Ryanodine and cyclopiazonic acid significantly reduced the rate of spontaneous beating and modified action potential characteristics in guinea-pig sino-atrial node preparations.
Calcium release from the sarcoplasmic reticulum plays a previously unrecognized role in sino-atrial node pacemaking, likely through regulation of sarcolemmal ionic currents.
Ryanodine and cyclopiazonic acid were used to alter the ability of the sarcoplasmic reticulum (SR) to store calcium. Interventions of this kind significantly reduced the rate of spontaneous beating of guinea-pig sino-atrial node preparations. In addition, both of these drugs decreased the rate of rise and modified other characteristics of the action potentials recorded from this region. It is proposed that calcium released from the SR plays an important, previously unrecognized, role in pacemaking in the sino-atrial node, possibly through regulation of sarcolemmal ionic currents.
Rigg et al. (Sun,) reported a other. Ryanodine and cyclopiazonic acid was evaluated on Rate of spontaneous beating and action potential characteristics. Ryanodine and cyclopiazonic acid significantly reduced the rate of spontaneous beating and modified action potential characteristics in guinea-pig sino-atrial node preparations.