Alpha 1-adrenoceptors mediate the responses to BHT-920 and rauwolscine in dog mesenteric artery after partial depolarization by KCl.
In normal (5 mM KCl) HEPES buffer solution, BHT-920 and rauwloscine did not produce any contractile responses in dog mesenteric artery strips. However, when the preparation was bathed in 20 mM KCl HEPES buffer solution, BHT-920 and rauwloscine evoked significant contractile responses. These effects were markedly inhibited by parazosin which caused a parallel shift to the right of the concentration-response curve to BHT-920. In 45Ca uptake experiments carried out in the 20 mM KCl HEPES buffer solution BHT-920 and rauwolscine significantly increased 45Ca influxes which were reduced by prazosin. These results suggest that postsynaptic alpha 1-adrenoceptors in dog mesenteric artery mediate the contractile responses and the 45Ca influxes induced by BHT-920 and rauwloscine after partial depolarization by 20 mM KCl.
Department of Pharmacology, Sun Yat-Sen University of Medical Sciences, Guangzhou.
Y Y
YY
Guan
K M
KM
Chen
J J
JJ
Sun
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D001381:Azepines / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism / Q000493:pharmacokinetics; D004285:Dogs; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008566:Membranes / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000502:physiology; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D011189:Potassium Chloride / Q000494:pharmacology*; D011224:Prazosin / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D015016:Yohimbine / Q000494:pharmacology*
D000316:Adrenergic alpha-Agonists; D001381:Azepines; D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D011189:Potassium Chloride; C024763:talipexole; D002118:Calcium; D011224:Prazosin