Abstract
Helical strips of rat tail artery were observed to relax in response to potassium after contraction induced by 10<sup>-7</sup> g/ml norepinephrine in potassium-free solution. After several minutes of relaxation, the strips showed an abrupt redevelopment of tension. The amplitude of the potassium-induced relaxation was employed as an index of the activity of the electrogenic sodium-potassium pump and hence of the Na<sup>+</sup>-K<sup>+</sup> ATPase. This assumption seemed justified because the observed amplitude of potassium-induced relaxation paralleled known effects of the following variables on Na<sup>+</sup>-K<sup>+</sup> ATPase: (1) intracellular sodium concentration; (2) ouabain administration; (3) magnesium; (4) temperature, and (5) potassium concentration. The relaxation that occurred in response to potassium is suggested to be due to an enhanced Na<sup>+</sup>-K<sup>+</sup> ATPase resulting in increased electrogenic transport of sodium and potassium and, consequently, hyperpolarization. We propose that potassium-induced relaxation of rat tail artery may be used as a functional indicator of Na<sup>+</sup>-K<sup>+</sup> ATPase activity in vascular smooth muscle.
Original language | English (US) |
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Pages (from-to) | 198-207 |
Number of pages | 10 |
Journal | Blood Vessels |
Volume | 15 |
Issue number | 1-3 |
DOIs | |
State | Published - Dec 1 1978 |
Keywords
- Electrogenic pump
- Magnesium
- Ouabain
- Potassium
- Rat tail artery
- Sodium
ASJC Scopus subject areas
- Physiology
- Cardiology and Cardiovascular Medicine