O'Rourke S T, Vanhoutte P M
Department of Physiology and Biophysics, Mayo Clinic, Rochester, Minnesota.
J Pharmacol Exp Ther. 1989 Apr;249(1):52-5.
Experiments were performed to determine the effect of ergonovine on adrenergic neurotransmission in the blood vessel wall. Strips of canine left circumflex coronary arteries and saphenous veins were incubated with [3H]norepinephrine and suspended for superfusion. Ergonovine (10(-6) M) decreased the overflow of [3H] norepinephrine to a modest degree in the coronary artery, whereas a profound inhibition of overflow was observed in the saphenous vein. Methiothepin, but not rauwolscine, reversed the inhibitory effect of ergonovine in both blood vessels. Treatment with atropine or droperidol did not alter the response to ergonovine in the coronary artery. The results demonstrate that ergonovine, by activating prejunctional serotonergic receptors, inhibits adrenergic neurotransmission to a greater extent in the saphenous vein than in the coronary artery. The differential effect of ergonovine on norepinephrine release in these vessels may provide evidence for heterogeneity in the prejunctional modulation of adrenergic neurotransmission.
进行实验以确定麦角新碱对血管壁肾上腺素能神经传递的影响。将犬左回旋冠状动脉和大隐静脉条与[3H]去甲肾上腺素一起孵育，并悬浮以进行灌流。麦角新碱（10^(-6) M）在冠状动脉中使[3H]去甲肾上腺素的溢出量适度降低，而在大隐静脉中观察到溢出的显著抑制。甲硫噻嗪而非育亨宾可逆转麦角新碱在两种血管中的抑制作用。用阿托品或氟哌利多处理并未改变冠状动脉对麦角新碱的反应。结果表明，麦角新碱通过激活节前5-羟色胺能受体，在大隐静脉中比在冠状动脉中更能抑制肾上腺素能神经传递。麦角新碱对这些血管中去甲肾上腺素释放的不同作用可能为肾上腺素能神经传递的节前调节异质性提供证据。
