Spinal origins of cardiac afferents from the region of the left anterior descending artery.

The origins of coronary artery afferents coursing in sympathetic nerves was determined using retrograde axonal transport methods. Cells labeled with horseradish peroxidase were found bilaterally in dorsal root ganglia (DRG) C8 to T6 were smaller in size than non-labeled DRG neurons. The findings indicate a more extensive segmental distribution of cardiac afferents than was previously believed to exist.