Premium
Bioimaging of NO in the Rat Mesentery
Author(s) -
Carvalho Helena,
Golub Aleksander S,
Pittman Roland N
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a484
Subject(s) - microcirculation , venule , fluorescence , chemistry , fluorescence microscope , biophysics , nitric oxide synthase , nitric oxide , intravital microscopy , pathology , microbiology and biotechnology , anatomy , biology , medicine , physics , organic chemistry , quantum mechanics , radiology
Nitric oxide (NO) in the microcirculation comes from several different sources in and near the microvessels. Under physiological conditions, the main enzymatic sources of NO are NO synthase (NOS) in the endothelial cells (NOS3) and in the nerve fibers associated with microvessels (NOS1). We examined the spatial NO distribution in microvessels and associated structures. The fluorescent NO indicators DAF‐2 and the diacetate form (DAF‐2DA) were topically applied to the rat mesentery. Cytosolic esterases convert DAF‐2DA to DAF‐2 which then reacts with an oxygenated derivative of NO to form the highly fluorescent DAF‐2T. Sequences of fluorescence images (exposure time 100 ms) were acquired at 10 sec intervals for 90 min with a digital CCD camera connected to a Zeiss fluorescence microscope. After 10 min of topical application of 10 μM DAF‐2DA, the fluorescence became evident first in vessel walls and mast cells. The fluorescence intensity further increased in larger vessels and most prominently in mast cells. Capillaries and small venules did not exhibit any detectable fluorescence, even after 50 min. In larger venule the wall was well defined by fluorescence and the arterioles exhibited fluorescence mainly from the nerve fibers. In conclusion, we demonstrated that the distributions of NO are heterogeneous within the microcirculation and that most of the NO originates from the NOS1, primarily from mast cells and nerve fibers associated with the arterioles. Supported by NIH grant HL18292 and HL079087 .