Estradiol mediates sex differences in aversion-resistant alcohol intake.

Area of Science:

• Neuroscience
• Endocrinology
• Behavioral Science

Background:

• Alcohol use disorder (AUD) is characterized by continued alcohol consumption despite negative consequences.
• Aversion-resistant drinking, modeled by quinine-adulterated alcohol, is a key symptom of AUD.
• Previous research indicates sex differences in aversion-resistant drinking, with females showing higher resistance.

Purpose of the Study:

• To investigate the role of circulating sex hormones in aversion-resistant alcohol intake.
• To determine which ovarian sex hormone mediates aversion-resistant alcohol consumption and associated neuronal activation patterns.

Main Methods:

• Ovariectomy was performed in female mice to assess the impact of circulating sex hormones.
• Hormonal addback of estradiol or progesterone was used to identify the mediating hormone.
• Neuronal activation patterns in response to quinine-adulterated alcohol intake were analyzed.

Main Results:

• Ovariectomy significantly reduced quinine-adulterated alcohol intake, indicating a role for circulating sex hormones.
• Neuronal activation in the ventral tegmental area (VTA) was reduced in ovariectomized mice.
• Estradiol supplementation reversed the effects of ovariectomy on both alcohol intake and VTA neuronal activation.

Conclusions:

• Circulating estradiol is a key contributor to aversion-resistant alcohol intake.
• Estradiol influences neuronal activity in the VTA, suggesting a neurobiological mechanism.
• The findings suggest a threshold level of estradiol, rather than cyclical fluctuations, underlies aversion-resistant drinking behavior.