Reduced Ia-afferent-mediated Hoffman reflex in streptozotocin-induced diabetic rats.
In addition to reduced nerve conduction velocity, diabetic neuropathic patients often exhibit a reduction in the amplitude of the compound muscle action potential elicited by stimulation of the Ia-afferent-mediated reflex pathway (Hoffman or H wave) that can contribute to diminished or absent tendon reflexes. In contrast to nerve conduction velocity deficits, changes in H-wave amplitudes have not been reproduced in diabetic animal models. Using electrophysiological techniques developed for repeated recordings in individual animals, we report H-wave deficits in streptozotocin (STZ)-treated insulin-dependent diabetic rats. After 4 weeks of diabetes induced by STZ treatment, a 47% reduction in the H-wave amplitude was demonstrated by recording compound muscle action potentials in foot muscles after stimulation of Ia afferents. Interestingly, we also demonstrate that the H-wave amplitude gradually recovers to a 26% deficit after 12 weeks of experimental diabetes. The recovery of the H wave in STZ-treated rats distinguishes this deficit mechanistically from other STZ-induced electrophysiological changes and may model a similar recovery of the H wave reported in diabetic patients.
Tonra
J R
JR
Regeneron Pharmaceuticals, Inc., 777 Old Saw Mill River Road, Tarrytown, New York 10591, USA.
Cliffer
K D
KD
Carson
S R
SR
Lindsay
R M
RM
Bodine
S C
SC
DiStefano
P S
PS
D000200:Action Potentials; D000344:Afferent Pathways / Q000503:physiopathology*; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology*; D004195:Disease Models, Animal; D018450:Disease Progression; D004558:Electric Stimulation; D004594:Electrophysiology; D005260:Female; D006181:H-Reflex; D006614:Hindlimb / Q000294:innervation / Q000473:pathology / Q000503:physiopathology; D009046:Motor Neurons; D018482:Muscle, Skeletal / Q000473:pathology; D009431:Neural Conduction; D009475:Neurons, Afferent; D051381:Rats; D017207:Rats, Sprague-Dawley; D012021:Reflex, Abnormal; D013311:Streptozocin
D013311:Streptozocin