The sympathetic nervous system is important in maintaining cardiovascular homeostasis. 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 is still not fully known. This neuroanatomical study aimed to map the topographical distribution of RVLM-projecting PVN neurons. Four different carboxylate FluoSphereTM retrograde tracers (blue, 365/415; green, 505/515; red, 565/580; and far-red, 660/680) were injected 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. RVLM-projecting neurons were also identified within the dorsal, ventral, and posterior parvocellular subnuclei of the PVN with no labeling found in the anterior parvocellular or magnocellular subnuclei. Additionally, we 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 data for future research investigating the functional and histochemical properties of these PVN neurons.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:honors-1902 |
| Date | 01 May 2022 |
| Creators | Fuller, Nicolas |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Undergraduate Honors Theses |
| Rights | Copyright by the authors., http://creativecommons.org/licenses/by-nc-nd/3.0/ |
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