Complexity of the outward K+ current of the rat megakaryocyte

The American Journal of Physiology
E Romero, R Sullivan

Abstract

Megakaryocytes isolated from rat bone marrow express a voltage-dependent, outward K+ current with complex kinetics of activation and inactivation. We found that this current could be separated into at least two components based on differential responses to K+ channel blockers. One component, which exhibited features of the "transient" or "A-type" K+ current of excitable cells, was more strongly blocked by 4-aminopyridine (4-AP) than by tetrabutylammonium (TBA). This current, which we designated as "4-AP-sensitive" current, activated rapidly at potentials more positive than -40 mV and subsequently underwent rapid voltage-dependent inactivation. A separate current that activated slowly was blocked much more effectively by TBA than by 4-AP. This "TBA-sensitive" component, which resembled a typical delayed rectifier current, was much more resistant to voltage-dependent inactivation. The relative contribution of each of these components varied from cell to cell. The effect of charybdotoxin was similar to that of 4-AP. Our data indicate that the voltage-dependent K+ current of resting megakaryocytes is more complex than heretofore believed and support the emerging concept that megakaryocytes possess intricate electrophysiological pro...Continue Reading

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Citations

Jun 30, 2012·Journal of Thrombosis and Haemostasis : JTH·M P Mahaut-Smith
May 7, 1999·Japanese Journal of Pharmacology·M MurakamiK Nishi
Mar 2, 1999·The Journal of Physiology·M P Mahaut-SmithM J Mason
Apr 20, 2021·Platelets·Joy R Wright, Martyn P Mahaut-Smith

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