Synapse density regulates independence at unitary inhibitory synapses

Linda S. Overstreet, Gary L. Westbrook

Research output: Contribution to journalArticlepeer-review

117 Scopus citations


Neurotransmitter transporters may promote synapse specificity by limiting spillover between release sites. At GABAergic synapses, transport block prolongs synaptic responses when many inputs are activated, yet it is unclear whether transporters alter signaling by single axons. We found that unitary IPSCs generated by paired recordings between hippocampal interneurons and granule cells could be either prolonged or totally unaffected by block of GABA transporters. This variability was explained by the density of active release sites rather than the number of active sites. Prolongation by transport block required release from multiple sites and was enhanced by repetitive activation. Furthermore, transport-sensitive unitary IPSCs were accelerated when the release probability was reduced, indicating that cross talk prolonged the time course of IPSCs even when transport was intact. Our results suggest that the release site density regulates the degree of cross talk as well as the contribution of transporters to GABA clearance. Thus, interplay between release site density and transporter action determines the independence of unitary inhibitory synapses.

Original languageEnglish (US)
Pages (from-to)2618-2626
Number of pages9
JournalJournal of Neuroscience
Issue number7
StatePublished - Apr 1 2003


  • Density
  • Dentate gyrus
  • GABA receptor
  • Granule cell
  • IPSC
  • Independence
  • NO711
  • Synaptic transmission
  • Transport

ASJC Scopus subject areas

  • Neuroscience(all)


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