Inositol 1,3,4,6-tetrakisphosphate mobilizes calcium in Xenopus oocytes with high potency.
Injection of Ins(1,3,4,6)P4 into Xenopus oocytes evoked Ca2(+)-dependent membrane currents with a potency 5-10 times less than Ins(1,4,5)P3, whereas Ins(1,3,4)P3 and Ins(1,3,4,5,6)P5 were almost ineffective. Responses to Ins(1,3,4,6)P4 arose through liberation of intracellular Ca2+ and through entry of extracellular Ca2+. These results, together with the observation that Ins(1,3,4,6)P4 facilitated responses to Ins(1,4,5)P3, suggests that both of these compounds may act on the same intracellular receptors.
Ivorra
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I
Department of Psychobiology, University of California, Irvine 92717.
Gigg
R
R
Irvine
R F
RF
Parker
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I
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005071:Evoked Potentials; D007295:Inositol Phosphates / Q000008:administration & dosage / Q000494:pharmacology*; D007536:Isomerism; D008564:Membrane Potentials / Q000187:drug effects*; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D014982:Xenopus laevis
D007295:Inositol Phosphates; C081653:inositol-1,3,4,6-tetrakisphosphate; D002110:Caffeine; D002118:Calcium