The dentato-olivary projection in the rat as a presumptive GABAergic link in the olivo-cerebello-olivary loop. An ultrastructural study.
It is here shown that autoradiographically labelled axon terminals of the dentato-olivary projection form a heterogeneous population. However, a majority of them constitute an even class of synapses, characterized by their small axonal size, their content in pleimorphic vesicles, and the establishment of symmetric synapses on small dendrites, about 5% of which are linked through a gap junction. The same material, used for immunocytochemistry of GABA with the postembedding technique, discloses that a majority of boutons with cytological features similar to the dentato-olivary terminals are GABA-immunoreactive, especially those synapsing on dendrites linked by gap junctions. The cerebello-olivary projection, despite its heterogeneity, thus appears as part of the GABAergic system which governs the synaptic modulation of the electrotonic coupling between olivary neurons.
Laboratoire de Neuromorphologie, INSERM U-106, Hôpital de la Salpêtriére, Paris, France.
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Angaut
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Sotelo
D000818:Animals; D001345:Autoradiography; D001369:Axons / Q000648:ultrastructure*; D002531:Cerebellum / Q000032:analysis / Q000648:ultrastructure*; D008854:Microscopy, Electron; D009434:Neural Pathways / Q000032:analysis / Q000648:ultrastructure; D009474:Neurons / Q000648:ultrastructure; D009847:Olivary Nucleus / Q000032:analysis / Q000648:ultrastructure*; D051381:Rats; D013569:Synapses / Q000648:ultrastructure; D005680:gamma-Aminobutyric Acid / Q000032:analysis*
D005680:gamma-Aminobutyric Acid