兔耳动脉的交感性血管收缩对α肾上腺素能受体拮抗剂的部分阻抗(英文)

Sympathetic vasoconstriction of the rabbit ear artery: partial resistance to alpha-adrenergic receptor antagonists

本文利用离体组织灌流技术,对刺激家兔颈上神经节内壁交感神经引起兔耳中央动脉收缩的本质进行探讨,α受体拮抗剂仅部分阻断跨壁神经刺激(TNS)引起的收缩,若预先使用利血平耗竭离体血管内源性儿茶酚胺,由TNS引起的此种家兔耳中央动脉收缩则明显减弱,与此同时,α受体拮抗剂却增强了后期(residual)收缩反应,这种增强作用可能是因突触前膜α受体同时被阻断而引起,由此可见,交感神经冲动引起的家兔耳中央动脉收缩绝大部分是由去甲肾上腺素(NE)介导的,但后期收缩反应则可能是由另一种不明递质所介导,而这种属于外周循环系统的耳动脉交感神经与血管之间冲动传递方式又有别于大脑动脉的传递方式。

Constriction of isolated central arteries of the rabbit ear upon excitation of the intramural sympathetic neurons of superior cervical ganglionic origin was examined, using an in vitro tissue bath technique. The transmural nerve stimulation-induced contractions were only partially blocked by a receptor antagonists. In arteries taken from animals pretreated with reserpine to deplete the endogenous cate cholamine, TNS-induced constrictions were significantly decreased. The residual constrictions, however, were potentiated by a adrenergic receptors antagonists. The potentiation probably resulted from inhibition of presynaptic a adrenergic receptors. It is concluded that the neurogenic sympathetic vasoconstriction of the rabbit ear artery was largely mediated by norepinephrine, but that a small component may be mediated by a second unidentified transmitter. The sympathetic neurovascular transmission to the peripheral ear artery is different from that to the cerebral artery.