title: Evidence for the substantia nigra pars compacta as an essential component of a memory system independent of the hippocampal memory system.
abstract: The aim of the present study was to test if the nigrostriatal pathway is an essential component for a water maze cued task learning and if it works independently of the hippocampal memory system. This hypothesis was tested using an animal model of Parkinson's disease in which male Wistar rats were lesioned in the substantia nigra pars compacta (SNc) by the intranigral infusion of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), thus causing a partial depletion of striatal dopamine. SNc-lesioned and sham-operated animals were implanted bilaterally with guide cannulae above the dorsal hippocampus in order to be tested after the administration of 0.4 microl 2% lidocaine or saline into this structure. The animals were tested in a spatial or in a cued version of the water maze, memory tasks previously reported to model hippocampal-dependent spatial/relational and striatal-dependent S-R learning, respectively. Hippocampal inactivation, but not SNc lesion, impaired learning and memory in the spatial version of the water maze. An opposite situation was observed with the cued version. No significant interaction was observed between the SNc lesion and hippocampal inactivation conditions affecting scores in the spatial or in the cued version of the water maze. These results suggest that the nigrostriatal pathway is an essential part of the memory system that processes S-R learning and that it works independently of the hippocampal memory system that processes spatial/relational memories.
authors.affiliation: Laboratório de Fisiologia e Farmacologia do Sistema Nervoso Central, Departamento de Farmacologia, UFPR, C.P. 19.031, 18.31-990, Curitiba, Brazil. dacunha@bio.ufpr.br <dacunha@bio.ufpr.br>
authors.forename: Claudio
authors.initials: C
authors.lastname: Da Cunha
authors.forename: Samantha
authors.initials: S
authors.lastname: Wietzikoski
authors.forename: Evellyn C
authors.initials: EC
authors.lastname: Wietzikoski
authors.forename: Edmar
authors.initials: E
authors.lastname: Miyoshi
authors.forename: Marcelo M
authors.initials: MM
authors.lastname: Ferro
authors.forename: Janete A
authors.initials: JA
authors.lastname: Anselmo-Franci
authors.forename: Newton S
authors.initials: NS
authors.lastname: Canteras
mesh_terms: D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000009:adverse effects; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects / Q000503:physiopathology*; D015259:Dopamine Agents / Q000009:adverse effects; D008297:Male; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D008569:Memory Disorders / Q000139:chemically induced / Q000503:physiopathology*; D009434:Neural Pathways / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013037:Spatial Behavior / Q000187:drug effects / Q000502:physiology*; D013378:Substantia Nigra / Q000187:drug effects / Q000503:physiopathology*
chemical_list: D015259:Dopamine Agents; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine