ALDOSE REDUCTASE INHIBITION, DOPPLER FLUX AND CONDUCTION IN DIABETIC RAT NERVE

Two chemically distinct aldose reductase inhibitors, ponalrestat and t olrestat, were tested against laser Doppler blood flow and conduction deficits in the sciatic nerve of diabetic rats. The effects of two mon ths of streptozotocin-induced diabetes and aldose reductase inhibition on body weight, plasma glucose, and nerve sugars and polyols were com parable to those reported previously. Nerve blood flow, reflected by l aser Doppler flow measurements, and motor nerve conduction velocity we re both significantly less in diabetic than in control animals. Both o f these reductions were prevented by ponalrestat, but not tolrestat. T hus, either deficits in laser Doppler blood flow and conduction are no t aldose reductase inhibitor-dependent or tolrestat has some other pro perty which offsets the beneficial effects of aldose reductase inhibit ion. In either case, these data are consistent with the hypothesis tha t reduced nerve blood flow contributes to conduction deficits in diabe tes.