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Platelet cytosolic free calcium in essential hypertension: responses to vasopressin

A F Dominiczak1, J J Morton, G Murray

  • 1MRC Blood Pressure Unit, Western Infirmary, Glasgow, Scotland, U.K.

Clinical Science (London, England : 1979)
|August 1, 1989
PubMed

Insights

Essential hypertension patients show normal resting platelet calcium but a blunted response to arginine vasopressin when extracellular calcium is present. Drug treatment for hypertension correlated with changes in platelet calcium levels.

Area of Science:

  • Cardiovascular Physiology
  • Cellular Biology

Background:

  • Essential hypertension is a complex cardiovascular condition.
  • Platelet calcium homeostasis plays a role in vascular function.

Purpose of the Study:

  • To investigate platelet free calcium concentrations in essential hypertension.
  • To assess the effect of arginine vasopressin on platelet calcium in hypertensive patients.
  • To examine the impact of antihypertensive drugs on platelet calcium.

Main Methods:

  • Measurement of platelet free calcium using the fluorescent probe quin2.
  • Stimulation of platelets with arginine vasopressin in the presence and absence of extracellular calcium.
  • Correlation analysis of blood pressure changes with platelet calcium alterations after drug treatment.

Main Results:

  • No significant difference in resting cytosolic free calcium between hypertensive and normotensive groups.
  • Arginine vasopressin induced a significantly lower increase in platelet free calcium in hypertensive patients compared to controls when extracellular calcium was present.
  • Absence of extracellular calcium abolished the difference in response between groups.
  • Reductions in systolic blood pressure after verapamil or atenolol treatment correlated with changes in platelet cytosolic free calcium.

Conclusions:

  • Essential hypertension is not associated with altered resting platelet calcium levels.
  • Hypertensive patients exhibit impaired platelet calcium mobilization in response to arginine vasopressin, particularly when extracellular calcium is available.
  • Antihypertensive therapy may influence platelet calcium dynamics, suggesting a potential link between blood pressure control and cellular calcium handling.

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