Objective To investigate the role of acid-sensing ion channels (ASICs) in dendritic development in hippocampal neurons. Methods F-GFP which targets at the membrane was transfected into primary cultured hippocampal neurons at the 5th days BR>EM>in vitro/EM> (DIV 5). Then ASICs antagonist amiloride and ASIC1a selective antagonist psalmotoxin 1 (PcTX1) were applied to the neuronal medium to inhibit the function of ASICs. Dendritic growth and arborization of cultured hippocampal neurons were observed in DIV8 and DIV14.Results Treatments with ASICs antagonist amiloride (10SUP>-5/SUP>mol/L) and ASIC1a selective antagonist PcTX1 (1∶20 000 dilution) for 3 days had no significant effect on the total dendritic branch length and total dendritic branch number of hippocampal neurons, which suggested that dendritic development was not affected by the inhibition of ASICs for a short time during early developmental period of hippocampal neurons. Chronic treatment with amiloride (10SUP>-5/SUP>mol/L) for 9 days significantly reduced the total dendritic branch length and total dendritic branch number, while chronic treatment with ASIC1a selective antagonist PcTX1 (1∶20 000 dilution) for 9 days also significantly reduced the total dendritic branch length, but had no significant effect on the total dendritic branch number, which suggested that dendritic development was impaired if ASICs are inhibited for a long time.Conclusion ASICs play an essential r