Differences in free-choice ethanol acceptance between taste aversion-prone and taste aversion-resistant rats

Area of Science:

• Behavioral Neuroscience
• Genetics
• Pharmacology

Background:

• Taste aversion (TA) conditioning is a learned response to stimuli paired with nausea-inducing agents.
• Individual differences in TA susceptibility exist and may influence other behaviors.
• Ethanol consumption patterns are complex and influenced by genetic and environmental factors.

Purpose of the Study:

• To investigate the relationship between susceptibility to conditioned taste aversion and ethanol acceptance in selectively bred rats.
• To determine if genetic lines differing in TA conditionability exhibit distinct ethanol consumption patterns.
• To explore the potential role of TA learning in modulating voluntary ethanol intake.

Main Methods:

• Utilized two rat lines: TA-prone (TAP) and TA-resistant (TAR), selectively bred for susceptibility to cyclophosphamide-induced conditioned TAs.
• Assessed naive, non-forced ethanol acceptance in TAP and TAR rats across a range of ethanol concentrations (1-10%).
• Measured ethanol consumption (g/kg) and preference scores (ethanol intake/total fluid intake) via two-bottle choice tests.

Main Results:

• No differences in ethanol consumption or preference were observed at 1% ethanol concentration.
• At concentrations from 2% to 10%, TAP rats consumed significantly less ethanol and showed lower preference compared to TAR rats.
• Maximum ethanol consumption for both lines occurred at 6% ethanol, with TAR rats consuming substantially more than TAP rats.

Conclusions:

• Differences in taste aversion conditionability are associated with variations in ethanol consumption propensity.
• High susceptibility to taste aversion learning may act as a deterrent to high-level ethanol consumption.
• These findings suggest a potential biological link between TA learning and reduced risk for alcohol dependence.