underlying activation of transient BK current in rabbit urethral smooth muscle cells and its modulation by IP3-generating agonists.

    PubMed

    Kyle, Barry D; Bradley, Eamonn; Large, Roddy; Sergeant, Gerard P; McHale, Noel G; Thornbury, Keith D; Hollywood, Mark A

    2013-09-15

    We used the perforated patch-clamp technique at 37°C to investigate the mechanisms underlying the activation of a transient large-conductance K(+) (tBK) current in rabbit urethral smooth muscle cells. The tBK current required an elevation of intracellular Ca(2+), resulting from ryanodine receptor (RyR) activation via Ca(2+)-induced Ca(2+) release, triggered by Ca(2+) influx through L-type Ca(2+) (CaV) channels. Carbachol inhibited tBK current by reducing Ca(2+) influx and Ca(2+) release and altered the shape of spike complexes recorded under current-clamp conditions. The tBK currents were blocked by iberiotoxin and penitrem A (300 and 100 nM, respectively) and were also inhibited when external Ca(2+) was removed or the CaV channel inhibitors nifedipine (10 μM) and Cd(2+) (100 μM) were applied. The tBK current was inhibited by caffeine (10 mM), ryanodine (30 μM), and tetracaine (100 μM), suggesting that RyR-mediated Ca(2+) release contributed to the activation of the tBK current. When IP3 receptors (IP3Rs) were blocked with 2-aminoethoxydiphenyl borate (2-APB, 100 μM), the amplitude of the tBK current was not reduced. However, when Ca(2+) release via IP3Rs was evoked with phenylephrine (1 μM) or carbachol (1 μM), the tBK current was inhibited. The effect of carbachol was abolished when IP3Rs were blocked with 2-APB or by inhibition of muscarinic receptors with the M3 receptor antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide (1 μM). Under current-clamp conditions, bursts of action potentials could be evoked with depolarizing current injection. Carbachol reduced the number and amplitude of spikes in each burst, and these effects were reduced in the presence of 2-APB. In the presence of ryanodine, the number and amplitude of spikes were also reduced, and carbachol was without further effect. These data suggest that IP3-generating agonists can modulate the electrical activity of rabbit urethral smooth muscle cells and may contribute to the effects of

  9. Contamination with retinoic acid receptor agonists in two rivers in the Kinki region of Japan.

    PubMed

    Inoue, Daisuke; Nakama, Koki; Sawada, Kazuko; Watanabe, Taro; Takagi, Mai; Sei, Kazunari; Yang, Min; Hirotsuji, Junji; Hu, Jianying; Nishikawa, Jun-ichi; Nakanishi, Tsuyoshi; Ike, Michihiko

    2010-04-01

    This study was conducted to investigate the agonistic activity against human retinoic acid receptor (RAR) alpha in the Lake Biwa-Yodo River and the Ina River in the Kinki region of Japan. To accomplish this, a yeast two-hybrid assay was used to elucidate the spatial and temporal variations and potential sources of RARalpha agonist contamination in the river basins. RARalpha agonistic activity was commonly detected in the surface water samples collected along two rivers at different periods, with maximum all-trans retinoic acid (atRA) equivalents of 47.6 ng-atRA/L and 23.5 ng-atRA/L being observed in Lake Biwa-Yodo River and Ina River, respectively. The results indicated that RARalpha agonists are always present and widespread in the rivers. Comparative investigation of RARalpha and estrogen receptor alpha agonistic activities at 20 stations along each river revealed that the spatial variation pattern of RARalpha agonist contamination was entirely different from that of the estrogenic compound contamination. This suggests that the effluent from municipal wastewater treatment plants, a primary source of estrogenic compounds, seemed not to be the cause of RARalpha agonist contamination in the rivers. Fractionation using high performance liquid chromatography (HPLC) directed by the bioassay found two bioactive fractions from river water samples, suggesting the presence of at least two RARalpha agonists in the rivers. Although a trial conducted to identify RARalpha agonists in the major bioactive fraction was not completed as part of this study, comparison of retention times in HPLC analysis and quantification with liquid chromatography-mass spectrometry analysis revealed that the major causative contaminants responsible for the RARalpha agonistic activity were not RAs (natural RAR ligands) and 4-oxo-RAs, while 4-oxo-RAs were identified as the major RAR agonists in sewage in Beijing, China. These findings suggest that there are unknown RARalpha agonists with high

  10. β‐Arrestin 2 dependence of δ opioid receptor agonists is correlated with alcohol intake

    PubMed Central

    Chiang, T; Sansuk, K

    2016-01-01

    Background and Purpose δ Opioid receptor agonists are being developed as potential treatments for depression and alcohol use disorders. This is particularly interesting as depression is frequently co‐morbid with alcohol use disorders. Yet we have previously shown that δ receptor agonists range widely in their ability to modulate alcohol intake; certain δ receptor agonists actually increase alcohol consumption in mice. We propose that variations in β‐arrestin 2 recruitment contribute to the differential behavioural profile of δ receptor agonists. Experimental Approach We used three diarylmethylpiperazine‐based non‐peptidic δ receptor selective agonists (SNC80, SNC162 and ARM390) and three structurally diverse δ receptor agonists (TAN‐67, KNT127 and NIH11082). We tested these agonists in cAMP and β‐arrestin 2 recruitment assays and a behavioural assay of alcohol intake in male C57BL/6 mice. We used β‐arrestin 2 knockout mice and a model of depression‐like behaviour to further study the role of β‐arrestin 2 in δ receptor pharmacology. Key Results All six tested δ receptor agonists were full agonists in the cAMP assay but displayed distinct β‐arrestin 2 recruitment efficacy. The efficacy of δ receptor agonists to recruit β‐arrestin 2 positively correlated with their ability to increase alcohol intake (P < 0.01). The effects of the very efficacious recruiter SNC80 on alcohol intake, alcohol place preference and depression‐like behaviour were β‐arrestin 2‐dependent. Conclusions and Implications Our finding that δ receptor agonists that strongly recruit β‐arrestin 2 can increase alcohol intake carries important ramifications for drug development of δ receptor agonists for treatment of alcohol use disorders and depressive disorders. © 2015 The British Pharmacological Society PMID:26507558

  11. Electrophysiological perspectives on the therapeutic use of nicotinic acetylcholine receptor partial agonists.

    PubMed

    Papke, Roger L; Trocmé-Thibierge, Caryn; Guendisch, Daniela; Al Rubaiy, Shehd Abdullah Abbas; Bloom, Stephen A

    2011-05-01

    Partial agonist therapies rely variously on two hypotheses: the partial agonists have their effects through chronic low-level receptor activation or the partial agonists work by decreasing the effects of endogenous or exogenous full agonists. The relative significance of these activities probably depends on whether acute or chronic effects are considered. We studied nicotinic acetylcholine receptors (nAChRs) expressed in Xenopus laevis oocytes to test a model for the acute interactions between acetylcholine (ACh) and weak partial agonists. Data were best-fit to a basic competition model that included an additional factor for noncompetitive inhibition. Partial agonist effects were compared with the nAChR antagonist bupropion in prolonged bath application experiments that were designed to mimic prolonged drug exposure typical of therapeutic drug delivery. A primary effect of prolonged application of nicotine was to decrease the response of all nAChR subtypes to acute applications of ACh. In addition, nicotine, cytisine, and varenicline produced detectable steady-state activation of α4β2* [(α4)(2)(β2)(3), (α4)(3)(β2)(2), and (α4)(2)(β2)(2)α5)] receptor subtypes that was not seen with other test compounds. Partial agonists produced no detectable steady-state activation of α7 nAChR, but seemed to show small potentiation of ACh-evoked responses; however, "run-up" of α7 ACh responses was also sometimes observed under control conditions. Potential off-target effects of the partial agonists therefore included the modulation of α7 responses by α4β2 partial agonists and decreases in α4β2* responses by α7-selective agonists. These data indicate the dual effects expected for α4β2* partial agonists and provide models and insights for utility of partial agonists in therapeutic development.

  12. In vitro and in vivo efficacy of a potent opioid receptor agonist, biphalin, compared to subtype-selective opioid receptor agonists for stroke treatment.

    PubMed

    Yang, Li; Islam, Mohammad R; Karamyan, Vardan T; Abbruscato, Thomas J

    2015-06-03

    To meet the challenge of identification of new treatments for stroke, this study was designed to evaluate a potent, nonselective opioid receptor (OR) agonist, biphalin, in comparison to subtype selective OR agonists, as a potential neuroprotective drug candidate using in vitro and in vivo models of ischemic stroke. Our in vitro approach included mouse primary neuronal cells that were challenged with glutamate and hypoxic/aglycemic (H/A) conditions. We observed that 10nM biphalin, exerted a statistically significant neuroprotective effect after glutamate challenge, compared to all selective opioid agonists, according to lactate dehydrogenase (LDH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Moreover, 10nM biphalin provided superior neuroprotection after H/A-reoxygenation compared to selective opioid agonists in all cases. Our in vitro investigations were supported by in vivo studies which indicate that the nonselective opioid agonist, biphalin, achieves enhanced neuroprotective potency compared to any of the selective opioid agonists, evidenced by reduced edema and infarct ratios. Reduction of edema and infarction was accompanied by neurological improvement of the animals in two independent behavioral tests. Collectively these data strongly suggest that concurrent agonist stimulation of mu, kappa and delta ORs with biphalin is neuroprotective and superior to neuroprotection by activation of any single OR subtype.

