Adolescent binge drinking causes sex-specific deficits in behavioral reactivity, endocrine recovery from stress and altered expression of hypothalamic KCC2 in males.

RATIONALE: Binge drinking during adolescence is associated with a higher risk of developing Alcohol Use Disorders and impaired stress reactivity in adulthood. The hypothalamic-pituitary-adrenal axis matures during adolescence and is under strict GABAergic control. Yet, how early binge drinking alters GABAergic signaling in this region, and whether these changes contribute to later-life disruptions in stress reactivity, remain unknown.

OBJECTIVES

Our goal with these set of experiments was to test the hypothesis that adolescent binge drinking would impair maturation of GABAergic signaling in the paraventricular nucleus (PVN) and lead to aberrant behavioral and neuroendocrine stress reactivity.

METHODS

Adolescent male and female C57BL/6J mice were given access to 20% ethanol or tap water under Drinking in the Dark-Multiple Scheduled Access paradigm from PD28 to PD42 and went through abstinence until adulthood. At adulthood (PD60+), the behavioral and endocrine response to two stressors, forced swim stress and social defeat stress, were evaluated.

RESULTS

Only females with a history of adolescent drinking showed abnormal behavioral reactivity to stress, with increased immobility in the forced swim stressor task. Females with a history of adolescent binge drinking displayed a hypo-corticosterone response after social stress and males showed delayed negative feedback to the forced swim stressor. PVN-enriched tissue from these mice showed no changes in transcription of Gabrg2, but males showed a significant increase in expression of Slc12a5, which encodes for the chloride potassium co-transporter, KCC2. These males showed no change in KCC2 protein when evaluated by immunohistochemistry.

CONCLUSIONS

Taken together, these data show that adolescent binge drinking in pair-housed mice is associated with male-specific potential vulnerability in hypothalamic inhibitory signaling and disrupted adult stress reactivity in a sex- and stressor- dependent manner.