Scaling of transepithelial potential difference in the mammalian trachea.

摘要: Tracheal epithelia of different mammalian species differ widely with regard to the relative rates Na+ absorption and Cl− secretion. However, short circuit current, a measure total ion transport, appears be consistently greater in large than small mammals. Thus, we hypothesized that vivo tracheal electrical potential difference (PD) would vary among as function body mass (M). To test this hypothesis measured PD ten ranged 1000-fold mass. The results mV (mean ± SE, lumen negative) were: 11.4 1.0 mice; 11.6 1.2 gerbils; 12.9 1.4 rats; 19.3 0.9 guinea pigs; 27.2 2.2 ferrets; 23.0 1.6 cats; 27.0 0.6 rabbits; 32.5 2.6 dogs; 37.0 1.9 sheep; 49.0 3.3 pigs. Log-log correlation analysis mean (in mV) M kg) yielded = 20.9 M0.19 (r 0.96, P < 0.001). Analysis published current (SCC, μA/cm2) data revealed similar relationship: SCC 38.2 M0.21. transepithelial active charge transport by epithelium are allometric variables may have direct physiological significance. These raise questions regarding importance net osmotic solute water across epithelium.