Yohimbine and rauwolscine inhibit 5-hydroxytryptamine-induced contraction of large coronary arteries of calf through blockade of 5 HT2 receptors

@article{Kaumann2004YohimbineAR,
  title={Yohimbine and rauwolscine inhibit 5-hydroxytryptamine-induced contraction of large coronary arteries of calf through blockade of 5 HT2 receptors},
  author={Alberto Julio Kaumann},
  journal={Naunyn-Schmiedeberg's Archives of Pharmacology},
  year={2004},
  volume={323},
  pages={149-154}
}
  • A. Kaumann
  • Published 2004
  • Chemistry, Medicine
  • Naunyn-Schmiedeberg's Archives of Pharmacology
Summary5-Hydroxytryptamine (5 HT)-induced contractions were investigated on cocaine-treated strips of bovine large coronary arteries.1.The α2-adrenoceptor blockers rauwolscine and yohimbine antagonized competitively 5 HT-induced contractions. The estimated equilibrium dissociation constantsKB (−log mol/l) were 7.1 for rauwolscine and 7.3 for yohimbine. The affinity of yohimbine for the receptors mediating the response to 5HT appears to be 10 times higher than for postsynaptic α1-adrenoceptor… Expand
A paradox: the 5-HT2-receptor antagonist ketanserin restores the 5-HT-induced contraction depressed by methysergide in large coronary arteries of calf
TLDR
It is proposed that methysergide depresses 5- HT-induced contractions by acting on an allosteric site and the existence of a low affinity receptor for ketanserin activated by 5-HT is suggested. Expand
Ketanserin causes surmountable antagonism of 5-hydroxytryptamine-induced contractions of large coronary arteries of dog
TLDR
It is found that the antagonism by ketanserin can be surmounted, provided the concentrations of 5-HT are high enough, and that large coronary arteries of dog are contracted by 5-hydroxytryptamine mainly though5-HT2-receptors and to a smaller extent through receptors different from 5- HT2. Expand
5-HT1-like and 5-HT2A receptors mediate 5-hydroxytryptamine-induced contraction of rabbit isolated mesenteric artery
TLDR
It is suggested that this kind of amplification may be a common feature of vascular 5-HT1-like type receptor as has been shown in other vascular segments such as rabbit femoral, iliac and renal arteries, and guinea-pig iliAC artery. Expand
Alpha-adrenoceptors, 5-hydroxytryptamine receptors and the action of dihydroergotamine in human venous preparations obtained during saphenectomy procedures for varicose veins
TLDR
The present results strongly suggest that in human saphenous veins the constrictor activity of dihydroergotamine is mediated at least in part through stimulation of 5-HT receptors. Expand
Effects of tryptamine mediated through 2 states of the 5-HT2 receptor in calf coronary artery
TLDR
The mode of action of tryptamine was investigated on strips of left circumflex coronary artery of calf and appears to bind also to the R′ state of the 5-HT2 receptor thereby causing the slowly developing contractions, consistent with an interaction oftryptamine at different sites of the allosteric 5- HT2-receptor system. Expand
Sumatriptan contracts large coronary arteries of beagle dogs through 5-HT1-like receptors
TLDR
The rank order of contractile potency of the agonists, the antagonism by methiothepin and the resistance to blockade by ketanserin are consistent with a nearly exclusive involvement of 5-HT1-like receptors. Expand
Allosteric properties of the 5-HT2 receptor system of the rat tail artery
TLDR
Both methysergide and ritanserin appear to antagonize the effects of 5-HT through an allosteric site which is distinct from the 5-hydroxytryptamine receptor system of strips of rat tail artery. Expand
Interaction of ketanserin and its metabolite ketanserinol with 5HT2 receptors in pulmonary and coronary arteries of calf
TLDR
The evidence is consistent with the assumption that smooth muscle 5HT receptors of both pulmonary artery and large coronary artery are of the 5HT2 class and reported peak plasma levels of ketanserinol are too low to account for a contribution of the metabolite to the blockade of 5HT effects by ketanserserin. Expand
Allosteric properties of 5-HT2 receptors in tracheal smooth muscle
TLDR
The results support for tracheal smooth muscle a model of an allosteric regulation of 5-HT2-receptors which was proposed for arterial smooth muscle by Kaumann and Frenken. Expand
The 5-hydroxytryptamine 5-HT1D receptor subtype is negatively coupled to adenylate cyclase in calf substantia nigra
TLDR
The results strongly support the contention that 5-HT1D binding sites are negatively coupled to adenylate cyclase in calf substantia nigra. Expand
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