Feldman P D, Felder R B
Department of Internal Medicine, College of Medicine, University of Iowa, Iowa City 52242.
Brain Res. 1989 Feb 20;480(1-2):190-7. doi: 10.1016/0006-8993(89)91582-5.
These studies examined the effects of the alpha-adrenergic agonist clonidine on spontaneous and synaptically evoked activity in the solitary tract nucleus in superfused rat brain slices. In one group of neurons which showed no spontaneous spike activity (n = 27), clonidine superfusion induced a dose-dependent increase of postsynaptic responsiveness to input from the ipsilateral solitary tract. In another group of neurons which were spontaneously active but unresponsive to tract input (n = 20), clonidine induced a dose-dependent depression of spontaneous discharge. A third group of neurons which were both spontaneously active and responsive to tract input (n = 11) showed primarily a depression of both activities. The neuronal responses to clonidine in all 3 groups were selectively blocked by the alpha 2-adrenoceptor antagonist yohimbine but not by the alpha 1-antagonist prazosin. These results provide insight into the possible actions of endogenous adrenergic systems in the synaptic processing of afferent sensory information within the solitary tract nucleus.
这些研究考察了α-肾上腺素能激动剂可乐定对灌流大鼠脑片孤束核中自发活动和突触诱发活动的影响。在一组无自发峰活动的神经元中（n = 27），灌流可乐定可使对同侧孤束输入的突触后反应性呈剂量依赖性增加。在另一组自发活动但对孤束输入无反应的神经元中（n = 20），可乐定可使自发放电呈剂量依赖性抑制。第三组既自发活动又对孤束输入有反应的神经元（n = 11），两种活动主要都受到抑制。所有3组神经元对可乐定的反应均被α2-肾上腺素能受体拮抗剂育亨宾选择性阻断，而未被α1-拮抗剂哌唑嗪阻断。这些结果为内源性肾上腺素能系统在孤束核内传入感觉信息的突触处理中的可能作用提供了见解。