  13. In vitro and in vivo efficacy of a potent opioid receptor agonist, biphalin, compared to subtype-selective opioid receptor agonists for stroke treatment

    PubMed Central

    Yang, Li; Islam, Mohammad R; Karamyan, Vardan T.; Abbruscato, Thomas J.

    2015-01-01

    To meet the challenge of identification of new treatments for stroke, this study was designed to evaluate a potent, nonselective opioid receptor (OR) agonist, biphalin, in comparison to subtype selective OR agonists, as a potential neuroprotective drug candidate using in vitro and in vivo models of ischemic stroke. Our in vitro approach included mouse primary neuronal cells that were challenged with glutamate and hypoxic/aglycemic (H/A) conditions. We observed that 10 nM biphalin, exerted a statistically significant neuroprotective effect after glutamate challenge, compared to all selective opioid agonists, according to lactate dehydrogenase (LDH) and 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assays. Moreover, 10 nM biphalin provided superior neuroprotection after H/A-reoxygenation compared to selective opioid agonists in all cases. Our in vitro investigations were supported by in vivo studies which indicate that the nonselective opioid agonist, biphalin, achieves enhanced neuroprotective potency compared to any of the selective opioid agonists, evidenced by reduced edema and infarct ratios. Reduction of edema and infarction was accompanied by neurological improvement of the animals in two independent behavioral tests. Collectively these data strongly suggest that concurrent agonist stimulation of mu, kappa and delta ORs with biphalin is neuroprotective and superior to neuroprotection by activation of any single OR subtype. PMID:25801116

  14. Phenylephrine preconditioning in embryonic heart H9c2 cells is mediated by up-regulation of SUR2B/Kir6.2: A first evidence for functional role of SUR2B in sarcolemmal KATP channels and cardioprotection.

    PubMed

    Jovanović, Sofija; Ballantyne, Thomas; Du, Qingyou; Blagojević, Miloš; Jovanović, Aleksandar

    2016-01-01

    ATP-sensitive K(+) (KATP) channels were originally described in cardiomyocytes, where physiological levels of intracellular ATP keep them in a closed state. Structurally, these channels are composed of pore-forming inward rectifier, Kir6.1 or Kir6.2, and a regulatory, ATP-binding subunit, SUR1, SUR2A or SUR2B. SUR1 and Kir6.2 form pancreatic type of KATP channels, SUR2A and Kir6.2 form cardiac type of KATP channels, SUR2B and Kir6.1 form vascular smooth muscle type of KATP channels. The presence of SUR2B has been described in cardiomyocytes, but its functional significance and role has remained unknown. Pretreatment with phenylephrine (100nM) for 24h increased mRNA levels of SUR2B and Kir6.2, without affecting those levels of SUR1, SUR2A and Kir6.1 in embryonic heart H9c2 cells. Such increase was associated with increased K(+) current through KATP channels and Kir6.2/SUR2B protein complexes as revealed by whole cell patch clamp electrophysiology and immunoprecipitation/Western blotting respectively. Pretreatment with phenylephrine (100nM) generated a cellular phenotype that acquired resistance to chemical hypoxia induced by 2,4-dinitrophenol (DNP; 10mM), which was accompanied by increased in K(+) current in response to DNP (10mM). Cytoprotection afforded by phenylephrine (100nM) was abolished by infection of H9c2 cells with adenovirus containing Kir6.2AFA, a mutant form of Kir6.2 with largely reduced K(+) conductance. Taking all together, the present findings demonstrate that the activation of α1-adrenoceptors up-regulates SUR2B/Kir6.2 to confer cardioprotection. This is the first account of possible physiological role of SUR2B in cardiomyocytes.

  15. Benzodiazepine agonist and inverse agonist actions on GABAA receptor-operated chloride channels. I. Acute effects of ethanol

    SciTech Connect

    Buck, K.J.; Harris, R.A. )

    1990-05-01

    Acute exposure to ethanol was found to enhance the ability of a benzodiazepine (BZ) inverse agonist, methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM), to reduce muscimol-activated 36Cl- uptake by membranes isolated from mouse cerebral cortex. Pretreatment in vivo with a hypnotic dose of ethanol (but not a subhypnotic dose), or exposure to a corresponding concentration in vitro, was effective. This increase in sensitivity of gamma-aminobutyric acid receptor-operated chloride channels to the actions of DMCM was due to an increase in both the potency and efficacy of DMCM. Sensitization to DMCM was reversible and was not observed 24 hr after a single injection of ethanol. Pretreatment with ethanol (10, 50 and 100 mM) in vitro produced sensitization to DMCM in a concentration-dependent manner, similar to that produced by in vivo exposure; this increase in sensitivity did not develop if the membranes were pretreated with ethanol at 0 degrees C. Similarly, in vitro exposure to pentobarbital (200 microM) or flunitrazepam (1 microM) enhanced the actions of the inverse agonist Ro15-4513 (ethyl-8-azido-5,6-dihydro-5-methyl-6-oxo-4H-imidazo(1,5a)(1,4)BZ-3- carboxylate). Acute ethanol exposure did not alter low-affinity gamma-aminobutyric acidA receptor binding or muscimol action, or the ability of a BZ agonist, flunitrazepam, to augment muscimol-activated chloride flux. Ethanol exposure did not alter (3H)flumazenil (Ro15-1788) binding to central BZ receptors, its displacement by DMCM or allosteric modulation of DMCM binding by muscimol (muscimol-shift).

  16. Trial Watch: Immunostimulation with Toll-like receptor agonists in cancer therapy.

    PubMed

    Iribarren, Kristina; Bloy, Norma; Buqué, Aitziber; Cremer, Isabelle; Eggermont, Alexander; Fridman, Wolf Hervé; Fucikova, Jitka; Galon, Jérôme; Špíšek, Radek; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2016-03-01

    Accumulating preclinical evidence indicates that Toll-like receptor (TLR) agonists efficiently boost tumor-targeting immune responses (re)initiated by most, if not all, paradigms of anticancer immunotherapy. Moreover, TLR agonists have been successfully employed to ameliorate the efficacy of various chemotherapeutics and targeted anticancer agents, at least in rodent tumor models. So far, only three TLR agonists have been approved by regulatory agencies for use in cancer patients. Moreover, over the past decade, the interest of scientists and clinicians in these immunostimulatory agents has been fluctuating. Here, we summarize recent advances in the preclinical and clinical development of TLR agonists for cancer therapy.

  17. Analysis of agonist dissociation constants as assessed by functional antagonism in guinea pig left atria

    SciTech Connect

    Molenaar, P.; Malta, E.

    1986-04-01

    In electrically driven guinea pig left atria, positive inotropic responses to (-)-isoprenaline and the selective beta 1-adrenoceptor agonist RO363 were obtained in the absence and in the presence of the functional antagonists adenosine, carbachol, gallopamil, nifedipine, and Ro 03-7894. Each of the functional antagonists reduced the maximum response to both agonists and produced nonparallel rightward shifts in the cumulative concentration effect curves. For both agonists, dissociation constants (KA) were calculated using the equation described by Furchgott (1966) for irreversible antagonism. For RO363, which is a partial agonist with high agonist activity, the equations outlined for functional interaction by Mackay (1981) were also employed to calculate KA values. The KA values obtained by each method were compared with the dissociation constants (KD) for the two agonists determined from their ability to displace the radioligand (-)-(/sup 125/I)iodocyanopindolol from beta 1-adrenoceptors in guinea pig left atrial membrane preparations. The estimates of KA varied substantially from KD values. The KD values were taken as more accurate estimates of the true values for the dissociation constants because a high degree of correlation exists between pKD and pD2 values for a number of other beta-adrenoceptor agonists that behave as partial agonists and between pKD and pKB values for a number of beta-adrenoceptor antagonists. Thus, it appears that there are serious limitations in the current theory for using functional antagonism as a means of obtaining agonist dissociation constants.

  18. The pharmacology of epanolol (ICI 141292)--a new beta 1-selective adrenoceptor partial agonist.

    PubMed

    Bilski, A J; Hadfield, S E; Wale, J L

    1988-08-01

    The clinical benefit of beta-adrenoceptor partial agonists is still debated. To clarify the situation, epanolol, ICI 141,292 [N-[-2-(3-o-cyanophenoxy-2-hydroxypropylamino)ethyl]-4- hydroxyphenylactamide], has been developed to assess the role of modest beta-adrenoceptor partial agonist activity in humans. Animal studies have shown that epanolol is a potent beta-adrenoceptor partial agonist with a greater affinity for beta 1- than beta 2-adrenoceptors. In vitro, the PA2 values obtained for espanolol at atrial and tracheal beta-adrenoceptors were 8.42 and 6.33, respectively (isoproterenol as agonist), giving a selectivity ratio of 123. The potency was studied in vivo in the dog, where it was also shown that as an antagonist at the cardiac beta 1-adrenoceptor, it was 18 and 40 times more potent than atenolol and practolol, respectively. Espanolol has less partial agonist activity in the rat than pindolol, but more than practolol. In this species, it is also a classical partial agonist, exhibiting agonist activity at all beta-adrenoceptor blocking doses. This is in contrast to pindolol, which caused predominantly beta-adrenoceptor blockade at low doses and partial agonist activity at higher doses. These differences were confirmed in haemodynamic studies in the dog. In contrast to many other partial agonists, the partition coefficient, log P, of epanolol in octanol and water is low (0.92).

