Fig. 1. (A ) Example of an inward chloride current (I^Cl(Ca)) induced by 10 s administration of lysophosphatidate (LPA, 1 μm) in oocytes expressing endogenous LPA receptors (0.96 μA). (B ) LPA evokes I^Cl(Ca)in a concentration-dependent manner. Curve fitting using the Hill equation revealed a half-maximal effect concentration (EC⁵⁰) of 288 ± 30 nm. (C ) Example trace of I^Cl(Ca)induced by 10 s administration of methylcholine (MCh, 1 μm) in oocytes expressing muscarinic m3 receptors (0.87 μA). (D ) Concentration–response relation for MCh-induced I^Cl(Ca). Curve fitting using the Hill equation revealed an EC⁵⁰of 200 ± 70 nm.