Deficit in brain reward function and acute and protracted anxiety-like behavior after discontinuation of a chronic alcohol liquid diet in rats

Abstract

Discontinuation of chronic and excessive alcohol consumption leads to a dysphoric state in humans. It is not known if there are changes in brain reward function after the discontinuation of an alcohol liquid in rats. The aim of these studies was to investigate the effect of withdrawal from an alcohol liquid diet on brain reward function and acute and protracted anxiety-like behavior. The intracranial self-stimulation procedure was used to assess brain reward function, and the elevated plus maze test was used to assess anxiety-like behavior. Discontinuation of chronic, 12 weeks, exposure to a 6.2% v/v alcohol liquid diet lead to a minor deficit in brain reward function and did not increase anxiety-like behavior. Discontinuation of chronic, 12 weeks, exposure to a 10% v/v alcohol liquid diet lead to a pronounced deficit in brain reward function and increased anxiety-like behavior. Two weeks after discontinuation of the 10% v/v alcohol liquid diet, the rats with a history of alcohol dependence did not display increased anxiety-like behavior. Restraint stress increased anxiety-like behavior in the rats with a history of alcohol dependence, but not in the control rats. Brain reward thresholds were assessed during the chronic 10% v/v alcohol exposure period. During this period, there were no differences between the brain rewards thresholds of the alcohol and control rats. These findings indicate that withdrawal from a 10% v/v alcohol liquid diet leads to a pronounced deficit in brain reward function and acute and protracted anxiety-like behavior in rats.