European Journal of Pharmacology: Molecular Pharmacology最新文献

{"title":"Effects of methylene blue and LY83583 on neuronal nitric oxide synthase and NADPH-diaphorase","authors":"Dasan Luo,&nbsp;Sheela Das,&nbsp;Steven R. Vincent","doi":"10.1016/0922-4106(95)00084-4","DOIUrl":"10.1016/0922-4106(95)00084-4","url":null,"abstract":"<div><p>Methylene blue and 6-anilino-5,8-quinolinedine (LY83583) have often been used as ‘selective’ inhibitors of soluble guanylyl cyclase. We report that in vitro assays, both these compounds were potent inhibitors of rat cerebellar nitric oxide synthase activity. Methylene blue had an apparent <em>K</em>_i of 2.7 μM, while for LY83583 the <em>K</em>_i was 15.8 μM. Furthermore, methylene blue, but not LY83583, inhibited the NADPH-diaphorase histochemical reaction associated with nitric oxide synthase. Our results indicate that many of the effects of these drugs which have been attributed to inhibition of guanylyl cyclase, may derive from their direct inhibition of nitric oxide synthase activity instead.</p></div>","PeriodicalId":100502,"journal":{"name":"European Journal of Pharmacology: Molecular Pharmacology","volume":"290 3","pages":"Pages 247-251"},"PeriodicalIF":0.0,"publicationDate":"1995-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0922-4106(95)00084-4","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18594740","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time course of phorbol ester-induced contraction and protein kinase C activation in rat aorta","authors":"Eulalia Bazan ,&nbsp;Anita K. Campbell,&nbsp;Robert M. Rapoport","doi":"10.1016/0922-4106(95)90001-2","DOIUrl":"10.1016/0922-4106(95)90001-2","url":null,"abstract":"<div><p>This study investigates the relationship between the rate of phorbol ester-induced contraction of intact rat aorta and protein kinase C activation, as assessed by the translocation of protein kinase C from the cytosolic to the particulate fraction. Aorta was exposed to Ca²⁺-free physiologic salt solution prior to phorbol ester to prevent Ca²⁺-induced protein kinase C translocation during tissue homogenization. Phorbol myristate acetate, as well as phorbol dibutyrate, decreased cytosolic and/or increased particulate protein kinase C activity as early as 5 s following phorbol ester addition, which was prior to, or coincident with, the onset of contraction. These results suggests that phorbol ester-induced contraction of intact vascular smooth muscle is associated in a time-dependent manner with protein kinase C activation.</p></div>","PeriodicalId":100502,"journal":{"name":"European Journal of Pharmacology: Molecular Pharmacology","volume":"290 3","pages":"Pages 253-257"},"PeriodicalIF":0.0,"publicationDate":"1995-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0922-4106(95)90001-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18594741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"PCA-4248, a PAF receptor antagonist, inhibits PAF-induced phosphoinositide turnover","authors":"R.Edgardo Catalán ,&nbsp;Ana M. Martínez ,&nbsp;M.Dolores Aragonés ,&nbsp;Manuel Lombardía ,&nbsp;Esther Garde","doi":"10.1016/0922-4106(95)00063-1","DOIUrl":"10.1016/0922-4106(95)00063-1","url":null,"abstract":"<div><p>The effect of a new PAF(platelet activating factor; 1-<em>O</em>-alkyl-2-acetyl-sn-glycero-3-phosphoryl-choline) receptor antagonist, PCA-4248 (2-phenylthio)ethyl-5-metoxycarbonyl-2,4,6-trimethyl-1, 4-dihydropyridine-3-carboxylate), on phosphoinositide turnover evoked by PAF was investigated. PAF treatment resulted in an increased ³²P incorporation into phosphoinositides and phosphatidic acid in rabbit platelets. Treatment with PCA-4248 abolished both effects in a dose-dependent manner, 10 μM being the most effective dose. In thrombin stimulated platelets, phosphoinositide turnover was not influenced by PCA-4248. In addition, PAF caused a rapid and significant increase in protein phosphorylation. Thus, PAF treatment resulted in a marked phosphorylation of two proteins of 47 kDa and 20 kDa. Treatment with PCA-4248 resulted in an inhibition of these actions. Serotonin secretion evoked by PAF was also inhibited by PCA-4248. It is concluded that PCA-4248 antagonizes the PAF effects by acting as a competitive antagonist at the PAF receptor level as evidenced from binding studies.