Effects of heroin on regulation of painful perception in hippocampus neurons of rat / 中华行为医学与脑科学杂志

ABSTRACT

ObjectiveThe heroin-dependent animal model of rats was used to investigate the effects ofheroin on regulation of pain perception in the dorsal and ventral hippocampus of the heroin-dependent rats. Meth odsHeroin was injected subcutaneously twice a lay for 9 days according to the principle of daily increasing dose in the Sprague-Dawley rats. From the 10th day,rats were given heroin at dose of 27 mg · kg-1 once a day until the14th day, then the unit discharges of the dorsal and ventral hippocampus of rats were observed respectively afternoxious electric stimulation of the rat-tail by the extracellular single-unit recording with glass microelectrodes. ResultsWhen given noxious stimulation, most of the neurons in the dorsal hippocampus in the heroin-dependent ratswere unaffected(59.09％ ) ,whereas in the control rats ,the ratio of the neurons of the dorsal hippocampus affectedby noxious stimulation was about 66.67％, respectively(P ＜ 0.05 ). However,in the ventral hippocampus, the ratioof the neurons activated,inhibitory or unaffected was 20. 69％ ,41.38％ and 37.93％ from the control and was40.74％ ,33. 33％ and 25.93％ from the heroin group respectively with no significant difference between two groups (P ＞ 0.05 ) . ConclusionHeroin changed the regulation of pain perception in the hippocampus,primarily the dorsal hippocampus of rats.