Ebong O O
Clin Exp Pharmacol Physiol. 1986 Jan;13(1):9-16. doi: 10.1111/j.1440-1681.1986.tb00310.x.
This paper reports the effects of lowering (bath) temperature upon contractile responses of prostatic and epididymal ends of the rat isolated vas deferens to electrical field stimulation. Responses to field stimulation with single pulses at 60 s intervals were potentiated by lowering the bath temperature. This effect was maximal at temperatures of 25-27 degrees C and was reduced in preparations treated with phentolamine (5 mumol/l). Field stimulation with trains of 50 pulses at 5 Hz every 5 min produced biphasic contractions of preparations. The initial, twitch-like component, prominent at the prostatic end and resistant to blockade by phentolamine (5 mumol/l) was little affected by lowering the bath temperature from 37.5 degrees C to 19 degrees C. In contrast, the second, more prolonged, component of the response to pulse trains, which was prominent at the epididymal end of the tissue was decreased by lowering the bath temperature and by phentolamine. In the epididymal segment, responses to exogenous noradrenaline were enhanced by lowering the bath temperature. It is concluded that lowering the bath temperature enhances the contractility of the vas deferens in response to the release of neurotransmitters and to the application of exogenous noradrenaline via a postsynaptic action. In addition, via a presynaptic action, lowering the bath temperature depresses or delays the release of the noradrenergic transmitter from the sympathetic nerve terminals.
本文报道了降低（浴槽）温度对大鼠离体输精管前列腺端和附睾端电场刺激收缩反应的影响。每隔60秒用单个脉冲进行电场刺激时，降低浴槽温度可增强反应。此效应在25 - 27摄氏度时最大，在用酚妥拉明（5微摩尔/升）处理的标本中则减弱。每5分钟以5赫兹频率施加50个脉冲串进行电场刺激时，标本会产生双相收缩。最初的类似抽搐的成分在前列腺端较为突出，且不受酚妥拉明（5微摩尔/升）阻断的影响，将浴槽温度从37.5摄氏度降至19摄氏度对其影响很小。相反，对脉冲串反应的第二个持续时间更长的成分在组织的附睾端较为突出，降低浴槽温度和使用酚妥拉明会使其减弱。在附睾段，降低浴槽温度可增强对外源性去甲肾上腺素的反应。结论是，降低浴槽温度可通过突触后作用增强输精管对神经递质释放和外源性去甲肾上腺素应用的收缩性。此外，通过突触前作用，降低浴槽温度会抑制或延迟去甲肾上腺素能递质从交感神经末梢的释放。
