Abstracts of the 8th Meeting of the Italian Peripheral Nerve Study Group: 42

Autor: B Bossi, G Ardolino, GM Fabrizi, L Bertolasi, T Cavallaro, S Polo, S Barbieri, N Rizzuto, A Priori
Rok vydání: 2003
Předmět:
Zdroj: Journal of the Peripheral Nervous System. 8:29-58
ISSN: 1085-9489
Popis: Connexin 32 (Cx32), a protein involved in gap-junction formation, in the peripheral nervous system is mainly localized in non-compact myelin of paranodes and Schmidt-Lanterman incisures. Despite patients with Cx32 mutations have a polyneuropathic phenotype, the pathophysiological correlates of Cx32 defects on axonal function are unknown in humans. Non-invasive methods for assessing axonal excitability have been recently developed (Burke et al., Clin. Neurophysiol. 2001, Priori et al. Brain 2002) in humans. These methods allow the indirect estimate of specific ionic conductances of human axons. We assessed the strength-duration function descriptors, the axonal refractoriness and supernormality in a group of Cx32 defective patients with polyneuropathy. Twenty-three healthy control subjects (38 nerves) and 5 patients (10 nerves) with a polyneuropathy and a genetic defect of Cx32 were studied. The ulnar nerve was bipolarly stimulated at the wrist and the CMAP was recorded from the abductor digiti minimi muscle. The descriptors (time constant: tsd, rheobasic current: rh50%, threshold: thr100%) of the motor axonal strength-duration function were estimated according to Priori et al. (2002). Axonal refractoriness was tested by delivering pairs (S1 and S2) of stimuli at variable intervals (10–300 ms). S1 strength was supramaximum, S2 intensity was adjusted to evoke a CMAP 50% of the maximum. The rh50% and the thr100% were markedly increased (rh50% patients [n = 10, mean ± SD] 13 ± 5.7 mA, controls [n = 26] 4.8 ± 2.1 mA, p
Databáze: OpenAIRE
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