C-6 NBD ceramide is a fluorescent sphingolipid analogue that is permeable to cell membranes and is a vital stain for the Golgi apparatus, endoplasmic reticulum, and nuclear envelope of mammalian cells. In the presence of 10 microM monensin the visibility of the fluorescence is diminished on the plasma membrane, whereas the appearance of the Golgi apparatus is amplified. C-6 NBD ceramide has been known to produce the two fluorescent metabolites sphingomyelin and glucocerebroside intracellularly in the Golgi apparatus, which are then transported to the cell surface. In addition, monensin inhibits the ability to remove the fluorescent metabolites sphingomyelin and glucocerebroside from the cell surface by back exchange.