Effects of d-amphetamine on temporal distributions of schedule-induced polydipsia.
Food-deprived rats were divided into four groups according to the equal interval and time durations of a multiple fixed-interval, fixed-time schedule (15, 30, 60, and 120 s). Fixed-time components were signaled by a tone and lever withdrawal. d-Amphetamine (0.25-4.0 mg/kg) produced similar dose-dependent reductions in the drinking and licking induced by fixed-interval and fixed-time schedules. These dose-dependent decrements were a function of the interfood interval length. More licks occurred early in the interfood intervals with doses of d-amphetamine. Dose-dependent shifts to the left were observed in the distribution of licking, and there were dose-dependent decreases in the quarter-life, which were a function of fixed-interval and fixed-time lengths. The maximum lick rate within interfood intervals occurred at about the same absolute time in schedules up to 60 s; therefore, the effects of d-amphetamine were not mediated by its effects on temporal discrimination.
Flores
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Facultad de Psicología, Universidad Nacional de Educación a Distancia, Ciudad Universitaria, Madrid, Spain.
Pellón
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D000704:Analysis of Variance; D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects*; D003913:Dextroamphetamine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004327:Drinking Behavior / Q000187:drug effects*; D016014:Linear Models; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012055:Reinforcement Schedule; D013997:Time Factors
D000697:Central Nervous System Stimulants; D003913:Dextroamphetamine