</p></div>","PeriodicalId":100502,"journal":{"name":"European Journal of Pharmacology: Molecular Pharmacology","volume":"290 3","pages":"Pages 183-188"},"PeriodicalIF":0.0,"publicationDate":"1995-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0922-4106(95)00063-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18595354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stable expression and pharmacological properties of the human α7 nicotinic acetylcholine receptor","authors":"Murali Gopalakrishnan ,&nbsp;Bruno Buisson ,&nbsp;Edward Touma ,&nbsp;Tony Giordano ,&nbsp;Jeff E. Campbell ,&nbsp;Iris C. Hu ,&nbsp;Diana Donnelly-Roberts ,&nbsp;Stephen P. Arneric ,&nbsp;Daniel Bertrand ,&nbsp;James P. Sullivan","doi":"10.1016/0922-4106(95)00083-6","DOIUrl":"https://doi.org/10.1016/0922-4106(95)00083-6","url":null,"abstract":"<div><p>The α₇ neuronal nicotinic acetylcholine receptor subtype forms a Ca²⁺-permeable homooligomeric ion channel sensitive to α-bungarotoxin in <em>Xenopus</em> oocytes. In this study, we have stably and functionally expressed the human α₇ cDNA in a mammalian cell line, HEK-293 and examined its pharmacologic properties. [¹²⁵I]α-Bungarotoxin bound to transfected cellswith a <em>K</em>_d value of 0.7 nM and a <em>B</em>_max value of 973 pmol/mg protein. No specific binding was detected in untransfected cells. Specific binding could be displaced by unlabeled α-bungarotoxin (<em>K</em>_i = 0.5 nM and an excellent correlation was observed between binding affinities of a series of nicotinic cholinergic ligands in transfected cells and those in the human neuroblastoma IMR-32 cell line. Additionally, cell surface expression of α₇ receptors was detected by fluorescein isothiocyanate-conjugated α-bungarotoxin in transfected cells. Whole cell currents sensitive to blockade by α-bungarotoxin, and with fast kinetics of activation and inactivation, were recorded from transfected cells upon rapid application of (−)-nicotine or acetylcholine with EC₅₀ values of 49 μM and 155 μM respectively. We conclude that the human α₇ subunit when expressed alone can form functional ion channels and that the stably transfected HEK-293 cell line serves as a unique system for studying human μ₇ nicotinic receptor function and regulation, and for examining ligand interactions.</p></div>","PeriodicalId":100502,"journal":{"name":"European Journal of Pharmacology: Molecular Pharmacology","volume":"290 3","pages":"Pages 237-246"},"PeriodicalIF":0.0,"publicationDate":"1995-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0922-4106(95)00083-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71784669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Allosteric modulation of the glutamate site on the NMDA receptor by four novel glycine site antagonists","authors":"Sarah Grimwood,&nbsp;Janusz J. Kulagowski,&nbsp;Ian M. Mawer,&nbsp;Michael Rowley,&nbsp;Paul D. Leeson,&nbsp;Alan C. Foster","doi":"10.1016/0922-4106(95)00081-X","DOIUrl":"10.1016/0922-4106(95)00081-X","url":null,"abstract":"<div><p>Using radioligand binding studies, we have investigated the binding properties of four 4-hydroxy-2-quinolones, a novel series of selective antagonists for the glycine site on the <span><math><mtext>N-</mtext><mtext>methyl</mtext><mtext>-</mtext><mtext>d</mtext><mtext>-</mtext><mtext>aspartate</mtext></math></span> (NMDA) receptor. L-701,324, L-703,717, L-698,532 and L-695,902 inhibited [³H]L-689,560 (glycine site antagonist) binding to rat cortex/hippocampus P₂ membranes with IC₅₀ values of 1.97, 4.47, 209 and 6448 nM, respectively, whilst also inhibiting non-equilibrium [³H]dizocilpine binding to the NMDA receptor ion-channel. All four compounds partially inhibited <span>l</span>-[³H]glutamate (∼ 50% inhibition; agonist) binding and enhanced [³H]<em>cis</em>-4-phosphonomethyl-2-piperidine carboxylate ([³H]CGS-19755; 41–81% enhancement; ‘C-5’ antagonist) and [³H]3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonate ([³H]CPP; 28–66% enhancement; ‘C-7’ antagonist) binding to the glutamate recognition site of the NMDA receptor with EC₅₀ values similar to those observed for [³H]L-689,560 binding. These results provide further evidence for allosteric interactions between the glutamate and glycine recognition sites of the NMDA receptor complex, and as the 4-hydroxy-2-quinolones are ‘full’ antagonists at the glycine site, indicate that these interactions are not caused by the intrinsic activity of a compound.