Yu L C, Han J S
Department of Physiology, Beijing Medical University, China.
Int J Neurosci. 1989 Sep;48(1-2):71-8. doi: 10.3109/00207458909002152.
The present study was performed to explore the possible involvement of the arcuate nucleus of hypothalamus (ARH) and beta-endorphinergic pathway in the connection from nucleus accumbens to periaqueductal grey (PAG). It was found that the analgesic effect of morphine administered to nucleus accumbens of the rabbit was significantly attenuated by the antiserum against beta-endorphin (beta-EP) injected into PAG. The antagonistic effect was totally abolished by lesioning of the ARH. However, in the rabbit with ARH lesioning, no significant change in basal nociceptive threshold was seen nor was there any significant change in the efficacy of analgesia induced by injecting morphine into nucleus accumbens. The latter effect was attenuated by intra-PAG-administered naloxone, as in the normal control rabbits. These results indicate that (1) ARH and its efferent beta-endorphinergic fibers are involved in the descending pathway from the nucleus accumbens to PAG, subserving an antinociceptive effect, (2) endogenous opioid peptides other than beta-EP seem to play an equally important role in mediating analgesia.
本研究旨在探讨下丘脑弓状核（ARH）和β-内啡肽能通路在伏隔核与导水管周围灰质（PAG）连接中的可能作用。研究发现，向兔PAG注射抗β-内啡肽（β-EP）抗血清可显著减弱向兔伏隔核注射吗啡的镇痛效果。损毁ARH可完全消除这种拮抗作用。然而，在损毁ARH的兔中，基础痛觉阈值未见明显变化，向伏隔核注射吗啡诱导的镇痛效果也无显著变化。与正常对照兔一样，PAG内注射纳洛酮可减弱后一种效应。这些结果表明：（1）ARH及其传出的β-内啡肽能纤维参与了从伏隔核到PAG的下行通路，发挥抗伤害感受作用；（2）除β-EP外，内源性阿片肽在介导镇痛中似乎起着同样重要的作用。
