Background: Accumulation of α-synuclein in multiple system atrophy (MSA) affects medullary autonomic and respiratory control areas, including the rostral ventrolateral medulla and raphe nuclei. Relative neuronal vulnerability and its relationship to α-synuclein accumulation in these areas are unknown. The aim of this study was to determine the extent of loss of adrenergic neurons in the rostral ventrolateral medulla and serotonergic neurons in the ventrolateral medulla and raphe nuclei and its relationship with α-synuclein accumulation.
Methods: Medullary sections from 7 MSA and 6 control subjects were processed for tyrosine hydroxylase, tryptophan hydroxylase, and α-synuclein immunoreactivity. Neuronal counts were performed stereologically, whereas α-synuclein burden in oligodendrocytes and neurons was quantified using object detection density (area/mm2).
Results: All MSA cases had orthostatic hypotension; 5 had laryngeal stridor. There was marked neuronal loss in the rostral ventrolateral medulla and medullary raphe in all cases. Most severely affected were tyrosine hydroxylase ventrolateral medulla (C1) neurons (83% reduction), followed by tryptophan hydroxylase neurons in the ventrolateral medulla (70%), raphe obscurus (56%), pallidus (57%), and magnus (47%). α-Synuclein accumulation occurred predominantly as glial cytoplasmic inclusions with rare α-synuclein accumulation occurring within the remaining neurons. Density of α-synuclein did not correlate with neuronal loss in any of the areas analyzed, and there was no correlation between α-synuclein density and disease duration for any regions of interest.
Conclusions: These findings indicate that in MSA adrenergic neurons are more susceptible than serotonergic neurons in the medulla. Further, loss of medullary monoaminergic neurons may progress independently from α-synuclein accumulation in MSA. © 2016 International Parkinson and Movement Disorder Society.
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http://dx.doi.org/10.1002/mds.26798 | DOI Listing |
Auton Neurosci
January 2025
Departments of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA. Electronic address:
During exercise circulatory adjustments to meet oxygen demands are mediated by multiple autonomic mechanisms, the skeletal muscle exercise pressor reflex (EPR), the baroreflex (BR), and by feedforward signals from central command neurons in higher brain centers. Insulin resistance in peripheral tissues includes sensitization of skeletal muscle afferents by hyperinsulinemia which is in part responsible for the abnormally heightened EPR function observed in diabetic animal models and patients. However, the role of insulin signaling within the central nervous system (CNS) is receiving increased attention as a potential therapeutic intervention in diseases with underlying insulin resistance.
View Article and Find Full Text PDFBackground: Prostaglandin E (PGE) in the rostral ventrolateral medulla (RVLM) has been recognized as a pivotal pressor substance in hypertension, yet understanding of its effects and origins in the RVLM remains largely elusive. This study aimed to elucidate the pivotal enzymes and molecular mechanisms underlying PGE synthesis induced by central Ang II (angiotensin II) and its implications in the heightened oxidative stress and sympathetic outflow in hypertension.
Methods And Results: RVLM microinjections of PGE and Tempol were administered in Wistar-Kyoto rats.
Front Physiol
December 2024
Biomedical Science Department, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States.
Myocardial ischemia causes the production and release of metabolites such as bradykinin, which stimulates cardiac spinal sensory afferents, causing chest pain and an increase in sympathetic activity referred to as the cardiogenic sympathetic afferent reflex. While the brain stem nuclei, such as the nucleus tractus solitarius and rostral ventrolateral medulla, are essential in the cardiogenic sympathetic afferent reflex, the role of other supramedullary nuclei in the cardiogenic sympathetic afferent reflex are not clear. The dorsomedial hypothalamic nucleus (DMH) is involved in cardiovascular sympathetic regulation and plays an important role in the sympathetic response to stressful stimuli.
View Article and Find Full Text PDFCardiovasc Res
December 2024
Laboratory of Cardiorespiratory Control, Department of Physiology, Pontificia Universidad Católica de Chile, Av. Libertador Bernardo O'Higgins 340, Santiago 8331150, Chile.
Aims: Heart failure (HF) is an emerging epidemic worldwide. Despite advances in treatment, the morbidity and mortality rate of HF remain high, and the global prevalence continues to rise. Common clinical features of HF include cardiac sympathoexcitation, disordered breathing, and kidney dysfunction; kidney dysfunction strongly contributes to sodium retention and fluid overload, leading to poor outcomes of HF patients.
View Article and Find Full Text PDFBrain Behav Immun
February 2025
Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-Sen University, Guangzhou, Guangdong, 510080, China; National-Local Joint Engineering Research Center for Stem Cells and Regenerative Medicine, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, Guangdong, 510080, China. Electronic address:
The reduction in B lymphocytes observed in individuals with anxiety disorders may compromise antiviral responses, yet the precise mechanisms behind this decline remain unclear. While elevated glucocorticoid levels have been suggested as contributing factors, anxiety disorders are associated with diminished glucocorticoid signaling. Given that autonomic nervous system dysfunction is a hallmark of anxiety disorders, we established an anxiety-related behavior mouse model by stimulating C1 neurons in the rostral ventrolateral medulla.
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