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Titolo:
ATP-sensitive potassium channels in capillaries isolated from guinea-pig heart
Autore:
Schnitzler, MMY; Derst, C; Daut, J; Preisig-Muller, R;
Indirizzi:
Univ Marburg, Inst Normale & Pathol Physiol, D-35037 Marburg, Germany UnivMarburg Marburg Germany D-35037 l Physiol, D-35037 Marburg, Germany
Titolo Testata:
JOURNAL OF PHYSIOLOGY-LONDON
fascicolo: 2, volume: 525, anno: 2000,
pagine: 307 - 317
SICI:
0022-3751(20000601)525:2<307:APCICI>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
CORONARY ENDOTHELIAL-CELLS; ARTERIAL SMOOTH-MUSCLE; PROTEIN-KINASE-C; INTACT RAT AORTA; K+ CHANNELS; SULFONYLUREA RECEPTOR; NITRIC-OXIDE; STIMULATED ENDOTHELIUM; ELECTRICAL-PROPERTIES; CALCIUM-CONCENTRATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
53
Recensione:
Indirizzi per estratti:
Indirizzo: Daut, J Univ Marburg, Inst Normale & Pathol Physiol, Deutschhausstr 2, D-35037 Marburg, Germany Univ Marburg Deutschhausstr 2 Marburg Germany D-35037 rg, Germany
Citazione:
M.M.Y. Schnitzler et al., "ATP-sensitive potassium channels in capillaries isolated from guinea-pig heart", J PHYSL LON, 525(2), 2000, pp. 307-317

Abstract

1. The full-length cDNAs of two different alpha-subunits (Kir6.1 and Kir6.2) and partial cDNAs of three different beta-subunits (SUR1, SUR2A and SUR2B) of ATP-sensitive potassium (K-ATP) channels of the guinea-pig (gp) were obtained by screening a cDNA library from the ventricle of guinea-pig heart.2. Cell-specific reverse-transcriptase PCR with gene-specific intron-spanning primers showed that gpKir6.1, gpKir6.2 and gpSUR2B were expressed in a purified fraction of capillary endothelial cells. In cardiomyocytes, gpKir6.1, gpKir6.2, gpSUR1. and gpSUR2A were detected.3. Patch-clamp measurements were carried out in isolated capillary fragments consisting of 3-15 endothelial cells. The membrane capacitance measured in the whole-cell mode was 19.9 +/- 1.0 pF and was independent of the length of the capillary fragment, which suggests that the endothelial cells werenot electrically coupled under our experimental conditions.4. The perforated-patch technique was used to measure the steady-state current-voltage relation of capillary endothelial cells. Application of K+ channel openers (rilmakalim or diazoxide) or metabolic inhibition (250 mu M 2,4-dinitrophenol plus 10 mM deoxyglucose) induced a current that reversed near the calculated K+ equilibrium potential.5. Rilmakalim (1 mu M), diazoxide (300 mu M) and metabolic inhibition increased the slope conductance measured at -55 mV by a factor of 9.0 (+/- 1.8), 2 5 (+/- 0.2) and 3.9 (+/- 1.7), respectively. The effects were reversed by glibenclamide (1 mu M).6. Our results suggest that capillary endothelial cells from guinea-pig heart express K-ATP channels composed of SUR2B and Kir6.1 and/or Kir6.2 subunits. The hyperpolarization elicited by the opening of K-ATP channels may lead to an increase in free cytosolic Ca2+, and thus modulate the synthesis of NO and the permeability of the capillary wall.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 17:20:30