QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

This Article Full Text (PDF) Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ko, C. P. Articles by Folsom, D. B. Search for Related Content PubMed PubMed Citation Articles by Ko, C. P. Articles by Folsom, D. B.

 Previous Article  |  Next Article 

Journal of Neuroscience, Vol 9, 3392-3399, Copyright © 1989 by Society for Neuroscience

ARTICLE

Induction of active zones at ectopic neuromuscular junctions in the frog

CP Ko and DB Folsom
Department of Biological Sciences, University of Southern California, Los Angele 90089.

To examine de novo differentiation of the active zone, ectopic neuromuscular junctions were studied in adult frog muscles. Ectopic junctions induced by excising the original endplate region and implanting the nerve to an endplate-free site were examined by light and electron microscopy 4 weeks-1 year after operations. The earliest time point at which ectopic junction formation was detected with freeze fracture was 6 weeks postoperation, when clusters of active zone particles were observed scattered across the nerve ending. Subsequently, short active zones (6-10 weeks postoperation, length mean = 0.36 +/- 0.24 microns) composed of the characteristic 2 double rows of particles are detected. Before junctional folds are observed with freeze fracture, many active zones are parallel to each other and to the long axis of the nerve. The average angle 6-10 weeks postoperation is 27 degrees +/- 23 degrees. Even during these early stages of formation, active zones are functional. As time passes, active zones attain a more typical, perpendicular orientation (12-18 weeks postoperation, mean = 62 degrees +/- 24 degrees) and also increase in length (mean = 0.69 +/- 0.45 microns). However, even after 1 year, the orientation (angle, mean = 70 degrees +/- 22 degrees) and the length (mean = 0.78 +/- 0.63 microns) of active zones at ectopic junctions are still not well correlated with active zones at normal junctions (normal active zone angle mean = 85 degrees +/- 5 degrees, length mean = 1.00 +/- 0.57 microns).(ABSTRACT TRUNCATED AT 250 WORDS)

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help