Behavioural microanalysis of the role of dopamine in amphetamine anorexia.
A microstructural analysis paradigm was used to study amphetamine anorexia. Doses above 0.40 mg/kg significantly reduced food intake by reducing eating time; in contrast, eating rate was increased at these doses. Examination of the frequency distribution of interresponse times (IRTs) revealed a significant shift to shorter IRTs at doses as low as 0.125 mg/kg. Pimozide blocked amphetamine anorexia at 0.5 and 1.0 mg/kg, suggesting that at both doses amphetamine anorexia has a dopaminergic substrate. However, the atypical neuroleptic thioridazine did not antagonize amphetamine. Furthermore, effects of amphetamine were additive with those of apomorphine, administered at a dose known to suppress feeding by inhibiting mesolimbic DA neurons. These results provide evidence against an involvement of the mesolimbic DA system in amphetamine anorexia.
Towell
A
A
Psychology Department, City of London Polytechnic, London.
Muscat
R
R
Willner
P
P
D000818:Animals; D000855:Anorexia / Q000139:chemically induced / Q000503:physiopathology*; D001058:Apomorphine / Q000494:pharmacology; D003913:Dextroamphetamine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005247:Feeding Behavior / Q000187:drug effects*; D001068:Feeding and Eating Disorders / Q000503:physiopathology*; D008297:Male; D010868:Pimozide / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values; D013881:Thioridazine / Q000494:pharmacology; D013997:Time Factors
D010868:Pimozide; D001058:Apomorphine; D013881:Thioridazine; D003913:Dextroamphetamine