中脑导水管周围灰质内微量注射神经肽Y减弱慢性神经痛大鼠对伤害性刺激的反应

探讨神经肽Y(neruopride Y, NPY) 在SD大鼠中脑导水管周围灰质 (periaqueductal grey, PAG) 对伤害性刺激反应的作用.应用热板和机械压力实验法,以大鼠后爪缩爪瓜潜伏期(paw withdrawal latency, PWL) 为痕阈指标, 观察PAG 内微量注射NPY对PWLs的影响.PAG内注射 0.05、0.1、 0.2 nmol NPY 均显著地增加慢性神经痛大鼠的双侧PWLs, 且呈量效关系.NPY引起的PWLs增加可被Y1受体拮抗剂和阿片剂所阻断.结果提示,在大鼠PAG 微量注射NPY可产生明显的镇痛作用.

Microinjection of neuropeptide Y into periaqueductal grey produces anti-nociception in rats with mononeuropathy

The present study was carried out to investigate the effects of neuropeptide Y (NPY) in the midbrain periaqueductalgrey (PAG) on the nociceptive modulation in mononeuropathic rats. NPY was microinjected into the PAG. The latency of pawwithdrawal (PWL), assessed by the hot-plate (52℃) and the Randall Selitto test, was measured. Intra-PAG administration of 0.05,0.1 and 0.2 nmol of NPY significantly increased the PWLs in a dose-dependent manner. Co-administration of 0.2 nmol of NPY28-36 and5.5 nmol of naloxone significantly attenuated the NPY-induced increase in PWLs. The results suggest that Y1 receptor may mediateNPY-induced anti-nociception, and that the opioid receptors in PAG may also be involved in this process in mononeuropathic rats.