Apomorphine and amphetamine produce differential effects on the speed and success of reaction time responding in the rat

Pharmacol Biochem Behav. 1993 Dec;46(4):769-75. doi: 10.1016/0091-3057(93)90199-4.

Abstract

Apomorphine, a nonselective, direct-acting dopamine agonist, and amphetamine, a nonselective indirect-acting dopamine agonist, were compared for their effects on the reaction time response in rats. Animals were shaped to release a lever in response to an auditory/visual stimulus to avoid mild foot shock. The characteristics of the reaction time response of primary interest were percent successful avoidance and response latency. Apomorphine (0, 1, and 5 mg/kg, IP) significantly decreased successful avoidance, but had no effect on response latencies. Thus, the decrease in successful avoidance was not a direct result of longer latencies. Amphetamine (0, 0.5, and 1 mg/kg, IP) produced a different pattern of effects on the reaction time response. Successful avoidance was not affected by amphetamine treatment. However, response latencies were dose-dependently decreased in response to amphetamine. These results demonstrate that dopamine receptor stimulation by different dopamine agonists produces a different pattern of effects on the characteristics of the reaction time response. In addition, these results demonstrate that successful avoidance can be modulated independently of response latencies.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amphetamine / pharmacology*
  • Animals
  • Apomorphine / pharmacology*
  • Avoidance Learning
  • Dose-Response Relationship, Drug
  • Male
  • Psychomotor Performance / drug effects*
  • Rats
  • Rats, Sprague-Dawley
  • Reaction Time / drug effects*

Substances

  • Amphetamine
  • Apomorphine