Hyperosmolarity and electroretinogram (ERG) potentials in isolated rat retinas: possible implications in diabetic models.

In this report, the effects of increases in the osmolarity of media superfusing isolated rat retinas on the a-wave, b-wave and oscillatory potentials of the electroretinogram (ERG) were examined. Osmolarity of the media was raised from 310 milliosmoles (control) to 340 and 370 milliosmoles by addition of NaCl or sucrose. Increases in osmolarity led to rapid decreases in the amplitudes of the b-wave and oscillatory potentials with little change in the amplitude of the a-wave. Excellent recovery of the ERG potentials was observed when control conditions were restored. The implications of these effects of an hyperosomotic load on ERG potentials in vitro are discussed with regard to a possible role of this load in models of experimental diabetes.