Related Experiment Video
Updated: Aug 12, 2026

Isolation of Human Atrial Myocytes for Simultaneous Measurements of Ca2+ Transients and Membrane Currents
Published on: July 3, 2013
Effect of acetylcholine on aconitine induced delayed afterdepolarisation in the frog atrium and ventricle
T Sawanobori1, Y Hirano, M Hiraoka
1Department of Cardiovascular Diseases, Tokyo Medical and Dental University, Japan.
Abstract:
The effect of acetylcholine on the aconitine induced delayed afterdepolarisation and triggered electrical activities under nominally calcium free conditions were studied in frog atrium and ventricle. The changes in intracellular potassium activity were also examined. The aconitine induced delayed afterdepolarisation and triggered electrical activities in atrial muscles were transiently suppressed by acetylcholine. This inhibition was correlated with the time course of the development of hyperpolarisation in the resting membrane potential during acetylcholine application. Propranolol did not abolish the transient inhibition of delayed afterdepolarisation during continuous application of acetylcholine, whereas atropine completely inhibited this effect of acetylcholine. Intracellular potassium activity decreased with time after acetylcholine application, whereas the resting potential became hyperpolarised at an early stage, showing slow recovery thereafter. These results indicate that the transient inhibition of delayed afterdepolarisation by acetylcholine is associated with transient hyperpolarisation of the membrane potential, which is assumed to be caused by potassium accumulation or desensitisation of the muscarinic receptor, or both.
More Related Videos
Related Concept Videos
G-Protein Gated Ion Channels
Sensory organs,...
Cholinergic Neurons: Neurotransmission
Indirect-Acting Cholinergic Agonists: Mechanism of Action
Reversible inhibitors like edrophonium bind to a specific part of the enzyme called the anionic catalytic site. They form noncovalent bonds, which means they are not strongly attached to the enzyme. This creates a temporary and less stable enzyme–inhibitor complex, leading to...
Indirect-Acting Cholinergic Agonists: Pharmacological Actions
At the neuromuscular junction, these agents work by inhibiting the breakdown of acetylcholine, allowing it to remain bound to the receptor and bind to nearby receptors. This process leads to repetitive firing of the endplate, causing muscle...
Depolarizing Blockers: Mechanism of Action
Succinylcholine is the most commonly used depolarizing blocker. Chemically, it constitutes two molecules of acetylcholine joined together by an acetate methyl group. They act on the receptors in the same way as acetylcholine. Because succinylcholine...
Depolarizing Blockers: Pharmocokinetics

