Fig. 4. Influence of the peptide of the inhibitor protein (CKIINtide) of CaMKII on halothane-induced biphasic effects on pCa-induced force. 0/0 = time controls (without halothane or CKIINtide); Force = pCa 6.3–induced force expressed as a percentage of the control force (steady state force before the administration of halothane) in mean ± SD (n = 3–6); [CKIINtide]= concentrations of CKIINtide where 0/0 = without halothane or CKIINtide; 0 or [CKIINtide]i = 0 μm or a specific CKIINtide concentration up 1 μm plus one of the halothane concentrations (1, 2, or 3%); *=P < 0.05 compared to no halothane or bisindolylmaleimide (0/0); #= compared to 0 μm in the presence of halothane (0). The increased force (0 vs.  0/0, A ) by 2% halothane was not significantly affected by CKIINtide, and by 3% halothane was reduced by 0.1 μm CKIINtide. In contrast, the decreased force (0/0 vs.  0, B ) was partially prevented by 0.01 and 0.1 mm CKIINtide at 1% halothane, by 0.1 and 1 μm CKIINtide at 2% halothane, and by 1 μm at 3% halothane.