Lesions of central serotonin systems affect responding on a progressive ratio schedule reinforced either by intravenous cocaine or by food.
The effect of intraventricular infusions of the serotonergic neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), was examined in rats trained on a progressive ratio schedule for either IV cocaine or food reinforcement. Animals in the 5,7-DHT treatment group responded to significantly higher breaking points than vehicle-injected control animals, regardless of whether food or cocaine was used as the reinforcing stimulus. Analysis of the regional brain amines indicated that depletions of mesencephalic 5-HT correlated with postsurgical alterations in responding. These findings suggest that depletion of forebrain 5-HT produces a general effect on responding rather than a specific alteration in the reinforcing effects of psychomotor stimulant drugs.
Roberts
D C
DC
Department of Psychology, Carleton University, Ottawa, Ontario, Canada.
Loh
E A
EA
Baker
G B
GB
Vickers
G
G
D015116:5,7-Dihydroxytryptamine / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D003042:Cocaine / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology*; D005108:Extinction, Psychological / Q000187:drug effects; D005502:Food; D005795:Generalization, Stimulus / Q000187:drug effects; D007276:Injections, Intraventricular; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012055:Reinforcement Schedule; D012646:Self Administration; D012701:Serotonin / Q000378:metabolism / Q000502:physiology*
D015116:5,7-Dihydroxytryptamine; D012701:Serotonin; D003042:Cocaine