利血平预处理对输精管神经效应器传递的影响。

Effects of reserpine pretreatment on neuroeffector transmission in the vas deferens.

Cunnane T C, Manchanda R

University Department of Pharmacology, Oxford, UK.

Clin Exp Pharmacol Physiol. 1989 Jun;16(6):451-5. doi: 10.1111/j.1440-1681.1989.tb01586.x.

Abstract

The effects of reserpine pretreatment on neurotransmission in the guinea-pig vas deferens have been re-examined with a view to study the role of noradrenaline (NA) in mediating postjunctional electrical responses and, in particular, excitatory junction potentials (EJP). 2. Reserpine (5 mg/kg, i.p.) caused almost total depletion (below detection levels) of the NA content of the vas deferens. However, spontaneous and evoked excitatory junction potentials (SEJP, EJP) and currents (SEJC, EJC) could still be recorded in NA-depleted tissues. The amplitude distribution of SEJC in control and reserpinized tissues was similar. 3. Facilitation of EJP and EJC was markedly slowed in reserpinized tissues, EJP taking 50-60 pulses to facilitate fully. However the amplitudes of fully facilitated EJP were comparable to EJP recorded in control tissues. 4. EJPs in reserpinized vasa deferentia were unaffected by the NA synthesis inhibitor, alpha-methyl tyrosine, but were abolished in the presence of the stable ATP analogue alpha,beta-methylene ATP which desensitizes postjunctional P2-purinoceptors. 5. Local application of ATP, but not NA, mimicked the EJP. These results indicate that EJP are mediated by a non-noradrenergic neurotransmitter possibly ATP.

摘要

为了研究去甲肾上腺素（NA）在介导节后电反应尤其是兴奋性接头电位（EJP）中的作用，我们重新研究了利血平预处理对豚鼠输精管神经传递的影响。2. 利血平（5毫克/千克，腹腔注射）几乎使输精管中的NA含量完全耗尽（低于检测水平）。然而，在NA耗尽的组织中仍可记录到自发和诱发的兴奋性接头电位（SEJP、EJP）及电流（SEJC、EJC）。对照组织和经利血平处理的组织中SEJC的幅度分布相似。3. 在经利血平处理的组织中，EJP和EJC的易化明显减慢，EJP需要50 - 60个脉冲才能完全易化。然而，完全易化后的EJP幅度与对照组织中记录到的EJP相当。4. 经利血平处理的输精管中的EJP不受NA合成抑制剂α-甲基酪氨酸的影响，但在稳定的ATP类似物α,β-亚甲基ATP存在时被消除，α,β-亚甲基ATP会使节后P2嘌呤受体脱敏。5. 局部应用ATP而非NA可模拟EJP。这些结果表明EJP由一种可能是ATP的非去甲肾上腺素能神经递质介导。