ISSN:
1432-1912
Keywords:
Key wordsγ-Mangostin
;
5-Hydroxytryptamine
;
5-Hydroxytryptamine 2A receptor antagonist
;
Rabbit aorta
;
Rat coronary
;
Rabbit platelet
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract γ-Mangostin, purified from the fruit hull of the medicinal plant Garcinia mangostana caused a parallel rightwards shift of the concentration/response curve for the contraction elicited by 5-hydroxytryptamine (5-HT) in the rabbit aorta (pA2 = 8.2) without affecting the contractile responses to KCl, phenylephrine (α1) or histamine (H1). The perfusion pressure response of rat coronary artery to 5-HT (5-HT2A) was reduced concentration dependently by γ-mangostin (IC50 = 0.32 μM). 5-HT amplified, ADP-induced aggregation of rabbit platelets (5-HT2A) was inhibited by γ-mangostin (IC50 = 0.29 μM), whereas that induced by thrombin was not affected, nor did γ-mangostin affect 5-HT-induced contraction of the guinea-pig ileum (5-HT3)in the presence of 5-HT1, 5-HT2 and 5-HT4 receptor antagonists. Furthermore, 5-HT-induced contraction of the rat fundus (5-HT2B) and 5-HT-induced relaxation of the rabbit aorta in the presence of ketanserin (5-HT1) and carbachol-induced contraction of the guinea-pig ileum (muscarinic M3) were not affected by γ-mangostin (5 μM). γ-Mangostin inhibited [3H]spiperone binding to cultured rat aortic myocytes (IC50 = 3.5 nM). The K d for [3H]spiperone binding was increased by γ-mangostin (3 nM) from 11.7 to 27.4 nM without affecting B max. These results suggest that γ-mangostin is a novel competitive antagonist, free from a nitrogen atom, for the 5-HT2A receptors in vascular smooth muscles and platelets.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/PL00005134
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