Aldose reductase inhibition with imirestat — effects on impulse conduction and insulin-stimulation of Na+/K+-adenosine triphosphatase activity in sciatic nerves of streptozotocin-diabetic rats

✍ Scribed by A. L. Carrington; C. B. Ettlinger; N. A. Calcutt; D. R. Tomlinson

• Publisher: Springer
• Year: 1991
• Tongue: English
• Weight: 633 KB
• Volume: 34
• Category: Article
• ISSN: 0012-186X
• DOI: 10.1007/bf00403177

✦ Synopsis

This study describes reduced motor nerve conduction velocity and increased resistance to hypoxia-induced conduction failure in sciatic nerves of rats after four weeks of streptozotocin-induced diabetes (both effects were significant at p < 0.05). These changes occurred in the absence of any deficit in the steady-state ouabain-sensitive adenosine triphosphatase (ATPase) activity of sciatic nerve endoneurial homogenates. The addition of 10 nmol/1 insulin to endoneurial homogenates from control animals resulted in a 34% increase in ouabain-sensitive ATPase activity and a 19% reduction in onabain-insensitive ATPase activity (both p < 0.01). This stimulation of ouabain-sensitive ATPase activity by insulin did not occur in homogenates from diabetic rats. Treating diabetic rats daily with the aldose reductase in-hibitor, imirestat (1 mg/kg) improved nerve conduction velocity (p < 0.05) but was without effect upon the resistance to hypoxic conduction blockade or the deficit in insulin-stimulated oubain-sensitive ATPase activity. These data suggest that in streptozotocin-diabetic rats the functional disorders of reduced motor nerve conduction velocity and increased resistance to hypoxic conduction blockade do not share a common aetiology and that impaired nerve conduction is not related to reduced maximal potential oubain-sensitive ATPase activity.