Effect of oxytocin and vasopressin on memory consolidation: sites of action and catecholaminergic correlates after local microinjection into limbic-midbrain structures.
The effects of local postlearning microinjections of arginine-vasopressin (AVP) and oxytocin (OXT) on one-trial learning passive avoidance behavior and the influence of AVP on alpha-MPT-induced disappearance of norepinephrine (NE) and dopamine (DA) in discrete brain regions have been studied in the rat. OXT injected bilaterally in the hippocampal dentate gyrus (25-25 pg) or in the midbrain dorsal raphe nucleus (50 pg) significantly attenuated passive avoidance behavior. Facilitation of passive avoidance behavior was observed when the peptide was injected into the dorsal septal nucleus. AVP facilitated passive avoidance behavior when administered into the hippocampal dentate gyrus, dorsal raphe nucleus or dorsal septal nucleus. Injection of either neuropeptides into the central amygdaloid nucleus appeared to be ineffective. One week after the behavioral experiments a repeated injection of AVP into the hippocampal dentate gyrus increased the disappearance of NE in the dentate gyrus and in the nucleus ruber. An injection into the dorsal septal nuclei decreased the NE disappearance in the dorsal septal nucleus itself and increased it in the nucleus ruber. Injection in the dorsal raphe nucleus led to an increase in the disappearance of DA in the locus coeruleus and in the nucleus ruber. It is concluded that memory consolidation can be oppositely influenced by local application of minute amounts of either OXT or AVP into certain limbic-midbrain structures, suggesting an involvement of these brain regions in the memory effects of these peptides. Modulation of catecholamine turnover in specific brain areas after AVP administration may be related to this behavioral effect.
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001362:Avoidance Learning / Q000187:drug effects; D004298:Dopamine / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D008032:Limbic System / Q000187:drug effects*; D008125:Locus Coeruleus / Q000378:metabolism; D008297:Male; D008568:Memory / Q000187:drug effects*; D011939:Mental Recall / Q000187:drug effects*; D008636:Mesencephalon / Q000187:drug effects*; D009638:Norepinephrine / Q000378:metabolism*; D010121:Oxytocin / Q000494:pharmacology*; D011903:Raphe Nuclei / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012012:Red Nucleus / Q000378:metabolism; D012153:Retention, Psychology / Q000187:drug effects; D012686:Septal Nuclei / Q000187:drug effects / Q000378:metabolism
D001127:Arginine Vasopressin; D010121:Oxytocin; D004298:Dopamine; D009638:Norepinephrine