Substance P: Immunocytochemical Localization and Codistribution with Tyrosine Hydroxylase in the Vagal Nuclei of the Rat
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Authors
Emig, Laura L.
Issue Date
1992
Type
Thesis
Language
en_US
Keywords
Alternative Title
Abstract
The dorsal motor nucleus of the vagus (DMV) located in the hindbrain
medulla of the brain is the origin of preganglionic parasympathetic outflow to
the stomach. Neurotransmitters and neuropeptides contained within the
DMV are ultimately responsible for innervation of the stomach. Innervation
occurs through the vagus nerve which connects the DMV to the the stomach
and causes gastric motility. In the present study, immunocytochemical
labeling in the medulla of rats was used to determine the distribution pattern
of substance P (SP) a neuropeptide, and its relationship to tyrosine
hydroxylase (TH), an enzyme precursor to dopamine. Results showed a dense
network of SP-immunoreactive (SP-ir) fibers and terminals throughout the
levels of the DMV as well as in the adjacent nucleus tractus solitarius (NTS)
which is the afferent vagal nuclei. Some SP-ir cell bodies were present in the
DMV at caudal levels, however, none were observed in this nucleus at
further rostral levels. This result is in contrast to the situation in the cat,
where SP-ir neurons are dense throughout the DMV and, therefore, indicates
a species difference regarding distribution of SP-ir cells in the vagal nuclei.
To evaluate the distribution of SP in relation to that of tyrosine hydroxylase
(TH) in the area of the DMV, dual-staining immunocytochemical techniques
were used for both SP and TH. The pep tides were found to have similar
distribution patterns in the caudal DMV and rostral NTS. Thus, SP and TH
are said to be codistributed which suggests a functional interaction between
the two neuromodulators. in controlling gastric motility; however, further
experimental studies are necessary to elucidate the possibility of coexistence of
the two peptides within the same neuron in the DMV and NTS.
Description
v, 46 p.
Citation
Publisher
Kalamazoo College
License
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