Functional interaction of caveolin-1 and eNOS in myocardial capillary endothelium revealed by immunoelectron microscopy.
Immunogold labeling on samples of isolated perfused rat hearts embedded by an innovative low-temperature LR White procedure provided detailed insight into the interaction of caveolin-1 and endothelial NOS in myocardial capillary endothelium at the subcellular level. Separately, the localization of caveolin-1 and eNOS at caveolae under steady state conditions was visualized. A double-labeling experiment supported their close co-localization. Short-term bradykinin stimulation caused a detectable dissociation of eNOS from caveolin and its redistribution to different cell compartments, whereas caveolin itself remained stationary at caveolae. Morphometric analysis revealed that more than 80% of detectable eNOS was co-localized with caveolin-1 at caveolae under control conditions. After brief stimulation for 2 min with 10(-7) M bradykinin, only 26% of the eNOS signals were associated with caveolin-1 and randomly distributed over the endothelial cells. After stimulation, eNOS was found at the plasmalemmal and intracellular membranes, freely in the cytoplasm, and at outer mitochondrial membranes.
Reiner
M
M
Department of Anatomy I, University of Cologne, Cologne, Germany. michael.reiner@uni-koeln.de
Bloch
W
W
Addicks
K
K
D000818:Animals; D002196:Capillaries / Q000378:metabolism; D051242:Caveolin 1; D022461:Caveolins / Q000378:metabolism*; D003331:Coronary Vessels / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism*; D008297:Male; D016253:Microscopy, Immunoelectron; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D051381:Rats; D017208:Rats, Wistar
C495537:Cav1 protein, rat; D051242:Caveolin 1; D022461:Caveolins; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat