REGULATION OF RETINAL ACTIVITY IN AN EX-VIVO GUINEA PIG MODEL BY EXPERIMENTAL CONDITIONS AND EFFECTS OF ISOFLURANE AND PROPOFOL ANESTHETICS

Abstract

Electroretinoraphic signals (ERGs) are affected when recorded under isoflurane anesthesia in the operating room. We explored the effect of isoflurane and propofol in ex vivo guinea pig retinal preparations using a multielectrode array to record simultaneously ERGs and retinal ganglion cell (RGC) activity. The viability and light-response characteristics of the model were documented. In the presence of isoflurane, the ERG and RGC activity was reduced in a dose-dependent manner, even at sub-clinical doses; the OFF responses were consistently more affected. Propofol had minimal effects: at subclinical doses, a small excitation was measured while a concentration a hundred times stronger than the clinical concentration was required to measure a significant decline in EGR and RGC signals. This study confirms the usefulness of the guinea pig model to study clinically relevant retinal issues and shows that propofol is a better anesthetic to use in the operating room when retinal investigations are required.