{"title":"[Congress of French-language Pharmacology. Rouen, 5-7 May 1986. Abstracts].","authors":"","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":14817,"journal":{"name":"Journal de pharmacologie","volume":"17 3","pages":"375-478"},"PeriodicalIF":0.0,"publicationDate":"1986-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14913965","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}
The chemotactic response of polymorphonuclear leukocytes using the agarose method, has been studied in six healthy volunteers, immediately prior and after a 5-day oral administration of spiramycin, 6 million units per day. The influence of spiramycin proved to be small as the directed and spontaneous migration were decreased by 21% and 18% respectively. Despite the fact that spiramycin can penetrate into leukocytes, these results indicate that no clinically relevant alterations of chemotaxis are likely under therapeutic conditions.
{"title":"[Chemotactic response of human polynuclear neutrophils after in vivo administration of spiramycin].","authors":"J Y Lombard, J Descotes, A Eyraud, J C Evreux","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The chemotactic response of polymorphonuclear leukocytes using the agarose method, has been studied in six healthy volunteers, immediately prior and after a 5-day oral administration of spiramycin, 6 million units per day. The influence of spiramycin proved to be small as the directed and spontaneous migration were decreased by 21% and 18% respectively. Despite the fact that spiramycin can penetrate into leukocytes, these results indicate that no clinically relevant alterations of chemotaxis are likely under therapeutic conditions.</p>","PeriodicalId":14817,"journal":{"name":"Journal de pharmacologie","volume":"17 3","pages":"328-30"},"PeriodicalIF":0.0,"publicationDate":"1986-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14914024","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}
The hypothesis linking decreased serotonin transmission to reduced anxiety as the mechanism in the anxiolytic activity of benzodiazepines conflicts with most clinical observations. Serotonin antagonists show no marked capacity to alleviate anxiety. On the other hand, clinical signs of reduced serotonergic transmission (low 5-HIAA levels in the cerebrospinal fluid) are frequently associated with aggressiveness, suicide attempts and increased anxiety. This brief review attempts to reconcile these human and animal findings by investigating whether anxiety reduction or increased impulsivity are likely to account for animal behavioral changes associated with decreased serotonergic transmission. The effects of manipulating central serotonin on experimental anxiety paradigms in animals (punishment, novelty) are reviewed and compared to the effects of anti-anxiety drugs. Anxiety seems neither necessary nor sufficient to induce control by serotonergic neurons on behavior. Further evidence suggests that behavioral effects of anxiolytics thought to be mediated by decreases in anxiety are not caused by the ability of these drugs to reduce serotonin transmission. Blockade of serotonin transmission, especially at the level of the substantia nigra, results in a shift of behavior towards facilitation of responding. This behavioral shift is particularly marked when there is competition between acting and restraining response tendencies and when obstacles prevent the immediate attainment of an anticipated reward. It is proposed that serotonergic neurons are not only involved in behavioral arousal but also in enabling the organism to arrange or tolerate delay before acting. Decreases in serotonin transmission seem to be associated with the increased performance of behaviors which are usually suppressed though not necessarily because of the alleviation of anxiety which might contribute to the suppression.
