Summary
Degenerating nerve fibres and boutons were searched with the aid of the electron microscope in the arcuate nucleus of rats 2–7 days after bilateral destruction of the retina.
In the arcuate nucleus of the control animals as well as in the operated animals, 4 types of boutons were distinguished on the basis of vesicular contents and glial ensheathment. In the operated animals changes interpreted as degenerating were found in small myelinated axons and boutons of type II (boutons containing both synaptic and granular vesicles). The changes were similar to those described in the literature as the “dark” type of degeneration in experimentally interrupted axons and boutons. Similar changes were not found in the unoperated animals. The conclusion is reached, that a small number of fibres of the optic tract reach the arcuate nucleus to terminate here.
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Financial support for this work was given by the “Calouste Gulbenkian Foundation” and by the “3rd Development Plan” of the Portuguese Ministry of Education.
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Sousa-Pinto, A. Electron microscopic observations on the possible retinohypothalamic projection in the rat. Exp Brain Res 11, 528–538 (1970). https://doi.org/10.1007/BF00233973
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DOI: https://doi.org/10.1007/BF00233973