1. The nociceptive inputs of the paraventricular hypothalamic nucleus in formalin stimulated mice.
- Author
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Ren S, Wang S, Lv S, Gao J, Mao Y, Liu Y, Xie Q, Zhang T, Zhao L, and Shi J
- Subjects
- Animals, Male, Calcitonin Gene-Related Peptide metabolism, Mice, Nociception drug effects, Nociception physiology, Proto-Oncogene Proteins c-fos metabolism, Neurons metabolism, Neurons drug effects, Oxytocin metabolism, Pain metabolism, Pain chemically induced, Parabrachial Nucleus metabolism, Parabrachial Nucleus drug effects, Paraventricular Hypothalamic Nucleus metabolism, Paraventricular Hypothalamic Nucleus drug effects, Formaldehyde toxicity
- Abstract
The paraventricular hypothalamic nucleus (PVH) is an important neuroendocrine center involved in pain regulation, but the nociceptive afferent routes for the nucleus are still unclear. We examined the profile of PVH receiving injurious information by a combination of retrograde tracing with Fluoro-Gold (FG) and FOS expression induced by formalin stimuli. The result showed that formalin injection induced significantly increased expression of FOS in the PVH, among which oxytocin containing neurons are one neuronal phenotype. Immunofluorescent staining of FG and FOS revealed that double labeled neurons were strikingly distributed in the area 2 of the cingulate cortex (Cg2), the lateral septal nucleus (LS), the periaqueductal gray (PAG), the posterior hypothalamic area (PH), and the lateral parabrachial nucleus (LPB). In the five regions, LPB had the biggest number and the highest ratio of FOS expression in FG labeled neurons, with main subnuclei distribution in the external, superior, dorsal, and central parts. Further immunofluorescent triple staining disclosed that about one third of FG and FOS double labeled neurons in the LPB were immunoreactive for calcitonin gene related peptide (CGRP). In conclusion, the present study demonstrates the nociceptive input profile of the PVH area under inflammatory pain and suggests that neurons in the LPB may play essential roles in transmitting noxious information to the PVH., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)
- Published
- 2024
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