Aortic Baroreceptor Afferents Express Receptors and Mediators of the Inflammatory Response

Study objective: To investigate whether baroreceptor afferents in rats subjected to systemic inflammation express receptors and mediators of the inflammatory response. Hypothesis: Baroreceptor afferents, traditionally known for regulating blood pressure, may also express receptors and mediators of inflammation, contributing to the communication between the immune system and the central nervous system during endotoxemia. Methods: Systemic inflammation was induced in male Sprague-Dawley rats (7–8 weeks old) using lipopolysaccharide (LPS; 1.5 milligrams/kilogram, intravenously). The aortic depressor nerve (ADN), aortic arch (AA), and nodose ganglion (NG) were collected at different time points: before (basal) and after saline (30 minutes) or LPS administration (30, 60, 90, and 120 minutes). Gene expression and total protein content of immune mediators were analyzed using RT-qPCR and Western blot. Data and results:Gene and protein expression analyses revealed that the ADN, AA, and NG express multiple immune mediators, including toll-like receptor 4 (TLR-4), nuclear factor kappa B (NF-κB), myeloid differentiation factor 88 (MyD88), mitogen-activated protein kinases (MAPK), interleukin (IL)-1β, IL-1β receptor (IL-1β-R), tumor necrosis factor (TNF)-α, TNF receptors (TNF-R1 and TNF-R2) in both control and LPS-treated animals. Notably, in the ADN, gene expression of NF-κB (2.84 ± 0.8 fold-change; n = 6; p = 0.04), IL-1β-R (5.01 ± 1.2 fold-change; n = 5; p = 0.005), and TNF-R2 (3.07 ± 1 fold-change; n = 6; p = 0.03) was upregulated 120 minutes post-LPS, suggesting activation of these pathways in baroreceptor afferents during systemic inflammation.Conclusions: These findings suggest a novel role for the ADN, previously recognized primarily for its role in blood pressure regulation, by showing that it may also participate in the sensing of inflammatory mediators and triggering reflex responses. Our research indicates that aortic baroreceptor afferents contribute to the modulation of inflammation, expanding the understanding of their function beyond cardiovascular regulation. FAPESP (2021/03764-8; 2021/05554-0; 2022/13361-0; 2020/06043-7), CAPES (88881.823812/2023-01) and CRID (2013/08216-2). This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.