Functional contributions of the plasma membrane calcium ATPase and the sodium–calcium exchanger at mouse parallel fibre to Purkinje neuron synapses

We investigated how two calcium clearance mechanisms, the sodium–calcium exchanger—NCX, and the plasma membrane calcium ATPase—PMCA2, function at the facilitating cerebellar parallel fibre to Purkinje neuron (PF-PN) synapse. Forward mode NCX helped recover PF presynaptic calcium elevations when the...

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Bibliographic Details
Published in:Pflügers Archiv 2013-02, Vol.465 (2), p.319-331
Main Authors: Roome, Chris J., Knöpfel, Thomas, Empson, Ruth M.
Format: Article
Language:English
Subjects:
Action Potentials
Animals
Biomedical and Life Sciences
Biomedicine
Ca super(2+)-transporting ATPase
Calcium - metabolism
Cell Biology
Cerebellum - cytology
Cerebellum - metabolism
Cerebellum - physiology
Computer Simulation
Human Physiology
Mice
Mice, Knockout
Molecular Medicine
Nerve Fibers - metabolism
Nerve Fibers - physiology
Neuroscience
Neurosciences
Plasma Membrane Calcium-Transporting ATPases - genetics
Plasma Membrane Calcium-Transporting ATPases - metabolism
Purkinje Cells - metabolism
Purkinje Cells - physiology
Receptors
Sodium-Calcium Exchanger - metabolism
Synapses - metabolism
Synapses - physiology
Synaptic Transmission
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Summary:We investigated how two calcium clearance mechanisms, the sodium–calcium exchanger—NCX, and the plasma membrane calcium ATPase—PMCA2, function at the facilitating cerebellar parallel fibre to Purkinje neuron (PF-PN) synapse. Forward mode NCX helped recover PF presynaptic calcium elevations when the PFs received a double stimulation and the calcium load was sufficiently high. A smaller presynaptic calcium load evoked by a single PF stimulation failed to recruit NCX in wild-type mice but did so when PMCA2 was absent in PFs from PMCA2 knockout mice. Simulated calcium dynamics using a simple single-compartment model reported qualitatively similar effects. Functionally, reduced NCX activity in the absence of PMCA also prolonged the recovery of facilitation at the PF-PN synapse, beyond that seen by reduced NCX activity alone. We conclude that PMCA and NCX work in parallel to accurately shape residual presynaptic calcium recovery dynamics and fine-tune facilitation at this important cerebellar synapse.
ISSN:0031-6768
1432-2013
DOI:10.1007/s00424-012-1172-1