Role of GABAA receptors in dorsal raphe nucleus in stress-induced reinstatement of morphine-conditioned place preference in rats.

摘要: The serotonin (5-hydroxytryptamine, 5-HT) system plays an important role in stress-related psychiatric disorders and substance abuse. Our data indicate that stress inhibits the dorsal raphe nucleus (DRN)-5-HT via stimulation of GABA synaptic activity by neurohormone corticotropin-releasing factor and, more recently, morphine history sensitizes DRN-5-HT neurons to GABAergic inhibitory effects stress. We tested hypothesis DRN GABAA receptors contribute stress-induced reinstatement morphine-conditioned place preference (CPP). First, we if activation would reinstate CPP. Second, blockade attenuate swim CPP was induced (5 mg/kg) a 4-day conditioning phase followed test. Upon acquiring criteria, subjects underwent 4 days extinction training animals For first experiment, receptor agonist muscimol (50 ng) or vehicle injected into prior second antagonist bicuculline (75 ng) forced stress, then, were for Intraraphe injection reinstated CPP, while intraraphe attenuated reinstatement. These provide evidence receptor-mediated inhibition serotonergic contributes