In acute experiments on cats, stimulation of the caudal cardiac nerve inhibited tonic and synchronizing components of the vagal chronotropic effects and suppressed arrhythmogenic effect of vagal stimulation. By contrast, stimulation of ansa subclavia potentiated the effects of vagal stimulation. A novel model of vagosympathetic interactions in the heart of mammals is proposed.
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http://dx.doi.org/10.1023/a:1020209220174 | DOI Listing |
Auton Neurosci
December 2024
Stress Physiology Lab, Department of Chemistry, Life Sciences and Environmental Sustainability, University of Parma, Parma, Italy. Electronic address:
The identification of reliable biomarkers of transcutaneous auricular vagus nerve stimulation (taVNS) responsiveness is a key challenge both at the clinical and preclinical level. Vagally-mediated heart rate variability (vmHRV), a surrogate measure of cardiac vagal efferent activity, is an ideal candidate. Yet, the effects of taVNS on vmHRV remain inconclusive, likely due to the high degree of heterogeneity in stimulation protocols (e.
View Article and Find Full Text PDFClin Transplant
November 2024
Department of Cardiology, J.C. Walter Jr. Transplant Center & DeBakey Heart and Vascular Center, Houston Methodist Hospital, Houston, Texas, USA.
Background: Vagal nerve denervation during the heart transplant procedure results in higher resting heart rates in these recipients compared to the general population. Relative bradycardia (RB) is a common and often temporary post-operative complication that can be managed with agents like terbutaline; however, little data exist on the efficacy, safety, and necessity of long-term terbutaline use post-heart transplant.
Methods: This was a single-center, retrospective, descriptive study conducted at a large academic medical center investigating oral terbutaline use for RB management in heart transplant recipients.
Oxf Med Case Reports
August 2024
Emergency Medicine Department, Hamad General Hospital, P.O. Box: 3050, Doha, Qatar.
Melatonin, a pineal gland hormone closely associated with the circadian rhythm, has been trending over the past years as an over-the-counter medication to aid with sleep disturbances. Although generally believed to be safe, recent studies show negative inotropic and chronotropic effects on the heart rate and blood pressure in humans. Several studies suggested that melatonin induces cardiac vagal tone and affects heart rate and mean arterial pressure.
View Article and Find Full Text PDFPhysiol Res
April 2024
Laboratory of Neurochemistry, Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic.
Muscarinic acetylcholine receptors are metabotropic G-protein coupled receptors. Muscarinic receptors in the cardiovascular system play a central role in its regulation. Particularly M2 receptors slow down the heart rate by reducing the impulse conductivity through the atrioventricular node.
View Article and Find Full Text PDFNaunyn Schmiedebergs Arch Pharmacol
August 2024
Institut Für Pharmakologie Und Toxikologie, Medizinische Fakultät, Martin-Luther-Universität Halle-Wittenberg, D-06097, Magdeburger Str. 4, 06112, Halle, Germany.
The vagal regulation of cardiac function involves acetylcholine (ACh) receptor activation followed by negative chronotropic and negative as well as positive inotropic effects. The resulting signaling pathways may include G protein-coupled reduction in adenylyl cyclase (AC) activity, direct G protein-coupled activation of ACh-activated potassium current (I), inhibition of L-type calcium ion channels, and/or the activation of protein phosphatases. Here, we studied the role of the protein phosphatases 1 (PP1) and 2A (PP2A) for muscarinic receptor signaling in isolated atrial preparations of transgenic mice with cardiomyocyte-specific overexpression of either the catalytic subunit of PP2A (PP2A-TG) or the inhibitor-2 (I2) of PP1 (I2-TG) or in double transgenic mice overexpressing both PP2A and I2 (DT).
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