Related Experiment Video
Updated: Oct 11, 2026

Loading a Calcium Dye into Frog Nerve Endings Through the Nerve Stump: Calcium Transient Registration in the Frog Neuromuscular Junction
Published on: July 8, 2017
Facilitation of plateau potentials in turtle motoneurones by a pathway dependent on calcium and calmodulin
J F Perrier1, S Mejia-Gervacio, J Hounsgaard
1Department of Medical Physiology, Panum Institute, University of Copenhagen, DK 2200 Copenhagen N, Denmark.
Abstract:
1. The involvement of intracellular calcium and calmodulin in the modulation of plateau potentials in motoneurones was investigated using intracellular recordings from a spinal cord slice preparation. 2. Chelation of intracellular calcium with BAPTA-AM or inactivation of calmodulin with W-7 or trifluoperazine reduced the amplitude of depolarization-induced plateau potentials. Inactivation of calmodulin also inhibited facilitation of plateau potentials by activation of group I metabotropic glutamate receptors or muscarinic receptors. 3. In low-sodium medium and in the presence of tetraethylammonium and tetrodotoxin, calcium action potentials evoked by depolarization were followed by a short hyperpolarization ascribed to the calcium-activated non-selective cationic current (ICAN) and by a dihydropyridine-sensitive afterdepolarization. The amplitude of the afterdepolarization depended on the number of calcium spikes and was mediated by L-type calcium channels. 4. The dihydropyridine-sensitive afterdepolarization induced by calcium spikes was reduced by blockade of calmodulin. 5. It is proposed that plateau potentials in spinal motoneurones are facilitated by activation of a calcium-calmodulin-dependent pathway.
More Related Videos
11:12Registration of Calcium Transients in Mouse Neuromuscular Junction with High Temporal Resolution using Confocal Microscopy
Published on: December 1, 2021
00:09Fluorescent Calcium Imaging and Subsequent In Situ Hybridization for Neuronal Precursor Characterization in Xenopus laevis
Published on: February 18, 2020
Related Concept Videos
Calmodulin-dependent Signaling
The Ca2+-CaM complex does not have enzymatic activity by itself. Instead, the complex binds downstream target proteins, including membrane proteins or enzymes,...
Feedback Regulation of Calcium Concentration
Various transmembrane receptors, such as G protein-coupled receptors (GPCRs), elicit a response to extracellular signals by increasing cytosolic calcium. Activated GPCRs...
Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
Long-term Potentiation
Long-term Potentiation
Hebbian LTP
LTP can occur when presynaptic neurons...
Ligand-Gated Ion Channel Receptor: Gating Mechanism