Chan P K, Chan S C, Yung W H
Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin.
Neuroreport. 1998 Mar 9;9(4):671-5. doi: 10.1097/00001756-199803090-00020.
Whole-cell patch-clamp recordings were made from substantia nigra pars reticulata (SNR) neurones in rat midbrain slices to investigate the electrophysiological effects of cannabinoids. The cannabinoid receptor agonist WIN 55212-2 (10 microM) significantly reduced intranigrally evoked and spontaneous inhibitory post-synaptic currents (IPSCs) which were mediated by GABA(A) receptors. The postsynaptic current induced by bath application of GABA was not affected by the presence of WIN 55212-2. The actions of WIN 55212-2 were not mimicked by the inactive enantiomer WIN 55212-3. WIN 55212-2 also hyperpolarized the membrane of SNR neurones in a tetrodotoxin/0-Ca2+-insensitive manner. These data suggest that cannabinoids modulate the activity of SNR neurones by presynaptic inhibition of GABA inputs. They may also exert a direct post-synaptic inhibition on these neurones.
采用全细胞膜片钳记录技术，对大鼠中脑切片黑质网状部（SNR）神经元进行记录，以研究大麻素的电生理效应。大麻素受体激动剂WIN 55212-2（10微摩尔）显著降低了由GABA(A)受体介导的黑质内诱发的和自发的抑制性突触后电流（IPSCs）。通过浴灌应用GABA诱导的突触后电流不受WIN 55212-2存在的影响。WIN 55212-2的作用不能被无活性对映体WIN 55212-3模拟。WIN 55212-2还以河豚毒素/零钙不敏感的方式使SNR神经元的膜超极化。这些数据表明，大麻素通过对GABA输入的突触前抑制来调节SNR神经元的活动。它们也可能对这些神经元施加直接的突触后抑制作用。
