Fig. 3. The effect of cadmium (50 µmol l^–1) and/or various effectors on pHi of isolated digestive gland cells of Mytilus galloprovincialis. Cells were treated with PMA, a potent activator of protein kinase C, alone (10 nmol l^–1) or cadmium (50 µmol l^–1) alone, or + 20 nmol l^–1 calphostin C (a specific inhibitor of protein kinase C). The results are mean ± S.D. of at least 7 independent experiments. In each experiment, the tissue of four animals was used. ^*Significant difference between the values obtained after treatment of the cells with PMA or with cadmium and the control value at the respective time point; Dunnet's test, P<0.01.