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Facilitation of rat tall-flick reflex by intrathecal thyrotropin releasing hormone and its interaction with morphine

Tan Dongping, Zou Gang

Shanghai Institute of Maleria Medica, Academia Sinica. Shanghai, China

Abstract

In this experiment, the direct spinal effect of TRH on tail-flick reflex and its interaction with morphine were studied by intrathecal injection according to Yaksh and Rudy (1976). Intrathecal injection of 1 #mu#g, 5 #mu#g or 10 #mu#g of TRH produced a dose-related long lasting shortening of tail-flick latency..Either intrathecal or subcutaneous morphine could induce its full analgesic effect in spite of the presence of intrathecal TRH. When morphine was injected first, intrathecal TRH was unable to reverse the morphine prolongation of tail-flick latency. These results suggest that TRH acts on spinal elements closer to the efferent side, while morphine acts on spinal elements closer to the afferent side.

Key words: TRH;Morphine;Tail-flick latency;Intrathecal injection

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Citing This Article：

Tan Dongping, Zou Gang. Facilitation of rat tall-flick reflex by intrathecal thyrotropin releasing hormone and its interaction with morphine. Acta Physiol Sin 1985; 37 (2): (in Chinese with English abstract).