Memory disruption in rats with nigral lesions induced by MPTP: a model for early Parkinson's disease amnesia.
Intra-nigral administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyrindine (MPTP) caused a lesion in the substantia nigra, compact part (SNc) and a specific loss of dopamine and its metabolites in the striatum of rats. The animals were then tested in the two-way active avoidance task. MPTP-treated animals presented lower learning scores in the training and test sessions, an effect that was not caused by motor impairment or by a decreased sensitivity to footshock since their reaction time to the footshock (unconditioned stimulus - UCS) was not reduced. These lower scores were also not attributable to lower acoustic sensitivity or to a slowing in the association of the sound cue (conditioned stimulus - CS) with the UCS since the reaction time to the CS in the active avoidance response did not differ between MPTP-treated and control groups. Therefore, these results are more properly attributable to an impairment of the memory acquisition and retention processes. In addition, this study is presented as a model of early Parkinson's Disease amnesia and is discussed in terms of the importance of the nigrostriatal pathway to memory acquisition and storage processes.
Da Cunha
C
C
Laboratório de Fisiologia e Farmacologia do SNC, Departamento de Farmacologia, UFPR, CP.: 19.031, 81.531-990 Curitiba PR, Brazil. dacunha@bio.ufpr.br
Gevaerd
M S
MS
Vital
M A
MA
Miyoshi
E
E
Andreatini
R
R
Silveira
R
R
Takahashi
R N
RN
Canteras
N S
NS
D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000494:pharmacology; D000818:Animals; D001245:Association Learning / Q000187:drug effects / Q000502:physiology; D001362:Avoidance Learning / Q000187:drug effects* / Q000502:physiology; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology; D004298:Dopamine / Q000378:metabolism; D008297:Male; D011939:Mental Recall / Q000187:drug effects* / Q000502:physiology; D009434:Neural Pathways / Q000187:drug effects / Q000503:physiopathology; D020734:Parkinsonian Disorders / Q000139:chemically induced* / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D012153:Retention, Psychology / Q000187:drug effects / Q000502:physiology; D013378:Substantia Nigra / Q000187:drug effects* / Q000503:physiopathology
D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D004298:Dopamine