Hay M, Bishop V S
Department of Pharmacology, University of Texas Health Science Center, San Antonio 78284-7764.
Am J Physiol. 1991 Apr;260(4 Pt 2):H1359-64. doi: 10.1152/ajpheart.1991.260.4.H1359.
Previous studies have suggested that neurons of the area postrema may modulate cardiovascular function through an interaction at the level of the nucleus of the solitary tract (NTS). Using an in vitro brain slice preparation of the rabbit medulla, the present study investigated the electrophysiological and pharmacological effects of area postrema stimulation on NTS neuronal activity. In the majority of neurons tested (85.7%), electrical stimulation of the area postrema consistently produced either single or multiple action potentials in NTS neurons. Latency values for neurons showing single spike responses to area postrema stimulation ranged from 3.0 to 17.0 ms with an average latency of 9.3 +/- 4.3 ms. The average threshold for area postrema activation of these nonspontaneously active NTS neurons was 99.8 +/- 12 microA with a stimulus threshold range between 15 and 200 microA (n = 53). Perfusion of the slice with phentolamine (1.0 microM) or yohimbine (200 nM) blocked the area postrema-evoked action potentials, whereas perfusion of the slice with prazosin (200 nM) had no effect. These findings suggest that area postrema neurons do modulate NTS neuronal activity and that this modulation results in an increase in NTS neuronal activation.
以往的研究表明，最后区的神经元可能通过孤束核（NTS）水平的相互作用来调节心血管功能。本研究利用兔延髓的体外脑片制备，研究了最后区刺激对NTS神经元活动的电生理和药理学效应。在大多数被测试的神经元（85.7%）中，最后区的电刺激始终在NTS神经元中产生单个或多个动作电位。对最后区刺激表现出单个尖峰反应的神经元的潜伏期值在3.0至17.0毫秒之间，平均潜伏期为9.3±4.3毫秒。这些非自发性活动的NTS神经元的最后区激活平均阈值为99.8±12微安，刺激阈值范围在15至200微安之间（n = 53）。用酚妥拉明（1.0微摩尔）或育亨宾（200纳摩尔）灌注脑片可阻断最后区诱发的动作电位，而用哌唑嗪（200纳摩尔）灌注脑片则没有效果。这些发现表明，最后区神经元确实调节NTS神经元活动，并且这种调节导致NTS神经元激活增加。
