Voltage difference between inside and outside of rod photoreceptor of retina caused by dark current

Range ~-40 mV
Organism Salamander
Reference F. Rieke and D. A. Baylor, Single-photon detection by rod cells of the retina, Rev. Mod. Phys. 70, 1027 – Published 1 July 1998 DOI: link p.1029 caption to figure 3b & right column bottom paragraph
Comments “In darkness Na+ ions enter the outer segment through channels in the surface membrane. The current loop is completed by the outward movement of K+ ions from channels in the inner segment. The inner segment also expends energy to pump Na+ out of the cell and K+ into the cell and thus maintain their concentration gradients. In darkness this circulating current produces a voltage difference of about -40mV between the inside and outside of the cell...In darkness, the circulating current, electromotive forces across the cell membrane, and resistance of the membrane set a voltage difference of about –40 mV between the inside and outside of the cell.”
Entered by Uri M
ID 111342