3,4-DIAMINOPYRIDINE-INDUCED IMPAIRMENT IN FROG MOTOR-NERVE TERMINAL RESPONSE TO HIGH-FREQUENCY STIMULATION

Citation
F. Miralles et C. Solsona, 3,4-DIAMINOPYRIDINE-INDUCED IMPAIRMENT IN FROG MOTOR-NERVE TERMINAL RESPONSE TO HIGH-FREQUENCY STIMULATION, Brain research, 789(2), 1998, pp. 239-244
Citations number
27
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Neurosciences
Journal title
Volume
789
Issue
2
Year of publication
1998
Pages
239 - 244
Database
ISI
SICI code
Abstract
The refractory period of the presynaptic Na+ current (I-Na) of the fro g neuromuscular junction before and after the block of the presynaptic delayed rectifier K+ conductance by 3,4-diaminopyridine (3,4-DAP) was studied by the perineurial recording technique. Application of 3,4-DA P 0.45 mM greatly prolonged the refractory period of the last nodes of Ranvier of frog motor axons. Suppression of the repetitive activity c aused by 3,4-DAP by 3-aminobenzoic acid ethyl eater (tricaine) 0.46 mM (a local anesthetic) decreased the refractory period back towards nor mal values. These results indicate that 3,4-DAP impairs conduction of high frequency nerve impulses along the last nodes of Ranvier due to i ts block of presynaptic K+ conductance. The spontaneous activation of the most excitable, last nerve segments seemed to be the main factor c ausing such impairment. This phenomenon could explain in part the adve rse motor effects shown by some patients treated with high doses of 3, 4-DAP. (C) 1998 Elsevier Science B.V.