EFFECTS OF BIOLOGICAL SEX ON ADDICTIVE BEHAVIOR
The neuropeptide dynorphin activates kappa opioid receptors (KORs) throughout the central nervous system. When KORs in reward-related brain regions are activated, aversive and depressive-like behaviors are observed in humans and rodents. However, these findings have predominantly been described in males. We found that females (rats) do not have the the same robust aversive response to KOR activation. This is consistent with males and females using different neural systems for stress responses and emotional regulation.
Russell SE, Rachlin AB, Smith KL, Muschamp J, Berry L, Zhao Z, Chartoff EH. Sex differences in sensitivity to the depressive-like effects of the kappa opioid receptor agonist U-50488 in rats. Biological Psychiatry. Biol. Psychiatry. 2014.76:213-222.