Imaging of Mitochondrial and Non-Mitochondrial Responses in Cultured Rat Hippocampal Neurons Exposed to Micromolar Concentrations of TMRMReportar como inadecuado




Imaging of Mitochondrial and Non-Mitochondrial Responses in Cultured Rat Hippocampal Neurons Exposed to Micromolar Concentrations of TMRM - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

Tetramethylrhodamine methyl ester TMRM is a fluorescent dye used to study mitochondrial function in living cells. Previously, we reported that TMRM effectively labeled mitochondria of neurons deep within mouse brain slices. Use of micromolar concentration of dye, which was required to get sufficient staining for two-photon imaging, resulted in typical fluctuations of TMRM. With prolonged exposure, we recorded additional responses in some neurons that included slow oscillations and propagating waves of fluorescence. Note: We use the terms -fluctuation- to refer to a change in the fluorescent state of an individual mitochondrion -oscillation- to refer to a localized change in fluorescence in the cytosol, and -wave- to refer to a change in cytosolic fluorescence that propagated within a cell. Use of these terms does not imply any underlying periodicity. In this report we describe similar results using cultured rat hippocampal neurons. Prolonged exposure of cultures to 2.5 µM TMRM produced a spontaneous increase in fluorescence in some neurons, but not glial cells, after 45–60 minutes that was followed by slow oscillations, waves, and eventually apoptosis. Spontaneous increases in fluorescence were insensitive to high concentrations of FCCP 100 µM and thapsigargin 10 µM indicating that they originated, at least in part, from regions outside of mitochondria. The oscillations did not correlate with changes in intracellular Ca2+, but did correlate with differences in fluorescence lifetime of the dye. Fluorescence lifetime and one-photon ratiometric imaging of TMRM suggested that the spontaneous increase and subsequent oscillations were due to movement of dye between quenched hydrophobic and unquenched hydrophilic compartments. We propose that these movements may be correlates of intracellular events involved in early stages of apoptosis.



Autor: Andrew Monteith, William Marszalec, Philip Chan, Juliette Logan, Weiming Yu, Nicholas Schwarz, David Wokosin, Philip Hockberger

Fuente: http://plos.srce.hr/



DESCARGAR PDF




Documentos relacionados