Facilitating and nonfacilitating synapses on pyramidal cells: A correlation between physiology and morphology

J. M. Bower, L. B. Haberly

Research output: Contribution to journalArticle

58 Scopus citations

Abstract

Pyramidal cells in piriform cortex receive excitatory inputs from two different sources that are segregated onto adjacent segments of their apical dendrites. The present studies show that excitatory postsynaptic potentials (EPSPs) evoked by primary olfactory tract afferents that terminate on distal apical segments display paired shock facilitation whereas ESPSs evoked by intrinsic association fibers that terminate on proximal apical segments do not. An ultrastructural comparison of the presynaptic elements of these two fiber systems has revealed that the facilitating olfactory tract afferent synapses have a much lower packing density of synaptic vesicles than do the nonfaciliting association fiber synapses. Further, a search of the literature has revealed that where both morphological and physiological data are available for the same synapses, this same correlation appears to apply. We propose a hypothesis to account for this correlation based on synaptic vesicles to buffer internal calcium and the biochemical characteristics of preterminal calcium-dependent mechanisms affecting the number of vesicles available for release.

Original languageEnglish (US)
Pages (from-to)1115-1119
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume83
Issue number4
DOIs
StatePublished - 1986

ASJC Scopus subject areas

  • General

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