Postdoctoral Associate

Psychiatry

University of Minnesota, Twin Cities (Minneapolis, MN)

Marilyn Carroll

I am studying the neural mechanisms of the negative affective symptoms of opiate withdrawal, using the withdrawal-potentiated startle model.

Withdrawal from opiates produces negative emotional symptoms, such as anxiety, that occur even after the first exposure to the drug. These early affective symptoms of withdrawal are hypothesized to motivate further drug taking. The opponent process theory of motivation predicts that the first step in the induction of drug withdrawal is the activation of reward-related circuitry. My research has demonstrated that anxiety during opiate withdrawal emerges after direct infusion of morphine into the ventral tegmental area (VTA), the origin of the mesolimbic dopamine system. Expression of anxiety during withdrawal from systemic morphine exposure requires a decrease in opiate receptor stimulation in the VTA and can be relieved by administration of dopamine receptor agonists, both systemically and into the shell of the nucleus accumbens. Together, these results suggest that the emergence of anxiety during withdrawal from acute opiate exposure begins with activation of VTA mesolimbic dopamine circuitry and provide a mechanism for the opponent process view of withdrawal.

2009 Charles and Dorothy Bird Award presented by UMN Chapter of Sigma Xi