  19. Trial Watch: Immunostimulation with Toll-like receptor agonists in cancer therapy

    PubMed Central

    Iribarren, Kristina; Bloy, Norma; Buqué, Aitziber; Cremer, Isabelle; Eggermont, Alexander; Fridman, Wolf Hervé; Fucikova, Jitka; Galon, Jérôme; Špíšek, Radek; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2016-01-01

    ABSTRACT Accumulating preclinical evidence indicates that Toll-like receptor (TLR) agonists efficiently boost tumor-targeting immune responses (re)initiated by most, if not all, paradigms of anticancer immunotherapy. Moreover, TLR agonists have been successfully employed to ameliorate the efficacy of various chemotherapeutics and targeted anticancer agents, at least in rodent tumor models. So far, only three TLR agonists have been approved by regulatory agencies for use in cancer patients. Moreover, over the past decade, the interest of scientists and clinicians in these immunostimulatory agents has been fluctuating. Here, we summarize recent advances in the preclinical and clinical development of TLR agonists for cancer therapy. PMID:27141345

  20. Agonist signalling properties of radiotracers used for imaging of dopamine D2/3 receptors

    PubMed Central

    2014-01-01

    Background Dopamine D2/3 receptor (D2/3R) agonist radiopharmaceuticals are considered superior to antagonists to detect dopamine release, e.g. induced by amphetamines. Agonists bind preferentially to the high-affinity state of the dopamine D2R, which has been proposed as the reason why agonists are more sensitive to detect dopamine release than antagonist radiopharmaceuticals, but this theory has been challenged. Interestingly, not all agonists similarly activate the classic cyclic adenosine mono phosphate (cAMP) and the ?-arrestin-2 pathway, some stimulate preferentially one of these pathways; a phenomenon called biased agonism. Because these pathways can be affected separately by pathologies or drugs (including dopamine releasers), it is important to know how agonist radiotracers act on these pathways. Therefore, we characterized the intracellular signalling of the well-known D2/3R agonist radiopharmaceuticals NPA and PHNO and of several novel D2/3R agonists. Methods cAMP accumulation and ?-arrestin-2 recruitment were measured on cells expressing human D2R. Results All tested agonists showed (almost) full agonism in both pathways. Conclusions The tested D2/3R agonist radiopharmaceuticals did not exhibit biased agonism in vitro. Consequently, it is likely that drugs (including psychostimulants like amphetamines) and/or pathologies that influence the cAMP and/or the ?-arrestin-2 pathway may influence the binding of these radiopharmaceuticals. PMID:25977878

  1. Melatonin and melatonin agonist for delirium in the elderly patients.

    PubMed

    Chakraborti, Dwaipayan; Tampi, Deena J; Tampi, Rajesh R

    2015-03-01

    The objective of this review is to summarize the available data on the use of melatonin and melatonin agonist for the prevention and management of delirium in the elderly patients from randomized controlled trials (RCTs). A systematic search of 5 major databases PubMed, MEDLINE, PsychINFO, Embase, and Cochrane Library was conducted. This search yielded a total of 2 RCTs for melatonin. One study compared melatonin to midazolam, clonidine, and control groups for the prevention and management of delirium in individuals who were pre- and posthip post-hip arthroplasty. The other study compared melatonin to placebo for the prevention of delirium in older adults admitted to an inpatient internal medicine service. Data from these 2 studies indicate that melatonin may have some benefit in the prevention and management of delirium in older adults. However, there is no evidence that melatonin reduces the severity of delirium or has any effect on behaviors or functions in these individuals. Melatonin was well tolerated in these 2 studies. The search for a melatonin agonist for delirium in the elderly patients yielded 1 study of ramelteon. In this study, ramelteon was found to be beneficial in preventing delirium in medically ill individuals when compared to placebo. Ramelteon was well tolerated in this study.

  2. GLP-1 receptor agonist-induced polyarthritis: a case report.

    PubMed

    Ambrosio, Maria Luisa; Monami, Matteo; Sati, Lavinia; Marchionni, Niccolò; Di Bari, Mauro; Mannucci, Edoardo

    2014-08-01

    Occasional cases of bilateral, symmetrical, seronegative polyarthritis have been reported in patients treated with dipeptidyl peptidase-4 inhibitors (Crickx et al. in Rheumatol Int, 2013). We report here a similar case observed during treatment with a GLP-1 receptor agonist. A 42-year-old man with type 2 diabetes treated with metformin 1,500 mg/day and liraglutide 1.8 mg/day. After 6 months from the beginning of treatment, the patient complained of bilateral arthralgia (hands, feet, ankles, knees, and hips). Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and leukocytes were increased. Rheumatoid factor, anticyclic citrullinated protein antibody, antinuclear antibodies, anti-Borrelia, and burgdorferi antibodies were all negative, and myoglobin and calcitonin were normal. Liraglutide was withdrawn, and the symptoms completely disappeared within 1 week, with normalization of ESR, CRP, fibrinogen, and leukocytes. Previously described cases of polyarthritis associated with DPP4 inhibitors had been attributed to a direct effect of the drugs on inflammatory cells expressing the enzyme. The present case, occurred during treatment with a GLP-1 receptor agonists, suggests a possibly different mechanism, mediated by GLP-1 receptor stimulation, which deserved further investigation.

  3. Nicotinic acetylcholine receptor agonist attenuates ILC2-dependent airway hyperreactivity

    PubMed Central

    Galle-Treger, Lauriane; Suzuki, Yuzo; Patel, Nisheel; Sankaranarayanan, Ishwarya; Aron, Jennifer L.; Maazi, Hadi; Chen, Lin; Akbari, Omid

    2016-01-01

    Allergic asthma is a complex and chronic inflammatory disorder that is associated with airway hyperreactivity (AHR) and driven by Th2 cytokine secretion. Type 2 innate lymphoid cells (ILC2s) produce large amounts of Th2 cytokines and contribute to the development of AHR. Here, we show that ILC2s express the α7-nicotinic acetylcholine receptor (α7nAChR), which is thought to have an anti-inflammatory role in several inflammatory diseases. We show that engagement of a specific agonist with α7nAChR on ILC2s reduces ILC2 effector function and represses ILC2-dependent AHR, while decreasing expression of ILC2 key transcription factor GATA-3 and critical inflammatory modulator NF-κB, and reducing phosphorylation of upstream kinase IKKα/β. Additionally, the specific α7nAChR agonist reduces cytokine production and AHR in a humanized ILC2 mouse model. Collectively, our data suggest that α7nAChR expressed by ILC2s is a potential therapeutic target for the treatment of ILC2-mediated asthma. PMID:27752043

  4. Agonist-stimulated alveolar macrophages: apoptosis and phospholipid signaling.

    PubMed

    Lütjohann, J; Spiess, A N; Gercken, G

    1998-08-01

    Bovine alveolar macrophages (BAM) were labeled with [3H]-choline or [3H]-ethanolamine and exposed to quartz dust, metal oxide-coated silica particles, Escherichia coli-derived lipopolysaccharide (LPS) or tumor promotor 12-O-tetradecanoyl phorbol 13-acetate (PMA). The activation of phospholipases A2, C and D (PLA2, PLC and PLD) acting on phosphatidylcholine and phosphatidylethanolamine was determined by high performance liquid chromatography (HPLC) separation and liquid scintillation counting of water- and lipid-soluble phospholipid metabolites. Exposure of BAM to quartz dust, metal oxide-coated silica particles, and LPS led to a transient PLD activation while treatment with PMA caused a prolonged rise in PLD activity. LPS and quartz dust induced a short-term increase of PLC cleavage products. All agonists caused a transient activation of PLA2. To induce apoptosis, BAM were stimulated with C8-ceramide, calcium-ionophore 23187, or gliotoxin. Apoptosis was investigated by qualitative and quantitative methods like flow cytometry, propidium iodide/Hoechst 33258 double staining, Cell Death Detection ELISA, and electrophoretical detection of DNA fragmentation. All three agonists led to apoptosis of BAM in a time- and concentration-dependent manner. After stimulation with gliotoxin an increase in ceramide and a drastic decrease in sphingosine-1-phosphate levels were observed, suggesting an involvement of these sphingolipids in gliotoxin-mediated apoptosis.

