Increased alcohol self-administration following exposure to the predator odor TMT in active coping female rats

• Published in: Behavioural brain research Vol. 402; p. 113068
• Main Authors: Ornelas, Laura C., Tyler, Ryan E., Irukulapati, Preethi, Paladugu, Sudheesha, Besheer, Joyce
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 26.03.2021
• Subjects: Adaptation, Psychological - physiology; Alcohol; Alcohol Drinking - physiopathology; Alcohol use disorder; Alcoholism - physiopathology; Animals; Behavior, Animal - physiology; Disease Models, Animal; Female; Individual differences; Individuality; Male; Odorants; Post-traumatic stress disorder; Predator odor stress; Rats; Rats, Long-Evans; Sex differences; Stress Disorders, Post-Traumatic - physiopathology; Stress, Psychological - physiopathology; Thiazoles; TMT; Alcohol use disorder; Individual differences; Post-traumatic stress disorder; Alcohol; Sex differences; TMT; Predator odor stress
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2020.113068

•Exposure to TMT produces distinct behavioral phenotypes in male and female rats.•Prior exposure to TMT produces enhanced behavioral reactivity to TMT-paired context.•Active coping behavior during TMT related to increased alcohol drinking in females.•Stress-reactivity produces individual differences to stress and alcohol drinking.•Individual differences in stress-reactivity can impact alcohol drinking. Post-traumatic stress disorder (PTSD) and alcohol use disorder (AUD) are highly comorbid. Additionally, individual differences in response to stress suggest resilient and susceptible populations. The current study exposed male and female Long Evans rats to the synthetically produced predator odor 2,5-dihydro-2,4,5-trimethylthiazoline (TMT) to examine individual differences in stress-reactive behaviors (digging and immobility) and whether these differences were related to subsequent alcohol drinking. Male and female Long Evans rats were trained on operant alcohol self-administration. After 9 sessions, rats underwent exposure to TMT or water (Control) in a distinct context. 6 days after TMT exposure, rats underwent re-exposure to the TMT-paired context (without TMT), and a series of behavioral assessments (acoustic startle, zero maze, light/dark box), after which rats resumed alcohol self-administration. TMT subgroups were created using a ratio of digging to immobility behavior during TMT exposure and rats with a ratio score < 1.0 or> 1.0 were grouped into TMT-1 (low digging/high immobility) or TMT-2 (high digging/low immobility), respectively. All male rats exposed to TMT met criteria for TMT-1, while female rats were divided into the two subgroups. In females, high digging/low immobility behavior during TMT exposure (TMT-2) was related to increased alcohol self-administration, but this was not observed in males or females that engaged in low digging/high immobility (TMT-1). These data show that individual differences in stress-reactivity can lead to lasting behavioral changes which may lead to a better understanding of increases in alcohol drinking following stress in females.