Related Experiment Video

Updated: Oct 5, 2026

Electrocardiogram Recordings in Anesthetized Mice using Lead II
04:16

Electrocardiogram Recordings in Anesthetized Mice using Lead II

Published on: June 20, 2020

Labetalol: an alpha- and beta-blocker

C S Conner

    Drug Intelligence & Clinical Pharmacy
    |July 1, 1983
    PubMed

    Related Concept Videos

    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...
    Antihypertensive Drugs: Action of β1 Blockers01:17

    Antihypertensive Drugs: Action of β1 Blockers

    β1-receptors are primarily located in the heart and kidneys. In cardiac myocytes, these receptors interact with neurotransmitters released by the sympathetic nervous system during heightened activity or danger. As a result, β1-receptors get activated, initiating a series of biochemical processes. Excessive activation of beta receptors due to chronic stress can abnormally increase heart rate and contractility, resulting in high blood pressure or hypertension. To counteract this, β1-blockers...
    Antihypertensive Drugs: Types of β-Blockers01:28

    Antihypertensive Drugs: Types of β-Blockers

    β receptors are classified into three subclasses: β1, β2, and β3. β1 receptors are primarily located in the heart and kidneys. When they get activated, they increase heart rate, contractility, and renin release. This process enhances blood pressure and aids in stress management. In contrast, β2 receptors are situated mainly in the lungs, blood vessels, and skeletal muscles. Upon activation, they trigger smooth muscle relaxation, causing bronchodilation and vasodilation. This widens airways and...
    Antiarrhythmic Drugs: Class II Agents as β-Adrenergic Blockers01:24

    Antiarrhythmic Drugs: Class II Agents as β-Adrenergic Blockers

    Adrenergic stimulation generally impacts cardiac rate and rhythm. Specifically, stimulation of the β-adrenoceptors triggers an increase in intracellular calcium ion influx and pacemaker currents, which may cause arrhythmias. Catecholamines like adrenaline also demonstrate β2-adrenoceptor-mediated hypokalemia, impacting cardiac action potential and disrupting the normal cardiac rhythm. Class II antiarrhythmic drugs are β-adrenoceptor antagonists or β-blockers, which indirectly block calcium...