  5. The evolution of histamine H₃ antagonists/inverse agonists.

    PubMed

    Lebois, Evan P; Jones, Carrie K; Lindsley, Craig W

    2011-01-01

    This article describes our efforts along with recent advances in the development, biological evaluation and clinical proof of concept of small molecule histamine H₃ antagonists/inverse agonists. The H3 receptor is a presynaptic autoreceptor within the Class A GPCR family, but also functions as a heteroreceptor modulating levels of neurotransmitters such as dopamine, acetylcholine, norepinephrine, serotonin, GABA and glutamate. Thus, H₃R has garnered a great deal of interest from the pharmaceutical industry for the possible treatment of obesity, epilepsy, sleep/wake, schizophrenia, Alzheimer's disease, neuropathic pain and ADHD. Within the two main classes of H₃ ligands, both imidazole and non-imidazole derived, have shown sufficient potency and specificity which culminated with efficacy in preclinical models for various CNS disorders. Importantly, conserved elements have been identified within the small molecule H₃ ligand scaffolds that resulted in a highly predictive pharmacophore model. Understanding of the pharmacophore model has allowed several groups to dial H₃R activity into scaffolds designed for other CNS targets, and engender directed polypharmacology. Moreover, Abbott, GSK, Pfizer and several others have reported positive Phase I and/or Phase II data with structurally diverse H₃R antagonists/inverse agonists.

  6. Trial Watch: Toll-like receptor agonists in oncological indications.

    PubMed

    Aranda, Fernando; Vacchelli, Erika; Obrist, Florine; Eggermont, Alexander; Galon, Jérôme; Sautès-Fridman, Catherine; Cremer, Isabelle; Henrik Ter Meulen, Jan; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2014-01-01

    Toll-like receptors (TLRs) are an evolutionarily conserved group of enzymatically inactive, single membrane-spanning proteins that recognize a wide panel of exogenous and endogenous danger signals. Besides constituting a crucial component of the innate immune response to bacterial and viral pathogens, TLRs appear to play a major role in anticancer immunosurveillance. In line with this notion, several natural and synthetic TLR ligands have been intensively investigated for their ability to boost tumor-targeting immune responses elicited by a variety of immunotherapeutic and chemotherapeutic interventions. Three of these agents are currently approved by the US Food and Drug Administration (FDA) or equivalent regulatory agencies for use in cancer patients: the so-called bacillus Calmette-Guérin, monophosphoryl lipid A, and imiquimod. However, the number of clinical trials testing the therapeutic potential of both FDA-approved and experimental TLR agonists in cancer patients is stably decreasing, suggesting that drug developers and oncologists are refocusing their interest on alternative immunostimulatory agents. Here, we summarize recent findings on the use of TLR agonists in cancer patients and discuss how the clinical evaluation of FDA-approved and experimental TLR ligands has evolved since the publication of our first Trial Watch dealing with this topic.

  7. Mood Disorders, Circadian Rhythms, Melatonin and Melatonin Agonists

    PubMed Central

    Quera Salva, M.A.; Hartley, S.

    2012-01-01

    Recent advances in the understanding of circadian rhythms have led to an interest in the treatment of major depressive disorder with chronobiotic agents. Many tissues have autonomous circadian rhythms, which are orchestrated by the master clock, situated in the suprachiasmatic nucleus (SNC). Melatonin (N-acetyl-5-hydroxytryptamine) is secreted from the pineal gland during darkness. Melatonin acts mainly on MT1 and MT2 receptors, which are present in the SNC, regulating physiological and neuroendocrine functions, including circadian entrainment, referred to as the chronobiotic effet. Circadian rhythms has been shown to be either misaligned or phase shifted or decreased in amplitude in both acute episodes and relapse of major depressive disorder (MDD) and bipolar disorder. Manipulation of circadian rhythms either using physical treatments (such as high intensity light) or behavioral therapy has shown promise in improving symptoms. Pharmacotherapy using melatonin and pure melatonin receptor agonists, while improving sleep, has not been shown to improve symptoms of depression. A novel antidepressant, agomelatine, combines 5HT2c antagonist and melatonin agonist action, and has shown promise in both acute treatment of MDD and in preventing relapse. PMID:23650464

  8. Long-Acting Beta Agonists Enhance Allergic Airway Disease

    PubMed Central

    Knight, John M.; Mak, Garbo; Shaw, Joanne; Porter, Paul; McDermott, Catherine; Roberts, Luz; You, Ran; Yuan, Xiaoyi; Millien, Valentine O.; Qian, Yuping; Song, Li-Zhen; Frazier, Vincent; Kim, Choel; Kim, Jeong Joo; Bond, Richard A.; Milner, Joshua D.; Zhang, Yuan; Mandal, Pijus K.; Luong, Amber; Kheradmand, Farrah

    2015-01-01

    Asthma is one of the most common of medical illnesses and is treated in part by drugs that activate the beta-2-adrenoceptor (β2-AR) to dilate obstructed airways. Such drugs include long acting beta agonists (LABAs) that are paradoxically linked to excess asthma-related mortality. Here we show that LABAs such as salmeterol and structurally related β2-AR drugs such as formoterol and carvedilol, but not short-acting agonists (SABAs) such as albuterol, promote exaggerated asthma-like allergic airway disease and enhanced airway constriction in mice. We demonstrate that salmeterol aberrantly promotes activation of the allergic disease-related transcription factor signal transducer and activator of transcription 6 (STAT6) in multiple mouse and human cells. A novel inhibitor of STAT6, PM-242H, inhibited initiation of allergic disease induced by airway fungal challenge, reversed established allergic airway disease in mice, and blocked salmeterol-dependent enhanced allergic airway disease. Thus, structurally related β2-AR ligands aberrantly activate STAT6 and promote allergic airway disease. This untoward pharmacological property likely explains adverse outcomes observed with LABAs, which may be overcome by agents that antagonize STAT6. PMID:26605551

  9. Long-Acting Beta Agonists Enhance Allergic Airway Disease.

    PubMed

    Knight, John M; Mak, Garbo; Shaw, Joanne; Porter, Paul; McDermott, Catherine; Roberts, Luz; You, Ran; Yuan, Xiaoyi; Millien, Valentine O; Qian, Yuping; Song, Li-Zhen; Frazier, Vincent; Kim, Choel; Kim, Jeong Joo; Bond, Richard A; Milner, Joshua D; Zhang, Yuan; Mandal, Pijus K; Luong, Amber; Kheradmand, Farrah; McMurray, John S; Corry, David B

    2015-01-01

    Asthma is one of the most common of medical illnesses and is treated in part by drugs that activate the beta-2-adrenoceptor (β2-AR) to dilate obstructed airways. Such drugs include long acting beta agonists (LABAs) that are paradoxically linked to excess asthma-related mortality. Here we show that LABAs such as salmeterol and structurally related β2-AR drugs such as formoterol and carvedilol, but not short-acting agonists (SABAs) such as albuterol, promote exaggerated asthma-like allergic airway disease and enhanced airway constriction in mice. We demonstrate that salmeterol aberrantly promotes activation of the allergic disease-related transcription factor signal transducer and activator of transcription 6 (STAT6) in multiple mouse and human cells. A novel inhibitor of STAT6, PM-242H, inhibited initiation of allergic disease induced by airway fungal challenge, reversed established allergic airway disease in mice, and blocked salmeterol-dependent enhanced allergic airway disease. Thus, structurally related β2-AR ligands aberrantly activate STAT6 and promote allergic airway disease. This untoward pharmacological property likely explains adverse outcomes observed with LABAs, which may be overcome by agents that antagonize STAT6.

  10. Pharmacology and toxicology of Cannabis derivatives and endocannabinoid agonists.

    PubMed

    Gerra, Gilberto; Zaimovic, Amir; Gerra, Maria L; Ciccocioppo, Roberto; Cippitelli, Andrea; Serpelloni, Giovanni; Somaini, Lorenzo

    2010-01-01

    For centuries Cannabis sativa and cannabis extracts have been used in natural medicine. Delta(9)-tetrahydrocannabinol (THC) is the main active ingredient of Cannabis. THC seems to be responsible for most of the pharmacological and therapeutic actions of cannabis. In a few countries THC extracts (i.e. Sativex) or THC derivatives such as nabilone, and dronabinol are used in the clinic for the treatment of several pathological conditions like chemotherapy-induced nausea and vomiting, multiple sclerosis and glaucoma. On the other hand the severe side effects and the high abuse liability of these agents represent a serious limitation in their medical use. In addition, diversion in the use of these active ingredients for recreational purpose is a concern. Over recent years, alternative approaches using synthetic cannabinoid receptor agonists or agents acting as activators of the endocannabinoid systems are under scrutiny with the hope to develop more effective and safer clinical applications. Likely, in the near future few of these new molecules will be available for clinical use. The present article review recent study and patents with focus on the cannabinoid system as a target for the treatment of central nervous system disorders with emphasis on agonists.

