Serotonin (5-HT) has been implicated in centrally mediated compensatory responses to volume loss in rats. Accordingly, we hypothesized that slowly developing, non-hypotensive hypovolemia increases serotonin in the hindbrain nucleus of the solitary tract (NTS). We produced volume loss in adult male rats by administering hyperoncotic polyethylene glycol (PEG) and then assessed 5-HT levels in the NTS using measurements of tissue 5-HT content or 5-HT immunohistochemistry. The results show selective increases of 5-HT in the caudal NTS after PEG treatment, but no change in the primary 5-HT metabolite, 5-HIAA. Moreover, the intensity of 5-HT immunolabeled fibers in the caudal NTS was increased after PEG treatment. These findings suggest that, after PEG-induced hypovolemia, 5-HT accumulates in neural elements in the caudal NTS. We propose that this accumulation is attributable to an initial release of 5-HT that then acts at presynaptic autoreceptors to inhibit subsequent 5-HT release.
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http://dx.doi.org/10.1007/s12576-012-0229-4 | DOI Listing |
Am J Physiol Lung Cell Mol Physiol
January 2025
Instituto de Ciencias Biomédicas, Universidad Autónoma de Chile, Santiago, Chile.
Chronic intermittent hypoxia (CIH), the main feature of obstructive sleep apnea, heightened chemosensory discharges of the carotid body (CB), which contributes to potentiate the ventilatory hypoxic response and elicits hypertension. We aimed to determine: 1) whether the persistence of cardiorespiratory alterations found in long-term CIH depend on the inputs from the CB and, 2) in what extension the activation of glial cells and neuroinflammation in the caudal region of the nucleus of the Solitary Tract (NTS) requires functional CB chemosensory activity. To evaluate these hypotheses, we exposed male mice to CIH for 60 days.
View Article and Find Full Text PDFJ Comp Neurol
December 2024
Department of Neurology, University of Iowa, Iowa City, Iowa, USA.
Mol Metab
January 2025
Research Institute of the McGill University Health Centre, McGill University Health Centre, 1001 boulevard de Decarie, Montreal, QC, H4A 3J1, Canada; Division of Experimental Medicine, Department of Medicine, McGill University, 1001 boulevard de Decarie, Montreal, QC, H4A 3J1, Canada; Integrated Program in Neuroscience, Department of Medicine, McGill University, Room 302 Irving Ludmer Building, 1033 Pine Ave. W. Montreal, QC, H3A 1A1, Canada. Electronic address:
Objective: Growth differentiation factor 15 (GDF15) acts on the receptor dimer of GDNF family receptor alpha-like (GFRAL) and Rearranged during transfection (RET). While Gfral-expressing cells are known to be present in the area postrema and nucleus of the solitary tract (AP/NTS) located in the brainstem, the presence of Gfral-expressing cells in other sites within the central nervous system and peripheral tissues is not been fully addressed. Our objective was to thoroughly investigate whether GFRAL is expressed in peripheral tissues and in brain sites different from the brainstem.
View Article and Find Full Text PDFNeurosci Bull
November 2024
Department of Neurobiology, Hebei Medical University, Shijiazhuang, 050017, China.
The central amygdala (CeA) is a crucial modulator of emotional, behavioral, and autonomic functions, including cardiovascular responses. Despite its importance, the specific circuit by which the CeA modulates blood pressure remains insufficiently explored. Our investigations demonstrate that photostimulation of GABAergic neurons in the centromedial amygdala (CeM), as opposed to those in the centrolateral amygdala (CeL), produces a depressor response in both anesthetized and freely-moving mice.
View Article and Find Full Text PDFInnovation (Camb)
November 2024
National Institute of Biological Sciences, Beijing 102206, China.
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