Effects of 2,5-Dimethoxy-4-Methylamphetamine (DOM,STP) on Successive Sensory Discrimination Behavior Maintained by Electrical Stimulation of the Brain Reinforcement in the Rat

Abstract

The effects of DOM (2, 5-dimethoxy-4-methylamphetamine) on behavior reinforced by electrical stimulation of the brain were observed in five male Sprague-Dawley rats. The animals were trained on a successive discrimination task: the S^D interval lasted as long as it took the animal to make one lever-press; the S^Δ interval was variable, with a mean duration of 60 sec. Following DOM administration, response latencies to the S^D were longer during the first 75 min. and S^Δ responding was augmented over the 2-hr. session. Gross behavioral effects such as hypokinesia and ataxia were observed for a large part of the session. While increased response latencies may be attributed to hypokinesia and ataxia, increases in S^Δ responding reflect a breakdown of discrimination itself. Severe behavioral depression was not observed, suggesting that electrical stimulation of the brain may have counteracted the depressive effect of the amphetamine.