  11. How does agonistic behaviour differ in albino and pigmented fish?

    PubMed Central

    Horký, Pavel; Wackermannová, Marie

    2016-01-01

    In addition to hypopigmentation of the skin and red iris colouration, albino animals also display distinct physiological and behavioural alterations. However, information on the social interactions of albino animals is rare and has mostly been limited to specially bred strains of albino rodents and animals from unique environments in caves. Differentiating between the effects of albinism and domestication on behaviour in rodents can be difficult, and social behaviour in cave fish changes according to species-specific adaptations to conditions of permanent darkness. The agonistic behaviours of albino offspring of pigmented parents have yet to be described. In this study, we observed agonistic behaviour in albino and pigmented juvenile Silurus glanis catfish. We found that the total number of aggressive interactions was lower in albinos than in pigmented catfish. The distance between conspecifics was also analysed, and albinos showed a tendency towards greater separation from their same-coloured conspecifics compared with pigmented catfish. These results demonstrate that albinism can be associated with lower aggressiveness and with reduced shoaling behaviour preference, as demonstrated by a tendency towards greater separation of albinos from conspecifics. PMID:27114883

  12. Towards understanding the tandem mass spectra of protonated oligopeptides. 2: The proline effect in collision-induced dissociation of protonated Ala-Ala-Xxx-Pro-Ala (Xxx = Ala, Ser, Leu, Val, Phe, and Trp).

    PubMed

    Bleiholder, Christian; Suhai, Sándor; Harrison, Alex G; Paizs, Béla

    2011-06-01

    The product ion spectra of proline-containing peptides are commonly dominated by y(n) ions generated by cleavage at the N-terminal side of proline residues. This proline effect is investigated in the current work by collision-induced dissociation (CID) of protonated Ala-Ala-Xxx-Pro-Ala (Xxx includes Ala, Ser, Leu, Val, Phe, and Trp) in an electrospray/quadrupole/time-of-flight (QqTOF) mass spectrometer and by quantum chemical calculations on protonated Ala-Ala-Ala-Pro-Ala. The CID spectra of all investigated peptides show a dominant y(2) ion (Pro-Ala sequence). Our computational results show that the proline effect mainly arises from the particularly low threshold energy for the amide bond cleavage N-terminal to the proline residue, and from the high proton affinity of the proline-containing C-terminal fragment produced by this cleavage. These theoretical results are qualitatively supported by the experimentally observed y(2)/b(3) abundance ratios for protonated Ala-Ala-Xxx-Pro-Ala (Xxx = Ala, Ser, Leu, Val, Phe, and Trp). In the post-cleavage phase of fragmentation the N-terminal oxazolone fragment with the Ala-Ala-Xxx sequence and Pro-Ala compete for the ionizing proton for these peptides. As the proton affinity of the oxazolone fragment increases, the y(2)/b(3) abundance ratio decreases.

  13. Mutation of the Highly Conserved Ser-40 of the HIV-1 p6 Gag Protein to Phe Causes the Formation of a Hydrophobic Patch, Enhances Membrane Association, and Polyubiquitination of Gag

    PubMed Central

    Hahn, Friedrich; Setz, Christian; Friedrich, Melanie; Rauch, Pia; Solbak, Sara Marie; Frøystein, Nils Åge; Henklein, Petra; Votteler, Jörg; Fossen, Torgils; Schubert, Ulrich

    2014-01-01

    The HIV-1 p6 Gag protein contains two late assembly (l-) domains that recruit proteins of the endosomal sorting complex required for transport (ESCRT) pathway to mediate membrane fission between the nascent virion and the cell membrane. It was recently demonstrated that mutation of the highly conserved Ser-40 to Phe (S40F) disturbs CA-SP1 processing, virus morphogenesis, and infectivity. It also causes the formation of filopodia-like structures, while virus release remains unaffected. Here, we show that the mutation S40F, but not the conservative mutation to Asp (S40D) or Asn (S40N), augments membrane association, K48-linked polyubiquitination, entry into the 26S proteasome, and, consequently, enhances MHC-I antigen presentation of Gag derived epitopes. Nuclear magnetic resonance (NMR) structure analyses revealed that the newly introduced Phe-40, together with Tyr-36, causes the formation of a hydrophobic patch at the C-terminal α-helix of p6, providing a molecular rationale for the enhanced membrane association of Gag observed in vitro and in HIV-1 expressing cells. The extended exposure of the S40F mutant to unidentified membrane-resident ubiquitin E3-ligases might trigger the polyubiquitination of Gag. The cumulative data support a previous model of a so far undefined property of p6, which, in addition to MA, acts as membrane targeting domain of Gag. PMID:25279819

  14. Mutation of the highly conserved Ser-40 of the HIV-1 p6 gag protein to Phe causes the formation of a hydrophobic patch, enhances membrane association, and polyubiquitination of Gag.

    PubMed

    Hahn, Friedrich; Setz, Christian; Friedrich, Melanie; Rauch, Pia; Solbak, Sara Marie; Frøystein, Nils Age; Henklein, Petra; Votteler, Jörg; Fossen, Torgils; Schubert, Ulrich

    2014-10-02

    The HIV-1 p6 Gag protein contains two late assembly (l-) domains that recruit proteins of the endosomal sorting complex required for transport (ESCRT) pathway to mediate membrane fission between the nascent virion and the cell membrane. It was recently demonstrated that mutation of the highly conserved Ser-40 to Phe (S40F) disturbs CA-SP1 processing, virus morphogenesis, and infectivity. It also causes the formation of filopodia-like structures, while virus release remains unaffected. Here, we show that the mutation S40F, but not the conservative mutation to Asp (S40D) or Asn (S40N), augments membrane association, K48-linked polyubiquitination, entry into the 26S proteasome, and, consequently, enhances MHC-I antigen presentation of Gag derived epitopes. Nuclear magnetic resonance (NMR) structure analyses revealed that the newly introduced Phe-40, together with Tyr-36, causes the formation of a hydrophobic patch at the C-terminal α-helix of p6, providing a molecular rationale for the enhanced membrane association of Gag observed in vitro and in HIV-1 expressing cells. The extended exposure of the S40F mutant to unidentified membrane-resident ubiquitin E3-ligases might trigger the polyubiquitination of Gag. The cumulative data support a previous model of a so far undefined property of p6, which, in addition to MA, acts as membrane targeting domain of Gag.

  15. High-resolution high-performance liquid chromatography with electrospray ionization mass spectrometry and tandem mass spectrometry characterization of a new isoform of human salivary acidic proline-rich proteins named Roma-Boston Ser22(Phos) → Phe variant

    PubMed Central

    Iavarone, Federica; D’Alessandro, Alfredo; Tian, Na; Cabras, Tiziana; Messana, Irene; Helmerhorst, Eva J.; Oppenheim, Frank G.; Castagnola, Massimo

    2015-01-01

    During a survey of human saliva by a top-down reversed-phase high-performance liquid chromatography with electrospray ionization mass spectrometry approach, two proteins eluting at 27.4 and 28.4 min, with average masses of 15 494 ± 1 and 11 142 ± 1 Da, were detected in a subject from Boston. The Δmass value (4352 Da) of the two proteins was similar to the difference in mass values between intact (150 amino acids, [a.a.]) and truncated acidic proline-rich proteins (aPRPs; 106 a.a.) suggesting an a.a. substitution in the first 106 residues resulting in a strong reduction in polarity, since under the same experimental conditions aPRPs eluted at ~22.5 min (intact) and 23.5 min (truncated forms). Manual inspection of the high-resolution high-performance liquid chromatography with electrospray ionization tandem mass spectra of the truncated isoform showed the replacement of the phosphorylated Ser-22 in PRP-3 with a Phe residue. Inspection of the tandem mass spectra of the intact isoform confirmed the substitution, which is allowed by the code transition TCT→TTT and is in agreement with the dramatic increase in elution time. The isoform was also detected in two other subjects, one from Boston (unrelated to the previous) and one from Rome. For this reason we propose to name this variant PRP-1 (PRP-3) RB (Roma-Boston) Ser22(phos)→Phe. PMID:24771659

  16. Coupling between agonist and chloride ionophore sites of the GABA(A) receptor: agonist/antagonist efficacy of 4-PIOL.

    PubMed

    Rabe, H; Picard, R; Uusi-Oukari, M; Hevers, W; Lüddens, H; Korpi, E R

    2000-12-15

    Eight gamma-aminobutyric acid (GABA) mimetics were tested on their ability to differentiate native GABA(A) receptor subtypes present in various rat brain regions. In rat brain cryostat sections, little regional variations by the agonistic actions of muscimol, thiomuscimol, 4,5,6,7-tetrahydroisoazolo(5,4-c)pyridin-3-ol, piperidine-4-sulphonic acid, taurine and beta-alanine on [35S]t-butylbicyclophosphorothionate ([35S]TBPS) binding to GABA(A) receptor channels were found. They were very similar to those found for GABA itself and indicated no direct correlation with single subunit distributions for any of these compounds. Only the low-efficacy GABA mimetic 5-(4-piperidyl)isoxazol-3-ol (4-PIOL) acted like a weak partial agonist or antagonist depending on the brain area. As the cerebellar granule cell layer was relatively insensitive to both modes of action, we tested 4-PIOL in recombinant alpha1beta2gamma2 (widespread major subtype) and alpha6beta2gamma2 (cerebellar granule cell restricted) receptors where it had different effects on GABA-modulated [35S]TBPS binding and on electrophysiological responses. 4-PIOL may thus serve as a potential lead for receptor subtype selective compounds.

