Regional cardiac ganglia projections in the guinea pig heart studied by postmortem DiI tracing.

Our purpose was to identify and localize intrinsic cardiac ganglia innervating distinct regions of the heart using postmortem tracing of nerve projections with DiI, a method not previously used to study the intrinsic cardiac nervous system. We also investigated the possibility of collateral innervation of myocardium and intrinsic ganglia. In isolated paraformaldehyde-fixed guinea pig hearts, crystals of DiI (1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate) were inserted into the posterior ventricular myocardium below the atrioventricular groove, the right atrium, or the left ventricular septum.