{"title":"[Serotonergic neurons and behavior].","authors":"P Soubrié","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The hypothesis linking decreased serotonin transmission to reduced anxiety as the mechanism in the anxiolytic activity of benzodiazepines conflicts with most clinical observations. Serotonin antagonists show no marked capacity to alleviate anxiety. On the other hand, clinical signs of reduced serotonergic transmission (low 5-HIAA levels in the cerebrospinal fluid) are frequently associated with aggressiveness, suicide attempts and increased anxiety. This brief review attempts to reconcile these human and animal findings by investigating whether anxiety reduction or increased impulsivity are likely to account for animal behavioral changes associated with decreased serotonergic transmission. The effects of manipulating central serotonin on experimental anxiety paradigms in animals (punishment, novelty) are reviewed and compared to the effects of anti-anxiety drugs. Anxiety seems neither necessary nor sufficient to induce control by serotonergic neurons on behavior. Further evidence suggests that behavioral effects of anxiolytics thought to be mediated by decreases in anxiety are not caused by the ability of these drugs to reduce serotonin transmission. Blockade of serotonin transmission, especially at the level of the substantia nigra, results in a shift of behavior towards facilitation of responding. This behavioral shift is particularly marked when there is competition between acting and restraining response tendencies and when obstacles prevent the immediate attainment of an anticipated reward. It is proposed that serotonergic neurons are not only involved in behavioral arousal but also in enabling the organism to arrange or tolerate delay before acting. Decreases in serotonin transmission seem to be associated with the increased performance of behaviors which are usually suppressed though not necessarily because of the alleviation of anxiety which might contribute to the suppression.</p>","PeriodicalId":14817,"journal":{"name":"Journal de pharmacologie","volume":"17 2","pages":"107-12"},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14011760","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}
We had previously demonstrated that (3H)-piretanide binds to a receptor located on medullary membranes of canine kidney. Here we show that binding is specific for a particular group of loop diuretics. Sulfonamide diuretics of the benzoic acid family, other substituted sulfonamides, and phenoxy-acetic acid derivates displace (3H)-piretanide from its receptor. Loop diuretics that do not act at the luminal tubular membrane do not displace piretanide, nor do diuretics with a different site and mode of action (thiazides; inhibitors of the Na+/H+ antiporter (amiloride), of Na+K+ ATPase (ouabain), or of carbonic anhydrase (acetazolamide). We demonstrate that no interference occurs between the piretanide receptor and membrane bound receptors of several neurotransmitters.
{"title":"Binding of (3H)-piretanide to a specific receptor of renal medulla.","authors":"E M Giesen-Crouse, P Fandeleur, J L Imbs","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>We had previously demonstrated that (3H)-piretanide binds to a receptor located on medullary membranes of canine kidney. Here we show that binding is specific for a particular group of loop diuretics. Sulfonamide diuretics of the benzoic acid family, other substituted sulfonamides, and phenoxy-acetic acid derivates displace (3H)-piretanide from its receptor. Loop diuretics that do not act at the luminal tubular membrane do not displace piretanide, nor do diuretics with a different site and mode of action (thiazides; inhibitors of the Na+/H+ antiporter (amiloride), of Na+K+ ATPase (ouabain), or of carbonic anhydrase (acetazolamide). We demonstrate that no interference occurs between the piretanide receptor and membrane bound receptors of several neurotransmitters.</p>","PeriodicalId":14817,"journal":{"name":"Journal de pharmacologie","volume":"17 2","pages":"146-8"},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14152103","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}
This study aimed at comparing the effects of blockade or stimulation of beta-adrenoceptors on the head-twitch response induced in mice by direct (5-MeODMT) or indirect (5-HTP) activation of serotonergic receptors shows that: beta-agonists (clenbuterol and salbutamol) increased the 5-HTP-induced head-twitches and decreased the response to 5-MeODMT. beta-agonists (propranolol and penbutolol) reduced the head-twitches elicited by 5-HTP but enhanced those induced by 5-MeODMT. Under our experimental conditions, desipramine behaved like the beta-agonists studied. Prior intracerebroventricular injection of 5,7-DHT enhanced the response to 5-MeODMT but did not prevent the antagonism of clenbuterol against 5-MeODMT-induced head-twitches. These findings suggest that beta-receptors are in a position to regulate differentially serotonin transmission.
