Fig. 5. The proctolin-induced potentiation of K⁺-induced contracture is prevented by the PKC inhibitor BIM-1 and mimicked by the PKC activator PMA. Summary of independent experiments showing the maximum amplitude of contractures normalised to controls: in the presence of 1 µmol l^-1 proctolin (N=8), in the presence of proctolin and 10 nmol l^-1 BIM-1 (N=5), in the presence of BIM-1 (N=4) and in the presence of 1 µmol l^-1 of the PKC activator PMA (N=7) during high K⁺-saline application for 5 min. ^*Significantly different from controls, P<0.05.