Myo-inositol(1,4,5)trisphosphorothioate binds to specific ( super(3)H)inositol(1,4,5)trisphosphate sites in rat cerebellum and is resistant to 5-phosphatase

D-Myo-inositol(1,4,5)trisphosphorothioate, a synthetic analogue of inositol(1,4,5)trisphosphate was shown to bind with a relatively high affinity to specific sites in rat cerebellar membranes labelled with ( super(3)H)inositol(1,4,5)trisphosphate. Use of this binding assay has also established that unlike the trisphosphate, the trisphosphorothioate is completely resistant to a specific 5-phosphatase prepared from human erythrocytes. The ability of this novel analogue to release intracellular Ca super(2+) has already been reported and it offers considerable potential in the investigation of phosphoinositide-linked receptors.