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

Pflugers Arch. 2013 Feb;465(2):319-31. doi: 10.1007/s00424-012-1172-1. Epub 2012 Nov 9.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Action Potentials
  • Animals
  • Calcium / metabolism
  • Cerebellum / cytology
  • Cerebellum / metabolism
  • Cerebellum / physiology
  • Computer Simulation
  • Mice
  • Mice, Knockout
  • Nerve Fibers / metabolism*
  • Nerve Fibers / physiology
  • Plasma Membrane Calcium-Transporting ATPases / genetics
  • Plasma Membrane Calcium-Transporting ATPases / metabolism*
  • Purkinje Cells / metabolism*
  • Purkinje Cells / physiology
  • Sodium-Calcium Exchanger / metabolism*
  • Synapses / metabolism*
  • Synapses / physiology
  • Synaptic Transmission

Substances

  • Sodium-Calcium Exchanger
  • Plasma Membrane Calcium-Transporting ATPases
  • Atp2b2 protein, mouse
  • Calcium