中脑导水管周围灰质内微量注射神经肽γ减弱慢性神经痛大鼠对伤害性刺激的反应

探讨神经肽Y(neuropeptide 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,以大鼠后爪缩爪反应潜伏期(paw withdrawal latency,PWL)为痛阈指标。观察PAG内微量注射NPY对PWLS的影响。PAG内注射0．05、0．1、0．2nmol 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受体拮抗剂和阿片受体拮抗剂所阻断。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 periaqueductal grey (PAG) on the nociceptive modulation in mononeuropathic rats. NPY was microinjected into the PAG. The latency of paw withdrawal (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 NPY(28-36) and 5.5 nmol of naloxone significantly attenuated the NPY-induced increase in PWLs. The results suggest that Y(1) receptor may mediate NPY-induced anti-nociception, and that the opioid receptors in PAG may also be involved in this process in mononeuropathic rats.