Raised intracellular free calcium within the lens causes opacification and cellular uncoupling in the frog.

Publisher Website
Google Scholar
Abstract
Ion-sensitive micro-electrodes were used to measure the levels of intracellular free Ca2+ within the intact amphibian lens. The free [Ca2+] was found to constitute 0.4% of the total lens Ca. The pCa measured at the anterior lens surface was 6.59, while that at the posterior was 5.70. An 8-fold anterior/posterior Ca2+ gradient thus exists along the optical axis. The intracellular free Ca2+ could be manipulated by incubating the lens in high-Ca2+ or Ca2+-free EGTA [ethyleneglycol-bis-(.beta.-aminoethyl ether)N,N''-tetraacetic acid] Ringer solutions. Raising the intracellular free Ca2+ to 0.22 mM caused lens opacification and cellular uncoupling; the coupling ratio was reduced from 1 in control to 0.41 in high Ca2+.