[The role of accumbens nucleus in the inhibitory effect of somatic afferent inputs on the defence cardiovascular response and its mechanism].

After Accumbens Nucleus (AC) lesion, the inhibitory effect of deep peroneal nerve (DPN) on the pressor response and ECG-ST changes induced by excitation of dorsomedial nucleus of hypothalamus (DMH) was decreased as compared with that of before lesion (P < 0.05, P < 0.01). Electrical stimulation of AC could elicit prominent depressor response, which could be effectively lessened by microinjection of naloxone into ventral periaqueductal gray (vPAG). Lesion of vPAG could reverse the depressor response to AC stimulation to a slight pressor response (P < 0.01). After lesion of arcuate nucleus of hypothalamus (ARC), the depressor response to AC stimulation almost disappeared, which, again, could be largely mimicked by microinjection of naloxone into ARC.