Related Experiment Video

Updated: Aug 9, 2026

Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice
06:22

Contractility Measurements on Isolated Papillary Muscles for the Investigation of Cardiac Inotropy in Mice

Published on: September 17, 2015

Post-extrasystolic potentiation; effect of Ca, histamine, caffeine and epinephrine

W C De Mello

    Archives Internationales De Pharmacodynamie Et De Therapie
    |December 1, 1977
    PubMed

    More Related Videos

    Assessment of Sarcoplasmic Reticulum Calcium Reserve and Intracellular Diastolic Calcium Removal in Isolated Ventricular Cardiomyocytes11:00

    Assessment of Sarcoplasmic Reticulum Calcium Reserve and Intracellular Diastolic Calcium Removal in Isolated Ventricular Cardiomyocytes

    Published on: September 18, 2017

    Preparation of Human Myocardial Tissue for Long-Term Cultivation10:58

    Preparation of Human Myocardial Tissue for Long-Term Cultivation

    Published on: June 2, 2022

    Related Concept Videos

    Adrenergic Neurons: Neurotransmission01:27

    Adrenergic Neurons: Neurotransmission

    Postganglionic sympathetic fibers (except those supplying the sweat glands) releasing noradrenaline or norepinephrine are called noradrenergic or adrenergic neurons. Noradrenaline, dopamine, adrenaline, or epinephrine are collectively called "catecholamines" as they contain a catechol moiety and an amine side chain. The five stages of neurotransmitter release involve their synthesis, storage, release, reuptake and metabolism.
    Synthesis: Catecholamine synthesis requires tyrosine, which is taken...
    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 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...
    Integration of Synaptic Events01:28

    Integration of Synaptic Events

    Synaptic integration mainly includes the summation of graded potentials. Graded potentials, regardless of their type, cause subtle alterations in membrane voltage, resulting in either depolarization or hyperpolarization. These incremental changes, when combined or summed, can propel the neuron toward its threshold. Consider, for example, a membrane experiencing a +15 mV shift, causing it to depolarize from -70 mV to -55 mV. In this scenario, graded potentials govern the membrane's ability to...
    Heart Failure II: Pathophysiology01:29

    Heart Failure II: Pathophysiology

    Systolic Heart Failure and Compensatory MechanismsSystolic heart failure (also termed HFrEF, Heart Failure with Reduced Ejection Fraction) is the most prevalent type of heart filure. It results in a decreased volume of blood being pumped from the ventricle. The aortic arch and carotid sinuses have baroreceptors that detect reduced blood pressure, triggering the sympathetic nervous system (SNS) to release epinephrine and norepinephrine. Initially, this response aims to boost heart rate and...