Related Experiment Video

Updated: Aug 15, 2026

Use of a Hanging Weight System for Coronary Artery Occlusion in Mice
08:30

Use of a Hanging Weight System for Coronary Artery Occlusion in Mice

Published on: April 19, 2011

beta Adrenergic receptor desensitisation may serve a cardioprotective role

L B Tan1, I J Benjamin, W A Clark

  • 1Department of Cardiovascular Studies, University of Leeds, United Kingdom.

Cardiovascular Research
|June 1, 1992
PubMed
Abstract

Insights

Beta adrenoceptor desensitisation protects the heart from excessive adrenergic stimulation. This study demonstrates that desensitised hearts show reduced cardiomyocyte necrosis following isoprenaline challenge.

Area of Science:

  • Cardiovascular Physiology
  • Pharmacology
  • Cellular Biology

Background:

  • Excessive adrenergic stimulation can injure the myocardium.
  • Beta adrenoceptors play a key role in mediating the cardiac response to adrenergic agonists like isoprenaline.
  • Understanding mechanisms of cardioprotection is crucial for managing cardiovascular diseases.

Purpose of the Study:

  • To test if beta adrenoceptor desensitisation confers cardioprotection.
  • To investigate if desensitisation protects the myocardium from isoprenaline-induced injury.

Main Methods:

  • Used monoclonal antimyosin and immunofluorescence to identify cardiac myocyte necrosis.
  • Induced homologous beta adrenoceptor desensitisation via 9-day isoprenaline infusion in rats.
  • Induced heterologous desensitisation using propylthiouracil in the diet for six weeks.

Main Results:

  • Isoprenaline induced significant cardiac myocyte necrosis and haemodynamic changes (tachycardia, hypotension) in control rats.
  • Rats with homologous desensitisation showed attenuated haemodynamic responses and minimal myocyte necrosis after isoprenaline challenge.
  • Rats with heterologous desensitisation also exhibited diminished haemodynamic response and reduced cardiac myocyte necrosis.

Conclusions:

  • Beta adrenoceptor desensitisation, both homologous and heterologous, significantly reduces myocardial susceptibility to isoprenaline-induced cytotoxicity.
  • These findings support the hypothesis that beta adrenoceptor desensitisation is a cardioprotective mechanism.

More Related Videos

Testing the Efficacy of Pharmacological Agents in a Pericardial Target Delivery Model in the Swine10:05

Testing the Efficacy of Pharmacological Agents in a Pericardial Target Delivery Model in the Swine

Published on: July 7, 2016

Simultaneous Isolation of High Quality Cardiomyocytes, Endothelial Cells, and Fibroblasts from an Adult Rat Heart09:38

Simultaneous Isolation of High Quality Cardiomyocytes, Endothelial Cells, and Fibroblasts from an Adult Rat Heart

Published on: May 19, 2017

Related Concept Videos

GPCR Desensitization01:12

GPCR Desensitization

G protein-coupled receptor (GPCR) signaling plays a crucial role in cell functioning. GPCR desensitization is an equally essential process. It allows cells to respond to changing environments and regain sensitivity to new stimuli while preventing unnecessary stimulation when no longer needed. Prolonged exposure to stimuli leads to GPCR desensitization. It involves blocking the receptors from binding and activating additional G proteins. This inhibits activation of downstream effectors, thereby...
Adrenergic Receptors: β Subtype01:26

Adrenergic Receptors: β Subtype

β-adrenoceptors have varied sensitivities towards adrenaline, noradrenaline, and isoprenaline. The order of agonist potency is as follows:
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Adrenergic Antagonists: Pharmacological Actions of ɑ-Receptor Blockers01:22

Adrenergic Antagonists: Pharmacological Actions of ɑ-Receptor Blockers

α-Adrenergic antagonists, known as α-blockers, exert their effects by inhibiting α-adrenoceptors, leading to specific physiological actions. α1-blockers and α2-blockers have distinct pharmacological actions and therapeutic applications.
α1-blockers: These drugs inhibit α1-adrenoceptors on smooth muscle cells, resulting in vasodilation. This vasodilation lowers blood pressure, making α1-blockers valuable in treating hypertension. Additionally, α1-blockers effectively address urinary obstruction...
Adrenergic Antagonists: Chemistry and Classification of β-Receptor Blockers01:25

Adrenergic Antagonists: Chemistry and Classification of β-Receptor Blockers

β-adrenergic antagonists, or β-blockers, modulate the sympathetic nervous system by targeting β-adrenoceptors and inhibiting catecholamine-mediated sympathetic responses. β-blockers differ in their adrenoceptor subtype affinity, lipophilicity, and α-blocking capabilities. The history of β-blocker development began with the prototype, dichloroisoprenaline, which exhibited partial agonist activity. As a result, propranolol was developed as a pure antagonist but nonselective agent, paving the way...
Adrenergic Antagonists: Pharmacological Actions of β-Receptor Blockers01:27

Adrenergic Antagonists: Pharmacological Actions of β-Receptor Blockers

β-receptor blockers significantly impact the cardiovascular system by counteracting catecholamine-induced sympathetic responses. These medications decrease heart rate, contractility, and cardiac output, potentially leading to cardiac depression, life-threatening bradycardia, and death. Therapeutically, β-blockers function as mild antihypertensives and are utilized in treating angina pectoris and cardiac arrhythmias. However, nonselective β-blockers inhibit β2-receptors in bronchial smooth...
Adrenergic Antagonists: ɑ and β-Receptor Blockers01:31

Adrenergic Antagonists: ɑ and β-Receptor Blockers

Third-generation β-blockers, such as labetalol and carvedilol, represent a significant advancement in managing cardiovascular conditions. Unlike conventional β-blockers, which can induce peripheral vasoconstriction, third-generation drugs block α1 adrenoceptors. This promotes vasodilation through several mechanisms, such as increased nitric oxide production, inhibition of calcium ion entry, opening of potassium ion channels, and antioxidant action. Labetalol, for instance, is clinically...