The innervation of the rat stomach has been re-analyzed using
immunohistochemical localization of cholinergic markers. These
include the common type of choline acetyltransferase (cChAT) and the
peripheral type (pChAT), which is the product of a splice variant of
ChAT mRNA and preferentially localized to peripheral cholinergic
nerves. In addition we studied the immunolocalization of vesicular
acetylcholine transporter (VAChT), neuronal nitric oxide synthase
(nNOS) and tyrosine hydroxylase (TH). Paraffin embedded tangential
sections from the rat stomach were used to demonstrate the
immunolocalization of cholinergic and nitrergic neurons and nerve
fibers in the rat stomach using antibodies to pChAT, cChAT, VAChT
and nNOS. A ganglionated submucosal plexus (SP) was almost absent
from the gastric wall, apart from some scattered neurons. Most
myenteric plexuses (MP) in the rat stomach showed positive
immunostaining for pChAT, cChAT and nNOS only, whereas VAChTand
TH-immunoreactivities (IR) were observed in the form of varicose
nerve fibers and nerve terminals in the rat gastric wall. These results
indicate that in the rat gastric wall, submucosal and myenteric nerve
fibers showed heterogeneous staining with regard to the examined regulatory peptides and transmitters. The submucosal neurons were
almost absent, while the myenteric neurons showed only pChAT,
cChAT and nNOS immunostaining suggesting morphological evidence
for the roles of cholinergic, nitrergic and adrenergic mechanisms in
stomach secretory and motor functions.