Context-dependent catalepsy intensification is due to classical conditioning and sensitization.
Haloperidol-induced catalepsy represents a model of neuroleptic-induced Parkinsonism. Daily administration of haloperidol, followed by testing for catalepsy on a bar and grid, results in a day-to-day increase in catalepsy that is completely context dependent, resulting in a strong placebo effect and in a failure of expression after a change in context. The aim of this study was to analyse the associative learning process that underlies context dependency. Catalepsy intensification was induced by a daily threshold dose of 0.25 mg/kg haloperidol. Extinction training and retesting under haloperidol revealed that sensitization was composed of two components: a context-conditioning component, which can be extinguished, and a context-dependent sensitization component, which cannot be extinguished. Context dependency of catalepsy thus follows precisely the same rules as context dependency of psychostimulant-induced sensitization. Catalepsy sensitization is therefore due to conditioning and sensitization.
Amtage
J
J
Neuropharmacology, Zoological Institute, University of Tuebingen, Auf der Morgenstelle 28E, 72076 Tuebingen, Germany.
Schmidt
W J
WJ
D000818:Animals; D001245:Association Learning / Q000187:drug effects / Q000502:physiology; D002385:Cataplexy / Q000139:chemically induced / Q000503:physiopathology / Q000523:psychology*; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology; D003342:Corpus Striatum / Q000187:drug effects / Q000503:physiopathology; D004298:Dopamine / Q000502:physiology; D018492:Dopamine Antagonists; D005108:Extinction, Psychological / Q000187:drug effects / Q000502:physiology; D006220:Haloperidol; D007274:Injections, Intraperitoneal; D008297:Male; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D020734:Parkinsonian Disorders / Q000139:chemically induced / Q000503:physiopathology / Q000523:psychology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012054:Reinforcement, Psychology; D012931:Social Environment
D018492:Dopamine Antagonists; D006220:Haloperidol; D004298:Dopamine