[en] Autoradiographic techniques were used to investigate the characteristics of tritiated inositol(1,4,5)trisphosphate ([³H]IP₃) and inositol(1,2,3,4,5)tetrakisphosphate ([³H]IP₄) binding to human brain. In brain sections ([³H]IP₃) exhibited a two-site binding with K_D values of 87 nM and 9.3 μM respectively for the higher and lower affinity sites. [³H]IP₄, also bound to two sites with K_D values of 43 nM and 1.4 μM. respectively. With the conditions fixed in this study, [³H]IP₃ and [³H]IP₄ autoradiography in the cortex, caudate, hippocampus and cerebellum were performed. The most prominent [³H]IP₃ binding among these regions was found in the cerebellum, particularly in the molecular layer. Within the hippocampus, the subiculum and the CA1 region showed much more prominent binding than the other subfields. [³H]IP₄ binding was fairly homogeneous in the regions studied, with the exception of a slightly higher binding in the molecular layer of the cerebellum. (author)