Abstract:
:1. gamma-Aminobutyric acid (GABA) was applied by the 'concentration clamp' technique to isolated neurones of Aplysia. GABA induced a chloride current (ICl) due to activation of a single class of chloride-channel. 2. The concentration-response curve for the peak ICl gave an apparent dissociation constant of 6.4 X 10(-5) M and a Hill coefficient of 0.88. The current-voltage relationship was linear in the voltage range examined (-40 to +10 mV). 3. The activation phase of the ICl could be fitted to a single exponential function and desensitization followed the sum of two exponential functions. The time constants of activation and desensitization decreased with increasing concentrations of GABA but were voltage-independent. The recovery process from desensitization also followed the sum of two exponential functions. 4. As for the rate-limiting step of the channel activation, the hyperbolic relationship between the activation rate and GABA concentration showed that the rapid binding assumption holds, suggesting that the isomerization step is rate-limiting. The apparent channel closing rate constant was estimated to be 10 s-1 from the ordinate intercept of the linear part of the above relationship at lower concentrations. 5. Muscimol and beta-alanine induced a ICl, which cross-desensitized with that evoked by GABA. The GABA-ICl was not enhanced by diazepam (10(-6) M) or alpha-chloralose (10(-3) M), in fact depressant effects were evident. 6. Pentobarbitone decreased the GABA-ICl non-competitively without altering activation or desensitization kinetics. The concentration-inhibition curve gave a KD value of 8.9 x 10(-5) M and a Hill coefficient of 1.0. 7. These results suggest that GABA activates a single class of Cl channel in Aplysia neurones, which have one binding site for the agonist. The GABA receptor-Cl channel complex in Aplysia is pharmacologically and perhaps structurally different from that in vertebrates.
journal_name
Br J Pharmacoljournal_title
British journal of pharmacologyauthors
Ikemoto Y,Akaike N,Kijima Hdoi
10.1111/j.1476-5381.1988.tb11718.xsubject
Has Abstractpub_date
1988-11-01 00:00:00pages
883-95issue
3eissn
0007-1188issn
1476-5381journal_volume
95pub_type
杂志文章abstract:BACKGROUND AND PURPOSE:Montelukast and S-carbocysteine have been used in asthmatic patients as an anti-inflammatory or mucolytic agent respectively. S-carbocysteine also exhibits anti-inflammatory properties. EXPERIMENTAL APPROACH:Ovalbumin (OVA) sensitized BALB/c mice were challenged with OVA for 3 days followed by s...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.2010.00797.x
更新日期:2010-07-01 00:00:00
abstract::1. The relative potencies of muscarinic agonists on bovine tracheal smooth muscle were unchanged as a consequence of aging and were carbachol greater than oxotremorine greater than muscarine greater than pilocarpine greater than McNeil A-343. 2. During aging, the potencies of carbachol, oxotremorine, McNeil A-343 and ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1988.tb11480.x
更新日期:1988-04-01 00:00:00
abstract::1. [35S]t-butylbicyclophosphorothionate (TBPS) is a high affinity ligand for the picrotoxin site of GABA(A) receptors. Here we examined TBPS binding to the cloned receptors made of alpha 1, alpha 3 or alpha 6 in combination with beta 2 or beta 2 and gamma 2 subunits, in the presence of GABA and several allosteric liga...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1994.tb13185.x
更新日期:1994-08-01 00:00:00
abstract::1. Superoxide dismutase (SOD, 60 u ml-1) or ferricytochrome c (70 microM) significantly inhibited thrombin-stimulated platelet adhesion to gelatin-coated plastic, whereas catalase (1000 u ml-1) or mannitol (1 mM) had no effect. 2. The platelet aggregation induced by low concentrations of thrombin (causing less than 45...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1989.tb12572.x
更新日期:1989-08-01 00:00:00
abstract::It has been proposed that the vagus nerve plays a role in mediating cholecystokinin-8 (CCK-8) effect on such gastric functions as motility, emptying and gastric acid secretion. To examine the contribution of the efferent pathways in realizing these effects, efferent mass activity in the ventral gastric vagal nerve in ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0703270
更新日期:2000-04-01 00:00:00
abstract::1 The cardiovascular effects of the anthelmintic drug diethylcarbamazine citrate (DECC) were examined in cats anaesthetized with pentobarbitone. There were two quite distinct haemodynamic responses, an initial transient hypotension (occurring within 10 s of an intravenous injection) and a pronounced secondary hyperten...
journal_title:British journal of pharmacology
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更新日期:1976-02-01 00:00:00
abstract::1. The pharmacological characteristics of alpha 1-adrenoceptor binding sites in rat pineal gland membranes, detected by use of a selective alpha 1-adrenoceptor antagonist ([125I]-iodo-2-[beta-(4-hydroxyphenyl) ethylaminomethyl]tetralone, [125I]-HEAT), were investigated with the alkylating agent, chloroethylclonidine (...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1996.tb15530.x
更新日期:1996-07-01 00:00:00
abstract:BACKGROUND AND PURPOSE:We sought to understand why (-)-cannabidiol (CBD) and (-)-cannabidiol-dimethylheptyl (CBD-DMH) exhibit distinct pharmacology, despite near identical structures. EXPERIMENTAL APPROACH:HEK293A cells expressing either human type 1 cannabinoid (CB1 ) receptors or CB2 receptors were treated with CBD ...
