| Objective: To observe the analgesic effect of neuropeptide oxytocin in the dorsal raphe nucleus of the nodel rats on pain and its regulation.Methods: The consider of using the method of behavioral pharmacology and immunohistochemical to do. Respectively in dorsal raphe nucleus microinjection of different concentrations of oxytocin and its receptor antagonist Atosiban in normal, inflammatory and neuropathic rats. Measured and recorded after the claw rats to noxious thermal stimuli and mechanical stimulation induced hinpaw withdrawal latency, as a measure of pain level indicators, in order to study whether the analgesia effect of oxytocin in the nucleus raphe dorsalis; expression the change by using immunohistochemistry method to measure c-fos protein in dorsal raphe nucleus, action research oxytocin in the dorsal raphe nucleus.Results: The dorsal raphe nucleus microinjection of different concentrations of oxytocin in normal, inflammatory and neuropathic rats, measure and record the noxious thermal stimulation and mechanical stimulation of the hindpaw withdrawal latency, the results mean that injection of oxytocin hindpaw withdrawal latency was significantly prolonged, the effect is the best at 15 min, the analgesic effect is dose dependent; in dorsal raphe nucleus of pre injection of antagonist Atosiban can completely block the analgesic effect on the outside stimulation caused by oxytocin, and regardless of the dose in oxyticin. The results immunohistochemistry indicated that the c-fos protein in dorsal raphe nucleus, speculated that its interior has oxytocin immunoreactive products.Conclusion: Oxytocin has analgesic effect in rat dorsal raphe nucleus; its receptor antagonist Atosiban can completely antagonistic effect of oxytocin and the analgesic effect is explained by the oxytocin receptor mediated. |
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