Botulinum Toxins Inhibit the Antidiuretic Hormone (ADH)-Stimulated Increase in Rabbit Cortical Collecting-Tubule Water Permeability
BURG, M. B., L. ISAACSON, J. GRANTHAM, AND J. ORLOFF. Electrical properties of isolated perfused rabbit renal tub&s. Am. J. Physiol. 2 15(4) : 788-794. 1968.-Electrical potential difference (PD) was measured across isolated perfused rabbit proximal renal tubules and collecting tubules in vitro. In the collecting tubule the PD stabilized after 2-3 hr of perfusion at a mean value of 25 mv (lumen negative). Ouabain caused depolarization, interpreted as indicating that the PD may be related to active Na+ transport. Vasopressin caused a transient increase in PD followed bv a sustained decrease. Electrical resistante of the collecting tubule wall was evaluated from measurements of the length constant for the decay of PD from a current source within the tubule lumen. This calculated resistance is much greater than that previously found in rat proximal tubule in vivo. . In proximal convoluted tubules under conditions optimal for net fluid absorption mean PD was -0.7 mv. This is in agreement with the recent finding that there is no measurable PD in rat proximal convoluted tubules in vivo.