A Family of Acid-sensing Ion Channels from the Zebrafish WIDESPREAD EXPRESSION IN THE CENTRAL NERVOUS SYSTEM SUGGESTS A CONSERVED ROLE IN NEURONAL COMMUNICATION*

Acid-sensing ion channels (ASICs) are excitatory re-ceptors for extracellular H. Proposed functions include synaptic transmission, peripheral perception of pain, and mechanosensation. Despite the physiological im-portance of these functions, the precise role of ASICs has not yet been established. In order to increase our understanding of the physiological role and basic struc-ture-function relationships of ASICs, we report here the cloning of six new ASICs from the zebrafish (zASICs). zASICs possess the basic functional properties of mam-malian ASICs: activation by extracellular H, Na selec-tivity, and block by micromolar concentrations of amilo-ride. The zasic genes are broadly expressed in the central nervous system, whereas expression in the pe-ripheral nervous system is scarce. This pattern suggest