Padrões de condução de impulsos nervosos, determinados eletronicamente, para análise de comportamento de nervos "in vivo"

Abstract

It has been stated that the nerve impulse is a wave of depolarization developed in the cell membrane, moving from the CNS to the effectors on motor nerve fibers, and from the receptors to the CNS on the sensory fibers. Moreover, it has been experimentally demonstrated that when isolated nerve cells or fibers are properly stimulated, the depolarization in the membrane occurs in all directions. Nevertheless, it is accepted that in normal biological conditions, the peripheral motor and sensory fibers conduct nerve impulses in one direction only. Or may we consider the antidromic conduction a normal fact in biology?The main scope of this paper is not to discuss this problem, but we have to consider it, since we are trying to establish which are the patterns of nerve conduction in vivo, based upon electronic data, with the purpose of subsequent analysis of peripheral nerves behavior in degeneration and regeneration processes. We have been working on this matter and on its practical application in men during the last years (Erhart et at. 3 » 4 > 5 -6 > 7 > s > 9 -10 ). At the present, our experiments are being supported by a grant which permitted us to build the necessary system, which is basically composed of a stimulator, an electromyograph and a cathode-ray oscilloscope. MATERIAL, AND METHODSDogs anesthetized with Nembutal (Abbott) were operated in order to expose properly all or some of the nerves chosen for the experiment in each dog: n. ulnaris (mixed), n. hypoglossus (chiefly motor) and n. cutaneus brachii medialis (chiefly sensory). In these experiments, 42 nerves of 14 dogs were used.The surgical procedure for the nerve exposition and the care taken to maintain each nerve, as much as possible, undisturbed in its natural connective tissue bed, to avoid nutritional deficiencies which interfere with the normal nerve biology and regenerative processes, are described and discussed in some of our former papers in the subject (Erhart & Rezze 5 , \ 8 ). After the experiments, the dogs were killed.Trabalho desenvolvido graças auxílio da Fundação de Amparo à Pesquisa do Estado de São Paulo (Proc. 68/475).