Individual differences in locomotor activity and sensitization

doi:10.1016/0091-3057(91)90308-O

Pharmacology Biochemistry and Behavior

Volume 38, Issue 2, February 1991, Pages 467-470

https://doi.org/10.1016/0091-3057(91)90308-O Get rights and content

Abstract

Male rats were screened for locomotor activity in a novel environment and divided into high (HR) and low (LR) responders based on whether their locomotor activity score for the first hour was above or below the median locomotor activity for the subject sample. Subsequently, the locomotor activity score for the peated administration of either amphetamine (AMPH; 0.5 mg/kg), cocaine (10 mg/kg), scopolamine (0.5 mg/kg) or saline was monitored in separate groups of HR and LR rats. HR rats had significantly higher overall scores than LR rats for all 3 drugs. Both HR and LR rats developed tolerance at the same rate to repeated scoppoamine administration. In contrast, only HR rats showed pronounced sensitization to the locomotor stimulating properties of AMPH and a direct correlation was evident between the locomotor response to novelty and the magnitude of sensitization. These results suggest that an individual's response to a novel environment can, to a certain extent, predict drug-induced locomotor activity and that individual differences in the response to novelty and sensitization to AMPH may result from individual variations in a common neural mechanism.

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Citation Excerpt :
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High novelty seeking increases the risk for drug experimentation and locomotor sensitization. Locomotor sensitization to psychostimulants is thought to reflect neurological adaptations that promote the transition to compulsive drug taking. Rats reared in enrichment (EC) show less locomotor sensitization when compared to rats reared in isolation (IC) or standard conditions (SC). The current research study was designed to test if novelty response contributed locomotor sensitization and more importantly, if the different housing environments could change the novelty response to protect against the development of locomotor sensitization in both adolescence and adulthood.
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Differential housing changes novelty and amphetamine locomotor response. Novelty response is altered into adulthood and provides evidence that enrichment can be used to reduce drug vulnerability.

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Brief communicationIndividual differences in locomotor activity and sensitization

Abstract

Brain Res.

Neurosci. Biobehav. Rev.

Brain Res.

Eur. J. Pharmacol.

Pharmacol. Biochem. Behav.

Brain Res. Rev.

Brain Res.

Response of mesocortical-frontal dopaminergic neurons in rats after long-term isolation

Nature

Repeated stress increases locomotor response to amphetamine

Psychopharmacology (Berlin)

Brief communication
Individual differences in locomotor activity and sensitization