Greater splanchnic nerve activity in the rat.

The greater splanchnic nerve trunks in the rat, unlike in other experimental animals, do not join celiac plexus directly. These nerve trunks join small ganglia, the cardiac ganglia, on either side. The cardiac ganglia are located about 1 cm rostro-lateral to unpaired celiac ganglion. The greater splanchnic nerve activity immediately proximal to celiac ganglion is predominantly post-ganglionic in the rat. On the other hand, the activity of the greater splanchnic nerve proximal to the celiac ganglion is predominantly preganglionic in other experimental animals, (e.g., cat), In the rat, preganglionic sympathetic nerve activity is predominant in the segment of the greater splanchnic nerve proximal to the cardiac ganglion.