Abstract
1 In the isolated basilar artery of the rabbit, gamma-aminobutyrate acid (GABA) (ED50 +/- s.e. mean, 2.4 +/- 1.1 x 10(-5) M) produced a relaxation, if the tone had been increased with 5-hydroxytryptamine (5-HT). 2 3-Aminoproprane sulphonic acid (3-APS) produced a similar, but smaller relaxation, while baclofen had no effect. The relaxation produced by GABA was inhibited by bicuculline. 3 Transmural electrical stimulation produced a reproducible contraction of the isolated basilar artery. In 9 out 14 preparations GABA (ED50 +/- s.e. mean, 5.6 +/- 2.1 x 10(-7) M) caused a reduction of the response, with a maximum of 49.2 +/- 4.3%. Bicuculline did not inhibit these responses to GABA. 4 Baclofen (ED50 +/- s.e. mean, 6.8 +/- 1.4 x 10(-7) M) produced a similar inhibition (47.4 +/- 3.2% maximum) but 3-APS had no effect. 5 GABA (10(-4) M) had no effect on the tone of isolated mesenteric or internal carotid arteries from the rabbit, whether or not the tone was increased with 5-HT. Similarly, GABA (10(-4) M) did not produce any change in the responses to transmural stimulation in isolated mesenteric or internal carotid arteries. 6 These findings are consistent with the presence of two types of GABA receptor on the rabbit basilar artery.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Bowery N. G., Hudson A. L. gamma-Aminobutyric acid reduces the evoked release of [3H]-noradrenaline from sympathetic nerve terminals [proceedings]. Br J Pharmacol. 1979 May;66(1):108P–108P. [PMC free article] [PubMed] [Google Scholar]
- Edvinsson L., Krause D. N. Pharmacological characterization of GABA receptors mediating vasodilation of verebral arteries in vitro. Brain Res. 1979 Sep 7;173(1):89–97. doi: 10.1016/0006-8993(79)91098-9. [DOI] [PubMed] [Google Scholar]
- Fujiwara M., Muramatsu I. Gamma-aminobutyric acid receptor on vascular smooth muscle of dog cerebral arteries. Br J Pharmacol. 1975 Dec;55(4):561–562. doi: 10.1111/j.1476-5381.1975.tb07434.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hill D. R., Bowery N. G. 3H-baclofen and 3H-GABA bind to bicuculline-insensitive GABA B sites in rat brain. Nature. 1981 Mar 12;290(5802):149–152. doi: 10.1038/290149a0. [DOI] [PubMed] [Google Scholar]
- Starke K., Weitzell R. gamma-Aminobutyric acid and postganglionic sympathetic transmission in the pulmonary artery of the rabbit. J Auton Pharmacol. 1980 Nov;1(1):45–51. doi: 10.1111/j.1474-8673.1980.tb00440.x. [DOI] [PubMed] [Google Scholar]