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Titolo:
NOVEL EFFECTS OF GUANIDINE ON THE NEUROMUSCULAR-JUNCTION
Autore:
RODRIGUESSIMIONI L; SILVACARVALHO I; HELUANY NF; LEITE GB; PRADOFRANCESCHI J; CRUZHOFLING MA; BALLEJO G; CORRADO AP;
Indirizzi:
UNICAMP,FAC MED SCI,DEPT PHARMACOL BR-13083970 CAMPINAS SP BRAZIL UNICAMP,INST BIOL,DEPT HISTOL & EMBRYOL BR-13083970 CAMPINAS SP BRAZIL USP,FAC MED,DEPT PHARMACOL RIBEIRAO PRET BRAZIL
Titolo Testata:
General pharmacology
fascicolo: 4, volume: 28, anno: 1997,
pagine: 599 - 605
SICI:
0306-3623(1997)28:4<599:NEOGOT>2.0.ZU;2-J
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOTOR-NERVE TERMINALS; CURRENTS; RELEASE; RAT;
Keywords:
GUANIDINE; NEUROMUSCULAR JUNCTION; POSTREMOVAL FACILITATION; NEUROMUSCULAR BLOCKADE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
20
Recensione:
Indirizzi per estratti:
Citazione:
L. Rodriguessimioni et al., "NOVEL EFFECTS OF GUANIDINE ON THE NEUROMUSCULAR-JUNCTION", General pharmacology, 28(4), 1997, pp. 599-605

Abstract

1. The effects of guanidine on the isolated mouse phrenic nerve diaphragm(MPND) and chick biventer cervicis (CBC) neuromuscular preparations were determined by myographic and electrophysiological methods. 2. Guanidine at concentrations of 5-10 mM induced an initial facilitation followed by neuromuscular blockade in both preparations. In the isolated MPND such blockade was associated with the abolition of miniature end-plate potentials (MEPPs), but in the CBC the acetylcholine-induced contracture remained unimpaired. After guanidine removal, a heretoforeundescribed pronounced facilitation of neuromuscular transmission associated with an increase in MEPP frequency was observed. Simultaneously, the muscular contractions exhibited delayed relaxation and aftercontractions. 3. The K+ channel opener, cromakalim (100-200 mu M) inhibited both the well-described initial and the novel postremoval facilitatory effects of guanidine in a concentration-dependent manner. These findings are consistent with the proposal that guanidine blocks K+ channels in motor nerve endings. 4. The guanidine-induced NMB was reverted by increasing the Ca2+ concentration (1.8-5 mM) in the nutritive solution. 5. Tetrodotoxin (TTX, 1.56 mu M) did not influence the increase in MEPPS frequency induced by guanidine (10 mM) but did reduce the risein MEPPS frequency observed after guanidine removal. 6. The present findings indicate that the effects of guanidine on the neuromuscular junction are more complex than currently described because they include a neuromuscular blockade and a postremoval facilitation previously unreported in the literature. (C) 1997 Elsevier Science Inc.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 30/09/20 alle ore 10:16:29