Dialysis of inositol 1,4,5-trisphosphate induces inward currents and Ca2+ uptake in frog olfactory receptor cells.
Frog olfactory receptor cells (Rana ridibunda) were isolated with an enzyme-free procedure and loaded with fura-2 from the patch pipette. The cells responded to superfusion with "IP3-odorants" with an inward current and an increase of the intracellular Ca2+ concentration. [Ca2+]i. An odorant-induced inward current and an increase in [Ca2+]i were also observed while flooding cells with 1 mM cAMP from the pipette, a condition which drives the cAMP signal pathway into adaptation. Flooding of cells with 50 microM IP3 from the pipette also induced an inward current with an increase in [Ca2+]i in normal Ringer solution and an inward current without changes in [Ca2+]i in Ca(2+)-free solution. The experiments suggest that IP3 activates a cation channel at the plasma membrane, allowing inflow of Na+ and Ca2+ ions.
Kashiwayanagi
M
M
Department of Physiology, Universität des Saarlandes, Homburg, Germany. yanagi@ph.hines.hokudai.ac.jp
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000242:Cyclic AMP / Q000494:pharmacology; D003956:Dialysis; D066298:In Vitro Techniques; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D017136:Ion Transport; D011895:Rana ridibunda; D018035:Receptors, Odorant / Q000187:drug effects / Q000378:metabolism*
D018035:Receptors, Odorant; D015544:Inositol 1,4,5-Trisphosphate; D000242:Cyclic AMP; D002118:Calcium