{"title":"Comparative study of the effects of stimulation or blockade of beta-adrenoceptors on the head-twitches induced in mice by 5-hydroxytryptophan versus 5-methoxy-N, N-dimethyltryptamine.","authors":"P Martin, P Soubrié, P Simon","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>This study aimed at comparing the effects of blockade or stimulation of beta-adrenoceptors on the head-twitch response induced in mice by direct (5-MeODMT) or indirect (5-HTP) activation of serotonergic receptors shows that: beta-agonists (clenbuterol and salbutamol) increased the 5-HTP-induced head-twitches and decreased the response to 5-MeODMT. beta-agonists (propranolol and penbutolol) reduced the head-twitches elicited by 5-HTP but enhanced those induced by 5-MeODMT. Under our experimental conditions, desipramine behaved like the beta-agonists studied. Prior intracerebroventricular injection of 5,7-DHT enhanced the response to 5-MeODMT but did not prevent the antagonism of clenbuterol against 5-MeODMT-induced head-twitches. These findings suggest that beta-receptors are in a position to regulate differentially serotonin transmission.</p>","PeriodicalId":14817,"journal":{"name":"Journal de pharmacologie","volume":"17 2","pages":"119-25"},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14011757","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}
The pharmacological properties of idazoxan, 2-[2-(1,4-benzodioxanyl)]-2-imidazoline, were first described four years ago; since then, this compound has been revealed to be one of the most selective alpha 2-adrenoceptor blocking agent presently available. At peripheral sites, idazoxan antagonized the effects of alpha 2 agonists such as azepexole, B-HT 920, M 7, UK 14,304, alpha-methylnoradrenaline, clonidine but was ineffective against alpha 1 agonists such as cirazoline and phenylephrine. At presynaptic sites idazoxan increased the tachycardia due to the stimulation of the cardioaccelerator nerve of the dog and antagonized the inhibitory effects of alpha 2 agonists in dogs and rats. As compared to the classical alpha 2-adrenoceptor blocking agents, idazoxan was more selective and as potent as yohimbine, rauwolscine, RS 21361, Wy 26703. At central sites, idazoxan has been found to antagonize the sympathoinhibitory effects of alpha 2 agonists. Therefore, idazoxan is a potent and probably the most selective alpha 2-adrenoceptor blocking agent presently available and is now frequently used for the investigation of peripheral and central alpha 2-adrenoceptors.
{"title":"Idazoxan: a novel pharmacological tool for the study of alpha 2-adrenoceptors.","authors":"H Dabiré","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The pharmacological properties of idazoxan, 2-[2-(1,4-benzodioxanyl)]-2-imidazoline, were first described four years ago; since then, this compound has been revealed to be one of the most selective alpha 2-adrenoceptor blocking agent presently available. At peripheral sites, idazoxan antagonized the effects of alpha 2 agonists such as azepexole, B-HT 920, M 7, UK 14,304, alpha-methylnoradrenaline, clonidine but was ineffective against alpha 1 agonists such as cirazoline and phenylephrine. At presynaptic sites idazoxan increased the tachycardia due to the stimulation of the cardioaccelerator nerve of the dog and antagonized the inhibitory effects of alpha 2 agonists in dogs and rats. As compared to the classical alpha 2-adrenoceptor blocking agents, idazoxan was more selective and as potent as yohimbine, rauwolscine, RS 21361, Wy 26703. At central sites, idazoxan has been found to antagonize the sympathoinhibitory effects of alpha 2 agonists. Therefore, idazoxan is a potent and probably the most selective alpha 2-adrenoceptor blocking agent presently available and is now frequently used for the investigation of peripheral and central alpha 2-adrenoceptors.</p>","PeriodicalId":14817,"journal":{"name":"Journal de pharmacologie","volume":"17 2","pages":"113-8"},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14011762","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}
In normal rats, PGE1, arachidonic acid, indomethacin and diclofenac did not modify the leucocyte content of sponge exudates withdrawn 4 hours after implantation while arachidonic acid increased the level in PGE2 and indomethacin reduced it. The leucocyte content of sponges exudates withdrawn 18 hours after implantation was not modified by PGE1 and TXB2, but diminished by indomethacin and NDGA and increased by arachidonic acid. As the chemotactic effect of arachidonic acid was slightly reduced by indomethacin and abolished by NDGA, it could depend on the formation of lipoxygenase derivatives. In normal rats, the leucocyte content of sponge exudates withdrawn 18 hours after implantation was increased slightly by normal serum and largely by serum from turpentine-treated rats. The blood leucocyte content was not modified in turpentine-treated rats. However in these rats, the leucocyte content of sponge exudates was low comparatively to the leucocyte content in normal rats. This low level was not affected by indomethacin, arachidonic acid and normal serum. The leucocytes of turpentine-treated rats seem to be desensitizated towards chemotactic factors. Similar desensitization was observed in rats treated by iota carrageenan.
