Facilitation of plateau potentials in turtle motoneurones by a pathway dependent on calcium and calmodulin
Research output: Contribution to journal › Journal article › Research › peer-review
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.
Original language | English |
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Journal | Journal of Physiology |
Volume | 528 Pt 1 |
Pages (from-to) | 107-13 |
Number of pages | 7 |
ISSN | 0022-3751 |
Publication status | Published - 1 Oct 2000 |
- Animals, Calcium, Calcium Channels, L-Type, Calmodulin, Dopamine Antagonists, Egtazic Acid, Intracellular Fluid, Membrane Potentials, Motor Neurons, Receptors, Metabotropic Glutamate, Receptors, Muscarinic, Sodium, Spinal Cord, Tetraethylammonium, Tetrodotoxin, Trifluoperazine, Turtles
Research areas
ID: 33731465