Differential impairment of the sudomotor and nociceptor axon-reflex in diabetic peripheral neuropathy.
It is not known whether C-fiber functional subclasses are differentially affected by diabetes mellitus or whether the patterns of C-fiber dysfunction are different between type 1 and type 2 diabetes. We therefore examined efferent sympathetic sudomotor and primary afferent nociceptor C-fiber function in diabetic patients. Acetylcholine (10%) was used to evoke C-fiber (axon-reflex)-mediated responses. The nociceptor (flare) response was measured using a laser Doppler device. The sudomotor response was quantified with silastic imprints. The nociceptor C-fiber-mediated flare response was reduced in type 2 diabetic patients (P < 0.008) but was similar to controls in type 1 diabetic patients. The sympathetic C-fiber-mediated responses, including sweat volume (P < 0.05) and the number of activated sweat glands (P = 0.003), were increased in patients with type 1 diabetes. There also was a trend toward a larger axon-reflex sweat area in patients with type 1 diabetes (P = 0.09). No differences in these sweat responses were found in patients with type 2 diabetes compared to controls. These findings suggest that the functional abnormalities in diabetic peripheral neuropathy are not homogeneous and that C-fiber subclasses are differentially affected in type 1 and 2 diabetes mellitus.
Berghoff
Martin
M
Department of Neurology, University of Münster, Münster, Germany.
Kilo
Sonja
S
Hilz
Max J
MJ
Freeman
Roy
R
D000109:Acetylcholine / Q000494:pharmacology; D000328:Adult; D001369:Axons / Q000502:physiology*; D003627:Data Interpretation, Statistical; D003922:Diabetes Mellitus, Type 1 / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology; D003928:Diabetic Nephropathies / Q000503:physiopathology*; D005260:Female; D005542:Forearm / Q000294:innervation / Q000502:physiology; D006801:Humans; D007478:Iontophoresis; D008297:Male; D008875:Middle Aged; D036421:Nerve Fibers, Unmyelinated / Q000502:physiology; D009619:Nociceptors / Q000502:physiology*; D012018:Reflex / Q000502:physiology*; D012039:Regional Blood Flow / Q000502:physiology; D012867:Skin / Q000098:blood supply / Q000294:innervation*; D013546:Sweating / Q000502:physiology*; D013564:Sympathetic Nervous System / Q000502:physiology*; D014664:Vasodilation / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology
D014665:Vasodilator Agents; D000109:Acetylcholine