Peng Y B, Lin Q, Willis W D
Department of Anatomy and Neurosciences, University of Texas Medical Branch, Galveston 77555-1069, USA.
Brain Res. 1996 Oct 14;736(1-2):189-201. doi: 10.1016/0006-8993(96)00668-3.
The effects of bicuculline and strychnine on the activity and periaqueductal gray (PAG)-induced inhibition of rat dorsal horn neurons of the lumbar spinal cord were tested. Extracellular single unit recordings were from 36 dorsal horn neurons near a microdialysis fiber passed through the spinal cord for drug application. The GABAA receptor antagonist, bicuculline, was tested on 19 cells, whereas the glycine receptor antagonist, strychnine, was tested on 17 cells. Both bicuculline and strychnine increased the background activity and responses to mechanical stimulation (BRUSH, PRESS, and PINCH) of the skin.06 They also significantly blocked the PAG-induced inhibition of responses to peripheral mechanical stimuli. This experiment suggests that the mechanism of PAG-induced descending inhibition of dorsal horn neuron activity involves GABA and/or glycine release in the spinal cord and that there is tonic release of these inhibitory neurotransmitters.
测试了荷包牡丹碱和士的宁对大鼠腰脊髓背角神经元活性及中脑导水管周围灰质（PAG）诱导的抑制作用。细胞外单单位记录来自36个背角神经元，这些神经元靠近一根穿过脊髓用于药物施加的微透析纤维。对19个细胞测试了GABAA受体拮抗剂荷包牡丹碱，而对17个细胞测试了甘氨酸受体拮抗剂士的宁。荷包牡丹碱和士的宁均增加了皮肤的背景活性以及对机械刺激（刷擦、按压和捏压）的反应。它们还显著阻断了PAG诱导的对周围机械刺激反应的抑制。该实验表明，PAG诱导的背角神经元活性下行抑制机制涉及脊髓中GABA和/或甘氨酸的释放，并且这些抑制性神经递质存在紧张性释放。
