Increased susceptibility to LTP generation and changes in NMDA-NR1 and -NR2B subunits mRNA expression in rat hippocampus after MCH administration.
The present study attempts to determine which mechanisms underlie the retrograde facilitation of memory induced by microinjection hippocampal melanin-concentrating hormone (MCH) on the inhibitory avoidance paradigm. Previous reports using this test on the hippocampus suggest that NMDA receptor-mediated mechanisms are involved in memory processing and are also necessary for the induction of long-term potentiation (LTP) of the hippocampal dentate gyrus. In addition, alterations in expression of synaptic NMDA subunits in the hippocampus have been associated with memory formation of an inhibitory avoidance task. We have studied the effects of the neuropeptide upon the electrophysiological parameters using hippocampal slices from rats injected with the peptide and tested in step-down tests as well as possible changes in the mRNA expression of NMDA receptor subunits. We postulate that the increased facility to induce LTP, and the overexpression of this N-methyl-D-aspartate mRNA receptor subunits induced by MCH, could be behind the retrograde facilitation observed after MCH hippocampal microinjection.
Varas
Mariana Marcela
MM
Departamento de Farmacología, Facultad de Ciencias Químicas, Haya de La Torre esq. Medina Allende, Universidad Nacional de Córdoba, Córdoba 5000, Argentina. mvara@mail.fcq.unc.edu.ar
Pérez
Mariela F
MF
Ramírez
Oscar A
OA
de Barioglio
Susana R
SR
D000818:Animals; D004594:Electrophysiology; D005786:Gene Expression Regulation / Q000187:drug effects*; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D007028:Hypothalamic Hormones / Q000494:pharmacology*; D017403:In Situ Hybridization; D007267:Injections; D017774:Long-Term Potentiation / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008543:Melanins / Q000494:pharmacology*; D016202:N-Methylaspartate / Q000378:metabolism*; D010907:Pituitary Hormones / Q000494:pharmacology*; D021122:Protein Subunits / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics* / Q000378:metabolism
D007028:Hypothalamic Hormones; D008543:Melanins; D010907:Pituitary Hormones; D021122:Protein Subunits; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; C019463:melanin-concentrating hormone