Related Experiment Videos
Dietary cholesterol affects Na+-K+ pump function in rabbit cardiac myocytes
D F Gray1, P S Hansen, M M Doohan
1Department of Cardiology, Royal North Shore Hospital, Sydney, Australia.
The American Journal of Physiology
|April 1, 1997
Summary
Dietary cholesterol impacts heart cell sodium-potassium pump (Na+-K+ pump) function. Modest cholesterol increases can stimulate the pump, while large increases inhibit it, affecting cardiovascular health.
Area of Science:
- Cardiovascular Physiology
- Membrane Biochemistry
- Cellular Electrophysiology
Background:
- In vitro studies show membrane cholesterol affects Na+-K+ pump activity.
- Dietary cholesterol is known to influence membrane cholesterol levels in vivo.
Purpose of the Study:
- To investigate if dietary cholesterol intake is a determinant of Na+-K+ pump function in vivo.
- To explore the relationship between serum cholesterol levels and cardiac Na+-K+ pump activity.
Main Methods:
- Rabbits were fed cholesterol-supplemented diets for 1-4 weeks.
- Cardiac myocytes were isolated and Na+-K+ pump currents (Ip) were measured using whole-cell patch-clamp.
- The Na+-K+ pump's affinity for cytoplasmic Na+ and extracellular K+ was assessed.
Main Results:
- A modest increase in serum cholesterol stimulated Ip at low intracellular Na+ concentrations (10 mM).
- Large increases in serum cholesterol inhibited Ip at 10 mM intracellular Na+.
- Dietary cholesterol affected the pump's affinity for cytoplasmic Na+ but not for extracellular K+.
Conclusions:
- Cholesterol intake significantly influences the sarcolemmal Na+-K+ pump function.
- These findings suggest potential clinical implications for cardiovascular health related to dietary cholesterol.
- The study highlights a direct link between dietary cholesterol and cardiac ion transport regulation.