The sympathetic nervous system plays an important role in maintaining cardiovascular regulation. Elevated cardiovascular-related sympathetic activity can lead to neurogenic hypertension and a host of other serious cardiac related abnormalities. The paraventricular nucleus (PVN) of the hypothalamus plays an important role in sympathetic cardiovascular regulation. Neurons from the PVN project to the rostral ventrolateral medulla (RVLM), which is the main brain stem sympathetic cardiovascular control center. While RVLM-projecting PVN neurons have been well characterized, the topographical organization within the PVN subnuclei are still not fully known. The goal of this neuroanatomical study was to map the topographical distribution of RVLM-projecting PVN neurons. To do this we microinjected four different carboxylate FluoSphere retrograde tracers (blue, 365/415; green, 505/515; red, 565/580; and far red, 660/680) at different rostro-caudal coordinates within the RVLM. The vast majority of RVLM-projecting PVN neurons were ipsilateral and located in the medial parvocellular subnucleus. Whereas most neurons were ipsilateral, there is a small fraction of neurons that crossed the midline. Neurons were also identified within the dorsal, ventral, and posterior parvocellular subnuclei of the PVN and no labeling in the anterior parvocellular or magnocellular subnuclei. We unexpectantly observed different efficiencies of the retrograde tracers with blue (365/415) being the least efficient and red (565/580) being the best. These neuroanatomical data will serve as important preliminary functional and histochemical data for future research studies.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:asrf-1990 |
| Date | 07 April 2022 |
| Creators | Fuller, Nicolas F, Zahner, Matthew R, Dr. |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Detected Language | English |
| Type | text |
| Source | Appalachian Student Research Forum & Jay S. Boland Undergraduate Research Symposium |
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