Changes in microtubular tau protein after morphine in a cultured human neuroblastoma cell line

1. Cultured human SH-SY5Y adrenergic neuroblastoma cells were used to examine the action of morphine sulfate on microtubular tau protein. 2. After 48 hr treatment morphine sulfate (200 microM) reduced tau protein in the cytoplasmic (supernatant) fraction of undifferentiated cells, and in the cytoplasmic as well as membrane (pellet) fractions of differentiated cells. 3. A 71% increase (P < 0.05) in total protein in the membrane (pellet) fraction of undifferentiated cells and a 188% increase (P < 0.01) in that of differentiated cells accompanied the decrease in tau protein. 4. A 51% reduction (P < 0.01) in the number of undifferentiated (but not differentiated) cells was seen after this drug (200 microM).