PROSTAGLANDIN-F2-ALPHA RECEPTOR IS COUPLED TO GQ IN CDNA-TRANSFECTED CHINESE-HAMSTER OVARY CELLS

We examined intracellular signal transduction of prostaglandin F-2 alp ha (PGF(2 alpha)) receptors by transfection and stable expression of t he receptor cDNA in Chinese hamster ovary (CHO-PGF(2 alpha)) cells. Th e binding to the membrane was specific for PGF(2 alpha), and the Scatc hard plot analysis showed a. single high-affinity binding site (Kd=25. 2 nM). PGF(2 alpha) gradually elevated intracellular Ca2+ and stimulat ed phosphoinositide metabolism in CHO-PGF(2 alpha) cells. In whole-cel l clamp recordings, PGF(2 alpha) induced an outward current in the pre sence of external Ca2+, but it induced a long-lasting inward Ca2+ curr ent in a Na+-free solution containing K+ channel blockers. G(q alpha) antibody applied intracellularly blocked both outward and inward curre nts induced by 1 mu M PGF(2 alpha). These results demonstrate that the PGF(2 alpha) receptor is coupled to phosphoinositide metabolism in CH O-PGF(2 alpha) cells via G(q). (C) 1994 Academic Press, Inc.