Related Experiment Video

Updated: Aug 8, 2026

Non-Terminal Blood Sampling Techniques in Guinea Pigs
07:58

Non-Terminal Blood Sampling Techniques in Guinea Pigs

Published on: October 11, 2014

Norepinephrine uptake in guinea pig lung. Effects of anaphylaxis, phenoxybenzamine and cocaine

A A Mathé, L Volicer

    International Archives of Allergy and Applied Immunology
    |January 1, 1977
    PubMed

    More Related Videos

    A Method of Nodose Ganglia Injection in Sprague-Dawley Rat09:28

    A Method of Nodose Ganglia Injection in Sprague-Dawley Rat

    Published on: November 25, 2014

    Assessment of Cocaine-induced Behavioral Sensitization and Conditioned Place Preference in Mice10:28

    Assessment of Cocaine-induced Behavioral Sensitization and Conditioned Place Preference in Mice

    Published on: February 18, 2016

    Related Concept Videos

    Drugs Acting on Autonomic Ganglia: Stimulants01:23

    Drugs Acting on Autonomic Ganglia: Stimulants


    Ganglionic stimulants activate NM nicotinic receptors in autonomic ganglia, falling into two categories: nicotine mimetics [e.g., lobeline, dimethylpiperazine, tetramethylammonium] and muscarinic receptor agonists [e.g., muscarine, methacholine]. The first category's action is rapid and blocked by nicotinic receptor antagonists, while the second category's action is delayed and blocked by atropine-like agents. Nicotine, an alkaloid, affects the heart rate by stimulating sympathetic or...
    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: Indirect-Acting Agents01:25

    Adrenergic Agonists: Indirect-Acting Agents

    Indirect-acting adrenergic agonists potentiate the effects of endogenous catecholamines through different mechanisms without directly binding to adrenoceptors.
    One mechanism involves depleting stored catecholamines by displacing them from synaptic vesicles. These agents, known as "displacers," are transported into vesicles at the expense of noradrenaline. Examples include amphetamine and tyramine, which lack a catechol moiety, resulting in prolonged action, improved oral bioavailability, and...
    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:...
    Drugs Affecting Neurotransmitter Release or Uptake01:21

    Drugs Affecting Neurotransmitter Release or Uptake

    Certain drugs can affect how neurotransmitters called catecholamines, are released or taken back up in the adrenergic neuron. They can have different effects on the body's sympathetic transmission. Reserpine, a natural compound found in the Rauwolfia shrub, blocks a transporter called vesicular monoamine transporter (VMAT), which leads to a buildup of catecholamines in the cell and reduces sympathetic transmission. Another drug called guanethidine works in multiple ways, including blocking...