Arginine8-vasopressin affects catecholamine metabolism in specific brain nuclei

Following the i.c.v. administration of arginine⁸-vasopressin (30 ng in 1 μl saline) to rats that had been injected i.p with α-MPT 30 min prior to the administration of the peptide catecholamine metabolism was altered in a restricted number of brain nuclei. Noradrenaline disappearance was accelerated as compared to saline treated controls in the dorsal septal nucleus, the anterior hypothalamic nucleus, the medial forebrain bundle, the parafascicular nucleus, the dorsal raphe nucleus, the locus coeruleus, the nucleus tractus solitarii and the Al-region. In the supraoptic nucleus and the nucleus ruber a decreased noradrenaline disappearnce was observed after the administration of the peptide. Dopamine disappearance was accelerated in the caudate nucleus, the median eminence, the dorsal raphe nucleus and the A8-region. These results support the view that vasopressin is participating in the regulation of a variety of physiological processes by modulating neurotransmission in specific brain nuclei.