Interruption of continuous opioid exposure exacerbates drug-evoked adaptations in the mesolimbic dopamine system.

ABSTRACT: Drug-evoked adaptations in the mesolimbic dopamine system are postulated to drive opioid abuse and addiction. These adaptations vary in magnitude and direction following different patterns of opioid exposure, but few studies have systematically manipulated the pattern of opioid administration while measuring neurobiological and behavioral impact. We exposed male and female mice to morphine for one week, with administration patterns that were either intermittent (daily injections) or continuous (osmotic minipump infusion). We then interrupted continuous morphine exposure with either naloxone-precipitated or spontaneous withdrawal. Continuous morphine exposure caused tolerance to the psychomotor-activating effects of morphine, whereas both intermittent and interrupted morphine exposure cause

SUBMITTER: Lefevre EM 

PROVIDER: S-EPMC7608117 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature