Functional Aspects and Pathogenetic Considerations of the Neuropathy in the Spontaneously Diabetic Bb‐wistar Rat

Abstract

Electrophysiological features were studied longitudinally in the spontaneously diabetic insulin-dependent, BB-Wistar rat. These were correlated in time with the state of the patency of the protective barriers in peripheral nerves. Motor nerve conduction velocity was significantly slowed only 3 weeks after the onset of the diabetes. When ultrastructural changes began, the maximal conduction velocity was further diminished. The amplitudes of evoked muscle potentials and distal latencies were significantly altered in diabetic rats. No change in the permeability of the blood-nerve barrier could be demonstrated before, during or after the onset of the nerve conduction defect. The possible pathogenetic mechanisms are discussed and a possible mechanism is suggested, namely a reduced availability of energy to axons in diabetes.

The linked roles of nitric oxide, aldose reductase and, (Na+,K+)-ATPase in the slowing of nerve conduction in the streptozotocin diabetic rat.

“…L-NAME also slowed NCV in nondiabetic rats, though only after prolonged administration, with an attendant reduction in (Na',K+)-ATPase activity. (26). The proximal and distal latencies of the compound muscle action potentials, recorded via bipolar electrodes from the first interosseous muscle of the hindpaw, were measured from the stimulus artifact to the onset of the negative M-wave deflection, subtracted, and divided into the distance between the stimulating and recording electrodes giving a value for NCV in m/s.…”

“…The left and right sciatic nerves were rapidly surgically exposed from the vertebral exit to the common peroneal bifurcation, excised, cleaned of adherent muscle and loose epineurial connective tissue, and immediately frozen in liquid nitrogen for subsequent determination of nerve osmolyte levels (25,26,28). Sciatic nerve MI, sorbitol, and fructose were determined by gas chromatography of aldonitrile acetate derivatives of lyophilized aliquots of deproteinized homogenates (2.0 ml 5% wt/vol trichloroacetic acid) of sciatic nerve containing 10 jg a-D-methyl mannopyranoside as an internal standard (25,26,28). A Varian 3700 gas-liquid chromatograph was equipped with a 30 m X 0.25 mm inner diameter SP-2100 fused silica capillary column with a 0.25 ,sm film thickness, a single flame ionization detector, a 8100 autosampler, and a Star Workstation Integrator (Varian Instruments, Sunnyvale, CA).…”

Role of sorbitol accumulation and myo-inositol depletion in paranodal swelling of large myelinated nerve fibers in the insulin-deficient spontaneously diabetic bio-breeding rat. Reversal by insulin replacement, an aldose reductase inhibitor, and myo-inositol.

“…Animals were lightly anesthetized with ethyl ether (Fisher Scientific Company, Fair Lawn, NJ). Motor nerve conduction velocity (MNCV) was determined noninvasively in the sciaticposterior tibial conduction system in a temperature controlled environment as previously described in detail (21). Briefly, the left sciatic-tibial nerve was stimulated proximally at the sciatic notch and distally at the ankle via bipolar electrodes using supramaximal stimuli (8 V) from a stimulater (TM 501, Tektronix, Inc., Beaverton, OR) at 20 Hz.…”

“…Motor nerve conduction velocity was calculated by subtracting the distal from the proximal latency measured in milliseconds from stimulus artifact to take off of the evoked muscle potential; the resultant difference was divided into the distance between the stimulating electrodes measured in millimeters, yielding a value for MNCV in meters per second. MNCV and EMPA were measured on a weekly basis throughout the study (21).…”

Diabetes Mellitus and Neuromuscular Blockade: Review

“…Five studies [2][3][4][5][6] show different changes in the neurophysiological parameters in diabetes mellitus. In diabetic nerve, conduction velocity of the action potential is decreased, the amplitude of action potentials, both sensory and motor, is smaller, and the latency time is elongated.…”