ORCID

https://orcid.org/0009-0007-9390-957X

Keywords

Spinal afferent, DRG, Dorsal root ganglia, Anterograde tracing, Stomach, Spinal afferents of the stomach, Dextrin Biotin injection, DRG injection

Abstract

Chronic pain afflicts over 25 million Americans, with approximately 2 million developing opioid addiction due to insufficient treatment options. Visceral chronic pain, particularly abdominal pain, poses a significant clinical challenge, yet its underlying neural mechanisms remain poorly defined. This thesis presents a comprehensive anatomical analysis of spinal afferent innervation in the muscularis externa and submucosal layers of the rat stomach—two tissue compartments implicated in visceral sensation and pain. Using anterograde tracing, dextran-biotin was injected into thoracic dorsal root ganglia (T7–T11) of male Sprague Dawley rats (3–5 months) to label spinal afferent axons in the stomach. Flat-mount preparations of muscular and submucosal layers were imaged with high-resolution microscopy and reconstructed with Neurolucida to generate detailed 3D distribution maps. In the muscular layer, spinal afferents formed distinct terminal morphologies—ganglionic, muscle, mixed, and vascular—distributed across the fundus, corpus, and antrum. In the submucosal layer, axons exhibited branching, vascular, and mixed endings, often in connective tissue and around blood vessels. Collectively, these dual-layer data establish a foundational anatomical framework for future investigations into visceral afferent signaling and the pathophysiology of chronic abdominal pain. Informing the development of targeted, non-opioid neuromodulatory interventions.

Completion Date

2025

Semester

Summer

Committee Chair

Cheng, Zixi (Jack)

Degree

Master of Science (M.S.)

College

College of Medicine

Department

Burnett school of biomedical science

Format

PDF

Identifier

DP0029573

Language

English

Document Type

Thesis

Campus Location

Orlando (Main) Campus

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