Measurement of calcium ion concentrations in the lateral line cupulae of Xenopus laevis.
1. Ion selective microelectrodes were used to measure the distribution of Ca2+ in the cupulae of Xenopus laevis, and to observe the effects of the Ca2+ blocker, La3+, and a Ca2+ chelating agent (EGTA) on the endocupular potential and K+ concentration. 2. Measurements of the endocupular Ca2+ and potential were found to be in the range of 2-30 muM and 55-10 mV respectively, and their relationship indicates that Ca2+ is passively distributed in the cupula. 3. The concentration of endocupular K+ and endocupular potential was found not to be influenced by addition of either 1 mM EGTA or 100 muM-La3+ to the bathing solution.
D000818:Animals; D002118:Calcium / Q000032:analysis*; D004533:Egtazic Acid / Q000494:pharmacology; D006198:Hair Cells, Auditory / Q000032:analysis* / Q000187:drug effects; D007811:Lanthanum / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D014981:Xenopus / Q000502:physiology*
D004533:Egtazic Acid; D007811:Lanthanum; D011188:Potassium; D002118:Calcium