Electrical and transport characteristics of skin of larval Rana catesbeiana.
Carefully dissected, mounted, and bathed with Ringer solution, the larval bullfrog skin has a resistance of about 9,000 omega.cm2 and a stable transepithelial electrical potential of about 20 mV (inside +). A short-circuit current of about 2 microA.cm-2 is generated that is comparable in magnitude to the net inward flux of Na+. At open circuit the flux ratio equation for Na+ is not satisfied. Larval skin is less sensitive to ouabain, amiloride, and ADH than adult skin. The current-voltage (C-V) relationship across the preparation is not linear; there are distinct breaks in both the hyperpolarizing and hypopolarizing regions. The former break, at about +130 mV, corresponds with a break observed in adult skin that corresponds with ENa. The shunt resistance (RS) and active pathway resistance (RA) were estimated by C-V curve analysis and by ion substitution. The two methods yielded comparable values with RS about 11 k omega.cm2 and RA about 62 k omega.cm2. It is suggested that transport is limited by the number of entry sites for sodium at the apical border of transport cells.
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001001:Anura; D001692:Biological Transport; D004594:Electrophysiology; D007814:Larva; D008564:Membrane Potentials; D009761:Nystatin / Q000494:pharmacology; D010042:Ouabain / Q000494:pharmacology; D011892:Rana catesbeiana; D012879:Skin Physiological Phenomena; D012964:Sodium / Q000378:metabolism; D014667:Vasopressins / Q000494:pharmacology
D014667:Vasopressins; D009761:Nystatin; D010042:Ouabain; D000584:Amiloride; D012964:Sodium