High-fat diet elevates blood pressure and cerebrovascular muscle Ca(2+) current

Hypertension. 2000 Mar;35(3):832-7. doi: 10.1161/01.hyp.35.3.832.

Abstract

Dietary fat contributes to the elevation of blood pressure and increases the risk of stroke and coronary artery disease. Previous observations have shown that voltage-gated Ca(2+) current density is significantly increased in hypertension and can be affected by free fatty acids (FAs). We hypothesized that a diet of elevated fat level would lead to an increase in blood pressure, an elevation of L-type Ca(2+) current, and an increase in saturated FA content in vascular smooth muscle cell membranes. Male Osborne-Mendel rats were fed normal rat chow or a high-fat diet (Ob/HT group) for 8 weeks. Blood pressures in the Ob/HT group increased moderately from 122.5+/-0.7 to 134.4+/-0.8 mm Hg (P<0.05, n=26). Voltage-clamp examination of cerebral arterial cells revealed significantly elevated L-type Ca(2+) current density in the Ob/HT group. Voltage-dependent inactivation of the Ob/HT L-type channels was significantly delayed. Total serum FA contents were significantly elevated in the Ob/HT group, and HPLC analyses of fractional pools of FAs from segments of abdominal aorta revealed that arachidonic acid levels were elevated in the phospholipid fraction in Ob/HT. No differences in vascular membrane cholesterol contents were noted. Plasma cholesterol was significantly elevated in portal venous and cardiac blood samples from Ob/HT rats. These findings suggest that an elevation of plasma FAs may contribute to the development of hypertension via a process involving the elevation of Ca(2+) current density and an alteration of channel kinetics in the vascular smooth muscle membrane.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blood Pressure / drug effects*
  • Calcium / metabolism*
  • Calcium Channels / physiology
  • Cerebrovascular Circulation / physiology*
  • Cholesterol / analysis
  • Cholesterol / blood
  • Chromatography, High Pressure Liquid
  • Dietary Fats / pharmacology*
  • Disease Models, Animal
  • Fatty Acids, Nonesterified / analysis
  • Fatty Acids, Nonesterified / blood
  • Hyperlipidemias / physiopathology
  • Hypertension / physiopathology
  • Ion Channel Gating / physiology
  • Kinetics
  • Male
  • Muscle, Smooth, Vascular / chemistry
  • Muscle, Smooth, Vascular / physiology*
  • Obesity / physiopathology
  • Patch-Clamp Techniques
  • Rats
  • Rats, Inbred Strains

Substances

  • Calcium Channels
  • Dietary Fats
  • Fatty Acids, Nonesterified
  • Cholesterol
  • Calcium