Effect of aldose reductase inhibition on nerve conduction velocity and resistance to ischemic conduction block in experimental diabetes.

The relationships between nerve polyol levels and both nerve conduction velocity (NCV) and resistance to ischemic conduction block (RICB) in streptozocin-induced diabetic rats were examined in two studies. In the first study, sciatic NCV and RICB of the tail nerve, assessed by measuring the time to disappearance of the nerve action potential after the tail was rendered ischemic, were measured in nondiabetic rats, untreated diabetic rats, and diabetic rats given Statil, an aldose reductase inhibitor (ARI). Sciatic NCV was lower in the untreated diabetic animals than in control animals (P less than .05), and RICB of the tail nerve was greater (P less than .001). Treatment with the ARI completely prevented the slowing of NCV but had no significant effect on the increase in RICB. In the second study, similar groups of rats were treated with either ARI, insulin, or myo-inositol. Sciatic NCV was lower in the untreated diabetic rats than in the nondiabetic rats (P less than .001). In diabetic rats treated with the ARI and in those treated with insulin, NCV was greater than in the untreated diabetic rats (P less than .05 and P less than .001, respectively) and was not significantly different from the nondiabetic rats. NCV in the myo-inositol-treated rats was not significantly different from that in the untreated diabetic rats. RICB was assessed by measuring the decline in sciatic nerve action potential amplitude at minute intervals after death.(ABSTRACT TRUNCATED AT 250 WORDS)