Inositol 1:2-cyclic,4,5-trisphosphate is only a weak agonist at inositol 1,4,5-trisphosphate receptors.
The activity of inositol 2,4,5-trisphosphate and inositol 1:2-cyclic,4,5-trisphosphate relative to inositol 1,4,5-trisphosphate was examined by two assays; firstly, in a binding assay using rat cerebellar membranes, and secondly, in a Ca2+-mobilization assay using permeabilized Swiss 3T3 cells. In both assays the first two phosphates have a potency at least an order of magnitude less than inositol 1,4,5-trisphosphate. The possible reasons for differences between these results and previous data are discussed, as are the implications for any putative physiological role for the cyclic trisphosphate.
Willcocks
A L
AL
Department of Pharmacology and Experimental Therapeutics, University of Leicester, U.K.
Strupish
J
J
Irvine
R F
RF
Nahorski
S R
SR
D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels; D002478:Cells, Cultured; D002531:Cerebellum / Q000378:metabolism; D015544:Inositol 1,4,5-Trisphosphate; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007295:Inositol Phosphates / Q000378:metabolism*; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear; D013403:Sugar Phosphates / Q000378:metabolism*
D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007295:Inositol Phosphates; D011956:Receptors, Cell Surface; D018160:Receptors, Cytoplasmic and Nuclear; D013403:Sugar Phosphates; D015544:Inositol 1,4,5-Trisphosphate; C049924:inositol-1,2-cyclic-4,5-triphosphate; D002118:Calcium