| Range |
at embryonic day 16 of gestation 2,000-3,000: at birth ~9,000 sites/µm^2
|
| Organism |
Mouse Mus musculus |
| Reference |
Matthews-Bellinger JA, Salpeter MM. Fine structural distribution of acetylcholine receptors at developing mouse neuromuscular junctions. J Neurosci. 1983 Mar3(3):644-57. abstractPubMed ID6827314
|
| Method |
"The distribution of acetylcholine receptors (AChRs) in neuromuscular junctions of embryonic
and newborn mice (strain 129/ReJ) was examined on the fine structural level using [125I]a-bungarotoxin
labeling and quantitative electron microscope autoradiography. Changes in junctional receptor
site density were related to changes in the structure of the postjunctional membrane, in particular
the differentiation of morphologically distinct regions of thickened membrane and the formation of
junctional folds." |
| Comments |
"The following sequence of development is described: (1) At the earliest age
examined, embryonic day 16 of gestation (i.e., at approximately the time when junctional receptor
accumulations are first detected), subneural receptor aggregates have poorly defined boundaries and
seem to extend beyond the region of direct axonal or Schwann cell contact. At that time the
subneural AChR site density is somewhat variable but averages ~2000 to 3000sites/µm^2, and the
subneural muscle membrane shows discontinuous membrane specialization (membrane thickening
plus a cytoplasmic amorphous layer). There seems to be no preferential labeling of contact regions rich in such specialization compared with those where membrane thickening was less obvious or absent. (2) By birth, junctional AChRs are strongly correlated with morphologically specialized membrane, at a constant density of approximately 9000sites/µm^2 (comparable to that in adult animals of this strain of mouse)." |
| Entered by |
Uri M |
| ID |
111079 |