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用脊髓薄片全细胞电压钳法观察激活γ 氨基丁酸B亚型受体 (GABABR)对大鼠脊髓背角胶状质(SG)神经元活动的影响。选择性GABABR激动剂baclofen减少所有被记录SG神经元 (n =15)的微小兴奋性突触后电流 (mEPSCs)的发放频率 ,同时引起一缓慢的抑制性 (外向 )膜电流并伴有膜电导增加。细胞内电泳G蛋白偶联受体抑制剂 (GDP β S)抑制被钳制神经元的G蛋白偶联受体后 ,baclofen引起的缓慢外向电流被抑制 ,但对mEPSC频率的减低作用依然存在。结果提示脊髓内baclofen敏感的GABAB 受体被激活后直接引起SG神经元超极化并能减少突触前递质的释放
Effect of γ - aminobutyric acid B subunit receptor (GABABR) on the activity of neurons in the dorsal horn of rat spinal dorsal horn was observed by means of whole - cell patch clamp method. The selective GABABR agonist baclofen reduced the frequency of release of minute excitatory postsynaptic currents (mEPSCs) for all recorded SG neurons (n = 15), while causing a slow inhibitory (extrinsic) membrane current accompanied by membrane conductance increase. Inhibition of intracellular G protein-coupled receptor inhibitor (GDPβS) inhibition of the G protein-coupled receptors of the clamped neurons was inhibited by baclofen-induced slow outward currents, but the reduction in mEPSC frequency was still present. The results suggest that activation of baclofen-sensitive GABAB receptors in the spinal cord directly leads to hyperpolarization of SG neurons and reduces the presynaptic release