血管紧张素Ⅱ在脊髓水平对吗啡作用的影响

INFLUENCE OF ANGIOTENSIN ⅡON THE INHIBITORY EFFECT OFMORPHINEON SPINAL DORSAL HORN NEURONS IN RAT

本工作以玻璃微电极记录脊髓腰段（Ｌ２－３）背角神经元电活动，观察血管紧张素Ⅱ（ＡⅡ）对其伤害性诱发放电的影响，并探讨ＡⅡ与吗啡抑制效应的相互关系。结果表明，ＡⅡ５０－５００ｎｇ脊髓表面微量滴注对背角神经元伤害性诱发放电主要为抑制效应，而ＡⅡ２μｇ为易化效应；注射吗啡（５ｍｇ／ｋｇ，ｉｐ）后１０ｍｈ；ＡⅡ２５０ｎｇ脊髓表面微量滴注不能对抗吗啡的抑制作用，而ＡⅡ２一４μｇ则能部分或完全抵消吗啡对背角神经元伤害性诱发放电的抑制作用。本工作提示，ＡⅡ可调制脊髓背角神经元对外周传入的伤害性反应；较大剂量ＡⅡ可对抗吗啡对伤害性诱发放电的抑制作用。

The nociceptive evoked discharges of spinal dorsal horn neurons were extracellularly re-corded by glass microelectrodes.The changes of nociceptive discharges in response to angiotensinⅡ(A Ⅱ)and the influence of AⅡon the inhibitory effect induced by morphine were observed.The results indicated that the nociceptive evoked discharges of spinal dorsal horn neurons weremainly inhibited by A Ⅱ 50-500ng applied to the surface of spinal cord and facilitated by A Ⅱ2μg. The inhibitory effect induced by morphine was counteracted by 2-4μg AⅡapplied to thesurface of spinal cord,but 250 ng A Ⅱ could not counteract the inhibitory effect induced by mor-phine. It is considered from the above results that A Ⅱ can modulate the peripheral nociceptivemessages of spinal dorsal horn neurons and influence the inhibitory effect induced by morphine.