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Titolo:
Protons inhibit the BKCa channel of rat small artery smooth muscle cells
Autore:
Schubert, R; Krien, U; Gagov, H;
Indirizzi:
Univ Rostock, Inst Physiol, D-18055 Rostock, Germany Univ Rostock Rostock Germany D-18055 t Physiol, D-18055 Rostock, Germany Bulgarian Acad Sci, Inst Biophys, Sofia, Bulgaria Bulgarian Acad Sci Sofia Bulgaria ad Sci, Inst Biophys, Sofia, Bulgaria
Titolo Testata:
JOURNAL OF VASCULAR RESEARCH
fascicolo: 1, volume: 38, anno: 2001,
pagine: 30 - 38
SICI:
1018-1172(200101/02)38:1<30:PITBCO>2.0.ZU;2-X
Fonte:
ISI
Lingua:
ENG
Soggetto:
CA2+-ACTIVATED K+ CHANNELS; INTRACELLULAR PH; ACIDOSIS; CALCIUM; POTASSIUM; TONE;
Keywords:
vascular smooth muscle; patch-clamp; calcium-activated potassium channel intracellular pH;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
21
Recensione:
Indirizzi per estratti:
Indirizzo: Schubert, R Univ Rostock, Inst Physiol, PSF 100888, D-18055 Rostock, Germany Univ Rostock PSF 100888 Rostock Germany D-18055 tock, Germany
Citazione:
R. Schubert et al., "Protons inhibit the BKCa channel of rat small artery smooth muscle cells", J VASC RES, 38(1), 2001, pp. 30-38

Abstract

The regulation of the activity of calcium-activated potassium (BKCa) channels by intracellular proton ions (pH(i)) was investigated using the patch-clamp technique in smooth muscle cells freshly isolated from rat tail small arteries. Single-channel conductance and voltage dependence of activation were not different at pH(i) 7.0, 7.4 and 7.8. However, the membrane potential at which channel open probability reached 0.5 was 74 +/- 5 mV (n = 6) (mean +/- SE) at pH(i) 7.4 and 54 +/- 2 mV (n = 4) at pHi 7.8 under conditionsof pCa 5.9, and 30 +/- 5 mV (n = 5) at pH(i) 7.4 and 62 +/- 4 mV (n = 5) at pH(i) 7.0 under conditions of pCa 5.4. Furthermore, at a membrane potential of 0 mV, the pD(2) for intracellular calcium ions was 5.19 +/- 0.04 (n =26) (mean +/- SD) at pH(i) 7.8, 5.02 +/- 0.05 (n = 28) at pH(i) 7.4, and 4.82 +/- 0.05 (0 = 30) at pH(i) 7.0. In addition, an alteration of pH(i) resulted in a profound change in the amplitude of BKCa currents in intact cells; it reversibly attenuated the current-voltage relationship decreasing thecurrent by 55 +/- 3% (n = 7) (p < 0.001) at 70 mV after lowering the extracellular NH4Cl concentration to decrease the calculated pH(i) from 7.2 to 6.8. Thus, alterations of pH(i) in the range from 7.0 to 7.8 did not affect single-channel conductance and voltage dependence of activation but markedly altered single BKCa channel activity as well as intact cell BKCa current amplitude, where an increase of the intracellular proton concentration inhibited this channel. Copyright (C) 2001 S. Karger AG,Basel.

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Documento generato il 03/04/20 alle ore 09:15:37