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Titolo:
CONSEQUENCES OF METABOLIC INHIBITION IN SMOOTH-MUSCLE ISOLATED FROM GUINEA-PIG STOMACH
Autore:
NAKAYAMA S; CHIHARA S; CLARK JF; HUANG SM; HORIUCHI T; TOMITA T;
Indirizzi:
NAGOYA UNIV,SCH MED,DEPT PHYSIOL,SHOWA KU,65 TSURUMA CHO NAGOYA AICHI466 JAPAN NAGOYA UNIV,SCH MED,DEPT HOSP PHARM,SHOWA KU NAGOYA AICHI 466 JAPAN UNIV OXFORD,DEPT BIOCHEM OXFORD OX1 3QU ENGLAND
Titolo Testata:
Journal of physiology
fascicolo: 1, volume: 505, anno: 1997,
pagine: 229 - 240
SICI:
0022-3751(1997)505:1<229:COMIIS>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
INTRACELLULAR-FREE MAGNESIUM; RABBIT PORTAL-VEIN; CIRCULAR MUSCLE; TAENIA-CECI; CONTRACTILE FAILURE; INORGANIC-PHOSPHATE; TENSION RESPONSES; CREATINE-KINASE; GASTRIC ANTRUM; RAT-HEART;
Tipo documento:
Article
Natura:
Periodico
Citazioni:
41
Recensione:
Indirizzi per estratti:
Citazione:
S. Nakayama et al., "CONSEQUENCES OF METABOLIC INHIBITION IN SMOOTH-MUSCLE ISOLATED FROM GUINEA-PIG STOMACH", Journal of physiology, 505(1), 1997, pp. 229-240

Abstract

1. In smooth muscle isolated from the guinea-pig stomach, cyanide (CN) and iodoacetic acid (IAA) were applied to block oxidative phosphorylation and glycolysis, respectively. Effects of IAA on generation of spontaneous mechanical and electrical activities were systematically investigated by comparing those of CN. Spontaneous activity ceased in 10-20 min during applications of 1 mM IAA. On the other hand, applicationof 1 mM CN also reduced the spontaneous activity, but never terminated it. In the presence of CN the negativity of the resting membrane potential was slightly reduced. 2. When spontaneous activity ceased with IAA, the resting membrane potential was not significantly affected. Also, before ceasing, the amplitude and duration of the spontaneous electrical activity were significantly reduced. The amplitude of the electrotonic potential was, however, not changed by IAA. Further, glibenclamide did not prevent the effects of IAA. These results suggest that, unlike cardiac muscle, activation of metabolism-dependent K+ channels in stomach smooth muscle does not seem to play a major role in reducingand terminating spontaneous activity during metabolic inhibition. 3. Carbachol-induced contraction transiently increased, and subsequently decreased gradually during application of IAA. 4. After 50 min application of IAA, when there was no spontaneous activity, the concentrations of phosphocreatine (PCr) and ATP measured with P-31 nuclear magneticresonance decreased to 60 and 80% of the control, respectively, whileinorganic phosphate (P-i) concentration paradoxically fell to below detectable levels. During subsequent prolonged application of IAA, high-energy phosphates steadily decreased. On the other hand, after 50 minCN application, [PCr] and [ATP] decreased to approximately 30 and 80%of the control, respectively, while [P-i] increased by 2.6-fold. 5. In the presence of either CN or IAA, spontaneous mechanical and electrical activities were reduced or eliminated, although amounts of high-energy phosphates sufficient to contract smooth muscle remained. It can be postulated that some mechanism(s) related to energy metabolism, butnot including ATP-sensitive K+ channels, plays an important role in generating spontaneous activity in guinea-pig stomach smooth muscle. During metabolic inhibition the energy metabolism-dependent mechanism(s)would preserve high-energy phosphates, and consequently cell viability by stopping spontaneous activity.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/12/20 alle ore 10:46:04