Taurine and nifedipine protect retinal rod outer segment structure altered by removal of divalent cations.

A protective effect of taurine on morphological alterations induced in isolated ROS by remotion of divalent cations is described. ROS damage is not observed when sodium or chloride is replaced by impermeant ions or in the presence of nifedipine (10 microM). An increased accumulation of 22Na but not of 36Cl occurs in retinas incubated in divalent cation free medium. Taurine (5-25 mM) provides a concentration-dependent protection to ROS structure. Taurine is also able to reduce the increased 22Na influx to control values. These results suggest a protective action of taurine probably involving an interaction with calcium sites on ROS membranes which regulate sodium permeability.