OPRL1 and pulmonary arterial hypertension: The up-regulated genes in this pathway were, DRD2, GLP1R, HTR1A, OPRL1 and PTGER3, and, the down-regulated genes were, P2RY13, PRLR. These genes are involved in G-protein coupled receptor signaling, and GLP1R is being recommended for PAH therapeutics31.