Methamphetamine-induced deficits in social interaction are not observed following abstinence from single or repeated exposures

Abstract

The purpose of the current study was to assess social interaction (SI) following acute and repeated methamphetamine (MA) administration. Rats were injected with 5.0 mg/kg of MA and SI was tested 30 minutes or 24 hours later. In another group of animals, MA sensitization was induced using 5.0 mg/kg of MA, and SI was assessed after one day or thirty days of abstinence. SI was reduced in rats injected with MA 30 minutes, but not 24 hours, prior to testing, compared with saline controls. Impaired SI was observed in combination with active avoidance of the conspecific animal. Repeated injections of MA progressively reduced locomotor activity and increased stereotypy, indicating that animals were sensitized. However, no differences in SI were observed 24 hours or 30 days following the induction of sensitization. The absence of detectable differences in SI following MA sensitization may be attributable to the relatively short regimen used to induce sensitization. However, the current series of experiments provides evidence that an acute injection of MA decreases SI and simultaneously increases avoidance behavior, which supports a link between psychostimulant use and impaired social functioning. These data suggest that the acute injection model may provide a useful model to explore the neural basis of impaired social functioning and antisocial behavior.