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Titolo:
INCREASE IN CALCIUM RESPONSIVENESS OF CARDIAC MYOFILAMENT ACTIVATION IN OVARIECTOMIZED RATS
Autore:
WATTANAPERMPOOL J;
Indirizzi:
MAHIDOL UNIV,FAC SCI,DEPT PHYSIOL,RAMA 4 RD BANGKOK 10400 THAILAND
Titolo Testata:
Life sciences (1973)
fascicolo: 11, volume: 63, anno: 1998,
pagine: 955 - 964
SICI:
0024-3205(1998)63:11<955:IICROC>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
POSTMENOPAUSAL WOMEN; HEART-FAILURE; DILATED CARDIOMYOPATHY; CARDIOVASCULAR-DISEASE; ISOMETRIC TENSION; SENSITIVITY; REPLACEMENT; PROTEINS; THERAPY; MYOSIN;
Keywords:
CARDIAC MYOFILAMENT ACTIVATION; MYOFIBRILLAR CALCIUM SENSITIVITY; THIN FILAMENT; OVARIAN SEX HORMONES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
31
Recensione:
Indirizzi per estratti:
Citazione:
J. Wattanapermpool, "INCREASE IN CALCIUM RESPONSIVENESS OF CARDIAC MYOFILAMENT ACTIVATION IN OVARIECTOMIZED RATS", Life sciences (1973), 63(11), 1998, pp. 955-964

Abstract

To evaluate a possible role of ovarian sex hormones in the Ca2+ responsiveness of cardiac myofilament activation, the relations of pCa (-log Ca2+ molar concentration) to actomyosin adenosine triphosphatase (ATPase) activity of isolated myofibrillar preparations from 8-10 week ovariectomized (Ovx) rat hearts were compared with those from sham-operated hearts. Deficiency of ovarian sex hormones in plasma of ovariectomized rats was indirectly verified by a significant reduction in uterine weights. Body weights of the ovariectomized rats were significantly greater than those of sham-operated controls. Despite a significant increase in heart weight of 10 week ovariectomized animals, the percent of heart weight-to-body weight ratio was not different from control group. The maximum myofibrillar ATPase activity at pH 7.0 was significantly suppressed after ovariectomy in both eight and ten week groups. However, the maximum ATPase activity at pH 6.5 was significantly suppressed only in 10 week ovariectomized hearts. Surprisingly, in every condition with depressed maximum myofibrillar ATPase activity, the pCa-actomyosin ATPase relationships of ovariectomized cardiac myofilaments demonstrated a significant leftward shift in pCa(50) (-log half-maximally Ca2+ activation) from those of sham-operated controls. There was, however, no change in the Hill-coefficient of these cardiac myofilamentsafter ovariectomy. Analysis of myofilament proteins using gel electrophoresis demonstrated neither change nor loss of any thin filament proteins. These results indicate a possible modulating effect of ovarian sex hormone deficiency on the Ca2+ responsiveness of cardiac myofilament activation by induction of myofilament Ca2+ hypersensitivity but suppression of maximum myofibrillar ATPase activity.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 31/05/20 alle ore 13:27:37