On the role of ascending catecholaminergic systems in intravenous self-administration of cocaine.
The role of ascending noradrenergic (NA) and dopaminergic (DA) systems in intravenous self-administration of cocaine in rats was investigated by examining the effects of 6-hydroxydopamine-induced lesions of these systems on responding for the drug on a FR-1 schedule of reinforcement. Lesions of the dorsal and ventral NA bundles that reduced hippocampal-cortical NA by 96% and hypothalamic NA by 72% failed to have any effects on responding for cocaine. Lesions of the nucleus accumbens that reduced the DA content of this nucleus by 90% resulted in a significant and long-lasting (15 days) reduction in self-administration of cocaine. Apomorphine self-administration was not affected in the same animals. Identical lesions of the n accumbens had only transient (2-3 days) effects on food-reinforced operant responding, suggesting that the prolonged disruption of cocaine self-administration was not the result of motor deficits. The results are discussed with reference to the possibility that DA terminals in the n accumbens may mediate some of the positive reinforcing properties of cocaine.
D000818:Animals; D001921:Brain / Q000502:physiology*; D002395:Catecholamines / Q000502:physiology*; D003042:Cocaine / Q000008:administration & dosage*; D006892:Hydroxydopamines / Q000633:toxicity; D007275:Injections, Intravenous; D008297:Male; D009638:Norepinephrine / Q000502:physiology; D009714:Nucleus Accumbens / Q000502:physiology; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000502:physiology; D011954:Receptors, Dopamine / Q000502:physiology; D012646:Self Administration
D002395:Catecholamines; D006892:Hydroxydopamines; D011941:Receptors, Adrenergic; D011954:Receptors, Dopamine; D016627:Oxidopamine; D003042:Cocaine; D009638:Norepinephrine