In vitro swelling of the kitten retina induced by sodium fluoride inhibition.

IN a previous report (Graymore, 1958) methods have been described for the rapid removal of rat retinae and the subsequent accurate determination of their Wet-weight: Dry-weight ratios following a period of incubation with Krebs-Ringer-Bicarbonate supplemented with glucose. It was shown that addition of sodium fluoride to the medium resulted in a tissue oedema. This was explained on the basis that living cells are not necessarily in osmotic equilibrium with their environment, and that the osmotic pressure of the cells is maintained at a higher level as a steady state, by some process requiring metabolic energy to pump water outwards through the cell membrane. This concept, and the supporting evidence, has been reviewed elsewhere (Robinson and McCance, 1952; Robinson, 1954). Ashton, Graymore, and Pedler (1957) induced vaso-obliteration in the kitten retina by intravitreal injection of sodium fluoride, and suggested that external pressure due to retinal oedema may play some role in this vessel closure. The present communication is designed to show that the retina of the kitten responds to in vitro treatment with sodium fluoride in the same way as that of the rat.