[Effect of ethanol and polyethylene glycol-400 on frequency dependence of the inotropic effect of verapamil on the frog myocardium].

The PEG-400 was found to be neutral in respect to the frequency-dependent V negative inotropic action whereas ethanol enhanced this dependence. The findings suggest a possibility for V inotropic activity to be modified by lipophilic agents, provided they sterically complementary to hydrophobic domains of the Ca2(+)-channel structure.