Behavioral and color variations between rat lines developed for differential alcohol sensitivity

Area of Science:

• Behavioral Neuroscience
• Genetics
• Pharmacology

Background:

• The AT and ANT rat lines were selectively bred for differing sensitivity to ethanol-induced motor impairment.
• These lines also exhibit distinct sober behaviors, suggesting a link beyond just alcohol response.

Purpose of the Study:

• To investigate behavioral differences in sober AT and ANT rat lines.
• To determine if coat color changes in these lines are independent of ethanol sensitivity.
• To evaluate optimal strategies for maintaining selected genetic lines for research.

Main Methods:

• Behavioral testing using escapable-shock, amphetamine-stress, and a low-stress forced-swimming test.
• Computer simulations to assess the independence of coat color changes from ethanol sensitivity.
• Analysis of genetic line maintenance strategies.

Main Results:

• Alcohol-insensitive AT rats displayed significantly higher activity in the low-stress forced-swimming test compared to ANT rats.
• No significant correlation between alcohol sensitivity and swimming activity was found in unselected Long Evans rats.
• Computer simulations indicated a substantial probability that coat color changes (agouti allele loss) were independent of ethanol sensitivity.
• Simulations suggested that permanent maintenance, revitalization, or replicate lines are suboptimal for identifying genetic factors; perpetual restarting is optimal.

Conclusions:

• Sober behavior, specifically locomotor activity in a low-stress environment, differs between rat lines selected for ethanol sensitivity.
• Genetic drift and selection for ethanol sensitivity can be independent of other phenotypic changes like coat color.
• Perpetual restarting of selected lines is the most effective strategy for uncovering genetically-based factors in selective breeding programs.