A delayed ATP-elicited K+ current in freshly isolated smooth muscle cells from mouse aorta

Article Article scientifique Article A delayed ATP-elicited K+ current in freshly isolated smooth muscle cells from mouse aorta eng 2006 author Serir Karima 51281 author Hayoz Sébastien 516409 author Fanchaouy Mohammed 543072 author Beny Jean-Louis 26368 author Bychkov Rostislav 45-54 10.1038/sj.bjp.0706432 16258525 0007-1188 Adenosine 5'-triphosphate (ATP) activated two sequential responses in freshly isolated mouse aortic smooth muscle cells. In the first phase, ATP activated Ca(2+)-dependent K(+) or Cl(-) currents and the second phase was the activation of a delayed outward current with a reversal potential of -75.9 +/- 1.4 mV. A high concentration of extracellular K(+) (130 mM) shifted the reversal potential of the delayed ATP-elicited current to -3.5 +/- 1.3 mV. The known K(+)-channel blockers, iberiotoxin, charybdotoxin, glibenclamide, apamin, 4-aminopyridine, Ba(2+) and tetraethylammonium chloride all failed to inhibit the delayed ATP-elicited K(+) current. Removal of ATP did not decrease the amplitude of the ATP-elicited current back to the control values. The simultaneous recording of cytosolic free Ca(2+) and membrane currents revealed that the first phase of the ATP-elicited response is associated with an increase in intracellular Ca(2+), while the second delayed phase develops after the return of cytosolic free Ca(2+) to control levels.ATP did not activate Ca(2+)-dependent K(+) currents, but did elicit Ca(2+)-independent K(+) currents, in cells dialyzed with ethylene glycol-bis (2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA). The delay of activation of Ca(2+)-independent currents decreased from 10.5 + 3.4 to 1.27 +/- 0.33 min in the cells dialyzed with 2 mM EGTA. Adenosine alone failed to elicit a Ca(2+)-independent K(+) current but simultaneous application of ATP and adenosine activated the delayed K(+) current. Intracellular dialysis of cells with guanosine 5'-O-(2-thiodiphosphate) transformed the Ca(2+)-independent ATP-elicited response from a sustained to a transient one. A phospholipase C inhibitor, U73122 (1 microM), was shown to abolish the delayed ATP-elicited response. These results indicate that the second phase of the ATP-elicited response was a delayed Ca(2+)-independent K(+) current activated by exogenous ATP. This phase might represent a new vasoregulatory pathway in vascular smooth muscle cells. Aortic smooth muscle cells Intracellular Ca2+ ATP GDPbs Ca2+-independent K+ current Purine receptors PLC blocker Dewey 570 Dewey 590 44 Département de génétique et évolution 162 false British journal of pharmacology 147 1 fae78abf-f53e-4719-a42b-1a53c65460f9 Article (Published version) Public K.Serir.pdf 261595 application/pdf openAccess Faculté des sciences / Section de biologie / Département de génétique et évolution

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Characterization of potassium currents activated by purinergic receptors in dissociated mouse aorta myocytes		2007	911	390
A delayed ATP-elicited K+ current in freshly isolated smooth muscle cells from mouse aorta	British journal of pharmacology	2006	548	200

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Hayoz, Sébastien