Localization of parasympathetic preganglionic cell bodies innervating the pancreas within the vagal nucleus and nucleus ambiguus of the rat brain stem: evidence of dual innervation based on the retrograde axonal transport of horseradish peroxidase.

Traditionally studies have shown cell bodies of origin for parasympathetic preganglionic fibers of the subdiaphragmatic segment of the vagus nerve to be located in the dorsal motor nucleus of X. The nucleus ambiguus have been regarded as the motor nucleus for fibers projecting exclusively to larynx, pharynx and cervical esophagus. The results of the present study indicate that the pancreas has a dual source of innervation derived from both of these medullary nuclei, and that this in fact may be applicable for all or most of the subdiaphragmatic organs similarly innervated by the vagus.