Ethanol induces conditioned social preference in male mice.
BACKGROUND
Affiliative social interactions promote alcohol consumption, and alcohol also promotes affiliative behavior. Furthermore, for most species, moderate doses of ethanol (EtOH) and social affiliation are each rewarding. However, animal studies of drug and EtOH reward typically test individuals in isolation. To address social dimensions of EtOH reward, this study tested EtOH-induced conditioned social preference in male C57BL/6 mice with (ORCHX+T) and without (ORCHX) testosterone.


METHODS
ORCHX+T males received EtOH (0, 1, 2, or 3 g/kg) intraperitoneally and were paired 4× for 30 minutes each with 1 of 2 stimulus males: with the CS- stimulus male after saline injection and with the CS+ male following EtOH. After pairing, time spent with CS+ and CS- males was measured in a 10-minute test.


RESULTS
ORCHX+T test males showed conditioned preference for the CS+ male in response to 3 g/kg EtOH (change in preference: +71.3 ± 30.0 s/10 min, p < 0.05), but not for 0, 1, or 2 g/kg. By contrast, ORCHX males did not demonstrate conditioned preference for 3 g/kg EtOH (+16.0 ± 24.3 s/10 min, p > 0.05). In separate groups of mice, stimulus males (IS+) received EtOH during pairing to determine whether test mice prefer another intoxicated mouse. Both ORCHX+T and ORCHX test mice showed an increase in preference score for the IS+ mouse (ORCHX+T: +68.1 ± 24.0 seconds; ORCHX: +58.9 ± 19.6 seconds, p < 0.05).


CONCLUSIONS
These data demonstrate that EtOH promotes social preference in male mice, as it does in females. Testosterone enhances this effect.
Department of Cell and Neurobiology , Keck School of Medicine of the University of Southern California, Los Angeles, California; Neuroscience Graduate Program, University of Southern California, Los Angeles, California.
Kelly
K
Kent
Kaelan
K
Butler
Ruth I
RI
Wood
D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000008:administration & dosage*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D012919:Social Behavior
D000431:Ethanol
Alcoholic Intoxication; Association Learning; Conditioning, Classical; Social Behavior; Testosterone