Nociceptive afferents from spinal dorsal root ganglia and vagal nodose ganglia innervate the stomach and send sensory signals centrally to the brain and locally to the enteric nervous system. Such nociceptive afferents are detected with a variety of markers and can be visualized using immunohistochemistry under the confocal laser scanning microscope. Calcitonin gene-related peptide (CGRP) is one of the main neurotransmitters of nociceptive sensory fibers and was used as a marker in this study to label afferent axons and terminals in the whole stomach flat-mount. Previous investigations in the sectioned stomach have shown the presence of these sensory nerve fibers, however, their topographical distribution across the whole stomach has not been well established. Using mice and rats as two rodent models, we combined the immunohistochemistry labeling with the latest advanced neuroimaging technologies to illustrate the topographical organization and morphological structure of CGRP-IR (immunoreactive) axons and terminals in the whole stomach across animals as well as investigate the variability of their innervation pattern based on laterality. These axons were found densely innervating the vasculature, myenteric ganglia, longitudinal muscles, and circular muscles. With MBF's novel software Neurolucida 360®, these axons and terminals were digitally marked, traced, and reconstructed into a map of a fully innervated stomach, then these topographical maps were mathematically integrated into a 3D stomach scaffold. For the first time, a wholistic map of the nociceptive afferent CGRP-IR axon innervation of a whole stomach at single cell/axon/synapse resolution is provided and integrated into the stomach-brain atlas. This map also improves the understanding of the functional roles that CGRP has in relaxation of the smooth muscles, vasodilation, and protective mechanisms that are crucial to physiological and pathological conditions.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:etd2020-2623 |
| Date | 01 January 2022 |
| Creators | Nguyen, Duyen |
| Publisher | STARS |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Electronic Theses and Dissertations, 2020- |
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