The C57BL/6 (B6) mouse is the most commonly used inbred mouse strain in biomedical research. While the B6 mouse originated at The Jackson Laboratory, a number of separate breeding colonies are now maintained at various sites, resulting in genetic drift that has led to the emergence of both genotypic and phenotypic differences among these colonies. Two distinct substrains of B6 mice, C57BL/6J (B6J) and C57BL/6NJ (B6N), have been shown to differ on several addiction-related phenotypes, such as ethanol preference and locomotor responses to psychostimulants. Therefore, the aim of this study was to assess possible differences in depression- and anxiety-like behaviors following ethanol withdrawal between B6J and B6N mice. Male and female mice (n = 78) were exposed to a regimen of chronic-intermittent ethanol vapor or plain air and subsequently subjected to several behavioral tests at weekly intervals for four weeks. Behavioral measures included the Sucrose Preference Test, a well-established test for depression-like anhedonia; the Light-Dark box Test, a commonly used index of anxiety-like behavior; and the Forced Swim Test, a standard assessment for depression-like learned helplessness. For the Forced Swim Test, the results showed strain main effect between the J’s and the N’s that the J’s spent more time immobile than the N’s did. There was also a sex by strain by condition effect in the Sucrose Preference Test where the female N Ethanol mice consumed significantly less Sucrose water than did their control counterparts. From this we can conclude that there are significant behavioral effects associated with Ethanol withdrawal across B6J and B6N mice.
LeVasseur, Eric L., "The Affective Disturbance of Ethanol Withdrawal on C57BL/6J and C57BL/6NJ Mice" (2018). Honors College. 339.