胍丁胺在大鼠输精管中的功能特性。

Functional properties of agmatine in rat vas deferens.

作者信息

Jurkiewicz N H, Garcez do Carmo L, Hirata H, da Costa Santos W, Jurkiewicz A

机构信息

Department of Pharmacology, Escola Paulista de Medicina, São Paulo, Brazil.

出版信息

Eur J Pharmacol. 1996 Jul 4;307(3):299-304. doi: 10.1016/0014-2999(96)00274-9.

DOI:10.1016/0014-2999(96)00274-9

PMID:8836618

Abstract

Experiments were performed with rat vas deferens to verify whether agmatine, an endogenous ligand for adrenoceptors and imidazoline receptors, can influence sympathetic neurotransmission, with respect to contractions induced by transmural nerve stimulation, contractions induced by exogenous noradrenaline, and overflow of endogenous noradrenaline. It was shown that agmatine (a) caused a dose-dependent potentiation of electrically induced twitches, up to about 70% in relation to controls, (b) shifted to the right the inhibitory concentration-response curves for clonidine on electrically induced twitches, indicating competitive antagonism at presynaptic alpha-adrenoceptors, with a pA2 value of 4.12 +/- 0.10, (c) shifted to the right the concentration-response curves for noradrenaline-induced contractions, indicating competitive antagonism at postsynaptic alpha-adrenoceptors as well, with a pA2 value of 4.03 +/- 0.10, and (d) caused a dose-dependent increase of KCI-induced overflow of noradrenaline, up to about 90% in relation to controls. It is concluded that agmatine has multiple effects on sympathetic neurotransmission in rat vas deferens.

摘要

利用大鼠输精管进行实验，以验证胍丁胺（一种肾上腺素能受体和咪唑啉受体的内源性配体）是否会影响交感神经传递，具体涉及经壁神经刺激诱发的收缩、外源性去甲肾上腺素诱发的收缩以及内源性去甲肾上腺素的溢出。结果表明，胍丁胺（a）引起电诱发抽搐的剂量依赖性增强，相对于对照组最高可达约70%；（b）使可乐定对电诱发抽搐的抑制浓度-反应曲线右移，表明在突触前α-肾上腺素能受体处存在竞争性拮抗作用，pA2值为4.12±0.10；（c）使去甲肾上腺素诱发收缩的浓度-反应曲线右移，表明在突触后α-肾上腺素能受体处也存在竞争性拮抗作用，pA2值为4.03±0.10；（d）引起氯化钾诱发的去甲肾上腺素溢出呈剂量依赖性增加，相对于对照组最高可达约90%。由此得出结论，胍丁胺对大鼠输精管的交感神经传递具有多种作用。