Cheung D W
Br J Pharmacol. 1985 Jan;84(1):265-71.
The effects of perivascular nerve stimulation and application of exogenous alpha-adrenoceptor agonists on the rat saphenous vein were studied by simultaneous recordings of electrical and mechanical activities. The resting membrane potential of the saphenous vein averaged -65 mV. Perivascular nerve stimulation elicited excitatory junction potentials (e.j.ps) and slow depolarizations. Contraction was observed when either the e.j.p. or the slow depolarization reached a critical threshold of about -55 mV. Exogenously applied noradrenaline, B-HT 920 and clonidine induced depolarization and contraction similar to the slow depolarization. The responses to these agonists and the slow depolarizations were antagonized by yohimbine, but not by prazosin. The selective alpha 1-adrenoceptor agonists phenylephrine and methoxamine had very little effect on the electrical and mechanical activities of the saphenous vein. It was concluded that in the rat saphenous vein, only alpha 2-adrenoceptors are present and that these receptors mediate the slow depolarization and contraction induced by nerve stimulation.
通过同时记录电活动和机械活动，研究了血管周围神经刺激和外源性α-肾上腺素能受体激动剂对大鼠隐静脉的影响。隐静脉的静息膜电位平均为-65mV。血管周围神经刺激引发兴奋性接头电位（e.j.ps）和缓慢去极化。当e.j.p.或缓慢去极化达到约-55mV的临界阈值时，观察到收缩。外源性应用去甲肾上腺素、B-HT 920和可乐定诱导的去极化和收缩类似于缓慢去极化。育亨宾可拮抗对这些激动剂的反应和缓慢去极化，但哌唑嗪无此作用。选择性α1-肾上腺素能受体激动剂去氧肾上腺素和甲氧明对隐静脉的电活动和机械活动影响很小。得出的结论是，在大鼠隐静脉中，仅存在α2-肾上腺素能受体，并且这些受体介导神经刺激诱导的缓慢去极化和收缩。
