Related Experiment Video

Updated: Aug 16, 2026

Quantitative Autonomic Testing
11:40

Quantitative Autonomic Testing

Published on: July 19, 2011

The potent pressor effect of phenylpropanolamine in patients with autonomic impairment

I Biaggioni, J Onrot, C K Stewart

    JAMA
    |July 10, 1987
    PubMed

    More Related Videos

    Quantifying Acute Changes in Renal Sympathetic Nerve Activity in Response to Central Nervous System Manipulations in Anesthetized Rats06:30

    Quantifying Acute Changes in Renal Sympathetic Nerve Activity in Response to Central Nervous System Manipulations in Anesthetized Rats

    Published on: September 11, 2018

    Assessment of Vascular Tone Responsiveness using Isolated Mesenteric Arteries with a Focus on Modulation by Perivascular Adipose Tissues08:41

    Assessment of Vascular Tone Responsiveness using Isolated Mesenteric Arteries with a Focus on Modulation by Perivascular Adipose Tissues

    Published on: June 3, 2019

    Related Concept Videos

    Adrenergic Agonists: Direct-Acting Agents01:30

    Adrenergic Agonists: Direct-Acting Agents

    Drugs that mimic the action of endogenous catecholamines like noradrenaline and adrenaline are called adrenergic agonists or sympathomimetics. Based on their mechanism of action, sympathomimetics can be classified as direct-, indirect-, or mixed-acting sympathomimetics. Direct-acting adrenergic agonists activate adrenoceptors without affecting presynaptic neurons, making them independent of neuronal catecholamine-depleting agents like reserpine and guanethidine.
    These agents can be classified...
    Adrenergic Agonists: Mixed-Action Agents01:28

    Adrenergic Agonists: Mixed-Action Agents

    Mixed-action adrenergic agonists, like ephedrine and pseudoephedrine, directly and indirectly affect adrenergic receptors. These agents stimulate adrenoceptors and indirectly release stored neurotransmitters, amplifying the adrenergic response.
    Ephedrine and pseudoephedrine lack a catecholamine group, making them less susceptible to degradation by metabolic enzymes. They have increased oral bioavailability and lipophilicity, resulting in a longer duration of action. Their response is reduced by...
    Adrenergic Agonists: Therapeutic Uses01:30

    Adrenergic Agonists: Therapeutic Uses

    Adrenergic agonists have diverse therapeutic uses across various medical conditions and emergencies.
    Emergency and Intensive Care Unit (ICU) applications: Pressor agents increase blood pressure, heart rate, and contractility in shock and organ failure situations. Dopamine can induce vasodilation and stimulate adrenoceptors. Endogenous catecholamines are effective in treating cardiogenic shock. α2-agonists like clonidine can reverse anesthesia-induced hypertension.
    Allergies and anaphylaxis:...
    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...
    Heart Failure Drugs: Inhibitors of Renin-Angiotensin System01:26

    Heart Failure Drugs: Inhibitors of Renin-Angiotensin System

    The activation of the sympathetic nervous system and the renin-angiotensin-aldosterone system (RAAS) contributes to cardiac remodeling, and inhibiting the RAAS is a pharmacological target in heart failure management. As a result, neurohumoral modulation is a crucial treatment principle for managing heart failure. This approach involves using medications like ACE inhibitors (ACEIs), angiotensin receptor blockers (ARBs), β-blockers, mineralocorticoid receptor antagonists (MRAs), and neutral...
    Heart Failure Drugs: β-Blockers01:22

    Heart Failure Drugs: β-Blockers

    β-adrenergic antagonists, commonly known as β-blockers, block the effects of sympathetic neurotransmitters such as noradrenaline (NA) and adrenaline (ADR). They have several beneficial effects in heart failure treatment. They reduce heart rate, the force of contraction, and cardiac muscle relaxation. They also slow the atrial-ventricular conduction rate and raise the threshold for arrhythmias. The concentration of β-blockers determines their effects on bronchodilation, vasodilation, and...