DISTRIBUTION OF [H-3] DIADENOSINE TETRAPHOSPHATE BINDING-SITES IN RAT-BRAIN

The distribution of the diadenosine tetraphosphate high-affinity bindi ng sites has been studied in rat brain by an autoradiographic method u sing [H-3]diadenosine tetraphosphate as the ligand. The binding charac teristics are comparable to those described in studies performed on ra t brain synaptosomes. White matter is devoid of specific binding. The range of binding site densities in gray matter varies from 3 to 15 fmo l/mg of tissue, exhibiting a widespread but heterogeneous distribution . The highest densities correspond to the seventh cranial nerve, media l superior olive, pontine nuclei, glomerular and external plexiform la yers of the olfactory bulb, and the granule cell layer of the cerebell ar cortex. Intermediate density levels of binding correspond to differ ent cortical areas, several nuclei of the amygdala, and the oriens and pyramidal layers of the hippocampal formation. The localization of di adenosine tetraphosphate binding sites in the brain may provide inform ation on the places where diadenosine polyphosphate compounds can be e xpected to function in the central nervous system. Copyright (C) 1997 IBRO.