Phosphatase inhibition by calyculin A increases if in canine Purkinje fibers and myocytes
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The actions of the phosphatase inhibitor calyculin A on the pacemaker current if were studied in canine Purkinje fibers and myocytes. Calyculin A increased if in response to hyperpolarizations toward the middle of the if activation curve. A three pulse protocol indicated this increase was due to a positive shift of if activation on the voltage axis. Taken together with our previous results (that kinase inhibition with H7 shits if activation in the negative direction on the voltage axis (2)), these results suggest that phosphorylation is an important regulator of the voltage dependence of if activation.
Key wordspacemaker current phosphorylation if Purkinje myocyte
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