Okabe S, Woch G, Kubin L
Department of Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104.
Neuroreport. 1994 Dec 20;5(18):2573-6. doi: 10.1097/00001756-199412000-00042.
There is little information on GABAB receptor-mediated effects on orofacial motoneurons. We recorded the inspiratory activity from both hypoglossal (XII) nerves in urethane-anesthetized, paralyzed, vagotomized and artificially ventilated rats. A GABAB receptor agonist, baclofen, or antagonist, CGP-35348, was microinjected into one XII nucleus. Baclofen rapidly reduced the XII nerve activity in a dose-dependent manner by over 50%. The antagonist caused a delayed suppression of activity by 40%. We conclude that: (1) GABAB receptors within the XII nucleus may suppress the activity of inspiratory XII motoneurons, but they are not tonically active under the conditions of our experiment; (2) there is a net endogenous excitatory effect in XII motoneurons that is mediated by GABAB receptors located in the reticular formation surrounding the XII nucleus.
关于γ-氨基丁酸B（GABAB）受体对口腔面部运动神经元的介导作用，目前所知甚少。我们在经氨基甲酸乙酯麻醉、麻痹、迷走神经切断并人工通气的大鼠中，记录了双侧舌下神经（XII）的吸气活动。将GABAB受体激动剂巴氯芬或拮抗剂CGP - 35348微量注射到一侧舌下神经核中。巴氯芬以剂量依赖的方式迅速使舌下神经活动降低超过50%。拮抗剂导致活动延迟抑制40%。我们得出以下结论：（1）舌下神经核内的GABAB受体可能抑制吸气性舌下运动神经元的活动，但在我们的实验条件下它们并非持续活跃；（2）舌下运动神经元存在一种由位于舌下神经核周围网状结构中的GABAB受体介导的内源性兴奋净效应。
