Binding of [3H]inositoltrisphosphate and [3H]phorbol 12,13-dibutyrate in rat hippocampus following transient global ischemia: A quantitative autoradiographic study

Abstract An in vitro quantitative autoradiographic binding study of the phosphatidylinositol system ligands [ 3 H]inositol 1,4,5-trisphosphate (IP 3 ) and [ 3 H]phorbol 12,13-dibutyrate (PDBU) to rat brain slices was performed at 6, 12, 24, 28 and 72 h following a 20 min ischemic injury. PDBU binding showed a transient 20% decrease in the dentate gyrus and the CA3 the first 24 h as well as a 50% decrease in the CA1 at 72h. A 50% decline in IP 3 binding was seen in all regions at 6–12 h except the pyramidal cell layer of the CA1. This downregulation of calcium mobilizing intracellular receptors is probably a defence against ischemic neuronal cell death.