Task-dependent ethanol effects on escape in rats bred for ethanol sensitivity

Area of Science:

• Neuroscience
• Pharmacology
• Animal Behavior

Background:

• Selective breeding has generated rat lines with differing sensitivities to ethanol's locomotor depressant effects.
• Understanding genetic contributions to ethanol sensitivity is crucial for addiction research.

Purpose of the Study:

• To investigate ethanol's effects on an active escape response in rats selectively bred for high (MA) and low (LA) ethanol sensitivity.
• To compare ethanol-induced impairment in an escape task with previous findings in passive avoidance tasks.

Main Methods:

• Rats from MA and LA lines were tested for ethanol-induced impairment of jumping to escape an electric shock.
• Dose-response effects of intraperitoneal ethanol injections (0.75-2.25 g/kg) on jump height and latency were measured.
• Sex differences in ethanol sensitivity were also assessed.

Main Results:

• The MA line exhibited significantly greater decreases in jump height and increases in jump latency compared to the LA line at higher ethanol doses (1.75 and 2.25 g/kg).
• Male rats showed greater ethanol-induced impairment than female rats across both lines and measures.
• These findings contrast with previous studies where the LA line showed greater impairment in a water escape task.

Conclusions:

• Ethanol sensitivity, as determined by selective breeding, influences active escape behaviors.
• The MA line's greater sensitivity extends to an active escape response, though the pattern differs from passive water escape tasks.
• Sex is a significant factor in ethanol's behavioral effects, with males being more susceptible to impairment.