The present study was designed to further characterize the presynaptic muscarinic M1-receptor responsible for the inhibition of neurogenic contractions in the isolated rabbit vas deferens. Electrically induced twitch contractions of this preparation were inhibited by the M1-agonist, McN-A-343, and by some of its analogs: 4-chloro-phenyl derivative greater than McN-A-343 greater than trans-olefinic analog greater than cis-olefinic analog. The same rank order of potency was observed for these agonists to raise the blood pressure of pithed rats by stimulation of M1-receptors in sympathetic ganglia. A highly significant correlation was found between the antimuscarinic potencies of atropine, pirenzepine and a series of 9 antagonists structurally related to the ganglionic M1 beta-receptor selective compounds, hexocyclium and hexahydro-difenidol, to antagonize the McN-A-343-induced inhibition of twitch contractions in rabbit vas deferens or the muscarine-induced depolarization in rat isolated superior cervical ganglia. It is suggested that the presynaptic muscarinic receptor that mediates inhibition of neurogenic contractions in rabbit vas deferens is of the ganglionic M1 beta-type.
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http://dx.doi.org/10.1016/0014-2999(88)90072-6 | DOI Listing |
Cardiovasc Toxicol
January 2025
Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, No. 250, Wuxing St., Taipei, 11031, Taiwan.
Ventricular arrhythmias (VAs) are major causes of sudden cardiac death in chronic kidney disease (CKD) patients. Indoxyl sulfate (IS) is one common uremic toxin found in CKD patients. This study investigated whether IS could induce VAs via increasing right ventricular outflow tract (RVOT) arrhythmogenesis.
View Article and Find Full Text PDFAnimals (Basel)
December 2024
Research and Education Board, IRSEA, Institute of Research in Semiochemistry and Applied Ethology, 84400 Apt, France.
Rabbits are subjected to challenges that induce stress and require them to continuously adapt. Veterinary procedures represent an important source of stress. In other pets, pheromone use was shown to help patients better cope with these procedures.
View Article and Find Full Text PDFPflugers Arch
August 2024
Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, Brazil.
6-Cyanodopamine is a novel catecholamine released from rabbit isolated heart. However, it is not known whether this catecholamine presents any biological activity. Here, it was evaluated whether 6-cyanodopamine (6-CYD) is released from rat vas deferens and its effect on this tissue contractility.
View Article and Find Full Text PDFPacing Clin Electrophysiol
September 2024
Baoshan Branch, Ren Ji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.
Objective: To investigate the role of protein kinase C (PKC) in action potential duration (APD) restitution and ventricular tachyarrhythmias (VAs).
Methods And Results: Rabbits hearts were isolated and prepared for Langendorff perfusion technique. The stimuli-extra-stimulus (S-S) method and dynamic S pacing protocol were performed to construct APD restitution and to induce APD alternans or VA, respectively, at 10 sites throughout the ventricular chamber.
Eur J Pharmacol
August 2024
Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan; Cardiovascular Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan. Electronic address:
Background: Ibrutinib, a Bruton's tyrosine kinase inhibitor used in cancer therapy, exerts ventricular proarrhythmic effects; however, the underlying mechanisms remain unclear. Excitation-contraction coupling (E-C) disorders are pivotal for the genesis of ventricular arrhythmias (VAs), which arise mainly from the right ventricular outflow tract (RVOT). In this study, we aimed to comprehensively investigate whether ibrutinib regulates the electromechanical activities of the RVOT, leading to enhanced arrhythmogenesis, and explore the underlying mechanisms.
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