Rapid reversal of a motor nerve conduction deficit in streptozotocin-diabetic rats by the angiotensin converting enzyme inhibitor lisinopril.

The effect of treatment of rats with the angiotensin converting enzyme inhibitor lisinopril after 5 weeks of untreated streptozotocin-diabetes was examined by daily monitoring of sciatic motor conduction velocity to tibialis anterior muscle. Diabetes produced a 31.5% decrease in conduction velocity (P < 0.001). Lisinopril treatment caused a progressive improvement which was significant after 3 days (P = 0.002), full normalization being achieved by 6 days (P < 0.0001). After 7 days of treatment there followed a 7-day washout period in which no lisinopril was given. During this time conduction velocity declined to untreated diabetic levels over 3 days. A subsequent treatment period resulted in complete normalization of conduction velocity within 2 days (P < 0.0001). Thus, the marked functional effects seen for vasodilator treatment with lisinopril suggest that angiotension converting enzyme inhibitors may have potential therapeutic value in the treatment of diabetic neuropathy.