[3H]inositol 1,4,5-triphosphate binding in human cerebral cortex.

Specific, saturable and reversible binding of [3H]inositol 1,4,5-triphosphate (IP3) was demonstrated to membranes prepared from autopsied cerebral cortices from 6 subjects who were free from psychiatric or neurological disease. The binding has an affinity of 27 +/- 8 nM (mean +/- S.E.M.); capacity (Bmax) of 1.09 +/- 0.18 pmol/mg protein and is reversible in the presence of an excess of unlabelled IP3. These [3H]IP3 binding sites are likely to be physiologically significant receptors which merit further characterization in the normal and diseased human brain.