{"title":"[The influence in the rat of counter-irritation by turpentine on the leukocyte content of exudates induced by sponge implants].","authors":"E Deflandre, J Damas","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>In normal rats, PGE1, arachidonic acid, indomethacin and diclofenac did not modify the leucocyte content of sponge exudates withdrawn 4 hours after implantation while arachidonic acid increased the level in PGE2 and indomethacin reduced it. The leucocyte content of sponges exudates withdrawn 18 hours after implantation was not modified by PGE1 and TXB2, but diminished by indomethacin and NDGA and increased by arachidonic acid. As the chemotactic effect of arachidonic acid was slightly reduced by indomethacin and abolished by NDGA, it could depend on the formation of lipoxygenase derivatives. In normal rats, the leucocyte content of sponge exudates withdrawn 18 hours after implantation was increased slightly by normal serum and largely by serum from turpentine-treated rats. The blood leucocyte content was not modified in turpentine-treated rats. However in these rats, the leucocyte content of sponge exudates was low comparatively to the leucocyte content in normal rats. This low level was not affected by indomethacin, arachidonic acid and normal serum. The leucocytes of turpentine-treated rats seem to be desensitizated towards chemotactic factors. Similar desensitization was observed in rats treated by iota carrageenan.</p>","PeriodicalId":14817,"journal":{"name":"Journal de pharmacologie","volume":"17 2","pages":"155-62"},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14224536","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}
The effects of selective inhibitions of both cyclo-oxygenase and lipoxygenase pathways were studied in the isolated, perfused and ventilated guinea-pig lungs. Leukotriene D4 (0.3 nmol) induced a significant bronchoconstriction. This effect was significantly inhibited by IPL 55712 (a SRS-A antagonist) and by Imidazole or Dazoxiben (specific thromboxane synthetase inhibitors), but aspirin and indomethacin were without significant effect on this broncho-constriction. Our results suggest that the principal component of leukotriene D4 induced bronchoconstriction in guinea-pig lungs is primary.
{"title":"[The effects of different inhibitors on bronchoconstriction induced by leukotriene D4 in isolated and perfused guinea pig lung].","authors":"G Trocklé, G Catau, C Kalt, M Jacque","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The effects of selective inhibitions of both cyclo-oxygenase and lipoxygenase pathways were studied in the isolated, perfused and ventilated guinea-pig lungs. Leukotriene D4 (0.3 nmol) induced a significant bronchoconstriction. This effect was significantly inhibited by IPL 55712 (a SRS-A antagonist) and by Imidazole or Dazoxiben (specific thromboxane synthetase inhibitors), but aspirin and indomethacin were without significant effect on this broncho-constriction. Our results suggest that the principal component of leukotriene D4 induced bronchoconstriction in guinea-pig lungs is primary.</p>","PeriodicalId":14817,"journal":{"name":"Journal de pharmacologie","volume":"17 2","pages":"163-5"},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14224537","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}
P Worms, J P Kan, A Perio, C G Wermuth, K Bizière, R Roncucci
Minaprine (MIN) is a 3-amino-pyridazine derivative which exhibits a profile of psychotropic activities which resembles that of antidepressant drugs as well as that of several dopaminomimetic drugs. This spectrum of activity differs from those observed in the same conditions for tricyclic (imipramine, clomipramine) and atypical (indalpine, nomifensine, amineptine, mianserin) antidepressant drugs. It must be noted that MIN is devoid of anticholinergic and motor stimulant effects. In addition, MIN induces behavioural effects predictive of a dopaminergic stimulation; the profile of this activity differs from that of apomorphine, as well as from those of amphetamine and nomifensine, but somewhat resembles that of bromocryptine. MIN does not induce neuroleptic, anxiolytic or anticonvulsant activities in rodents. These data suggest that MIN is an atypical antidepressant drug which activates both serotonergic and dopaminergic neurotransmissions, by as yet not clearly identified mechanisms.
