Oxytocin decreases alcohol self-administration in male baboons

The neurohormone oxytocin (OT) has been proposed as a treatment for alcohol and nicotine use disorders. The aim of the present study was to examine whether intravenous (IV) OT decreases alcohol oral self-administration and consumption in nonhuman primates under a 6-h alcohol access procedure as well as alcohol and nicotine (IV) self-administration under 6-h concurrent access conditions. The subjects were five male baboons (Papio anubis) that self-administered oral alcohol (4% w/v) during 6-h sessions under a fixed ratio 3 (FR3) schedule per drink. Baseline levels of alcohol self-administration were established and then OT treatment was initiated. A single dose of OT (20, 40, 80, 120 IU, IV) or its vehicle (saline) was administered before and again in the middle of the 6-h drinking session for 5 consecutive days (total oxytocin dose of 40, 80, 160, 240 IU/day). After each 5-day treatment, baseline levels of alcohol self-administration were reestablished before the next 5-day OT treatment. In addition, the effect of OT on concurrent alcohol and IV nicotine self-administration was explored in 3 of the baboons where alcohol and nicotine were concurrently available during the 6-hr session each under an FR3 schedule for each drug. Establishment of baseline self-administration and 5-day OT treatments were completed as in the alcohol only study. There was a significant overall reduction in alcohol consumption with OT compared to placebo. On post-hoc analysis, after correcting for multiple comparisons, the 40 and 80 IU doses of OT significantly reduced alcohol consumption compared with vehicle, and consumption did not vary significantly within each 5-day treatment period. OT, qualitatively, also reduced the coadministration of both alcohol and nicotine in each baboon for at least one of the OT doses administered. These results underscore the therapeutic potential of oxytocin as a treatment of alcohol use disorder and possibly, co-use of nicotine.