  17. Discriminative stimulus properties of indorenate, a serotonin agonist.

    PubMed Central

    Velázquez-Martínez, D N; López Cabrera, M; Sánchez, H; Ramírez, J I; Hong, E

    1999-01-01

    OBJECTIVE: To determine whether indorenate, a serotonin-receptor agonist, can exert discriminative control over operant responses, to establish the temporal course of discriminative control and to compare its stimulus properties to a (5-HT)IA receptor agonist. [3H]-8-hydroxy-2-(di-N-propylamino) tetralin (8-OH-DPAT). DESIGN: Prospective animal study. ANIMALS: Ten male Wistar rats. INTERVENTIONS: Rats were trained to press either of 2 levers for sucrose solution according to a fixed ratio schedule, which was gradually increased. Rats were given injections of either indorenate or saline solution during discrimination training. Once they had achieved an 83% accuracy rate, rats underwent generalization tests after having received a different dose of indorenate, the training dose of indorenate at various intervals before the test, various doses of 8-OH-DPT, or NAN-190 administered before indorenate or 8-OH-DPAT. OUTCOME MEASURES: Distribution of responses between the 2 levers before the first reinforcer of the session, response rate for all the responses in the session, and a discrimination index that expressed the drug-appropriate responses as a proportion of the total responses. RESULTS: Indorenate administration resulted in discriminative control over operant responses, maintained at fixed ratio 10, at a dose of 10.0 mg/kg (but not 3.0 mg/kg). When the interval between the administration of indorenate and the start of the session was varied, the time course of its cue properties followed that of its described effects on 5-HT turnover. In generalization tests, the discrimination index was a function of the dose of indorenate employed; moreover, administration of 8-OH-DPAT (from 0.1 to 1.0 mg/kg) fully mimicked the stimulus properties of indorenate in a dose-dependent way. The (5-HT)IA antagonist NAN-190 prevented the stimulus generalization from indorenate to 8-OH-DPAT. Also, NAN-190 antagonized the stimulus control of indorenate when administered 45 minutes before

  18. New Small Molecule Agonists to the Thyrotropin Receptor

    PubMed Central

    Ali, M. Rejwan; Ma, Risheng; David, Martine; Morshed, Syed A.; Ohlmeyer, Michael; Felsenfeld, Dan P.; Lau, Zerlina; Mezei, Mihaly; Davies, Terry F.

    2015-01-01

    Background Novel small molecular ligands (SMLs) to the thyrotropin receptor (TSHR) have potential as improved molecular probes and as therapeutic agents for the treatment of thyroid dysfunction and thyroid cancer. Methods To identify novel SMLs to the TSHR, we developed a transcription-based luciferase-cAMP high-throughput screening system and we screened 48,224 compounds from a 100K library in duplicate. Results We obtained 62 hits using the cut-off criteria of the mean±three standard deviations above the baseline. Twenty molecules with the greatest activity were rescreened against the parent CHO-luciferase cell for nonspecific activation, and we selected two molecules (MS437 and MS438) with the highest potency for further study. These lead molecules demonstrated no detectible cross-reactivity with homologous receptors when tested against luteinizing hormone (LH)/human chorionic gonadotropin receptor and follicle stimulating hormone receptor–expressing cells. Molecule MS437 had a TSHR-stimulating potency with an EC50 of 13×10−8 M, and molecule MS438 had an EC50 of 5.3×10−8 M. The ability of these small molecule agonists to bind to the transmembrane domain of the receptor and initiate signal transduction was suggested by their activation of a chimeric receptor consisting of an LHR ectodomain and a TSHR transmembrane. Molecular modeling demonstrated that these molecules bound to residues S505 and E506 for MS438 and T501 for MS437 in the intrahelical region of transmembrane helix 3. We also examined the G protein activating ability of these molecules using CHO cells co-expressing TSHRs transfected with luciferase reporter vectors in order to measure Gsα, Gβγ, Gαq, and Gα12 activation quantitatively. The MS437 and MS438 molecules showed potent activation of Gsα, Gαq, and Gα12 similar to TSH, but neither the small molecule agonists nor TSH showed activation of the Gβγ pathway. The small molecules MS437 and MS438 also showed upregulation of

  19. Analysis of full and partial agonists binding to beta2-adrenergic receptor suggests a role of transmembrane helix V in agonist-specific conformational changes.

    PubMed

    Katritch, Vsevolod; Reynolds, Kimberly A; Cherezov, Vadim; Hanson, Michael A; Roth, Christopher B; Yeager, Mark; Abagyan, Ruben

    2009-01-01

    The 2.4 A crystal structure of the beta(2)-adrenergic receptor (beta(2)AR) in complex with the high-affinity inverse agonist (-)-carazolol provides a detailed structural framework for the analysis of ligand recognition by adrenergic receptors. Insights into agonist binding and the corresponding conformational changes triggering G-protein coupled receptor (GPCR) activation mechanism are of special interest. Here we show that while the carazolol pocket captured in the beta(2)AR crystal structure accommodates (-)-isoproterenol and other agonists without steric clashes, a finite movement of the flexible extracellular part of TM-V helix (TM-Ve) obtained by receptor optimization in the presence of docked ligand can further improve the calculated binding affinities for agonist compounds. Tilting of TM-Ve towards the receptor axis provides a more complete description of polar receptor-ligand interactions for full and partial agonists, by enabling optimal engagement of agonists with two experimentally identified anchor sites, formed by Asp113/Asn312 and Ser203/Ser204/Ser207 side chains. Further, receptor models incorporating a flexible TM-V backbone allow reliable prediction of binding affinities for a set of diverse ligands, suggesting potential utility of this approach to design of effective and subtype-specific agonists for adrenergic receptors. Systematic differences in capacity of partial, full and inverse agonists to induce TM-V helix tilt in the beta(2)AR model suggest potential role of TM-V as a conformational "rheostat" involved in the whole spectrum of beta(2)AR responses to small molecule signals.

  20. Impact of efficacy at the μ-opioid receptor on antinociceptive effects of combinations of μ-opioid receptor agonists and cannabinoid receptor agonists.

    PubMed

    Maguire, David R; France, Charles P

    2014-11-01

    Cannabinoid receptor agonists, such as Δ(9)-tetrahydrocannabinol (Δ(9)-THC), enhance the antinociceptive effects of μ-opioid receptor agonists, which suggests that combining cannabinoids with opioids would improve pain treatment. Combinations with lower efficacy agonists might be preferred and could avoid adverse effects associated with large doses; however, it is unclear whether interactions between opioids and cannabinoids vary across drugs with different efficacy. The antinociceptive effects of μ-opioid receptor agonists alone and in combination with cannabinoid receptor agonists were studied in rhesus monkeys (n = 4) using a warm water tail withdrawal procedure. Etorphine, fentanyl, morphine, buprenorphine, nalbuphine, Δ(9)-THC, and CP 55,940 (2-[(1R,2R,5R)-5-hydroxy-2-(3-hydroxypropyl) cyclohexyl]-5-(2-methyloctan-2-yl)phenol) each increased tail withdrawal latency. Pretreatment with doses of Δ(9)-THC (1.0 mg/kg) or CP 55,940 (0.032 mg/kg) that were ineffective alone shifted the fentanyl dose-effect curve leftward 20.6- and 52.9-fold, respectively, and the etorphine dose-effect curve leftward 12.4- and 19.6-fold, respectively. Δ(9)-THC and CP 55,940 shifted the morphine dose-effect curve leftward only 3.4- and 7.9-fold, respectively, and the buprenorphine curve only 5.4- and 4.1-fold, respectively. Neither Δ(9)-THC nor CP 55,940 significantly altered the effects of nalbuphine. Cannabinoid receptor agonists increase the antinociceptive potency of higher efficacy opioid receptor agonists more than lower efficacy agonists; however, because much smaller doses of each drug can be administered in combinations while achieving adequate pain relief and that other (e.g., abuse-related) effects of opioids do not appear to be enhanced by cannabinoids, these results provide additional support for combining opioids with cannabinoids to treat pain.

