Summary
The olfactory tubercle of the rat was studied by electron microscopy both in the normal and after ipsilateral olfactory bulb ablation at survival times of from 14 hours to seven days. Particular emphasis was placed on synaptic structures and their changes following the lesion. Normal synapses are similar to those described in previous studies and presynaptic profiles are of at least three types. Types-A and -B contain round vesicles and form asymmetrical contacts and type-C profiles contain flattened vesicles and form symmetrical contacts.
There appear to be two major types of degenerative changes. The electron-lucent type predominates at early survival times and is seen first at 14 hours. These profiles show an early reduction in numbers of vesicles with mitochondrial swelling followed by shrinkage of the profile. These profiles become increasingly electron-dense at later survival times. The second major type of degenerating profile is initially electron-dense. The earliest changes in these profiles are an increased axoplasmic density and increased microtubular density and clumping without apparent loss of vesicles. These profiles also become progressively more electron-dense at longer survival times. The observations are discussed in relation to previous reports.
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This study represents a part of a thesis (C. A. Anderson) for the Doctor of Medicine degree, University of Washington School of Medicine. It was supported by PHS grants NS 04053, NS 02896 and NS 09678 from the N.I.N.D.S., National Institutes of Health. The authors gratefully acknowledge this support.
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Anderson, C.A., Westrum, L.E. An electron microscopic study of the normal synaptic relationships and early degenerative changes in the rat olfactory tubercle. Z.Zellforsch 127, 462–482 (1972). https://doi.org/10.1007/BF00306866
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DOI: https://doi.org/10.1007/BF00306866