DIABETES-INDUCED REDUCTION OF NEURONAL SURVIVAL IN HYPOTONIC ENVIRONMENTS IN CULTURE

Dorsal root ganglion (DRG) neurons from streptozotocin (STZ)-induced d iabetic and normal C57BL mice were exposed to three different hypotoni c environments (1/2, 1/4, and 1/8 osmolar solutions). After rapid appl ications of these hypotonic solutions to the neurons, the cell volume autoregulatory mechanism operated in 1/2 osmolar solution but was disr upted in superhypotonic solutions below 1/4 osmolar in both kinds of m ice. None of the neurons could survive 12 h after treatment with super hypotonic solutions. On the other hand, a gradual reduction of osmolar ity of the culture medium enabled neurons in the normal mice to surviv e in 1/2 and 1/4 osmolar solutions as well as in an isotonic solution. However, this reduction of osmolarity increased neuronal cell death i n the diabetic mice. These results suggest that the ability of DRG neu rons to survive in hypotonic environments in culture may be lost in di abetes.