Compartmentalization of NO signaling cascade in skeletal muscles.
Skeletal muscle functions regulated by NO are now firmly established. However, the literature on the compartmentalization of NO signaling in myocytes is highly controversial. To address this issue, we examined localization of enzymes engaged in L-arginine-NO-cGMP signaling in the rat quadriceps muscle. Employing immunocytochemical labeling complemented with tyramide signal amplification and electron microscopy, we found NO synthase expressed not only in the sarcolemma, but also along contractile fibers, in the sarcoplasmic reticulum and mitochondria. The expression pattern of NO synthase in myocytes showed striking parallels with the enzymes engaged in L-arginine-NO-cGMP signaling (arginase, phosphodiesterase, and soluble guanylyl cyclase). Our findings are indicative of an autocrine fashion of NO signaling in skeletal muscles at both cellular and subcellular levels, and challenge the notion that the NO generation is restricted to the sarcolemma.
Buchwalow
Igor B
IB
Gerhard Domagk Institute of Pathology, University of Muenster, Muenster, Germany. buchwalo@uni-muenster.de
Minin
Evgeny A
EA
Samoilova
Vera E
VE
Boecker
Werner
W
Wellner
Maren
M
Schmitz
Wilhelm
W
Neumann
Joachim
J
Punkt
Karla
K
D000818:Animals; D001483:Base Sequence; D002451:Cell Compartmentation; D017931:DNA Primers; D007150:Immunohistochemistry; D018482:Muscle, Skeletal / Q000201:enzymology / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D016133:Polymerase Chain Reaction; D051381:Rats; D015398:Signal Transduction
D017931:DNA Primers; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase