signal transduction in cells analyzed by imaging and protein rotation

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We have examined Ca^<2+> signaling, LDL uptake and the activity of cytochrome P450scc in individual rat brain glial cells and bovine adrenocortical fasciculata cells in order to investigate the molecular mechanisms of steroid hormonc synthesis. With fluorescence video-enhanced microscopy imaging, we have demonstrated that the Ca^<2+> signaling occurred in individual Calcium Green-1 loaded cells upon stimulation with neurotransmitters (scrotonin, glutamate, histamine) to astroglial cells and adrenocorticotropin (ACTH) to adrenal cells at physiological concentration. We observed three patterns of Ca^<2+> signaling which were 1)Ca^<2+> oscillations, 2)step increase in Ca^<2+> concentration, and 3)Ca^<2+> oscillations superimposed on a step-like increase in Ca^<2+>. The results indicated that the Ca^<2+> signaling is the second messenger.Traffic of cndosomes which contain DiI labeled LDL in astroglial cells and adrcnal cells was observed in the time scale of 30 min with video-cnhanced microscopy Some localization of LDL in the cytoplasm was observed for astrocytes. For oligodendrocytes, incorporated LDL was distributed over the entire cytoplasmic region of both cell body and multiple branched cell processes.confocal laser scanning microscopy.Confocal imaging of the activity of cytochrome P450scc was performed in adrenocortical cells. Upon conversion of cholesterol-resorufin by P450scc to pregncnolonc and resorufin, the P450scc activity was observed by the strong fluorescence spots and weak fluorescence patches of resorufin.