Effects of alpha-methyl tyrosine and adrenergic blocking agents on the facilitating action of amphetamine and nicotine on learning in rats

It is suggested that the facilitatory learning action of amphetamine and nicotine involves a common adrenergic mechanism and is attributed to depletion of “functional pools” of catecholamines.

Abstract

dl-amphetamine sulphate (2 mg/kg) and nicotine (0.2 mg/kg) showed a facilitatory action on the acquisition of a conditioned response in a shuttle-box by rats and this was reversed by pretreatment with α-MT (30 mg/kg). Pretreatment with dibenamine (10 mg/kg) impaired the action either of amphetamine or nicotine. Nethalide (5–10 mg/kg) exerted a partial protection on the depressant effect produced by the interaction between dibenamine and nicotine. Animals treated with α-MT (30 mg/kg) and kept in the cold (4–6° C for 3 h) also showed a depressed learning capacity. dl-Dopa (200 mg/kg) provided a partial protection on the depressive effects caused by the interaction of α-MT with amphetamine, nicotine or cold. It is suggested that the facilitatory learning action of amphetamine and nicotine involves a common adrenergic mechanism. The depressant effects of amphetamine, nicotine or cold after α-MT treatment are attributed to depletion of “functional pools” of catecholamines.