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Titolo:
CHARACTERIZATION OF SPONTANEOUS AND ACTION POTENTIAL-INDUCED CALCIUM TRANSIENTS IN DEVELOPING MYOTUBES INVITRO
Autore:
FLUCHER BE; ANDREWS SB;
Indirizzi:
NINCDS,NEUROBIOL LAB,BLDG 36,RM 2A-29 BETHESDA MD 20892
Titolo Testata:
Cell motility and the cytoskeleton
fascicolo: 2, volume: 25, anno: 1993,
pagine: 143 - 157
SICI:
0886-1544(1993)25:2<143:COSAAP>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
SKELETAL-MUSCLE FIBERS; INTRAMEMBRANE CHARGE MOVEMENT; SARCOPLASMIC-RETICULUM; RYANODINE RECEPTOR; DYSGENIC MUSCLE; RELEASE CHANNEL; CA-2+ RELEASE; FROG; CAFFEINE; DIFFERENTIATION;
Keywords:
CALCIUM; MUSCLE CULTURES; C2 CELLS; DEVELOPMENT; SARCOPLASMIC RETICULUM; T-TUBULES; CALCIUM RELEASE CHANNEL;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
48
Recensione:
Indirizzi per estratti:
Citazione:
B.E. Flucher e S.B. Andrews, "CHARACTERIZATION OF SPONTANEOUS AND ACTION POTENTIAL-INDUCED CALCIUM TRANSIENTS IN DEVELOPING MYOTUBES INVITRO", Cell motility and the cytoskeleton, 25(2), 1993, pp. 143-157

Abstract

We have investigated the onset and maturation of action potential- and calcium-induced calcium release from the sarcoplasmic reticulum during the differentiation of excitation-contraction coupling in skeletal muscle. Microfluorometry and video imaging of cultured myotubes loadedwith the fluorescent calcium indicator fluo-3 revealed the dynamics, time course, and physiological properties of calcium transients as well as their changes during development. Spontaneous and stimulated contractions in well-differentiated myotubes are accompanied by brief (200-500 ms) increases in the concentration of free cytoplasmic calcium. These transients are modulated by sub-threshold concentrations of caffeine, resulting in a plateau of elevated calcium. Two novel types of calcium transients were observed in non-contracting myotubes. 1) Fast localized transients (FLTs) are radially restricted focal release eventsthat occur spontaneously within the myoplasm at various densities andfrequencies. 2) Upon addition of caffeine, propagating calcium waves are generated (35-70 mum/s velocity), which are accompanied by contractures. Aside from caffeine sensitivity, calcium waves and contraction-related sustained release events are similar in amplitude and duration, as well as in their inactivation and refractory properties. Thus, these transients may represent calcium-induced calcium release in quiescent and active myotubes, respectively. Following one calcium-induced calcium release event, myotubes become refractory to new calcium-induced transients; however, action potential-induced transients and FLTs are not blocked. This suggests that these transients occur by distinct release mechanisms and that dual modes of calcium release exist prior to the coupling of calcium release to excitation.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 05:41:11