Premium
PERMEABILITY OF THE PERINEURIUM OF SMALL NERVE FASCICLES: AN ULTRASTRUCTURAL STUDY USING FERRITIN IN RATS
Author(s) -
OLDFORS A.
Publication year - 1981
Publication title -
neuropathology and applied neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.538
H-Index - 95
eISSN - 1365-2990
pISSN - 0305-1846
DOI - 10.1111/j.1365-2990.1981.tb00088.x
Subject(s) - endoneurium , perineurium , ferritin , vesicle , pinocytosis , hemosiderin , anatomy , axon , chemistry , biophysics , pathology , biology , sciatic nerve , medicine , peripheral nerve , cell , membrane , biochemistry , endocytosis
The permeability of the perineurial cells was studied with ferritin as a tracer. It was injected beneath the muscle fascia of the lateral aspect of the fore limb of rats. After various intervals the animals were killed and the distribution of ferritin in the nerves of the underlying muscle was observed. Two minutes after injection, ferritin was found surrounding nerve fascicles of various sizes. Some medium sized fascicles containing ten to twenty myelinated nerve fibres, were bounded by a single layer of perineurial cells. In the endoneurium of these fascicles only very occasional ferritin particles were observed. Ferritin was, however, found in perineurial micropinocytotic vesicles which communicated with the epineurial extracellular compartment and also in some vesicles which were entirely intracellular and in a few vesicles which had an opening towards the endoneurium. Occasionally two or more vesicles had fused with one another. Fifteen minutes after the injection of ferritin, numerous ferritin particles were seen in the endoneurium of all nerve fascicles covered by a single layer of perineurial cells. The vesicles of these cells then frequently contained numerous ferritin particles. Sixty minutes after injection of ferritin the tracer was observed within the endoneurium of fascicles of all sizes, including those with a multilayered perineurium. In the latter, ferritin was seen between all the perineurial cell layers as well as in micropinocytotic vesicles of the perineurial cells. The results of this study strongly indicate that the perineurium of small nerve fasicles is permeable to ferritin and that this permeability is due to pinocytosis in the perineurial cells.