A simulation model for putative neuromodulatory mechanisms in local cardiac control

Traditionally, arterial blood pressure, heart rate, atrial-ventricular conduction and myocardial contractility have been considered to be solely governed by the central nervous system. This convention is now challenged by the recent converging evidence that cardiac ganglia around the heart may have complex integrative function. Using neuronal tracing and laser confocal microscopy, we have mapped the local neural circuitry around the heart and proposed a local reflex loop. In order to study the functionality of this circuitry, we use a biophysical model to simulate the behavior of the proposed local reflex loop. The preliminary results show that this local cardiac reflex loop predicts behavior that is consistent with the Bainbridge reflex in the sense that venous infusion increases the heart rate without obvious change of the system blood pressure