Effects of MPTP on lever-pressing for light extinction in rats.
Rats were daily treated for seven days with 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP) at a dose of 20 mg/kg/day, i.p. Seven days after treatment withdrawal, the rats were individually tested in a brightly lit apparatus containing two levers: an active lever allowing periods of darkness, and an inactive one. The test was performed over two consecutive days, in 20-min sessions. While control rats had a higher number of total active lever pressings than inactive lever pressings, this was not the case for MPTP-treated rats. Control rats decreased their useless active lever pressings and inactive lever pressings across the two sessions, but MPTP-treated rats did not do either. The absence of the differential effect in rats injected with MPTP may be due to a reduction in reinforcement mechanisms caused by the mild depletion of dopamine in the striatum.
ETAP-Ethologie Appliquée, Pompey, France.
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M
Messaoudi
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Tricoire
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R
Lalonde
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F
Canini
A
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Minn
D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine / Q000494:pharmacology*; D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism; D015259:Dopamine Agents / Q000494:pharmacology*; D007858:Learning / Q000187:drug effects*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism
D015259:Dopamine Agents; D015102:3,4-Dihydroxyphenylacetic Acid; D015632:1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine; D004298:Dopamine