Loss of forebrain 5-HT1A receptors results in a depression-like phenotype Suppression of 5-HT1A heteroreceptors alters mPFC-DRN responses to stress Suppression of 5-HT1A heteroreceptors results in altered 5-HT tone Selective loss of mPFC 5-HT1A receptors at adolescence recapitulates the phenotype