The afferent innervation of the liver: a horseradish peroxidase study in the rat.

Scattered injections of horseradish peroxidase (HRP) into the rat liver produced labeling of a small number of large neurons located only in the rostral pole of the left nodose ganglion. The same amount injected in a single lobe also produced labeling of a few cells in Th7-Th10 dorsal root ganglia. No retrograde marking followed subcapsular injections. HRP injections around the porta hepatis yielded labeling of large and small neurons in the left nodose ganglion only. This indicates that most of the afferent fibers are of vagal origin, and that different receptors are located in different parts of the liver.