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Arquivos de Neuro-Psiquiatria

Print version ISSN 0004-282X

Arq. Neuro-Psiquiatr. vol.25 no.2 São Paulo June 1967

http://dx.doi.org/10.1590/S0004-282X1967000200004 

Alterações funcionais da junção neuromuscular provocadas em ratos pela administração diária e prolongada de um agente curarizante

 

Functional changes of the neuromuscular junction induced in rats by a daily and prolonged ministration of a curare agent

 

 

Antonio Carlos Zanini

Departamento de Farmacologia da Faculdade de Medicina da Universidade de São Paulo (Prof. Charles E. Corbett): Professor Assistente

 

 


RESUMO

A ratos adultos, machos, foi administrado durante 8 semanas, uma vez ao dia, o iodeto do dimetiléter da d-tubocurarina (DMT), pela via intraperitoneal. Os animais foram distribuídos em 3 lotes: os do 1.°, receberam 5,5 gama de DMT/kg/dia; os do 2.°, 16,6 gama/kg/dia; os do 3.° (controle), 1 ml da solução isotônica de cloreto de sódio. A força muscular dos animais foi avaliada uma vez por semana, de acordo com o método descrito no texto, antes e após a injeção intraperitoneal da referida substância.
Com o decorrer da experimentação, observou-se que: a) houve diminuição significativa da força muscular dos animais, avaliada após esvaecimento da atividade curarizante do DMT; b) a determinação da força muscular, feita logo após a injeção, mostrou que a dose de 5,5 gama/kg/dia provoca um aumento da suscetibilidade dos animais à ação curarizante do DMT; c) o efeito inibidor provocado pela dose de 16,6 gama/kg/dia de DMT aumentou no início mas diminuiu significantemente após a 5ª semana, muito embora houvesse uma progressiva diminuição da força muscular, sugerindo independência entre os dois efeitos. Com base nesses resultados, são discutidos alguns fenômenos que podem ocorrer na instalação e tratamento da miastenia grave.


SUMMARY

Dimethylether of d-tubocurarine iodide (DMT) was administered daily, by intraperitoneal route, to adult male rats during 8 weeks. The animals were divided in three groups: the animals of the first group were given 5.5 gama/kg/day of DMT; those of the second group were given 16.6 gama/ kg/day; the rats of the 3rd (the control group), received 1 cm3 of isotonic saline solution. The animals muscular force was evaluated once a week right before and after intraperitoneal injection of the drug.
During the course of the trial, it was noted: a)a significant reduction of the animals muscular force, evaluated after disappearance of the DMT curarizing effect; b)measurements of muscular force, performed straight after the injection, showed that a 5.5 gama/kg/daily dose induced an increase of the animals susceptibility to the blocking action of DMT; c) the inhibitory effect induced by DMT 16.6 gama/kg daily dose increased at the beginning but decreased significantly after the 5th week of the trial, despite a progressive decrease in muscular force suggest independence of the two effects. Based on these results, some of the phenomena that may occur at the heginning and during treatment of myasthenia gravis are discussed.


 

 

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Departamento de Farmacologia — Faculdade de Medicina da USP — Caixa Postal 2921 — São Paulo, SP — Brasil.
Nota do autor
— Agradecemos o auxilio prestado pela técnica Maria José Costa.

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