Enhancement of effects of dopaminergic agonists on neuronal activity in the caudate-putamen of the rat following long-term d-amphetamine administration.
Amphetamine- and apomorphine-induced changes in the activity of neurons in the caudate-putamen of paralyzed, locally anesthetized rats were recorded in animals pretreated with 2.5 mg/kg d-amphetamine sulphate for 6, 18 or 36 days, or in animals pretreated with saline for 36 consecutive days. In saline-pretreated animals, 2.5 mg/kg d-amphetamine sulphate (IP) produced an initial, brief potentiation of neuronal firing that was followed by a marked depression of neuronal activity lasting for approximately 35 to 110 min after injection. In amphetamine-pretreated animals, this depression of neuronal activity to the same dose of the drug was markedly prolonged, especially in animals given 36 consecutive days of d-amphetamine pretreatment. A similar enhancement occurred in response to 0.25 mg/kg apomorphine (IP) in animals pretreated with amphetamine for 36 days compared to saline-pretreated control animals. These results are discussed in relation to the known behavioral and biochemical effects of acute and long-term amphetamine administration.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D002421:Caudate Nucleus / Q000187:drug effects*; D003342:Corpus Striatum / Q000187:drug effects*; D003913:Dextroamphetamine / Q000494:pharmacology*; D004298:Dopamine / Q000502:physiology*; D004357:Drug Synergism; D004567:Electrodes, Implanted; D008297:Male; D009474:Neurons / Q000187:drug effects*; D011699:Putamen / Q000187:drug effects*; D051381:Rats; D013997:Time Factors
D001058:Apomorphine; D003913:Dextroamphetamine; D004298:Dopamine