Effects of bunazosin on electrical responses of smooth muscle cells of the guinea-pig mesenteric artery and vein to perivascular nerve stimulation and to noradrenaline.
The noradrenaline-induced depolarization of smooth muscle cell membrane was blocked by bunazosin in the mesenteric artery but not in the mesenteric vein. Bunazosin enhanced the excitatory junction potential (e.j.p.) evoked in the mesenteric artery but did not modulate the slow depolarization evoked in the mesenteric vein. Application of noradrenaline decreased the amplitude of e.j.p. enhanced by bunazosin but not by yohimbine. It was concluded that bunazosin is a highly selective alpha 1-adrenoceptor blocker in vascular tissues.
D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D006168:Guinea Pigs; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D008638:Mesenteric Arteries / Q000502:physiology; D008642:Mesenteric Veins / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology*; D011224:Prazosin / Q000494:pharmacology; D011799:Quinazolines / Q000494:pharmacology*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*; D015016:Yohimbine / Q000494:pharmacology
D011799:Quinazolines; D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; C018176:bunazosin; D009638:Norepinephrine; D011224:Prazosin