journal_title:British journal of pharmacology
pub_type: 杂志文章
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更新日期:2019-05-01 00:00:00
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更新日期:1999-03-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1991.tb12178.x
更新日期:1991-02-01 00:00:00
abstract::Recent advances have improved our understanding of the renin-angiotensin system (RAS). These have included the recognition that angiotensin (Ang)-(1-7) is a biologically active product of the RAS cascade. The identification of the ACE homologue ACE2, which forms Ang-(1-7) from Ang II, and the GPCR Mas as an Ang-(1-7) ...
journal_title:British journal of pharmacology
pub_type: 杂志文章,评审
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更新日期:2013-06-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1993.tb13797.x
更新日期:1993-09-01 00:00:00
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journal_title:British journal of pharmacology
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doi:10.1111/j.1476-5381.1995.tb16653.x
更新日期:1995-09-01 00:00:00
abstract:BACKGROUND AND PURPOSE:Although CB(1) receptor activation evokes neuroprotection in response to cannabinoids, some cannabinoids have been reported to be peroxisome proliferator activated receptor (PPAR) ligands, offering an alternative protective mechanism. We have, therefore, investigated the ability of a range of can...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1038/sj.bjp.0707478
更新日期:2007-11-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1992.tb09058.x
更新日期:1992-04-01 00:00:00
abstract::1. Inhalational anaesthetics modulate ligand-gated ion channels at clinical concentrations. In this paper we address submolecular mechanisms for gamma-aminobutyric acid (GABA) receptor modulation by isoflurane. 2. Wild-type Drosophila melanogaster homo-oligomeric GABA receptors were characterized and compared with an ...
journal_title:British journal of pharmacology
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doi:10.1038/sj.bjp.0701417
更新日期:1997-10-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
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更新日期:1986-09-01 00:00:00
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journal_title:British journal of pharmacology
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更新日期:1984-12-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
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更新日期:1986-07-01 00:00:00
abstract::1. Increased calcium (Ca2+) influx has been incriminated as a potential pathological mechanism in the chronic skeletal muscle degeneration exhibited by Duchenne muscular dystrophy (DMD) patients. We have studied the influence of the glucocorticoid alpha-methylprednisolone (PDN), the only drug known to have a beneficia...
journal_title:British journal of pharmacology
pub_type: 杂志文章
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更新日期:1995-12-01 00:00:00
abstract::1. The effects of pregnancy on mesenteric arterial function were examined in constantly perfused (5 ml min-1) mesenteric arterial beds isolated from 21-day pregnant rats. The function of sympathetic and sensory-motor perivascular nerves, endothelium and smooth muscle was examined. The role of nitric oxide and prostagl...
journal_title:British journal of pharmacology
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doi:10.1111/j.1476-5381.1996.tb15307.x
更新日期:1996-04-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
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更新日期:1972-02-01 00:00:00
abstract::1. We studied the ability of nitric oxide (NO) to physiologically antagonize endothelin-1 (ET-1) induced constrictions in human internal mammary artery (IMA). We also investigated the hypothesis that NO interacts directly with ET-receptor binding in human heart and aorta. 2. ET-1 potently contracted IMA (EC(50) 6.86 n...
journal_title:British journal of pharmacology
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更新日期:2001-01-01 00:00:00
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pub_type: 杂志文章
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更新日期:2001-11-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
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更新日期:1994-12-01 00:00:00
abstract::The pharmacological properties of endothelin receptors (ETR) were investigated in guinea-pig bronchus by comparing binding and functional results. In binding assays, both the ET(B) agonists, endothelin-3 (ET-3) and N-suc-[Glu9,Ala11,15]ET-1(8-21) (IRL 1620), and the antagonist, N-cis-2,6-dimethylpiperidinocarbonyl-L-g...
journal_title:British journal of pharmacology
pub_type: 杂志文章
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更新日期:1999-07-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
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更新日期:1992-08-01 00:00:00
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journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1990.tb14138.x
更新日期:1990-11-01 00:00:00
abstract::1. The uptake and release of (3)H-digitoxigenin by electrically driven, guinea-pig isolated atria (frequency 180/min) has been determined for two different medium concentrations of the genin. Both concentrations-1 x 10(-7) and 5 x 10(-7) g/ml.-caused a pronounced increase in contractile force.2. The uptake of (3)H-dig...
journal_title:British journal of pharmacology
pub_type: 杂志文章
doi:10.1111/j.1476-5381.1968.tb08490.x
更新日期:1968-11-01 00:00:00