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Titolo:
PLASTICITY IN SMOOTH-MUSCLE, A HYPOTHESIS
Autore:
FORD LE; SEOW CY; PRATUSEVICH VR;
Indirizzi:
UNIV CHICAGO,CARDIOL SECT,5841 S MARYLAND AVE CHICAGO IL 60637
Titolo Testata:
Canadian journal of physiology and pharmacology
fascicolo: 11, volume: 72, anno: 1994,
pagine: 1320 - 1324
SICI:
0008-4212(1994)72:11<1320:PISAH>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
VERTEBRATE SKELETAL-MUSCLE; CHEMICAL ENERGETICS; MYOSIN MOLECULES; LIGHT-CHAIN; PHOSPHORYLATION; CONTRACTION; FILAMENTS; FIBERS; RAT; CONFORMATION;
Keywords:
SMOOTH MUSCLE; MYOSIN; THICK FILAMENTS; CONTRACTION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
38
Recensione:
Indirizzi per estratti:
Citazione:
L.E. Ford et al., "PLASTICITY IN SMOOTH-MUSCLE, A HYPOTHESIS", Canadian journal of physiology and pharmacology, 72(11), 1994, pp. 1320-1324

Abstract

The controversial finding that the thick filaments of smooth muscle can be evanescent leads to the hypothesis that the large functional range of this muscle is accommodated by plastic rearrangements that placemore thick filaments in series at longer lengths. Our preliminary finding that the shortening velocity and compliance of dog tracheal muscle were strongly dependent on adapted muscle length, while force was much less length dependent, supports this hypothesis (V.R. Pratusevich, C.Y. Seow, and L.E. Ford. Biophys. J. 66: A139, 1994). The hypothesis leads to two further corollaries. The first is that the lengthening ofthe thick filaments that must accompany their reformation will cause a series to parallel transition: fewer long filaments span the muscle length, but the longer filaments have more cross bridges acting in parallel. The second is that there is more than one activating mechanism in smooth muscle. It is known that myosin light chain phosphorylation activates the actomyosin ATPase, but this same phosphorylation also causes a structural change that facilitates filament formation. The consideration that the unaggregated, phosphorylated myosin must be prevented from competing with myosin in thick filaments and hydrolyzing ATP suggests that there must be a second mechanism that must allow the thinfilaments to interact selectively with filamentous myosin. This need for a second activating mechanism may explain the presence of tropomyosin, calponin, and caldesmon on thin filaments. Although the two corollaries follow from the initial hypothesis, it should be emphasized that the three are not mutually dependent, and that the proof or disproofof any one of them would not prove or disprove the others.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 27/11/20 alle ore 13:36:14