Effects of vasopressin on single Cl- channels in the apical membrane of distal nephron cells (A6).
We have investigated how two types of Cl- channels found in sodium transporting epithelium are regulated by arginine vasopressin (AVP). A6 cells cultured on permeable supports for 10 to 14 days have two types of Cl- channels in the apical membrane that have single channel conductances of 3 and 8 pS. In cells without AVP pretreatment, the 3 pS Cl- channel was more frequently observed than the 8 pS Cl- channel. AVP increased the open probability (Po) and single channel conductance of the 3 pS Cl- channel without significantly changing the Po or conductance of the 8 pS Cl- channels. On the other hand, AVP did not affect the number of the 3 pS Cl- channel, but increased the number of 8 pS Cl- channels. These observations suggest that AVP has two different pathways to increase apical membrane chloride conductance in distal nephron A6 cells; i.e., (1) increases the Po and single channel conductance of 3 pS Cl- channels and (2) increases the number of 8 pS Cl- channels.
Marunaka
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Y
Division of Respiratory Research, Hospital for Sick Children Research Institute, University of Toronto Faculty of Medicine, Ontario, Canada.
Tohda
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H
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D002460:Cell Line / Q000187:drug effects / Q000648:ultrastructure; D018118:Chloride Channels / Q000145:classification / Q000187:drug effects*; D004553:Electric Conductivity; D009399:Nephrons / Q000187:drug effects* / Q000648:ultrastructure; D013223:Statistics as Topic
D018118:Chloride Channels; D001127:Arginine Vasopressin