Iarushkina N I, Bagaeva T R, Filaretova L P
Ross Fiziol Zh Im I M Sechenova. 2011 Dec;97(12):1327-35.
Corticotropin-releasing factor (CRF) participates in development of stress-induced analgesia. Midbrain periaqueductal grey matter (MPAG) is one of crucial structures of the brain antinociceptive system. The aim of the study was to investigate effects of the CRF administration into the MPAG on pain sensitivity in alert rats and contribution of opioid mechanisms to these CRF-induced effects. Somatic pain sensitivity was tested by tail flick response latency following thermal stimuli. The opioid antagonist naltrexone administered systemically or centrally into the MPAG was used to study involvement ofopioid mechanisms in the CRF-induced effects. The CRF administration (0.7 microg/rat) into the MPAG caused analgesic effect. The CRF-induced analgesic effects were eliminated by systemic as well as central naltrexone pretreatment. Effect of central naltrexone on the CRF-induced analgesia manifested itself faster as compared with effect of systemic naltrexone. The data obtained suggest that one of central mechanisms of the CRF-induced analgesic effect on somatic pain sensitivity in alert rats may be mediated by the MPAG neurons and provided by involvement of opioid mechanisms.
促肾上腺皮质激素释放因子（CRF）参与应激诱导镇痛的形成。中脑导水管周围灰质（MPAG）是脑内抗痛觉系统的关键结构之一。本研究旨在探讨向MPAG内注射CRF对清醒大鼠痛觉敏感性的影响以及阿片类机制在这些CRF诱导效应中的作用。通过热刺激后甩尾反应潜伏期来测试躯体痛觉敏感性。全身或向MPAG内注射阿片类拮抗剂纳曲酮，以研究阿片类机制在CRF诱导效应中的参与情况。向MPAG内注射CRF（0.7微克/只大鼠）可产生镇痛作用。全身及向MPAG内预先注射纳曲酮均可消除CRF诱导的镇痛作用。与全身注射纳曲酮相比，向MPAG内注射纳曲酮对CRF诱导镇痛的作用起效更快。所得数据表明，CRF对清醒大鼠躯体痛觉敏感性产生镇痛作用的中枢机制之一可能由MPAG神经元介导，并涉及阿片类机制。
