Comparison of neuronal inositol 1,4,5-trisphosphate 3-kinase and receptor mRNA distributions in the human brain using in situ hybridization histochemistry.

The distribution of the messenger RNA coding for the recently cloned inositol 1,4,5-trisphosphate (InsP3) 3-kinase, the enzyme phosphorylating InsP3 to InsP4, was compared to the localizations of InsP3 receptor mRNA in the human brain using in situ hybridization histochemistry and oligonucleotide probes. InsP3 3-kinase and receptor mRNA levels were high in the cerebellar Purkinje cells. They were also observed, to a much lesser degree than in the cerebellum, in the hippocampal CA1 pyramidal cells and dentate gyrus granule cells, in the majority of the cortical neurons and in the striatal medium-sized neurons. Both mRNAs were not detected in the brainstem and in the glial cells.