Amiloride-insensitive cation conductance in Xenopus laevis olfactory neurons: a combined patch clamp and calcium imaging analysis.
We used digital calcium imaging with Fura-2 in conjunction with the tight-seal whole-cell patch clamp technique to describe a novel cation conductance in olfactory neurons of the clawed toad Xenopus laevis. Substitution of extracellular Ca2+ and Na+ was used as a tool to change [Ca2+]i. When [Ca2+]i was increased to about 450 nM, a conductance gcat activated that was permeable for cations. Upon gcat activation, an increase in [Ca2+]i occurred in the dendritic knob. Once activated, gcat showed no further dependence upon [Ca2+]i. Icat is shown to be different from the current activated by a mixture of the odorants citralva and amyl acetate. We conclude that there are two different cation conductances in the peripheral compartments of olfactory neurons in X. laevis.
Schild
D
D
Physiologisches Institut, Universität Göttingen, Germany.
Lischka
F W
FW
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002118:Calcium / Q000378:metabolism*; D002412:Cations; D004351:Drug Resistance; D004553:Electric Conductivity; D066298:In Vitro Techniques; D007424:Intracellular Fluid / Q000378:metabolism; D015640:Ion Channel Gating; D017136:Ion Transport / Q000187:drug effects; D018034:Olfactory Receptor Neurons / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction; D014982:Xenopus laevis
D002412:Cations; D000584:Amiloride; D002118:Calcium