system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, BACKGROUND, METHODS, RESULTS. Meshes: Animals, Cell Membrane, Cyclic N-Oxides, Electron Spin Resonance Spectroscopy, Light, Male, NADPH Oxidases, Reactive Oxygen Species, Sheep, Spermatozoa, Spin Trapping.
user
Is the plasma membrane involved in the visible light-tissue interaction? Context: The aim of the present study was to determine whether the plasma membrane is also involved in the light-tissue interaction because of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase electron chain, which can serve as a photosensitizer. It has been suggested that the mechanism of photobiostimulation involves light-induced low levels of reactive oxygen species (ROS) that serve as signal transduction messengers. Production of ROS following visible-light irradiation was verified by the electron paramagnetic resonance (EPR) spin-trapping technique, and the mitochondrial cytochromes were suggested as the main cellular target for visible-light absorption. Isolated sperm membranes were illuminated with visible light and the increase in oxygen radical production was measured using the EPR spin-trapping technique coupled with the probe 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). A broadband visible light source (400-800 nm) at 40-130 mW/cm(2) with appropriate filters provided the illumination. In order to determine whether the light-induced ROS production is a result of a photo-accelerated electron transfer in the enzyme-catalyzed reaction with oxygen in the plasma membrane, or resulted from a photochemical reaction of the chromophores alone with oxygen, denatured membranes were irradiated as well. Visible-light-induced oxyradicals were detected in isolated sperm membranes. Blue light was found to be more effective than red. Illuminated denatured membranes produced the same amount of ROS as non-denatured membranes.
assistant
Visible-light illumination, especially in the blue region, increases ROS levels in isolated plasma membranes. The mechanism of ROS formation is probably a photochemical reaction of the membranal chromophhores, for example, cytochromes or flavins with oxygen, and not an enzyme-catalyzed photochemical reaction. Final Decision: yes