Toward an understanding of the molecules that sense myocardial ischemia.

Cardiac afferent neurons are activated in the setting of myocardial ischemia and mediate the sensation of angina. However, the precise stimuli and receptive molecules responsible are not completely understood. To further investigate the molecular components involved, cardiac afferents were isolated in dissociated culture and patch-clamp experiments were performed on these cells. It was found that acidic pH evoked large inward currents in almost all cardiac sympathetic afferents. By comparison, the responses to other potential chemical mediators were inconsistent and much smaller. The biophysical properties of the acid-evoked currents in cardiac afferents match the acid-sensing ion channel 3 (ASIC3).