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Cortisone: a potent GABAA antagonist in the guinea-pig isolated ileum.
- Source :
-
The Journal of pharmacy and pharmacology [J Pharm Pharmacol] 1990 Sep; Vol. 42 (9), pp. 662-4. - Publication Year :
- 1990
-
Abstract
- In the guinea-pig isolated ileum, cortisone at 0.001-10 nM induced a non-competitive, dose-dependent antagonism of GABAA-receptor-mediated contractile responses to applied GABA, depressing the maximum contractile response to GABA (100 microM), without affecting contractile responses to acetylcholine or cholinergic twitch contractions. At higher concentrations (greater than 10 nM), cortisone depressed contractile responses to acetylcholine (10-100 nM) and cholinergic twitch responses to transmural stimulation. Cortisone is thus the most potent non-competitive antagonist at GABAA-receptor complexes in the guinea-pig ileum. From molecular modelling, sterically there appeared little difference between cortisone and cortisol, the latter being an enhancer of GABAA-receptor-mediated action in the ileum. However, there were significant differences in electrostatic potentials between the two steroids, due to the different levels of oxidation at C11 which may contribute to such opposing actions.
- Subjects :
- Androstanes pharmacology
Animals
Azasteroids pharmacology
Female
GABA-A Receptor Antagonists
Guinea Pigs
Ileum drug effects
In Vitro Techniques
Male
Models, Molecular
Muscle Contraction drug effects
Picrotoxin analogs & derivatives
Picrotoxin pharmacology
Sesterterpenes
Cortisone pharmacology
Hydrocortisone pharmacology
Muscle, Smooth drug effects
gamma-Aminobutyric Acid physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0022-3573
- Volume :
- 42
- Issue :
- 9
- Database :
- MEDLINE
- Journal :
- The Journal of pharmacy and pharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 1981909
- Full Text :
- https://doi.org/10.1111/j.2042-7158.1990.tb06629.x