</p></div>","PeriodicalId":100502,"journal":{"name":"European Journal of Pharmacology: Molecular Pharmacology","volume":"290 3","pages":"Pages 221-226"},"PeriodicalIF":0.0,"publicationDate":"1995-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0922-4106(95)00081-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18594737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Muscarinic M2 receptor synthesis: study of receptor turnover with propylbenzilylcholine mustard","authors":"El-Bdaoui Haddad,&nbsp;Jonathan Rousell,&nbsp;Peter J. Barnes","doi":"10.1016/0922-4106(95)00072-0","DOIUrl":"10.1016/0922-4106(95)00072-0","url":null,"abstract":"<div><p>We have investigated the rate and the functional responsiveness of the newly synthesised M₂ muscarinic receptors in HEL 299 cells following propylbenzilylcholine mustard treatment at 37°C. Propylbenzilylcholine mustard induced a dose-dependent loss of the hydrophilic ligand [³H]<em>N</em>-methylscopolamine binding sites with 80% inactivation at 0.1 μM. The rate of muscarinic receptor synthesis in these cells, estimated from wash-out experiments following propylbenzilylcholine mustard treatment, was very slow and returned to control values after 36 h of propylbenzilylcholine mustard removal. The recovery of muscarinic receptors was blocked by the cycloheximide pre-treatment, indicating the synthetic pathway for the new receptors. In control cells as well as in cells treated with propylbenzilylcholine mustard and allowed to recover for 12 h, carbachol still inhibited forskolin-induced cAMP accumulation. These results show that (i) the rate of M₂ muscarinic receptor synthesis is slow (ii) the recovery of receptors is mainly through increased synthesis and (iii) the newly synthesised receptors retain their full functional activity.</p></div>","PeriodicalId":100502,"journal":{"name":"European Journal of Pharmacology: Molecular Pharmacology","volume":"290 3","pages":"Pages 201-205"},"PeriodicalIF":0.0,"publicationDate":"1995-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0922-4106(95)00072-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18594735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"8-substituted adenosine and theophylline-7-riboside analogues as potential partial agonists for the adenosine A1 receptor","authors":"Eleonora M. Van der Werten ,&nbsp;Helen R. Hartog-Witte ,&nbsp;Harlof C.P.F. Roelen ,&nbsp;Jacobien K. von Frijtag Drabbe Künzel ,&nbsp;Irene M. Pirovano ,&nbsp;Ron A.A. Mathôt ,&nbsp;Meindert Danhof ,&nbsp;Arthur Van Aerschot ,&nbsp;Margeris J. Lidaks ,&nbsp;Adriaan P. Ijzerman ,&nbsp;Willem Soudijn","doi":"10.1016/0922-4106(95)00064-X","DOIUrl":"10.1016/0922-4106(95)00064-X","url":null,"abstract":"<div><p>A series of 8-substituted adenosine and theophylline-7-riboside analogues (28 and 9 compounds, respectively) was tested on adenosine A₁ and A_2A receptors as an extensive exploration of the adenosine C8-region. Alkylamino substituents at the 8-position cause an affinity decrease for adenosine analogues, but an affinity increase for theophylline-7-riboside derivatives. The affinity decrease is probably due to a direct steric hindrance between the C8-substituent and the binding site as well as to electronic effects, not to a steric influence on the ribose moiety to adopt the <em>anti</em> conformation. The 8-substituents increase the affinity of theophylline-7-riboside analogues probably by binding to a lipophilic binding site. The intrinsic activity was tested in vitro for some 8-substituted adenosine analogues, by determining the GTP shift in receptor binding studies and the inhibition of adenylate cyclase in a culture of rat thyroid FRTL-5 cells, and in vivo in the rat cardiovascular system for 8-butylaminoadenosine. Thus, it was shown that 8-ethyl-, 8-butyl-, and 8-pentylamino substituted analogues of adenosine may be partial agonists in vitro, and that 8-butylaminoadenosine is a partial agonist for the rat cardiovascular A₁ receptor in vivo.</p></div>","PeriodicalId":100502,"journal":{"name":"European Journal of Pharmacology: Molecular Pharmacology","volume":"290 3","pages":"Pages 189-199"},"PeriodicalIF":0.0,"publicationDate":"1995-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0922-4106(95)00064-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18594734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[3H]N-methylscopolamine dissociation from muscarine receptors affected by low concentrations of allosteric modulators","authors":"Arthur Christopoulos,&nbsp;Fred Mitchelson","doi":"10.1016/0922-4106(95)90002-0","DOIUrl":"10.1016/0922-4106(95)90002-0","url":null,"abstract":"<div><p>The ability of allosteric ligands to modulate the dissociation rate of [³H]<em>N</em>-methylscopolamine from atrial muscarinic receptors in the presence of varying concentrations of unlabelled <em>N</em>-methylscopolamine or atropine was evaluated. Gallamine, at a concentration approximating its <em>K</em>_D value, slowed the dissociation of [³H] <em>N</em>-methylscopolamine in the presence of ca. 30× <em>K</em>_D of both unlabelled NMS or atropine. This was less evident when concentrations of ca. 1000× <em>K</em>_D of the unlabelled antagonists were employed. Similar findings were made with another allosteric modulator. These results indicate that gallamine can act allosterically at low concentrations.