Vascular smooth muscle and nitric oxide synthase.
The concept of endothelium-derived relaxing factor (EDRF) put forward in 1980 by Furchgott and Zawadzki implies that nitric oxide (NO) produced by NO synthase (NOS) in the endothelium diffuses to the underlying vascular smooth muscle, where it modulates vascular tone as well as vascular smooth muscle cell (VSMC) proliferation by increasing cGMP formation with subsequent activation of cGMP-dependent protein kinase. According to this concept, VSMC do not express NOS by themselves. This attractive, simple scheme is now under considerable debate. To address this issue, we designed this study with the use of a novel supersensitive immunocytochemical technique of signal amplification with tyramide and electron microscopic immunogold labeling complemented with Western blotting, as in our recent studies demonstrating NOS in the myocardial and skeletal muscles. We provide the first evidence that, in contrast to the currently accepted view, VSMC in various blood vessels express all three NOS isoforms depending on the blood vessel type. These findings suggest an alternative mechanism by which local NOS expression may modulate vascular functions in an endothelium-independent manner.
Buchwalow
Igor B
IB
Department of Medicine B, Westfälische Wilhelms-Universität Münster, D-48149 Münster, Germany. buchwalo@uni-muenster.de
Podzuweit
Thomas
T
Bocker
Werner
W
Samoilova
Vera E
VE
Thomas
Sylvia
S
Wellner
Maren
M
Baba
Hideo A
HA
Robenek
Horst
H
Schnekenburger
Jürgen
J
Lerch
Markus M
MM
D000818:Animals; D001808:Blood Vessels / Q000201:enzymology; D015153:Blotting, Western; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008856:Microscopy, Fluorescence; D009131:Muscle, Smooth, Vascular / Q000201:enzymology*; D019001:Nitric Oxide Synthase / Q000032:analysis* / Q000276:immunology; D020033:Protein Isoforms / Q000032:analysis / Q000276:immunology; D013552:Swine; D014439:Tyramine / Q000737:chemistry
D020033:Protein Isoforms; D019001:Nitric Oxide Synthase; D014439:Tyramine