Study on sympathetic purinergic transmission in blood vessels

电刺激狗离体肠系膜动脉，引起一种由肾上腺素能和非肾上腺素能成分组成的短暂收缩。与肾上腺素能成分相反，非肾上腺素能成分对哌唑嗪和其他肾上腺素受体阻滞剂耐药。然而，非肾上腺素能成分被乙啶和用，-亚甲基ATP脱敏P_2-嘌呤受体完全阻断<beta>。P_2-嘌呤受体的脱敏也抑制ATP引起的收缩反应，但不抑制电透壁刺激和外源性去甲肾上腺素引起的肾上腺素能反应。这些结果表明，电跨壁刺激引起的非肾上腺素能收缩是一种交感嘌呤能反应。在狗的大脑中动脉和基底动脉以及肠系膜静脉、门静脉和隐静脉中均观察到这种嘌呤能反应，提示交感嘌呤能传递在循环系统中可能具有重要的生理作用。

Electrical transmural stimulatin of isolated mesenteric artery of the dog produced a transient contractin which consisted of adrenergic and non-adrenergic components. In contrast to the adrenergic component, the nonadrenergic component was resistant to prazosin and other adrenoceptor-blocking agents. However, the nonadrenergic component was completely blocked by guanethidine and by desensitization of P_2-purinoceptors with ,<beta>-methylene ATP. Desensitization of P_2-purinoceptors also inhibited the contractile response to ATP but not the adrenergic responses induced by electrical transmural stimulation and exogenous noradrenaline. These results suggest that the nonadrencergic contraction induced by electrical transmural stimulation is a sympathetic, purinergic response. Such purinergic responses were observed in the dog basilar and middle cerebral arteries andin the mesenteric, portal and saphenous veins, suggesting that the sympathetic purinergic transmission may paly a physiologically important role in the circulatory system.