</p></div>","PeriodicalId":100502,"journal":{"name":"European Journal of Pharmacology: Molecular Pharmacology","volume":"290 3","pages":"Pages 259-262"},"PeriodicalIF":0.0,"publicationDate":"1995-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0922-4106(95)90002-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18594729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chronic fluoxetine or desmethylimipramine treatment alters 5-HT2 receptor mediated c-fos gene expression","authors":"Nanda Tilakaratne,&nbsp;Zhelin Yang,&nbsp;Eitan Friedman","doi":"10.1016/0922-4106(95)90003-9","DOIUrl":"10.1016/0922-4106(95)90003-9","url":null,"abstract":"<div><p>These studies examined the effects of a 21-day treatment regime with either the tricyclic antidepressant, desmethylimipramine (DMI), or the selective 5-HT uptake inhibitor, fluoxetine, on 5-HT₂ receptors in rat brain, as assessed by selective agonist-mediated c-<em>fos</em> gene expression. Chronic, but not acute, treatment with fluoxetine (10 mg/kg, i.p. for 21 days) resulted in supersensitization of the response to an acute challenge (4 mg/kg, i.p.) with the selective 5-HT₂ agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI), both in frontal cortex and in hippocampus. Chronic treatment with DMI (10 mg/kg, i.p. for 21 days) resulted in a significant desensitization of the response to DOI. These findings are discussed in relation to the possible modes of action of these two clinically useful agents.</p></div>","PeriodicalId":100502,"journal":{"name":"European Journal of Pharmacology: Molecular Pharmacology","volume":"290 3","pages":"Pages 263-266"},"PeriodicalIF":0.0,"publicationDate":"1995-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0922-4106(95)90003-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"18594730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterisation of δ-subunit containing GABAA receptors from rat brain","authors":"Kathleen Quirk,&nbsp;Paul J. Whiting,&nbsp;C. Ian Ragan,&nbsp;Ruth M. McKernan","doi":"10.1016/0922-4106(95)00061-5","DOIUrl":"https://doi.org/10.1016/0922-4106(95)00061-5","url":null,"abstract":"<div><p>Polyclonal antibodies have been raised in rabbits against the predicted cytoplasmic loop region of the δ-subunit of the GABA_A receptor. These specifically identify the expressed fragment by Western blot but do not cross react with analogous polypeptides from the γ₁, γ₂ or γ₃-subunits. Polyclonal antisera immunoprecipitated [³H]muscimol binding sites from several brain regions consistent with the reported distribution of δ-subunit mRNA and also detected the δ-subunit by Western blot, identifying a polypeptide of 55KDa. Receptors immunoprecipitated from rat brain with the δ-antisera exhibited an atypical profile with respect to their radioligand binding properties. Receptors immunoprecipitated from all regions tested bound [³H]muscimol, but did not bind benzodiazepine site ligands [³H]Ro 15,1788 or [³H]flunitrazepam with high affinity. Receptors containing a δ-subunit accounted for 10.7 ± 2% of all GABA_A receptors ([³H]muscimol binding sites) in the rat central nervous system as deduced from quantitative immunoprecipitation experiments, the largest population being in the cerebellum where approximately 27% of all receptors contained a δ-subunit. The pharmacology of the GABA (γ-aminonutyric acid) binding site on receptors immunoprecipitated from cerebellum with γ₂ and δ-antisera was compared. The rank order of potency of a series of 6 compounds to compete for [³H]muscimol binding sites was similar in these two populations, but muscimol had a significantly higher affinity for receptors containing the δ-subunit. These receptors therefore comprise a novel population of GABA_A receptors which do not bind benzodiazepines but have a 5-fold higher affinity for muscimol. Coexistence of the δ-subunit with γ-subunits was investigated by purifying receptor on a γ₁, γ₂ or γ₃-immunoaffinity resins, separating the subunit components by polyacrylamide gel electrophoresis, transferring to nitrocellulose and probing with δ-subunit specific antibodies. The δ-subunit could not be detected in combination with any γ-subunit.</p></div>","PeriodicalId":100502,"journal":{"name":"European Journal of Pharmacology: Molecular Pharmacology","volume":"290 3","pages":"Pages 175-181"},"PeriodicalIF":0.0,"publicationDate":"1995-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0922-4106(95)00061-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71784675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}