Effect of prostacyclin on platelet intracellular free calcium concentration of hypertensive and normotensive humans

Hiroaki Komura, Richard D. Bukoski, Njeri Karanja, Cynthia D. Morris, Tetsuji Shingu, David A. McCarron

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4 Scopus citations


Platelet intracellular free calcium concentration ([Ca2+]j) has been reported to be increased in essential hypertensive patients (EHT) as compared with normotensive controls (NT). Prostacyclin (PGI2), which influences cellular Ca2+, has been reported to be reduced in EHT. This study tested the hypothesis that the resting level of platelet [Ca2+]j in humans is influenced by PGI2. We also investigated the role of PGI2 in regulating platelet [Ca2+]iof 28 EHT subjects compared to 28 NT controls. Platelet [Ca2+] was measured using the fluorescent Ca2+ probe fura-2 under control conditions and a 10-min preincubation with PGI2. Simultaneous measurement of platelet cyclic-adenosine 3':5'- monophosphate (cAMP) was performed by radioimmunoassay. The resting level of platelet [Ca2+]iwas significantly higher in EHT than in NT (32.7 ±1.4 v 28.3 ± 0.9 nmol/L; P <.01). PGI2 from 30 nM to 1//mol/L lowered the resting level of platelet [Ca2 in a dose-dependent manner (EHT —22.2 ± 2.4, NT —22.9 ± 2.3%, 1/mol/L PGI2); however, no significant difference in platelet [Ca2+]i was observed between NT and EHT. While prostacyclin induced a transient rise in platelet cAMP, the magnitude of PGI2-induced cAMP level was similar between the two groups. These results do not support the hypothesis that endogenous PGI2 activity contributes to the increased level of platelet [Ca2+]i in EHT, although PGI2 incubation lowered the resting level of platelet [Ca2+]j.

Original languageEnglish (US)
Pages (from-to)730-735
Number of pages6
JournalAmerican Journal of Hypertension
Issue number9
StatePublished - Sep 1993



  • CAMP
  • Calcium
  • Essential hypertension
  • Platelet
  • Prostacyclin

ASJC Scopus subject areas

  • Internal Medicine

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