By ma Na+ measurements.  I test the effect of  1mM D-Aspartat on my astrocytes they do not respond. I try with 8mM K+ and they show a drop down in the ratio. But later on also no effect on Aspartat? What is the reason for that. Actualy I should see something maybe to low concentrations. The Dye is fine i calibrated it propperly. Some guesses would be nice. If you need more Informations tell me