  1. Sensitivity of GBM cells to cAMP agonist-mediated apoptosis correlates with CD44 expression and agonist resistance with MAPK signaling

    PubMed Central

    Daniel, Paul M; Filiz, Gulay; Mantamadiotis, Theo

    2016-01-01

    In some cell types, activation of the second messenger cAMP leads to increased expression of proapoptotic Bim and subsequent cell death. We demonstrate that suppression of the cAMP pathway is a common event across many cancers and that pharmacological activation of cAMP in glioblastoma (GBM) cells leads to enhanced BIM expression and apoptosis in specific GBM cell types. We identified the MAPK signaling axis as the determinant of cAMP agonist sensitivity in GBM cells, with high MAPK activity corresponding to cAMP resistance and low activity corresponding to sensitization to cAMP-induced apoptosis. Sensitive cells were efficiently killed by cAMP agonists alone, while targeting both the cAMP and MAPK pathways in resistant GBM cells resulted in efficient apoptosis. We also show that CD44 is differentially expressed in cAMP agonist-sensitive and -resistant cells. We thus propose that CD44 may be a useful biomarker for distinguishing tumors that may be sensitive to cAMP agonists alone or cAMP agonists in combination with other pathway inhibitors. This suggests that using existing chemotherapeutic compounds in combination with existing FDA-approved cAMP agonists may fast track trials toward improved therapies for difficult-to-treat cancers, such as GBM. PMID:27906173

  2. Modulation of [3H]diazepam binding in rat cortical membranes by GABAA agonists.

    PubMed

    Wong, E H; Iversen, L L

    1985-04-01

    GABAA receptor agonists modulate [3H]diazepam binding in rat cortical membranes with different efficacies. At 23 degrees C, the relative potencies for enhancement of [3H]diazepam binding by agonists parallel their potencies in inhibiting [3H]gamma-aminobutyric acid [( 3H]GABA) binding. The agonist concentrations needed for enhancement of [3H]diazepam binding are up to 35 times higher than for [3H]GABA binding and correspond closely to the concentrations required for displacement of [3H]bicuculline methochloride (BMC) binding. The maximum enhancement of [3H]diazepam varied among agonists: muscimol = GABA greater than isoguvacine greater than 3-aminopropane sulphonic acid (3APS) = imidazoleacetic acid (IAA) greater than 4,5,6,7-tetrahydroisoxazolo (4,5,6)-pyridin-3-ol (THIP) = taurine greater than piperidine 4-sulphonic acid (P4S). At 37 degrees C, the potencies of agonists remained unchanged, but isoguvacine, 3 APS, and THIP acquired efficacies similar to GABA, whereas IAA, taurine, and P4S maintained their partial agonist profiles. At both temperatures the agonist-induced enhancement of [3H]diazepam binding was reversible by bicuculline methobromide and by the steroid GABA antagonist RU 5135. These results stress the importance of studying receptor-receptor interaction under near-physiological conditions and offer an in vitro assay that may predict the agonist status of putative GABA receptor ligands.

  3. Use-dependent inhibition of P2X3 receptors by nanomolar agonist.

    PubMed

    Pratt, Emily B; Brink, Thaddeus S; Bergson, Pamela; Voigt, Mark M; Cook, Sean P

    2005-08-10

    P2X3 receptors desensitize within 100 ms of channel activation, yet recovery from desensitization requires several minutes. The molecular basis for this slow rate of recovery is unknown. We designed experiments to test the hypothesis that this slow recovery is attributable to the high affinity (< 1 nM) of desensitized P2X3 receptors for agonist. We found that agonist binding to the desensitized state provided a mechanism for potent inhibition of P2X3 current. Sustained applications of 0.5 nM ATP inhibited > 50% of current to repetitive applications of P2X3 agonist. Inhibition occurred at 1000-fold lower agonist concentrations than required for channel activation and showed strong use dependence. No inhibition occurred without previous activation and desensitization. Our data are consistent with a model whereby inhibition of P2X3 by nanomolar [agonist] occurs by the rebinding of agonist to desensitized channels before recovery from desensitization. For several ATP analogs, the concentration required to inhibit P2X3 current inversely correlated with the rate of recovery from desensitization. This indicates that the affinity of the desensitized state and recovery rate primarily depend on the rate of agonist unbinding. Consistent with this hypothesis, unbinding of [32P]ATP from desensitized P2X3 receptors mirrored the rate of recovery from desensitization. As expected, disruption of agonist binding by site-directed mutagenesis increased the IC50 for inhibition and increased the rate of recovery.

  4. Yawning and locomotor behavior induced by dopamine receptor agonists in mice and rats.

    PubMed

    Li, Su-Min; Collins, Gregory T; Paul, Noel M; Grundt, Peter; Newman, Amy H; Xu, Ming; Grandy, David K; Woods, James H; Katz, Jonathan L

    2010-05-01

    Dopaminergic (DA) agonist-induced yawning in rats seems to be mediated by DA D3 receptors, and low doses of several DA agonists decrease locomotor activity, an effect attributed to presynaptic D2 receptors. Effects of several DA agonists on yawning and locomotor activity were examined in rats and mice. Yawning was reliably produced in rats, and by the cholinergic agonist, physostigmine, in both the species. However, DA agonists were ineffective in producing yawning in Swiss-Webster or DA D2R and DA D3R knockout or wild-type mice. The drugs significantly decreased locomotor activity in rats at one or two low doses, with activity returning to control levels at higher doses. In mice, the drugs decreased locomotion across a 1000-10 000-fold range of doses, with activity at control levels (U-91356A) or above control levels [(+/-)-7-hydroxy-2-dipropylaminotetralin HBr, quinpirole] at the highest doses. Low doses of agonists decreased locomotion in all mice except the DA D2R knockout mice, but were not antagonized by DA D2R or D3R antagonists (L-741 626, BP 897, or PG01037). Yawning does not provide a selective in-vivo indicator of DA D3R agonist activity in mice. Decreases in mouse locomotor activity by the DA agonists seem to be mediated by D2 DA receptors.

  5. Prolonging Survival of Corneal Transplantation by Selective Sphingosine-1-Phosphate Receptor 1 Agonist

    PubMed Central

    Gao, Min; Liu, Yong; Xiao, Yang; Han, Gencheng; Jia, Liang; Wang, Liqiang; Lei, Tian; Huang, Yifei

    2014-01-01

    Corneal transplantation is the most used therapy for eye disorders. Although the cornea is somewhat an immune privileged organ, immune rejection is still the major problem that reduces the success rate. Therefore, effective chemical drugs that regulate immunoreactions are needed to improve the outcome of corneal transplantations. Here, a sphingosine-1-phosphate receptor 1 (S1P1) selective agonist was systematically evaluated in mouse allogeneic corneal transplantation and compared with the commonly used immunosuppressive agents. Compared with CsA and the non-selective sphingosine 1-phosphate (S1P) receptor agonist FTY720, the S1P1 selective agonist can prolong the survival corneal transplantation for more than 30 days with a low immune response. More importantly, the optimal dose of the S1P1 selective agonist was much less than non-selective S1P receptor agonist FTY720, which would reduce the dose-dependent toxicity in drug application. Then we analyzed the mechanisms of the selected S1P1 selective agonist on the immunosuppression. The results shown that the S1P1 selective agonist could regulate the distribution of the immune cells with less CD4+ T cells and enhanced Treg cells in the allograft, moreover the expression of anti-inflammatory cytokines TGF-β1 and IL-10 unregulated which can reduce the immunoreactions. These findings suggest that S1P1 selective agonist may be a more appropriate immunosuppressive compound to effectively prolong mouse allogeneic corneal grafts survival. PMID:25216235

  6. Bitter Taste Receptor Agonists Mitigate Features of Allergic Asthma in Mice

    PubMed Central

    Sharma, Pawan; Yi, Roslyn; Nayak, Ajay P.; Wang, Nadan; Tang, Francesca; Knight, Morgan J.; Pan, Shi; Oliver, Brian; Deshpande, Deepak A.

    2017-01-01

    Asthma is characterized by airway inflammation, mucus secretion, remodeling and hyperresponsiveness (AHR). Recent research has established the bronchodilatory effect of bitter taste receptor (TAS2R) agonists in various models. Comprehensive pre-clinical studies aimed at establishing effectiveness of TAS2R agonists in disease models are lacking. Here we aimed to determine the effect of TAS2R agonists on features of asthma. Further, we elucidated a mechanism by which TAS2R agonists mitigate features of asthma. Asthma was induced in mice using intranasal house dust mite or aerosol ova-albumin challenge, and chloroquine or quinine were tested in both prophylactic and treatment models. Allergen challenge resulted in airway inflammation as evidenced by increased immune cells infiltration and release of cytokines and chemokines in the lungs, which were significantly attenuated in TAS2R agonists treated mice. TAS2R agonists attenuated features of airway remodeling including smooth muscle mass, extracellular matrix deposition and pro-fibrotic signaling, and also prevented mucus accumulation and development of AHR in mice. Mechanistic studies using human neutrophils demonstrated that inhibition of immune cell chemotaxis is a key mechanism by which TAS2R agonists blocked allergic airway inflammation and exerted anti-asthma effects. Our comprehensive studies establish the effectiveness of TAS2R agonists in mitigating multiple features of allergic asthma.

  7. Marketed New Drug Delivery Systems for Opioid Agonists/Antagonists Administration: A Rapid Overview

    PubMed Central

    Soltani, Hoda; Pardakhty, Abbas

    2016-01-01

    Novel drug delivery systems for controlled-release of opioid agonists as a long time painkillers or opioid antagonists for opium, heroin, and alcohol addiction are under development or in clinical use today. In this article, the field of “new drug delivery systems” is momentarily reviewed from the viewpoint of the marketed opioid agonists/antagonists dosage forms today. PMID:27882209

  8. Identification of diarylsulfonamides as agonists of the free fatty acid receptor 4 (FFA4/GPR120).

    PubMed

    Sparks, Steven M; Chen, Grace; Collins, Jon L; Danger, Dana; Dock, Steven T; Jayawickreme, Channa; Jenkinson, Stephen; Laudeman, Christopher; Leesnitzer, M Anthony; Liang, Xi; Maloney, Patrick; McCoy, David C; Moncol, David; Rash, Vincent; Rimele, Thomas; Vulimiri, Padmaja; Way, James M; Ross, Sean

    2014-07-15

    The exploration of a diarylsulfonamide series of free fatty acid receptor 4 (FFA4/GPR120) agonists is described. This work led to the identification of selective FFA4 agonist 8 (GSK137647A) and selective FFA4 antagonist 39. The in vitro profile of compounds 8 and 39 is presented herein.

