中缝隐核投射至中脑导水管周围灰质腹侧部的递质分析

TRANSMITTERS RELATED TO THE PROJECTIONS FROM NUCLEUS RAPHE OBSCURUS TO VENTRAL PERIAQUEDUCTAL GRAY

实验在戊巴比妥钠麻醉大鼠上进行。双侧中脑导水管周围灰质腹侧部（ｖＰＡＧ）微量注射１μｇ／μｌ肾上腺素（每侧０．１μｌ），刺激中缝隐核（ＮＲＯ）引起的降压反应明显增强，但该效应可被ｖＰＡＧ预先注射心得安所阻断，而注射酚妥拉明对上述效应无明显影响；ｖＰＡＧ内单独微量注射１μｇ／μｌ心得安（每侧０．１μｌ），可部分阻断ＮＲＯ降压反应，而注射１μｇ／μｌ酚妥拉明（每侧０．１μｌ）无明显影响；双侧ｖＰＡＧ微量注射１０μｇ／μｌ吗啡或０．１ｍｏｌ／Ｌ５－ＨＴ（每侧０．１μｌ），基础血压无明显变化，ＮＫＯ的降压反应幅度减小（Ｐ＜０．０５）。提示，ＮＫＯ对ｖＰＡＧ的兴奋作用的可能递质为肾上腺素，通过β受体介导；吗啡或５－ＨＴ则可减弱ＮＲＯ对ｖＰＡＧ的兴奋性投射作用。

The experiments were performed in the rats anaesthetized with pentobarbitol sodium.Bilat-eral microinjection of 1μg/μl adrenaline(0.1μl/side)into ventral periaqueductal gray(vPAG)increased the depressor response induced by stimulation of nucleus raphe obscurus(NRO)andthis effect was blocked by pretreatment with microinjection of 1μg/μl propranolol(0.1μl/side)into vPAG but not 1μg/μl phentolamine(0.1μl/side).The depressor effect of NRO stimulationwas attenuated by microinjection of 1 μg/1μl propranolol(0.1μl/side)into vPAG,but not1μg/μl phentolamine(o.l μl/side),The depressor response evoked by stimulation of NRO wasdecreased after bilateral microin扣ction of morphine(10μg/μl,0.1 μl/side)into vPAG or 5-HT(0.1mol/L,0.1μl/side) into vPAG,but no effect on the basal blood pressure was observed.It issuggested that morphine and 5-HT can reduce the activity of the excitatory pathway projectingfrom the NRO to the vPAG and the excitatory effects of the NRO on the vPAG may be mediatedby βreceptor.