Figure 3.

Effects of PTx pretreatment on time- and concentration-dependencies of MCh-stimulated cyclic AMP accumulations in CHO-m2m3 cells. CHO-m2m3 cell monolayers were pretreated with PTx (100 ng ml⁻¹, 24 h) or vehicle before challenge with either 1 mM MCh for the times indicated (a), or with different concentrations of MCh for 5 min (b). Incubations were terminated and extracts prepared for cyclic AMP mass determination as described in the Methods section. Data are shown as means±s.e. mean for three separate experiments performed in duplicate.