Adrenaline may increase noradrenaline release and enhance sympathetic pressor effects through activation of pre-synaptic beta 2-adrenoceptors. Conversely, blockade of beta 2-receptors could lead to a fall in blood pressure. To test this hypothesis we performed a double-blind placebo controlled crossover study in nine patients with mild hypertension, comparing the effects of the beta 2-selective blocker ICI 118,551, 50 mg t.i.d. with those of propranolol, 80 mg t.i.d. Two hours after the first dose of ICI 118,551 or propranolol, plasma noradrenaline and blood pressure remained unchanged while heart rate and renin were reduced. After 1 week, blood pressure was significantly reduced by both drugs. The beta 2-selectivity of ICI 118,551 was confirmed by isoprenaline infusion studies. After 1 week of treatment ICI 118,551 had no effect on the beta 1-receptor mediated shortening of electromechanical systole (QS2I), the rise in systolic pressure and rise in renin, whereas these responses were blocked by a dose factor of eight after propranolol. ICI 118,551 and propranolol equally blocked the beta 2-receptor mediated fall in diastolic pressure and the rise in noradrenaline. We conclude that beta 2-selective blockade by ICI 118,551 lowers blood pressure. This finding is compatible with a role of pre-synaptic beta 2-receptors in blood pressure control.
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EClinicalMedicine
November 2024
Center for movement disorders, Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
Background: Essential tremor (ET) significantly impacts patients' daily lives and quality of life, presenting a considerable challenge in clinical practice. In recent years, novel therapeutic regimens have been investigated in randomized controlled trials (RCTs). This study aims to investigate and evaluate the relative efficacy and safety of various therapeutic interventions for ET.
View Article and Find Full Text PDFCommun Biol
April 2024
Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, University of Nottingham, Nottingham, NG7 2UH, UK.
The concept of agonist-independent signalling that can be attenuated by inverse agonists is a fundamental element of the cubic ternary complex model of G protein-coupled receptor (GPCR) activation. This model shows how a GPCR can exist in two conformational states in the absence of ligands; an inactive R state and an active R* state that differ in their affinities for agonists, inverse agonists, and G-protein alpha subunits. The proportion of R* receptors that exist in the absence of agonists determines the level of constitutive receptor activity.
View Article and Find Full Text PDFMol Cell Endocrinol
June 2024
Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, China, 221004. Electronic address:
Objective: Myocardial injuries resulting from hypoxia are a significant concern, and this study aimed to explore potential protective strategies against such damage. Specifically, we sought to investigate the cardioprotective effects of 16α-hydroxyestrone (16α-OHE1).
Methods: Male Sprague‒Dawley (SD) rats were subjected to hypoxic conditions simulating high-altitude exposure at 6000 m in a low-pressure chamber for 7 days.
Toxicol Lett
August 2023
German Sports University Cologne, Department of Molecular and Cellular Sport Medicine, Cologne, Germany. Electronic address:
Higenamine (Hige), a plant derived alkaloid is classified as β2 agonist by the World Anti-Doping Agency (WADA). However, pharmacologic mechanisms of its performance-enhancing activity have not been investigated so far. Therefore, we investigate the anabolic activity and associated molecular mechanisms of Hige in C2C12 myotubes.
View Article and Find Full Text PDFBiochim Biophys Acta Mol Cell Res
October 2023
Basic Medical Sciences Center, Shanxi Medical University, Taiyuan, PR China; Key Laboratory of Cellular Physiology (Shanxi Medical University), Taiyuan, PR China. Electronic address:
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