Journal of Neuroscience, Vol 6, 2371-2383, Copyright © 1986 by Society for Neuroscience
Topography of NPY-, somatostatin-, and VIP-immunoreactive, neuronal subpopulations in the guinea pig celiac-superior mesenteric ganglion and their projection to the pylorus
B Lindh, T Hokfelt, LG Elfvin, L Terenius, J Fahrenkrug, R Elde and M Goldstein
The topography of the peptidergic neuronal subpopulations in the guinea pig
celiac-superior mesenteric ganglion was studied analyzing the distribution
of immunoreactivity to neuropeptide Y (NPY), somatostatin (SOM), and
vasoactive intestinal polypeptide (VIP)/polypeptide HI (PHI). For
comparison, the ganglion was also studied using antisera against the 2
catecholamine-synthesizing enzymes tyrosine hydroxylase (TH) and dopamine
beta-hydroxylase (DBH). Approximately 65% of the neuronal cell bodies
contained NPY-like immunoreactivity (NPY-LI), whereas 25% of the principal
ganglion cells contained SOM-like immunoreactivity (SOM-LI). Though
occasional cells were found to contain both NPY-LI and SOM-LI, these
peptides had a complementary distribution in the ganglion, with NPY cells
in the celiac poles and SOM cells in the superior mesenteric pole. The vast
majority of both the NPY- and SOM-positive cells also contained TH-like
immunoreactivity (TH-LI), confirming their catecholaminergic, presumably
noradrenergic, nature. Some noradrenergic neurons seemed to lack NPY- and
SOM-LI. Small numbers of VIP/PHI-containing cell bodies were found in areas
where the NPY-immunoreactive neurons predominated. Many of the VIP/PHI-
positive cells contained NPY-LI and occasionally also TH-LI. The
immunohistochemical markers were also observed in fibers. Thus, a
comparatively weak NPY-LI was seen in smooth fibers, probably representing
axons and axon bundles. SOM-LI was seen in a similar type of fiber but also
in more strongly fluorescent fibers with a varicose appearance. The latter
fibers were observed only in the SOM-dominated part of the ganglion, often
surrounding the ganglion cells. Varicose fibers with a similar distribution
containing DBH-like immunoreactivity (DBH-LI) were also seen. In addition,
DBH- and TH-LI were seen in smooth axonlike processes. VIP-positive fibers
exhibited a very dense fiber network, almost exclusively related to the SOM
cell-dominated part of the ganglion. The projection of the postganglionic
sympathetic neurons was studied with special reference to the pylorus using
a combination of retrograde axonal tracing and indirect immunofluorescence
techniques. Seventy-two hours after injection of the fluorescent tracer
Fast Blue into the pyloric sphincter, labeled neurons were found in the
ganglion. By comparing the Fast Blue-labeled cells with the immunoreactive
cell bodies, neurons containing both dye and NPY- or SOM-LI were observed.
In elution-restaining experiments, it was established that the majority of
these cells were also immunoreactive to TH, indicating that they produce
noradrenaline.(ABSTRACT TRUNCATED AT 400 WORDS)