Estudo microneurográfico de fibras algesíferas C de indivíduos normais e de pacientes com dores neuropáticas / The microneurographic study of C fibers in controls and in patients with neuropathic pain

RESUMO

Neste estudo empregamos a técnica de microneurografia, introduzida por Hagbarth & Vallbo em 1968, para estudarmos os potenciais de ação provocados por estimulação da pele em fibras C de nervos peroneiros de indivíduos normais e de 15 pacientes portadores de neuropatia periférica. O estudo da atividade espontânea, de respostas a estímulos mecânicos e elétricos, limiar de ativação das fibras, limiar de percepção, mudanças de latências e velocidades de condução das fibras C revelou que as fibras C são ativadas por estímulos dolorosos mas estímulos mecânicos repetidos podem provocar potenciais nessas fibras / In the present study the microneurographic technique, introduced by Hagbarth & Vallbo in 1968, was employed to analyze the action potentials caused by cutaneous stimulation in C fibers of the peroneal nerves in both normal and in 15 neuropathic patients. The study of the spontaneous activity, of responses to mechanical and electrical stimulation, the threshold for stimulating C fibers, perception threshold, latencies and velocity of propagation of the impulses showed that these fibers are activated by painful stimulation but repeated mechanical stimuli may induce potentials in these fibers. The velocity of conduction of the earliest potentials is similar in both controls and patients but in the latter delayed potentials are conspicuously separated from the earliest. The threshold for perception of cutaneous stimuli in normals is lower than in the patients and the threshold to excite C fibers is also lower...