Anterograde tracing of spinal afferent innervation in flat-mounts of the rat stomach

Study Purpose: The dorsal root ganglia (DRG) project spinal afferent axons to the stomach. However, the distribution and morphology of spinal afferent axons in the stomach have not been well characterized. In this study, we injected anterograde tracer Dextran Biotin (DB) into the left thoracic DRG T7-T11 to characterize spinal afferent axons and their terminal structures in flat-mounts of the whole rat stomach muscular wall.

Data Collection: This dataset displays the digitally traced spinal afferent axons and their terminal structures in flat-mounts of the whole rat stomach muscular wall using tracer Dextran Biotin into the left thoracic DRG T7-T11.

Primary Conclusion: We found that DB-labeled axons innervated all stomach regions (fundus, corpus, antrum) with a variety of distinct terminal structures innervating gastric targets (myenteric ganglia, longitudinal and circular muscles, blood vessels): 1) The ganglionic type: some axons formed varicose contacts with individual neurons within myenteric ganglia. 2) The muscle type: the majority of axons ran in parallel with the longitudinal and circular muscles and expressed spherical varicosities. Furthermore, complex terminal structures were observed within the circular muscle layer. 3) The ganglia-muscle mixed type: some individual varicose axons innervated both myenteric ganglia and circular muscles, exhibiting polymorphic terminal structures. 4) The vascular type: individual varicose axons ran along the blood vessels and occasionally traversed the vessel wall. This work provides a foundation for future topographical anatomical, functional, and molecular mapping of spinal afferent axon innervation of the stomach under normal and pathophysiological conditions.

Curator's Notes

Experimental Design: A mixture of dextran conjugates was injected into the dorsal root ganglia T7- T11 of adult Sprague-Dawley rats. 16 days after the tracer injection, the animals were sacrificed, ventral and dorsal stomachs were prepared and processed for avidin-biotin permanent labeling and Cuprolinic Blue labeling. All flat-mounts were examined using a Zeiss M2 Imager and MicroBrightField’s Neurolucida tracing and digitization system to determine the distribution and terminal structures of spinal afferent axons.

Completeness: This dataset is part of a larger study: " Nociceptive Afferent Topographical Innervation of the Heart and Stomach"

Subjects & Samples: Male (n=6) adult Sprague Dawley (RRID: RGD_737903) rats were used in this study.

Primary vs derivative data: Primary data is organized in folders by subject ID and subfolders denoted by sample ID. Each folder contains Neurolucida tracing files .XML with digitally traced spinal afferent axons and their terminal structures. Currently, there is no derivative data folder.

Important Notes: For a comprehensive understanding of this dataset, including specific study protocols and findings, refer to the primary publication