Granulocyte-Colony Stimulating Factor Alters the Pharmacodynamic Properties of Cocaine in Female Mice.

Addiction to psychostimulants is a major public health crisis that leads to significant morbidity and mortality, for which there are currently no FDA-approved pharmacotherapies. Female subjects have increased propensity to develop pathological substance use disorders after initial use, suggesting the possibility of different pathophysiological mechanisms between males and females. Recently, we identified the neuroactive cytokine granulocyte-colony stimulating factor (G-CSF) as a key mediator of neuronal and behavioral plasticity in response to cocaine in male mice. Here, we found that G-CSF potentiated the rewarding effects of cocaine in female mice as well; however, the dopaminergic mechanism linked to these effects was highly dependent on the ovarian hormone cycle. G-CSF treatment enhanced the ability of cocaine to inhibit dopamine clearance; however, this effect was observed specifically during pro/estrus, when circulating ovarian hormone levels were high. These findings demonstrate important sex differences in the synaptic effects of this translationally relevant neuroimmune modulator.