α-激动剂对跨壁神经刺激反应的增强作用：在体内的一种可能作用。

Potentiation of the responses to transmural nerve stimulation by alpha-agonists: a possible role in vivo.

作者信息

Senaratne M P, Jayakody R L, Kappagoda C T

出版信息

Can J Physiol Pharmacol. 1987 Mar;65(3):427-32. doi: 10.1139/y87-072.

Abstract

This study was undertaken to assess the effects of exogenous alpha-agonists on the effector response to transmural nerve stimulation in canine saphenous vein rings. The response to a fixed train (5 s duration) of transmural nerve stimulation (8 Hz, 0.3 ms, 9 V) applied every 5 min was determined in the control state and in the presence of subthreshold (for contraction) concentrations of noradrenaline, adrenaline, clonidine, and methoxamine. The maximum potentiations achieved by the three drugs were 246.2 +/- 36.9, 220.5 +/- 38.8, 384.3 +/- 78.7, and 353.3 +/- 68.0%, respectively. The potentiation observed was significantly inhibited by indomethacin (10(-6) mol/L) and propranolol (5 X 10(-6) mol/L). Both indomethacin and propranolol potentiated the response to transmural nerve stimulation. The potentiation of the responses to transmural nerve stimulation by alpha-agonists suggests that, presynaptic alpha 2-inhibition by circulating catecholamines is likely to be of limited biological significance in modulating the effector responses in the canine saphenous vein.

摘要

本研究旨在评估外源性α-激动剂对犬隐静脉环跨壁神经刺激效应反应的影响。在对照状态下以及存在阈下（引起收缩）浓度的去甲肾上腺素、肾上腺素、可乐定和甲氧明的情况下，测定每5分钟施加一次的固定时长（5秒）跨壁神经刺激（8赫兹，0.3毫秒，9伏）的反应。三种药物所达到的最大增强幅度分别为246.2±36.9%、220.5±38.8%、384.3±78.7%和353.3±68.0%。观察到的增强作用被吲哚美辛（10⁻⁶摩尔/升）和普萘洛尔（5×10⁻⁶摩尔/升）显著抑制。吲哚美辛和普萘洛尔均增强了对跨壁神经刺激的反应。α-激动剂对跨壁神经刺激反应的增强表明，循环儿茶酚胺对突触前α₂的抑制在调节犬隐静脉的效应反应中可能具有有限的生物学意义。