Journal of Neurocytology

, Volume 2, Issue 3, pp 249–263 | Cite as

The nervous system of ctenophores III. Ultrastructure of synapses

  • Mari-Luz Hernandez-Nicaise


The ultrastructure of synapses from the nervous systems of seven species of ctenophores has been studied. All synaptic contacts so far observed show a peculiar organization characteristic of this phylum: the pre-synaptic neurite contains in sequence from the plasma membrane: a row of vesicles lining the synaptic membrane, a sac of endoplasmic reticulum which is connected with the rough reticulum of the neuron, and one or several mitochondria. The arrangement of these closely associated organelles is constant, forming a complex referred to as thepre-synaptic triad.

The pre-synaptic triad is found both in interneural synapses—which may be polarized, symmetrical or reciprocal — and in various neuro-receptor and neuro-effector junctions.

The possible functional implications of these features are discussed.


Nervous System Plasma Membrane Endoplasmic Reticulum Triad Organization Characteristic 
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Copyright information

© Chapman and Hall Ltd. 1973

Authors and Affiliations

  • Mari-Luz Hernandez-Nicaise
    • 1
  1. 1.Service d'Histologie et Biologie TissulaireUniversité Claude BernardVilleurbanneFrance

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