Referenced in: none

Automatically associated channels: Cav2.1

Title: Release probability of hippocampal glutamatergic terminals scales with the size of the active zone.

Authors: Noémi Holderith, Andrea Lorincz, Gergely Katona, Balázs Rózsa, Akos Kulik, Masahiko Watanabe, Zoltan Nusser

Journal, date & volume: Nat. Neurosci., 2012 Jul , 15, 988-97

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22683683

Abstract
Cortical synapses have structural, molecular and functional heterogeneity; our knowledge regarding the relationship between their ultrastructural and functional parameters is still fragmented. Here we asked how the neurotransmitter release probability and presynaptic [Ca(2+)] transients relate to the ultrastructure of rat hippocampal glutamatergic axon terminals. Two-photon Ca(2+) imaging-derived optical quantal analysis and correlated electron microscopic reconstructions revealed a tight correlation between the release probability and the active-zone area. Peak amplitude of [Ca(2+)] transients in single boutons also positively correlated with the active-zone area. Freeze-fracture immunogold labeling revealed that the voltage-gated calcium channel subunit Cav2.1 and the presynaptic protein Rim1/2 are confined to the active zone and their numbers scale linearly with the active-zone area. Gold particles labeling Cav2.1 were nonrandomly distributed in the active zones. Our results demonstrate that the numbers of several active-zone proteins, including presynaptic calcium channels, as well as the number of docked vesicles and the release probability, scale linearly with the active-zone area.