Ultrastructural localization of protein kinase C beta-subspecies in the axon terminal of rat neuromuscular junction.
Ultrastructural localization of protein kinase C (PKC) beta-subspecies in neuromuscular junctions of the rat lumbrical muscle was investigated by the immunoperoxidase and immunofluorescence methods. By light microscopy, PKC beta-like immunoreactivity (PKC beta-LIR) was found in the axon terminal expansions as well as in the preterminal axons. By confocal laser scanning microscopy, the staining for PKC beta-like immunoreactivity was more intense in the presynaptic regions just in contact with the acetylcholine receptor stained by FITC-alpha-bungarotoxin. By electron microscopy, PKC beta-like immunoreactivity was distributed non-uniformly in the terminal expansions. In the terminal expansions, PKC beta-like immunoreactivity was accumulated in the presynaptic regions in contact with the post-synaptic folds. This accumulation was approximately 0.1-0.2 microns in diameter, which comprised a part of the presynaptic plasma membrane and a group of synaptic vesicles adjacent to it. Weak immunoreactivity was also found diffusely in the axoplasmic matrix. The discrete presynaptic accumulation of PKC beta-subspecies may represent the strategical localization specialized for the effective regulation of neurotransmitter release.
Department of Anatomy, Kobe University School of Medicine, Japan.
M
M
Arakawa
A
A
Mizoguchi
M
M
Masutani
N
N
Kawakita
C
C
Ide
D000818:Animals; D001369:Axons / Q000201:enzymology* / Q000648:ultrastructure; D005260:Female; D005455:Fluorescent Antibody Technique; D007124:Immunoenzyme Techniques; D007834:Lasers; D008853:Microscopy / Q000379:methods; D009411:Nerve Endings / Q000201:enzymology* / Q000648:ultrastructure; D009469:Neuromuscular Junction / Q000201:enzymology* / Q000648:ultrastructure; D011493:Protein Kinase C / Q000145:classification / Q000378:metabolism* / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution
D011493:Protein Kinase C