It appears that exercise may shorten the time necessary for fluoxetine to become effective at reducing anxiety possibly through a similar desensitization of 5-HT2C receptors, especially as the anxiogenic effects of antidepressant treatment have been argued to be mediated by BNST 5-HT2C activation (Pelrine et al., 2016). The gene discussed is HTR2C; the disease is Anxiety.