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 1 June 1983
  • Biology
  • 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… 

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.

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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.

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TLDR
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TLDR
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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.

Allosteric properties of 5-HT2 receptors in tracheal smooth muscle

TLDR
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The 5-hydroxytryptamine 5-HT1D receptor subtype is negatively coupled to adenylate cyclase in calf substantia nigra

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Comparison of the effects of cromakalim, a potassium conductance enhancer, and nimodipine, a calcium antagonist, on 5-hydroxytryptamine responses in a variety of vascular smooth muscle preparations

TLDR
It is concluded that cromakalim, like nimodipine, possesses anti-vasospastic activity; however, differences exist in the sensitivity of the 5-HT mediated contractions of the three arterial preparations to the agents.

Effects of 6-hydroxydopamine on pre- and post-junctional 5-HT1-like receptor-mediated responses in dog saphenous vein

TLDR
The present results suggest that inhibition of cyclic AMP accumulation by 5-HT occurs predominantly in smooth muscle.

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