Prostaglandin F2α Receptor Is Coupled to Gq in cDNA-transfected Chinese Hamster Ovary Cells

Abstract We examined intracellular signal transduction of prostaglandin F 2α (PGF 2α ) receptors by transfection and stable expression of the receptor cDNA in Chinese hamster ovary (CHO-PGF 2α ) cells. The binding to the membrane was specific for PGF 2α , and the Scatchard plot analysis showed a single high-affinity binding site (Kd=25.2 nM). PGF 2α gradually elevated intracellular Ca 2+ and stimulated phosphoinositide metabolism in CHO-PGF 2α cells. In whole-cell clamp recordings, PGF 2α induced an outward current in the presence of external Ca 2+ , but it induced a long-lasting inward Ca 2+ current in a Na + -free solution containing K + channel blockers. G qα antibody applied intracellularly blocked both outward and inward currents induced by 1 μM PGF 2α . These results demonstrate that the PGF 2α receptor is coupled to phosphoinositide metabolism in CHO-PGF 2α cells via G q .