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Titolo:
Transient increases in diameter and [Ca2+](i) are not obligatory for myogenic constriction
Autore:
Hill, MA; Zou, H; Davis, MJ; Potocnik, SJ; Price, S;
Indirizzi:
RMIT Univ, Dept Human Biol & Movement Sci, Bundoora, Vic 3083, Australia RMIT Univ Bundoora Vic Australia 3083 Sci, Bundoora, Vic 3083, Australia Eastern Virginia Med Sch, Dept Physiol, Norfolk, VA 23501 USA Eastern Virginia Med Sch Norfolk VA USA 23501 siol, Norfolk, VA 23501 USA Texas A&M Univ, Dept Med Physiol, College Stn, TX 77843 USA Texas A&M Univ College Stn TX USA 77843 hysiol, College Stn, TX 77843 USA
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
fascicolo: 2, volume: 278, anno: 2000,
pagine: H345 - H352
SICI:
0363-6135(200002)278:2<H345:TIIDA[>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
SMOOTH-MUSCLE CELLS; ISOLATED ARTERIOLES; CALCIUM MOBILIZATION; ENDOTHELIAL-CELLS; STRETCH; CONTRACTION; MECHANISM; STRAIN; CA2+; MORPHOLOGY;
Keywords:
arterioles; myogenic response; calcium; mechanotransduction; stretch activation; vascular smooth muscle;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
41
Recensione:
Indirizzi per estratti:
Indirizzo: Hill, MA RMIT Univ, Dept Human Biol & Movement Sci, Plenty Rd, Bundoora, Vic 3083, Australia RMIT Univ Plenty Rd Bundoora Vic Australia 3083 c 3083, Australia
Citazione:
M.A. Hill et al., "Transient increases in diameter and [Ca2+](i) are not obligatory for myogenic constriction", AM J P-HEAR, 278(2), 2000, pp. H345-H352

Abstract

Studies were performed to determine the significance of temporal variationin vascular smooth muscle Ca2+ signaling during acute arteriolar myogenic constriction and, in particular, the importance of the stretch-induced intracellular Ca2+ concentration ([Ca2+](i)) transient in attaining a steady-state mechanical response. Rat cremaster arterioles (diameter similar to 100 mu m) were dissected from surrounding tissues, and vessel segments were pressurized in the absence of intraluminal flow. For [Ca2+](i) measurements, vessels were loaded with fura 2 and fluorescence emitted by excitation at 340 and 380 am was measured using video-based image analysis. Ca2+ and diameter responses were examined after increases in intravascular pressure were applied as an acute step increase or a ramp function. Additional studies examined the effect of longitudinal vessel stretch on [Ca2+](i) and arteriolardiameter. Step increase in intraluminal pressure (from 50 to 120 mmHg) caused biphasic change in [Ca2+](i) and diameter. [Ca2+](i) transiently increased to 114.0 +/- 2.0% of basal levels and subsequently declined to 106.7 +/- 4.4% at steady state. Diameter initially distended to 125.4 +/- 2.1% of basal levels before constricting to 71.1 +/- 1.2%. In contrast, when the same pressure increase was applied as a ramp function (over 5 min) transient vessel distension and transient increase in [Ca2+](i) were prevented, yet atsteady state vessels constricted to 71.3 +/- 2.5%. Longitudinal stretch resulted in a large [Ca2+](i) transient (158 +/- 19% of basal) that returned to baseline despite maintenance of the stretch stimulus. The data demonstrate that the initial vessel distension (reflecting myocyte stretch) and associated global [Ca2+](i) transient are not obligatory for myogenic contraction. Thus, although arteriolar smooth muscle cells are responsive to acute stretch, the resulting changes in myogenic tone may be more closely related to other mechanical variables such as wall tension.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/07/20 alle ore 22:27:46