Fig. 6. Dose–response relation of protein kinase C inhibitors on phorbol-12,13-dibutyrate (PDBu)–induced force. Bim = bisindolylmaleimide I HCl, a protein kinase C inhibitor of conventional–novel protein kinase C; Go6976 = a conventional protein kinase C inhibitor. Mean ± SD (n = 3). Force at 15 min after administration of the inhibitor is expressed as percent of control force (steady state force before administration of the inhibitor). Dimethyl sulfoxide, 1%, was used to dissolve Go6976. *P < 0.05 compared with that of time control at 0 μm bisindolylmaleimide or Go6976. This figure shows that PDBu-induced force was dose-dependently decreased by bisindolylmaleimide (A ), but not by Go6976, except at 30 μm (B ).