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Titolo:
HYPERPOLARIZATION OF ISOLATED CAPILLARIES FROM GUINEA-PIG HEART INDUCED BY K+ CHANNEL OPENERS AND GLUCOSE DEPRIVATION
Autore:
LANGHEINRICH U; DAUT J;
Indirizzi:
UNIV MARBURG,INST PHYSIOL,DEUTSCHHAUSSTR 2 D-35037 MARBURG GERMANY
Titolo Testata:
Journal of physiology
fascicolo: 2, volume: 502, anno: 1997,
pagine: 397 - 408
SICI:
0022-3751(1997)502:2<397:HOICFG>2.0.ZU;2-P
Fonte:
ISI
Lingua:
ENG
Soggetto:
MICROVASCULAR ENDOTHELIAL-CELLS; POTASSIUM CHANNELS; ELECTRICAL-PROPERTIES; CYTOSOLIC CALCIUM; ION CHANNELS; RAT AORTA; MEMBRANE; CURRENTS; AGONISTS; INFLUX;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
39
Recensione:
Indirizzi per estratti:
Citazione:
U. Langheinrich e J. Daut, "HYPERPOLARIZATION OF ISOLATED CAPILLARIES FROM GUINEA-PIG HEART INDUCED BY K+ CHANNEL OPENERS AND GLUCOSE DEPRIVATION", Journal of physiology, 502(2), 1997, pp. 397-408

Abstract

The present study was designed to test if microvascular coronary endothelial cells express ATP-sensitive K+ channels (K-ATP channels). We performed microfluorometric measurements of the membrane potential of freshly isolated guinea-pig coronary capillaries equilibrated with the voltage-sensitive dye bis-oxonol (bis-[1,3-dibutylbarbituric acid] trimethineoxonol, [DiBAC(4)(3)]). 2. The resting membrane potential of capillaries in physiological salt solution was -46 +/- 4.2 mV (n = 8) atroom temperature (22 degrees C) as determined after calibration of the fluorescence using the Na+-K+ ionophore gramicidin in the presence of different K+ concentrations. Spontaneous membrane potential fluctuations of 10-20 mV amplitude were often observed. 3. A reversible, sustained hyperpolarization to a new membrane potential close to the K+ equilibrium potential (E-K) could be induced by application of the K+ channel openers HOE 234 (100 nM to 1 mu M), diazoxide (10 pm to 100 nM) or pinacidil (100 nM). Subsequent addition of glibenclamide (200 nM to 2 mu M) reversed this hyperpolarization. 4. A glibenclamide-sensitive hyperpolarization of coronary capillaries to values near E-K was also observed upon omission of D-glucose (10 mar) from the superfusing solution or by substituting L-glucose for D-glucose. Maximum hyperpolarization was reached in less than IO min. 5. Our results suggest that microvascular coronary endothelial cells express K-ATP channels which may be activated during hypoglycaemia.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 18:26:12