ATP-dependent decay and recovery of K+ channels in guinea pig cardiac myocytes
| Autor: | Dayi Qin, A Noma, M. Takano |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Potassium Channels
Time Factors Physiology Adenylyl Imidodiphosphate Inward-rectifier potassium ion channel Myocardium Guinea Pigs Time constant Anatomy Biology Potassium channel Electrophysiology chemistry.chemical_compound Kinetics Adenosine Triphosphate chemistry Physiology (medical) Biophysics Myocyte Repolarization Animals Magnesium Cardiology and Cardiovascular Medicine Adenosine triphosphate |
| Zdroj: | The American journal of physiology. 258(1 Pt 2) |
| ISSN: | 0002-9513 |
| Popis: | ATP-dependent decay and recovery of the inward rectifier and ATP-sensitive K+ channels were investigated using inside-out patch recording in cardiac myocytes. The solution facing the inner side of the membrane was instantaneously changed with the oil-gate concentration jump method. Both channels were decayed by removing ATP and were recovered by reapplying ATP. The coexistence of Mg2+ was required for the recovery. 5'-Adenylylimidodiphosphate failed to reverse the ATP-dependent decay. The cumulative histograms of survival time and recovery time, obtained from the inward rectifier K+ channel, showed a single exponential distribution, time constants of which were 55 and 43 s, respectively. The time-dependent nature of decay and recovery was also confirmed in the ATP-sensitive K+ channel. The findings indicated that intracellular ATP is one of the factors that determines the activity of the K+ channels. It is most probable that phosphorylation of channel molecules is essential for maintaining the K+ channel in an operative state. |
| Databáze: | OpenAIRE |
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