Presynaptic Ca2+ channels: a functional patchwork

Trends Neurosci. 2003 Dec;26(12):683-7. doi: 10.1016/j.tins.2003.10.003.


A key step in the release of neurotransmitter is the entry of Ca(2+) into the presynaptic terminal via voltage-activated Ca(2+) channels. N-type and P/Q-type Ca(2+) channels play a predominant role but, surprisingly, their distribution across presynaptic terminals lacks any apparent order. They form a patchwork: at some terminals only N-type channels contribute to transmitter release and in others only P/Q-type channels contribute, but in many terminals both sub-types are active. The physiological implications of this non-uniform distribution are starting to emerge. Recent studies reveal that G-protein-mediated depression of N-type channels is stronger than that of P/Q-type channels, whereas voltage-dependent relief of inhibition is more pronounced for P/Q-type channels. The patchwork distribution of Ca(2+) channel subtypes might therefore enable terminal-specific modulation of transmitter release, enhancing the power of synaptic processing.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Calcium Channels / physiology*
  • Humans
  • Nerve Net / physiology*
  • Presynaptic Terminals / physiology*


  • Calcium Channels