A role for dopamine in the psychopharmacology of electrical self-stimulation.
The psychopharmacology of electrical self-stimulation of the lateral hypothalamus was studied using 6-hydroxydopamine, alpha-methyltyrosine, U-14, 624, and d-amphetamine. Reduction of brain dopamine, but not norepinephrine, with 6-hydroxydopamine produced an acute depression of responding which eventually recovered to pretreatment levels. A low dose of alpha-methyltyrosine, which did not affect responding in control rats, significantly depressed responding in the rats with brain dopamine reduced. This treatment did not alter responding of rats with norepinephrine reduced by 6-hydroxydopamine. A dopamine-beta-hydroxylase inhibitor, U-14, 624, depleted norepinephrine an additional 70% yet failed to alter self-stimulation in any of the groups. In other experiments, the 6-hydroxydopamine treatment which reduced brain dopamine was found to block the facilitation of self-stimulation produced by d-amphetamine. This facilitation of lateral hypothalmic self-stimulation was not influenced by treatments which reduced brain norepinephrine. An experiment suggesting that dopamine is of importance to locus coeruleus self-stimulation is also described. Implications of these data indicating a role for dopamine in self-stimulation responding are discussed in relation to the "catecholamine hypothesis of self-stimulation".
D000818:Animals; D001679:Biogenic Amines / Q000502:physiology; D002552:Cerebral Ventricles / Q000502:physiology; D003913:Dextroamphetamine / Q000494:pharmacology; D004298:Dopamine / Q000502:physiology*; D004558:Electric Stimulation; D006892:Hydroxydopamines / Q000494:pharmacology; D007031:Hypothalamus / Q000502:physiology; D008781:Methyltyrosines / Q000494:pharmacology; D051381:Rats; D012653:Self Stimulation / Q000187:drug effects*
D001679:Biogenic Amines; D006892:Hydroxydopamines; D008781:Methyltyrosines; D003913:Dextroamphetamine; D004298:Dopamine