Sex, strain, and estrous cycle influences on alcohol drinking in rats

• Published in: Pharmacology, biochemistry and behavior Vol. 152; pp. 61 - 67
• Main Authors: Priddy, Brittany M., Carmack, Stephanie A., Thomas, Lisa C., Vendruscolo, Janaina C.M., Koob, George F., Vendruscolo, Leandro F.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2017
• Subjects: Administration, Inhalation; Alcohol Drinking - physiopathology; Alcohol use disorders; Alcoholism; Animals; Conditioning, Operant - drug effects; Drug addiction; Estrous Cycle - physiology; Ethanol; Ethanol - administration & dosage; Ethanol - pharmacology; Female; Gender differences; Genetic differences; Male; Rats; Rats, Long-Evans; Rats, Wistar; Sex Characteristics; Species Specificity; Genetic differences; Drug addiction; Gender differences; Ethanol; Alcoholism; Alcohol use disorders
• ISSN: 0091-3057; 1873-5177
• DOI: 10.1016/j.pbb.2016.08.001

Although women appear to be more vulnerable to alcohol-induced pathophysiology than men, the neurobiological basis for sex differences is largely unknown, partially because most studies on alcohol drinking are conducted in male subjects only. The present study examined sex differences in alcohol consumption in two rat strains, Long Evans and Wistar, using multiple behavioral paradigms. The effects of the estrous cycle on alcohol consumption were monitored throughout the study. The results indicated that females drank more alcohol than males when given either continuous or intermittent access to alcohol (vs. water) in their home cages (voluntary drinking). Under operant conditions, no sex or strain differences were found in drinking prior to development of alcohol dependence. However, upon dependence induction by chronic, intermittent alcohol vapor exposure, Wistar rats of both sexes substantially escalated their alcohol intake compared with their nondependent drinking levels, whereas Long Evans rats only exhibited a moderate escalation of drinking. Under these conditions, the estrous cycle had no effect on alcohol drinking in any strain and drinking model. Thus, strain, sex, and drinking conditions interact to modulate nondependent and dependent alcohol drinking. The present results emphasize the importance of including sex and strain as biological variables in exploring individual differences in alcohol drinking and dependence. •Most studies on alcohol drinking are conducted in male subjects only.•Wistar and Long Evans female rats voluntary drank more alcohol than male rats.•There were no sex or strain differences in drinking under operant conditions.•Alcohol dependent Wistar but not Long Evans rats escalated their alcohol intake.•The estrous cycle did not affect drinking in any strain or experimental condition.