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Titolo:
ALPHA(1)-ADRENERGIC RECEPTOR STIMULATION DECREASES MAXIMUM SHORTENINGVELOCITY OF SKINNED SINGLE VENTRICULAR MYOCYTES FROM RATS
Autore:
STRANG KT; MOSS RL;
Indirizzi:
UNIV WISCONSIN,SCH MED,DEPT PHYSIOL,1300 UNIV AVE MADISON WI 53706
Titolo Testata:
Circulation research
fascicolo: 1, volume: 77, anno: 1995,
pagine: 114 - 120
SICI:
0009-7330(1995)77:1<114:ARSDMS>2.0.ZU;2-M
Fonte:
ISI
Lingua:
ENG
Soggetto:
PROTEIN-KINASE-C; LIGHT-CHAIN KINASE; ACTOMYOSIN MGATPASE ACTIVITY; RABBIT PAPILLARY-MUSCLE; CARDIAC TROPONIN-I; ALPHA-ADRENOCEPTORS; BETA-ADRENOCEPTORS; VERTEBRATE MUSCLE; SKELETAL-MUSCLE; MYOSIN;
Keywords:
ALPHA(1)-ADRENERGIC RECEPTOR; CARDIAC MYOCYTE; SHORTENING VELOCITY; PHOSPHORYLATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
45
Recensione:
Indirizzi per estratti:
Citazione:
K.T. Strang e R.L. Moss, "ALPHA(1)-ADRENERGIC RECEPTOR STIMULATION DECREASES MAXIMUM SHORTENINGVELOCITY OF SKINNED SINGLE VENTRICULAR MYOCYTES FROM RATS", Circulation research, 77(1), 1995, pp. 114-120

Abstract

alpha(1)-Adrenergic agonists have negative inotropic effects on mammalian myocardium under some conditions, and biochemical experiments measuring the Ca2+-activated actomyosin ATPase activity of myofibrillar preparations suggest that this may result from a decrease in cross-bridge cycling rate caused by phosphorylation of myofilament proteins. Experiments with intact ventricular preparations, however, have failed todemonstrate a mechanical manifestation of a decrease in cycling rate. The present study examined the effect of alpha(1)-adrenergic receptorstimulation on maximum shortening velocity in skinned single ventricular myocytes from rats. Enzymatically isolated myocytes were incubatedwith the beta-receptor antagonist propranolol in the presence or absence of the alpha(1)-adrenergic receptor agonist phenylephrine and werethen rapidly skinned to preserve the phosphorylation state of myofilament proteins. The velocity of unloaded shortening (V-0) was determined by use of the slack-test method and compared between skinned controland phenylephrine-treated cells. The relationship between isometric tension and [Ca2+] was also assessed for each myocyte. V-0 was significantly lower in the alpha(1)-adrenergic receptor agonist-treated cells than in the control cells, hut there was no effect on Ca2+ sensitivityof isometric tension. In addition, the myosin heavy chain isoform composition accounted for a significant amount of the variation in V-0 within the treatment groups. On the basis of thc se and previous resultswe propose that alpha(1)-adrenergic receptor stimulation inhibits cross-bridge cycling rate at the level of myofilament proteins by a mechanism that may involve phosphorylation of troponin I by protein kinase C.

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Documento generato il 07/07/20 alle ore 12:22:16