High calcium diet reduces blood pressure in exercised and nonexercised hypertensive rats

Kirsimarja Sallinen, Pertti Arvola, Heikki Wuorela, Heikki Ruskoaho, Heikki Vapaatalo, Ilkka Pörsti

Research output: Contribution to journalReview Articlepeer-review

23 Citations (Scopus)

Abstract

The effects of long-term high calcium diet and physical exercise and their combined effects on the development of hypertension, plasma and tissue atrial natriuretic peptide, and arterial function were studied in spontaneously hypertensive rats with Wistar-Kyoto rats serving as normotensive controls. Hypertensive rats were made to exercise by running on a treadmill up to 900 m/day. Calcium supplementation was instituted by increasing the calcium content of the chow from 1.1% to 2.5%. During the 23-week study, calcium supplementation attenuated the rise in blood pressure in both trained and nontrained hypertensive animals, whereas exercise training had no significant effect on blood pressure. The high calcium diet alone was associated with reduced plasma and ventricular tissue contents of atrial natriuretic peptide, both of which were increased by exercise. Responses of mesenteric arterial rings in vitro were examined at the end of the study. Neither increased dietary calcium nor endurance training affected the contractile sensitivity of endothelium-intact preparations to potassium chloride or norepinephrine. However, a high calcium diet enhanced the arterial relaxation induced by the return of potassium to the organ bath upon precontraction with potassium-free solution, and also moderately augmented relaxations to acetylcholine, sodium nitrite, and isoproterenol. Exercise training did not affect the potassium relaxation rate, but enhanced responses to acetylcholine, isoproterenol, and sodium nitrite. In conclusion, enhanced arterial potassium relaxation, a response reflecting the function of the vascular sodium pump, paralleled well the long-term blood pressure lowering action of increased dietary calcium intake in exercised and nonexercised hypertensive rats. However, augmented arterial relaxation to agonists could also be observed in the absence of reduced blood pressure following regular physical exercise.

Original languageEnglish
Pages (from-to)144-156
Number of pages13
JournalAmerican Journal of Hypertension
Volume9
Issue number2
DOIs
Publication statusPublished - Feb 1996
Externally publishedYes
Publication typeA2 Review article in a scientific journal

Keywords

  • Animals
  • Arteries/drug effects
  • Atrial Natriuretic Factor/blood
  • Blood Pressure/drug effects
  • Body Weight
  • Calcium/metabolism
  • Calcium, Dietary/pharmacology
  • Electrolytes/metabolism
  • Heart Rate
  • Hypertension/pathology
  • Intracellular Membranes/metabolism
  • Male
  • Physical Conditioning, Animal
  • Rats
  • Rats, Inbred SHR
  • Rats, Inbred WKY
  • Vasoconstrictor Agents/pharmacology
  • Vasodilator Agents/pharmacology

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