Topography and neurochemistry of the enteric ganglia in the proventriculus of the duck (Anas platyrhynchos)

The topographical distribution of the enteric ganglia has been investigated in the proventriculus of the duck using protein gene product 9.5 (PGP 9.5) immunohistochemistry. Myenteric ganglia were usually located between the outer longitudinal and the inner circular muscle layer. Submucous ganglia were sparsely distributed and seemed to be substituted by ganglia located in the tunica mucosa. The neurochemical profile of proventricular ganglion cells was also investigated using nicotinamide adenine dinucleotide phosphate reduced-diaphorase (NADPH-d)-histochemistry and pituitary adenylate cyclase activating peptide (PACAP)/galanin (Gal) double-labelling immunohistochemistry. The majority of mucosal ganglion cells were shown to contain the NADPH-d enzyme and both the investigated peptides. These findings provide evidence for the presence of a mucosal ganglionated plexus in the glandular stomach of birds. Moreover, the neurochemical characteristics of this plexus suggest that it plays an important role in regulating several mucosal functions and, in particular, the production and the composition of the gastric juice.