Oxygen sensitivity of gill neuroepithelial cells in the anoxia-tolerant goldfish

Abstract

In the zebrafish, O2-chemoreceptive neuroepithelial cells (NECs) of the gill arches detect changes in PO2 and are believed to initiate cardiorespiratory responses to hypoxia. Goldfish have gill NECs of similar morphology and innervation, yet these animals are naturally tolerant to prolonged periods of anoxia. Whole-cell, voltage-clamp experiments indicated that goldfish NECs express a variety of membrane ion channels, including background and Ca2+-activated K+ channels. Our initial studies suggest that goldfish NECs do not respond equally to hypoxia (N 2, 25 mmHg) as do those of zebrafish; however, current-clamp recordings indicated that anoxia produced membrane depolarization. In addition, we found that cyanide, which mimics hypoxia, depolarized NECs. Our goal is to further characterize these membrane conductances and determine their potential contribution to O2 sensing in NECs of the anoxia-tolerant goldfish. © Springer Science+Business Media Dordrecht 2012.