[Recording and identification of depolarization-activated current in intercalated cells].

The depolarization-activated current of intercalated cells in the distal nephron was detected for the first time, and the type of ion channel mediating the current was identified based on electrophysiological and pharmacological properties. The whole-cell current of distal nephron in kidney of C57BL/6J mice was recorded by Axon MultiClamp 700B patch-clamp system, and the effects of several K+ channel inhibitors on the depolarization-activated current in intercalated cells were observed. In addition, the immunofluorescence technique was used to investigate the localization of the channel in intercalated cells. The results showed that when K+ concentration of the bath solution was equal to intracellular fluid (140 mmol/L K+), the depolarization-activated current could be recorded in intercalated cells, but this current was not observed in the principal cells. The depolarization-activated current detected in the intercalated cells could be blocked by Kv4.1 inhibitors. The immunofluorescence experiment showed that the fluorescence of Kv4.1 protein was only present in intercalated cells and not observed in principal cells. Kv4.1 protein immunofluorescence was observed in the luminal and basolateral membrane of intercalated cells, but the fluorescence intensity of luminal membrane was higher than that of basolateral membrane. We conclude that the depolarization-activated current detected in intercalated cells is mediated by Kv4.1 and this channel is mainly expressed in the luminal membrane of intercalated cells.

[A method of acutely isolating rat dorsal root ganglion neurons for patch-clamp study of single-channel].

OBJECTIVE: To establish a method of acutely isolating dorsal root ganglion (DRG) neurons for patch clamp study of single-channel. METHODS: DRG neurons of rats were acutely isolated by enzymatic digestion and mechanical blowing. RESULTS: The acutely isolated DRG cells were easy to form the higher sealing resistance (> 5G Omega), which lowered noise level, so that pA-level single channel currents could be recorded. CONCLUSION: The acutely isolated DRG neurons in this study are an ideal for patch-clamp study of single-channel.