SLC6A4 and pulmonary arterial hypertension: Serotonin-dependent ROS production in hPASMCs was dependent on 5-HT1BR in control hPASMCs, whereas in PAH-hPASMCs this was mediated by both the SERT and the 5-HT1BR. Consistently, there is an increase in SERT expression in PAs and hPASMCs from PAH patients.26 Female mice overexpressing SERT have a PH phenotype.6 There is co-operation between SERT and 5-HT1BR in human and experimental PAH,5,20 and dual blockade of the 5-HT1BR and SERT is a plausible therapeutic approach.