An electrogenic component of the potential difference in the rabbit lens.
The normal resting potential of the rabbit lens, -70mV, is altered to -59mV by ouabain concentrations up to 5-1- minus 6M, and to -52mV at 4 degrees C. Ouabain acts only at the anterior lens surface. The temperature effect id completely reversible. The Hodgkin-Katz-Goldman equation can be used with the measured lens potentials and Na+ and K+ levels in the lens and bathing medium to obtain alpha, the ration of the membrane permeabilities to Na+ and K+. The alpha-values obtained were 0.052 at 4 degrees C and 0.053 in 5-10 minus 6M ouabain. These data suggest that the change in potential due to cold and ouabain is caused by an inhibition of an electrogenic Na+ ump in the anterior lens epithelium.
D000818:Animals; D001693:Biological Transport, Active; D004305:Dose-Response Relationship, Drug; D007908:Lens, Crystalline / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D008839:Microelectrodes; D010042:Ouabain / Q000494:pharmacology; D010539:Permeability; D011188:Potassium / Q000378:metabolism; D011817:Rabbits; D012964:Sodium / Q000378:metabolism; D013696:Temperature; D013997:Time Factors
D010042:Ouabain; D012964:Sodium; D011188:Potassium