{"title":"[Pharmacologic profile of an original psychotropic drug. Minaprine: comparison with six reference antidepressives].","authors":"P Worms, J P Kan, A Perio, C G Wermuth, K Bizière, R Roncucci","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Minaprine (MIN) is a 3-amino-pyridazine derivative which exhibits a profile of psychotropic activities which resembles that of antidepressant drugs as well as that of several dopaminomimetic drugs. This spectrum of activity differs from those observed in the same conditions for tricyclic (imipramine, clomipramine) and atypical (indalpine, nomifensine, amineptine, mianserin) antidepressant drugs. It must be noted that MIN is devoid of anticholinergic and motor stimulant effects. In addition, MIN induces behavioural effects predictive of a dopaminergic stimulation; the profile of this activity differs from that of apomorphine, as well as from those of amphetamine and nomifensine, but somewhat resembles that of bromocryptine. MIN does not induce neuroleptic, anxiolytic or anticonvulsant activities in rodents. These data suggest that MIN is an atypical antidepressant drug which activates both serotonergic and dopaminergic neurotransmissions, by as yet not clearly identified mechanisms.</p>","PeriodicalId":14817,"journal":{"name":"Journal de pharmacologie","volume":"17 2","pages":"126-38"},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14613113","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}
The mechanism by which a substance that binds to the benzodiazepine receptor acts as an agonist, an inverse agonist (e.g. methyl-beta-carboline-3-carboxylate (beta-CCM] or an antagonist (e.g. Ro 15-1788) was investigated. For this purpose, we studied the influence of bicuculline, an antagonist of gamma-aminobutyric acid (GABA), on the binding of these substances in crude synaptosomal preparation (P2 fraction) containing high levels of endogenous GABA. Displacement curves were performed, using 3H-flunitrazepam in the absence and in the presence of a high concentration (7.10(-5) M) of bicuculline. The ratios of IC50 values with and without bicuculline were significantly higher than 1 for all benzodiazepine agonists investigated (e.g. 1.91 +/- 0.11 (n = 3) for diazepam), about 1 for Ro 15-1788 (0.94 +/- 0.06 (n = 4)) and lower than 1 for beta-CCE (0.55 +/- 0.05 (n = 4)). Statistically significant differences were also observed among benzodiazepine agonists e.g. between flunitrazepam (a sedative-hypnotic drug) and clonazepam (an anticonvulsant drug) or lorazepam (an anxiolytic drug). These data indicate that the ratios of IC50 values with and without bicuculline might provide the basis for an in vitro, pharmacologically relevant, classification of drugs acting on the benzodiazepine receptor. This procedure does not require extensive washing of the membrane preparation, in contrast to the method in which the ratios of IC50 values were determined with and without addition of GABA.
{"title":"Classification of benzodiazepine receptor agonists, inverse agonists and antagonists using bicuculline in an in vitro test.","authors":"P Jacqmin, M Wibo, M Lesne","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The mechanism by which a substance that binds to the benzodiazepine receptor acts as an agonist, an inverse agonist (e.g. methyl-beta-carboline-3-carboxylate (beta-CCM] or an antagonist (e.g. Ro 15-1788) was investigated. For this purpose, we studied the influence of bicuculline, an antagonist of gamma-aminobutyric acid (GABA), on the binding of these substances in crude synaptosomal preparation (P2 fraction) containing high levels of endogenous GABA. Displacement curves were performed, using 3H-flunitrazepam in the absence and in the presence of a high concentration (7.10(-5) M) of bicuculline. The ratios of IC50 values with and without bicuculline were significantly higher than 1 for all benzodiazepine agonists investigated (e.g. 1.91 +/- 0.11 (n = 3) for diazepam), about 1 for Ro 15-1788 (0.94 +/- 0.06 (n = 4)) and lower than 1 for beta-CCE (0.55 +/- 0.05 (n = 4)). Statistically significant differences were also observed among benzodiazepine agonists e.g. between flunitrazepam (a sedative-hypnotic drug) and clonazepam (an anticonvulsant drug) or lorazepam (an anxiolytic drug). These data indicate that the ratios of IC50 values with and without bicuculline might provide the basis for an in vitro, pharmacologically relevant, classification of drugs acting on the benzodiazepine receptor. This procedure does not require extensive washing of the membrane preparation, in contrast to the method in which the ratios of IC50 values were determined with and without addition of GABA.</p>","PeriodicalId":14817,"journal":{"name":"Journal de pharmacologie","volume":"17 2","pages":"139-45"},"PeriodicalIF":0.0,"publicationDate":"1986-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"14011758","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}