Given the ongoing opioid crisis, there remains a need to elucidate the neural mechanisms underlying opioid use disorder with molecular, temporal and spatial precision using newer circuit manipulation strategies in animal models.<h4>Objectives</h4>We sought to characterize the behavioral effects of chemogenetic manipulations of 5-HT DRN neurons in male and female Tph2-iCre rats.<h4>Methods</h4>Subjects received intra-DRN viral infusions of Cre-dependent inhibitory or excitatory Designer Receptors Exclusively Activated by Designer Drugs (DREADDs). Here, TPH2 is linked to opioid use disorder.