Barbiturates protect retinal cells from hypoxia in cell culture

A culture system was used to screen for drugs that can protect mammalian retinal cells from damage induced by hypoxia. Using a special incubator, cultures could be made hypoxic for defined periods. Phase contrast photomicroscopy facilitated comparison of retinal cells before hypoxia and 1 to 2 days after hypoxia. Using 2- to 3-week-old cultures, certain glutamate antagonists, anesthetics, calcium blockers, and thiopental sodium were screened for their effect in protecting cells from hypoxia. The most remarkable effect was noted with thiopental. Quantitative measurements showed a significant increase in the percent of cells surviving after exposure to hypoxia in the presence of 100 mumol/L of thiopental sodium compared with control hypoxic cultures--82% vs 59% at 48 hours. A dose-response curve demonstrated maximal effect at 50 mumol/L of thiopental sodium, with toxic effects noted at 200 mumol/L of thiopental sodium. Our results show that thiopental reduces hypoxia-induced damage to retinal cells in culture.