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

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

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
Volume6
Issue number9
DOIs
StatePublished - Sep 1993

Keywords

  • CAMP
  • Calcium
  • Essential hypertension
  • Platelet
  • Prostacyclin

ASJC Scopus subject areas

  • Internal Medicine

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