Unraveling the relationship between macula densa cell volume and luminal solute concentration/osmolality.

摘要: At the macula densa, flow-dependent changes in luminal composition lead to tubuloglomerular feedback and renin release. Apical entry of sodium chloride both densa cortical thick ascending limb (cTAL) cells occurs via furosemide-sensitive sodium–chloride–potassium cotransport. In apical leads cell volume, although there are conflicting data regarding directional change volume with increases concentration. To further assess cells, cTAL-glomerular preparations were isolated perfused from rabbits, loaded fluorescent dyes calcein 1-(4-trimethylammoniumphenyl)-6-phenyl-1,3,5-hexatriene p -toluenesulfonate. Cell was determined wide-field multiphoton fluorescence microscopy. Increases concentration 0 80mmol/l at constant osmolality led swelling cTAL an effect that blocked by application furosemide. However, concomitant caused sustained decreases but transient volume. urea also resulted shrinkage. These studies suggest that, under physiologically relevant conditions concurrent osmolality, is shrinkage, which may play a role signaling process.