  9. The dopamine D1 receptor agonist SKF-82958 effectively increases eye blinking count in common marmosets.

    PubMed

    Kotani, Manato; Kiyoshi, Akihiko; Murai, Takeshi; Nakako, Tomokazu; Matsumoto, Kenji; Matsumoto, Atsushi; Ikejiri, Masaru; Ogi, Yuji; Ikeda, Kazuhito

    2016-03-01

    Eye blinking is a spontaneous behavior observed in all mammals, and has been used as a well-established clinical indicator for dopamine production in neuropsychiatric disorders, including Parkinson's disease and Tourette syndrome [1,2]. Pharmacological studies in humans and non-human primates have shown that dopamine agonists/antagonists increase/decrease eye blinking rate. Common marmosets (Callithrix jacchus) have recently attracted a great deal of attention as suitable experimental animals in the psychoneurological field due to their more developed prefrontal cortex than rodents, easy handling compare to other non-human primates, and requirement for small amounts of test drugs. In this study, we evaluated the effects of dopamine D1-4 receptors agonists on eye blinking in common marmosets. Our results show that the dopamine D1 receptor agonist SKF-82958 and the non-selective dopamine receptor agonist apomorphine significantly increased common marmosets eye blinking count, whereas the dopamine D2 agonist (+)-PHNO and the dopamine D3 receptor agonist (+)-PD-128907 produced somnolence in common marmosets resulting in a decrease in eye blinking count. The dopamine D4 receptor agonists PD-168077 and A-41297 had no effect on common marmosets' eye blinking count. Finally, the dopamine D1 receptor antagonist SCH 39166 completely blocked apomorphine-induced increase in eye blinking count. These results indicate that eye blinking in common marmosets may be a useful tool for in vivo screening of novel dopamine D1 receptor agonists as antipsychotics.

  10. Dopamine receptor agonists mediate neuroprotection in malonate-induced striatal lesion in the rat.

    PubMed

    Armentero, Marie-Thérèse; Fancellu, Roberto; Nappi, Giuseppe; Blandini, Fabio

    2002-12-01

    Mitochondrial bioenergetic defects are involved in neurological disorders associated with neuronal damage in the striatum, such as Huntington's disease and cerebral ischemia. The striatal release of neurotransmitters, in particular dopamine, may contribute to the development of the neuronal damage. Recent studies have shown that dopamine agonists may exert neuroprotective effects via multiple mechanisms, including modulation of dopamine release from nigrostriatal dopaminergic terminals. In rats, intrastriatal injection of malonate, a reversible inhibitor of the mitochondrial enzyme succinate dehydrogenase, induces a lesion similar to that observed following focal ischemia or in Huntington's disease. In this study, we used the malonate model to explore the neuroprotective potential of dopamine agonists. Sprague-Dawley rats were injected systemically with increasing concentrations of D(1), D(2), or mixed D(1)/D(2) dopamine agonists prior to malonate intrastriatal insult. Administration of increasing doses of the D(2)-specific agonist quinpirole resulted in increased protection against malonate toxicity. Conversely, the D(1)-specific agonist SKF-38393, as well as the mixed D(1)/D(2) agonist apomorphine, conferred higher neuroprotection at lower than at higher concentrations. Our data suggest that malonate-induced striatal toxicity can be attenuated by systemic administration of dopamine agonists, with D(1) and D(2) agonists showing different profiles of efficacy.

  11. Marketed New Drug Delivery Systems for Opioid Agonists/Antagonists Administration: A Rapid Overview.

    PubMed

    Soltani, Hoda; Pardakhty, Abbas

    2016-04-01

    Novel drug delivery systems for controlled-release of opioid agonists as a long time painkillers or opioid antagonists for opium, heroin, and alcohol addiction are under development or in clinical use today. In this article, the field of "new drug delivery systems" is momentarily reviewed from the viewpoint of the marketed opioid agonists/antagonists dosage forms today.

  12. The GLP-1 agonist, liraglutide, as a pharmacotherapy for obesity

    PubMed Central

    Crane, James; McGowan, Barbara

    2015-01-01

    There is a global obesity epidemic that will continue to be a financial burden on healthcare systems around the world. Tackling obesity through diet and exercise should always be the first intervention, but this has not proved to be effective for a large number of patients. Pharmacotherapeutic options have been limited and many previously available drugs have been withdrawn due to safety concerns. Currently, only bariatric surgery has the capability to induce both substantial and durable weight loss. This article briefly reviews the history of pharmacotherapy for obesity before focusing on the clinical trial evidence for the use of the GLP-1 agonist liraglutide as a weight loss agent and comparing its efficacy with other emerging drug therapies for obesity. PMID:26977279

  13. TSH and Thyrotropic Agonists: Key Actors in Thyroid Homeostasis

    PubMed Central

    Dietrich, Johannes W.; Landgrafe, Gabi; Fotiadou, Elisavet H.

    2012-01-01

    This paper provides the reader with an overview of our current knowledge of hypothalamic-pituitary-thyroid feedback from a cybernetic standpoint. Over the past decades we have gained a plethora of information from biochemical, clinical, and epidemiological investigation, especially on the role of TSH and other thyrotropic agonists as critical components of this complex relationship. Integrating these data into a systems perspective delivers new insights into static and dynamic behaviour of thyroid homeostasis. Explicit usage of this information with mathematical methods promises to deliver a better understanding of thyrotropic feedback control and new options for personalised diagnosis of thyroid dysfunction and targeted therapy, also by permitting a new perspective on the conundrum of the TSH reference range. PMID:23365787

  14. [Safety and tolerability of GLP-1 receptor agonists].

    PubMed

    Soldevila, Berta; Puig-Domingo, Manel

    2014-01-01

    Glucagon-like peptide-1 receptor agonists (GLP-1ra) are a new group of drugs with a glucose-lowering action due to their incretin effect. The GLP-1 receptor is expressed in various human tissues, which could be related to the pleiotropic effects of human GLP-1, as well as to the adverse effects described in patients treated with GLP-1ra. The risk of hypoglycaemia is low, which is one of the main considerations in the safety of this family of compounds and is also important to patients with diabetes. The most frequent adverse effect is nausea, which usually occurs at the start of treatment and is transient in 20-60% of affected patients. This article also reviews the information available on antibody formation, the potential effect on the thyroid gland, and the controversial association between this group of drugs with pancreatitis and cancer.

  15. [Safety and tolerability of GLP-1 receptor agonists].

    PubMed

    Soldevila, Berta; Puig-Domingo, Manel

    2014-09-01

    Glucagon-like peptide-1 receptor agonists (GLP-1ra) are a new group of drugs with a glucose-lowering action due to their incretin effect. The GLP-1 receptor is expressed in various human tissues, which could be related to the pleiotropic effects of human GLP-1, as well as to the adverse effects described in patients treated with GLP-1ra. The risk of hypoglycaemia is low, which is one of the main considerations in the safety of this family of compounds and is also important to patients with diabetes. The most frequent adverse effect is nausea, which usually occurs at the start of treatment and is transient in 20-60% of affected patients. This article also reviews the information available on antibody formation, the potential effect on the thyroid gland, and the controversial association between this group of drugs with pancreatitis and cancer.

  16. Locomotion induced by ventral tegmental microinjections of a nicotinic agonist.

    PubMed

    Museo, E; Wise, R A

    1990-03-01

    Bilateral microinjections of the nicotinic agonist cytisine (0.1, 1 or 10 nanomoles per side) into the ventral tegmental area increased locomotor activity. This increase in locomotion was antagonized by mecamylamine (2 mg/kg, IP), a nicotinic antagonist that readily crosses the blood-brain barrier, and by pimozide (0.3 mg/kg, IP), a central dopaminergic antagonist. Hexamethonium (2 mg/kg, IP), a nicotinic antagonist that, unlike mecamylamine, does not cross the blood-brain barrier, had no effect; this suggests that mecamylamine's attenuation of cytisine-induced locomotor activity resulted from a blockade of central and not peripheral nicotinic receptors. The data support the notion that nicotinic and dopaminergic substrates interact at the level of the VTA to produce increases in locomotor activity.

  17. Basal Insulin Use With GLP-1 Receptor Agonists.

    PubMed

    Anderson, Sarah L; Trujillo, Jennifer M

    2016-08-01

    IN BRIEF The combination of basal insulin and a glucagon-like peptide 1 receptor agonist is becoming increasingly common and offers several potential benefits to patients with type 2 diabetes. Clinical studies have demonstrated improved glycemic control and low risks of hypoglycemia and weight gain with the combination, which provides a safe and effective alternative to basal-bolus insulin with less treatment burden. Fixed-ratio combination products that administer both agents in a single injection are in the pipeline and will offer additional options for clinicians and patients. This review focuses on the rationale for, clinical evidence on, and implications of using this combination of therapies in the treatment of type 2 diabetes.