Nitric-oxide-mediated zinc release contributes to hypoxic regulation of pulmonary vascular tone.

The metal binding protein metallothionein (MT) is a target for nitric oxide (NO), causing release of bound zinc that affects myogenic reflex in systemic resistance vessels. Here, we investigate a role for NO-induced zinc release in pulmonary vasoregulation. We show that acute hypoxia causes reversible constriction of intraacinar arteries (<50 microm/L) in isolated perfused mouse lung (IPL).

Intravital fluorescence microscopy in pulmonary research.

Over the last several years, microscopy as a scientific tool has reinvented itself evolving from a group of principally descriptive methodologies to encompass a wide range of primary tools and techniques to investigate the molecular organization of organs, tissues and cells. Advances in microscope and camera design, fluorescent dye technology, the development of fluorescent proteins as well as the advent of inexpensive powerful computers, has led to the feasibility of simultaneous sub micron resolution and quantitation of multiple concurrent molecular markers for both protein and DNA. Confocal microscopy has allowed optical sectioning and reconstruction of tissues in three dimensions.

Nitric oxide-induced modification of protein thiolate clusters as determined by spectral fluorescence resonance energy transfer in live endothelial cells.

Low-molecular-weight S-nitrosothiols are found in many tissues and affect a diverse array of signaling pathways via decomposition to *NO or exchange of their -NO function with thiol-containing proteins (transnitrosation). We used spectral laser scanning confocal imaging to visualize the effects of D- and L-stereoisomers of S-nitrosocysteine ethyl ester (SNCEE) on fluorescence resonance energy transfer (FRET)-based reporters that are targets for the following NO-related modifications: (a) S-nitrosation, via the cysteine-rich protein metallothionein (FRET-MT), and (b) nitrosyl-heme-Fe, via guanosine 3',5'-cyclic monophosphate (cygnet-2). Conformational changes consistent with S-nitrosation of FRET-MT were specific to l-SNCEE.