Phentonium induces a transient increase of acetylcholine efflux from motor nerve terminals
Braz. j. med. biol. res
; 24(10): 1055-8, 1991. ilus
Article
em En
| LILACS
| ID: lil-102088
Biblioteca responsável:
BR1.1
ABSTRACT
Phenthonium (10-50 µM), a quaternary derivative of 1-hyoscyamine, increases the frequency of miniature end-plate potentials (205 fold) and blocks the nicotinic receptor-ionic channel in skeletal muscles. When tested on rat diaphragms previously incubated with [3H] choline, phenthonium (50µM) increased the spontaneous release of radiolabelled acetylcholine (ACh) from 11.6 ñ 6.4 to 110.5 ñ 40.2 x 10**3 dpm/g within 15 min. The effect was transient, declining to 24.6 ñ 14.7 after 50 min. Subsequent electrical stimulation still in the prsence of phenthonium increased the efflux to 164.7 ñ 45.3. The fractional release relative to the level before stimulation did not differ from controls. Phenthonium (20 µM) did not increase the spontaneous ACh release but doubled the efflux induced by nerve stimulation. The present results, compared to previous electrophysiological findeings, indicate that quantal and nonquantal release are increased by phenthonium. They also show that the transient effect is not due to ACh depletion in nerve terminals
Buscar no Google
Coleções:
01-internacional
Base de dados:
LILACS
Assunto principal:
Derivados da Atropina
/
Acetilcolina
/
Receptores Nicotínicos
/
Placa Motora
Limite:
Animals
Idioma:
En
Revista:
Braz. j. med. biol. res
Assunto da revista:
BIOLOGIA
/
MEDICINA
Ano de publicação:
1991
Tipo de documento:
Article
/
Congress and conference
País de publicação:
Brasil