Inhibition of cyclic GMP hydrolysis with zaprinast reduces basal and cyclic AMP-elevated L-type calcium current in guinea-pig ventricular myocytes.

(1) Cyclic GMP (cGMP) has been shown to be an important modulator of cardiac contractile function. A major component of cGMP regulation of contractility is cGMP-mediated inhibition of the cardiac calcium current (I(Ca)). An under-appreciated aspect of cyclic nucleotide signalling is hydrolysis of the cyclic nucleotide (i.