Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
MECHANISM OF CORONARY MICROVASCULAR RESPONSES TO METABOLIC STIMULATION
Autore:
EMBREY RP; BROOKS LA; DELLSPERGER KC;
Indirizzi:
UNIV IOWA,DEPT INTERNAL MED IOWA CITY IA 52246 UNIV IOWA,DEPT INTERNAL MED IOWA CITY IA 52246 UNIV IOWA,CTR CARDIOVASC IOWA CITY IA 52246 VET ADM MED CTR IOWA CITY IA 52246 UNIV IOWA,DEPT SURG IOWA CITY IA 52242
Titolo Testata:
Cardiovascular Research
fascicolo: 1, volume: 35, anno: 1997,
pagine: 148 - 157
SICI:
0008-6363(1997)35:1<148:MOCMRT>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
SENSITIVE POTASSIUM CHANNELS; NITRIC-OXIDE; CONSCIOUS DOGS; REACTIVE HYPEREMIA; AUTOREGULATORY RESPONSES; OXYGEN-CONSUMPTION; GUINEA-PIG; VASODILATION; RESISTANCE; DILATION;
Keywords:
CORONARY MICROCIRCULATION; DOBUTAMINE; EDRF; ARGININE ANALOGS; GLIBENCLAMIDE; POTASSIUM CHANNEL, ATP-SENSITIVE; NITRIC OXIDE; ENDOTHELIUM; INTRAVITAL MICROSCOPY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
32
Recensione:
Indirizzi per estratti:
Citazione:
R.P. Embrey et al., "MECHANISM OF CORONARY MICROVASCULAR RESPONSES TO METABOLIC STIMULATION", Cardiovascular Research, 35(1), 1997, pp. 148-157

Abstract

Previous studies from our laboratory have shown that coronary microvascular dilation to increased myocardial oxygen consumption (MVO2) is greater in vessels < 100 mu m. The mechanism responsible for this response is uncertain. Objectives: We tested the hypothesis that microvascular dilation to increased MVO2 is mediated by nitric oxide (NO). SinceNO release may occur in response to increased shear, we also tested the hypothesis that metabolic byproducts released in response to increases in MVO2 will stimulate opening of the ATP-sensitive potassium channel. Methods: Changes in epicardial coronary microvascular diameters were measured in 9 dogs given N-G-nitro-L-arginine (LNNA; 100 mu M, topically), 7 dogs given glibenclamide (10 mu M, topically) and 12 control (C) dogs during increases in metabolic demand using dobutamine (DOE,10 mu g/kg/min, i.v.) with rapid atrial pacing (PAC, 300 bpm). Diameters of arterioles were measured using intravital microscopy coupled tostroboscopic epi-illumination. Results: During the protocol, MVO2 increased to a similar degree in both experimental groups (LNNA and glibenclamide). Baseline hemodynamics and coronary microvascular diameters were similar between the two experimental groups and their respective control groups. In the presence of LNNA, coronary arteriolar (< 100 mum) dilation (% change from baseline) was impaired during the protocol(DOE: vehicle 18 +/- 5, LNNA 2 +/- 2 [P < 0.05]; DOE + RAP: vehicle 40 +/- 11, LNNA 6 + 2% [P < 0.05]). In contrast, glibenclamide did not impair coronary microvascular responses to increased MVO2 despite similar increases in MVO2. Conclusion: This study indicates that coronary microvascular dilation in response to increased metabolic stimulation using dobutamine in conjunction with rapid pacing is mediated through a nitric-oxide-dependent mechanism and not ATP-sensitive potassium channels. These results may have important implications in pathological disease states where nitric oxide mechanisms are impaired, such as diabetes and hypertension. (C) 1997 Elsevier Science B.V.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/12/20 alle ore 07:33:36