title: Cocaine and D-amphetamine induce changes in central beta-adrenoceptor sensitivity: effects of acute and chronic drug treatment.
abstract: The effects of acute and chronic treatment with psychomotor stimulants on specific binding of [3H]dihydroalprenolol to beta-adrenoceptors in rat brain were examined. At a dose of 10 mg/kg both acute and chronic treatment with cocaine and chronic treatment with D-amphetamine (10 mg/kg) caused increased binding of [3H]dihydroalprenolol. The molecular mechanism for this enhanced binding appears to be augmentation of the density of beta-adrenoceptors in rat brain. At a lower dose (5 mg/kg), however, chronic administration of D-amphetamine caused a decrease in the density of beta-adrenoceptors in rat brain. Chronic treatment with either D-amphetamine (10 mg/kg) or cocaine induced a marked increase in the magnitude of cyclic AMP accumulation in rat brain slices elicited by norepinephrine. Acute as well as chronic administration of D-amphetamine in vivo inhibited the temperature-dependent uptake of [3H]norepinephrine in rat brain synaptosomal homogenates, but no such inhibition was observed after chronic or acute treatment with cocaine. The results suggest that psychomotor stimulants induce beta-adrenoceptor supersensitivity which may be involved in the phenomenon of reverse tolerance and possibly psychosis in humans. The development of beta-adrenoceptor supersensitivity does not appear to be mediated through alterations in norepinephrine transport at the presynaptic sites.
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D003042:Cocaine / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism; D003913:Dextroamphetamine / Q000494:pharmacology*; D004082:Dihydroalprenolol / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*
chemical_list: D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D000242:Cyclic AMP; D003042:Cocaine; D003913:Dextroamphetamine; D009638:Norepinephrine