Clement M E, McCall R B
Upjohn Company, Kalamazoo, MI 49001.
Brain Res. 1993 May 28;612(1-2):78-84. doi: 10.1016/0006-8993(93)91646-a.
This study examined the effects of kainic acid and NMDA microinjections into the lateral tegmental field on the sympatholytic effect of the 5-HT1A agonist 8-OH-DPAT. Kainic acid has been reported to destroy cell bodies while leaving fibers of passage intact while NMDA excites the cell bodies but not the axons of neurons. Microinjection of kainic acid was found to block the usual sympatholytic effect of 8-OH-DPAT but not the sympathoinhibition produced by the alpha 2 agonist clonidine. Microinjection of NMDA elicited profound pressor responses related to an increase in sympathetic activity. Sympatholytic effects of 8-OH-DPAT and clonidine were transiently overridden by microinjections of NMDA, but not glutamate. A role for the lateral tegmental field in the generation of sympathetic tone and in the sympatholytic mechanism of 8-OH-DPAT is supported by the chemical lesion and stimulation studies.
本研究考察了向外侧被盖区微量注射海藻酸和N-甲基-D-天冬氨酸（NMDA）对5-羟色胺1A（5-HT1A）受体激动剂8-羟基二丙胺基四氢萘（8-OH-DPAT）的抗交感神经作用的影响。据报道，海藻酸可破坏细胞体，而使传入纤维保持完整，而NMDA可兴奋细胞体，但不兴奋神经元轴突。研究发现，微量注射海藻酸可阻断8-OH-DPAT通常的抗交感神经作用，但不阻断α2激动剂可乐定产生的交感神经抑制作用。微量注射NMDA可引发与交感神经活动增加相关的强烈升压反应。微量注射NMDA可短暂抵消8-OH-DPAT和可乐定的抗交感神经作用，但谷氨酸无此作用。化学损伤和刺激研究支持外侧被盖区在交感神经张力产生及8-OH-DPAT抗交感神经机制中的作用。
