1. The effects of beta-adrenoceptor blockade and reserpinization on the positive chronotropic and inotropic responses to lysophosphatidylcholine (LPC) were examined in isolated atrial and ventricular preparations from rat hearts. 2. The positive responses to 10(-4) M LPC were about 40-55% of those to 10(-5) M norepinephrine (NE) in each preparation. 3. The responses to LPC in the presence of propranolol or in the reserpinized preparations were significantly smaller than the corresponding values obtained in control preparations, and were about 10-25% of those to NE. 4. It was concluded that positive chronotropic and inotropic responses to LPC are at least partially mediated by release of NE from myocardial sympathetic nerve terminals.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/0306-3623(93)90041-u | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
BAY 2413555 is a novel selective and reversible positive allosteric modulator of the type 2 muscarinic acetylcholine (M2) receptor, aimed at enhancing parasympathetic signaling and restoring cardiac autonomic balance for the treatment of heart failure (HF). This study tested the safety, tolerability and pharmacokinetics of this novel therapeutic option. REMOTE-HF was a multicenter, double-blind, randomized, placebo-controlled, phase Ib dose-titration study with two active arms.
View Article and Find Full Text PDFCardiovascular problems in rabbits in reference to hypothyroidism - a four-year retrospective study.
Pol J Vet Sci
December 2024
Department of Epizootiology and the Clinic of Infectious Diseases, Faculty of Veterinary Medicine, University of Life Sciences in Lublin, Głęboka 30, 20-612 Lublin, Poland.
The effects of T4 are mainly manifested by positive ino- and chronotropism. The syndrome accompanying hypothyroidism in rabbits (impaired myocardial contractility and reduced ejection capacity) is caused by a deficiency of thyroid hormones - especially T4. The study group consisted of a total of 41 animals: 15 males and 26 females, ranging in age from 2 months to 8 years, with echocardiogram showing reduced fractional shortening (<30%), with normal results of heamatological and biochemical tests.
View Article and Find Full Text PDFSelective Inhibitory Effect of Hesperetin on the Automaticity of the Guinea Pig Pulmonary Vein Myocardium.
Biol Pharm Bull
December 2024
Department of Pharmacology, Faculty of Pharmaceutical Sciences, Toho University.
The effect of a citrus-derived flavonoid, hesperetin, on the automaticity and contraction of isolated guinea pig myocardium was examined. Hesperetin inhibited the rate of ectopic action potential firing of the pulmonary vein myocardium; the slope of the diastolic depolarization was decreased with minimum change in the action potential waveform. The effect was dependent on the concentration; the EC value for firing rate was 56.
View Article and Find Full Text PDFPERIPHERAL CHEMORECEPTOR, A NEW PLAYER IN METABOLIC SENSING DURING PHYSICAL EXERTION: A HYPOTHETICAL SCENARIO.
J Neurophysiol
December 2024
Exercise Applied Physiology Laboratory, Centro de Investigación en Fisiología y Medicina de Altura (FIMEDALT), Departamento Biomedico, Facultad de Ciencias de la Salud,Universidad de Antofagasta,, Antofagasta, Chile.
The cardiorespiratory and metabolic response to exercise has been associated with meeting the organism's metabolic demands during physical exertion. Of note, an incremental exercise is characterized by i) cardiodynamic phase related to cardiac output enhancement mainly determined by a positive chronotropic response, ii) ventilatory threshold one, associated with a significant contribution of cardiovascular and pulmonary ventilation, and iii) ventilatory threshold two, correlated with a tremendous increase in breathing and metabolic responses to exercise. Notably, it has been shown that the ventilatory response to exercise increases concomitantly with the release and accumulation of metabolites (i.
View Article and Find Full Text PDFChronotropic and Inotropic Effects of Sudachitin, a Polymethoxyflavone from the Peel of Citrus sudachi on Isolated Rat Atria and Its Underlying Mechanisms.
Biol Pharm Bull
December 2024
Laboratory of Functional Food Sciences, Department of Health and Bio-Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University.
Article Synopsis
- - Sudachitin, a polymethoxyflavone from sudachi peel, shows promise in improving hyperlipidemia but its effects on heart function were investigated, revealing that it enhances heart rate and contractility in rat atria in a dose-dependent manner.
- - Unlike isoproterenol, which has a stronger impact, sudachitin and other similar compounds like demethoxysudachitin and nobiletin also increase heart function but to a lesser degree; their effects appear non-specific across these compounds.
- - The study found that sudachitin enhances heart function through cAMP-dependent pathways rather than through β-adrenoceptors, suggesting a unique mechanism for its action among polymethoxyflavones.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!