Antagonism of the behavioral effects of cocaine andd-amphetamine by prazosin

✍ Scribed by Richard E. Tessel; James E. Barrett

• Publisher: Springer
• Year: 1986
• Tongue: English
• Weight: 551 KB
• Volume: 90
• Category: Article
• ISSN: 0033-3158
• DOI: 10.1007/bf00174057

✦ Synopsis

Key pecking by pigeons was maintained under a 30-response fixed-ratio schedule of food delivery; lever pressing by squirrel monkeys was maintained under a 3-min fixed-interval schedule of food delivery. Administered alone, d-amphetamine (0.1-3.0 mg/kg), cocaine (1.0-3.0 mg/kg) and bupropion (1.0-30 mg/kg) either did not affect or decreased fixed-ratio responding of pigeons, whereas d-amphetamine (0.056-0.3 mg/kg) either increased or decreased (0.56 mg/kg) responding of monkeys maintained under the fixed-interval schedule. Prazosin, a selective centrally-active alphaz antagonist, produced a dosedependent reversal of the rate-decreasing effects of d-amphetamine and cocaine but not of bupropion on fixed-ratio responding in pigeons. Prazosin also reversed both the rateincreasing and rate-decreasing effects of d-amphetamine on fixed-interval responding of squirrel monkeys. In contrast, the non-selective alpha-antagonist phentolamine enhanced d-amphetamine-induced decreases in fixed-ratio responding. These findings suggest that the behavioral effects of d-amphetamine and cocaine are produced at least in part by activation of central alpha~ receptors. Prazosin may be a useful tool for better understanding the mechanisms through which cocaine, amphetamine, and other abused stimulant drugs exert their potent behavioral effects.