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Titolo:
EXCITATION CALCIUM-RELEASE UNCOUPLING IN AGED SINGLE HUMAN SKELETAL-MUSCLE FIBERS
Autore:
DELBONO O; OROUKE KS; ETTINGER WH;
Indirizzi:
WAKE FOREST UNIV,BOWMAN GRAY SCH MED,DEPT PHYSIOL & PHARMACOL,MED CTRBLVD WINSTON SALEM NC 27157 WAKE FOREST UNIV,BOWMAN GRAY SCH MED,DEPT INTERNAL MED GERONTOL WINSTON SALEM NC 27157 WAKE FOREST UNIV,BOWMAN GRAY SCH MED,DEPT INTERNAL MED RHEUMATOL WINSTON SALEM NC 27157 WAKE FOREST UNIV,BOWMAN GRAY SCH MED,DEPT PUBL HLTH SCI WINSTON SALEMNC 27157
Titolo Testata:
The Journal of membrane biology
fascicolo: 3, volume: 148, anno: 1995,
pagine: 211 - 222
SICI:
0022-2631(1995)148:3<211:ECUIAS>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
EXTENSOR DIGITORUM LONGUS; CHARGE MOVEMENT; FAST-TWITCH; SARCOPLASMIC-RETICULUM; CONTRACTILE PROPERTIES; SLOW-TWITCH; GASTROCNEMIUS-MUSCLE; MAMMALIAN MUSCLE; PROTEIN-KINASE; CA2+ CHANNELS;
Keywords:
DIHYDROPYRIDINE RECEPTOR; MUSCLE CONTRACTION; CALCIUM RELEASE; VOLTAGE-CLAMP; CALCIUM CHANNELS; MUSCLE WEAKNESS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
66
Recensione:
Indirizzi per estratti:
Citazione:
O. Delbono et al., "EXCITATION CALCIUM-RELEASE UNCOUPLING IN AGED SINGLE HUMAN SKELETAL-MUSCLE FIBERS", The Journal of membrane biology, 148(3), 1995, pp. 211-222

Abstract

The biological mechanisms underlying decline in muscle power and fatigue with age are not completely understood. The contribution of alterations in the excitation-calcium release coupling in single muscle fibers was explored in this work. Single muscle fibers were voltage-clamped using the double Vaseline gap technique. The samples were obtained by needle biopsy of the vastus lateralis (quadriceps) from 9 young (25-35 years; 25.9 +/- 9.1; 5 female and 4 male) and 11 old subjects (65-75 years; 70.5 +/- 2.3; 6 f, 5 m), Data were obtained from 36 and 39 fibers from young and old subjects, respectively. Subjects included in this study had similar physical activity. Denervated and slow-twitch muscle fibers were excluded from this study. A significant reduction of maximum charge movement (Q(max)) and DHP-sensitive Ca current were recorded in muscle fibers from the 65-75 group. Q(max) values were 7.6 +/- 0.9 and 3.2 +/- 0.3 nC/mu F for young and old muscle fibers, respectively (P < 0.01). No evidences of charge inactivation or interconversion (charge 1 to charge 2) were found. The peak Ca current was (-)4.7 +/- 0.08 and (-)2,15 +/- 0.11 mu A/mu F for young and old fibers, respectively (P < 0.01). The peak calcium transient studied with mag-fura-a(400 mu M) was 6.3 +/- 0.4 mu M and 4.2 +/- 0.3 mu M for young and old muscle fibers, respectively. Caffeine (0.5 mM) induced potentiation of the peak calcium transient in both groups. The decrease in the voltage-/Ca-dependent Ca release ratio in old fibers (0.18 +/- 0.02) compared to young fibers (0.47 +/- 0.03) (P < 0.01), was recorded in the absence of sarcoplasmic reticulum calcium depletion. These data support a significant reduction of the amount of Ca available for triggering mechanical responses in aged skeletal muscle and, the reduction of Ca release is due to DHPR-ryanodine receptor uncoupling in fast-twitch fibers. These alterations can account, at least partially far the skeletal muscle function impairment associated with aging.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 09:40:45