ATP and the binding of ( super(3)H)inositol 1,4,5-trisphosphate to its receptor

There are now several reports of the specific reversible binding of inositol 1,4,5-trisphosphate (InsP sub(3)) to permeabilized cells or particulate preparations of several tissues. The authors have reported that ATP, which is generally present in millimolar concentrations in Ca super(2+)-release assays, inhibited the specific binding of ( super(3)H)Ins-(1,4,5)P sub(3) to a particulate site prepared from rat cerebellum. Using their cerebellar membrane preparation, which has been carefully evaluated for stereo- and positional specificity, they have failed to reproduce the results.