Morphological characteristics of neuromuscular junctions of the opossum (Didelphis albiventris) extraocular muscles: A scanning-electron-microscopic study
Smm. Matheus et Jc. Soares, Morphological characteristics of neuromuscular junctions of the opossum (Didelphis albiventris) extraocular muscles: A scanning-electron-microscopic study, CELLS T ORG, 166(4), 2000, pp. 330-337
Three types of neuromuscular junctions were described in the extraocular mu
scles of the opossum, The present study demonstrates the three-dimensional
characteristics of these neuromuscular junctions after HCl connective tissu
e digestion. Adult opossum of both sexes were used and the neuromuscular ju
nctions of the extraocular muscles were examined after removal of the intra
muscular connective tissue and basal layer. This material was examined with
a scanning electron microscope, Two types of 'en plaque' neuromuscular jun
ction were described: the continuous type revealed elongated and branched p
rimary synaptic grooves separated from each other by sarcolemma protuberanc
es with different sizes, and the discontinuous or punctiform type which pre
sents very shallow and discontinuous grooves when compared with the former.
The multiple neuromuscular junctions were observed as two or three junctio
ns associated with the same muscular fiber. The multiple junctions were pre
sent in thin fibers (around 11 mu m caliber); the en plaque junctions were
associated with large diameter fibers (around 21 mu m), This study confirms
and reveals the detailed morphological characteristics of the three neurom
uscular junction types previously described by transmission electron micros
cope in the extraocular muscles of opossum,
Copyright (C) 2000 S. Karger AG, Basel.