Differential regulation of Ca2+ sparks and Ca2+ waves by UTP in rat cerebral artery smooth muscle cells

Jonathan Jaggar, Mark T. Nelson

Research output: Contribution to journalArticle

108 Citations (Scopus)

Abstract

Uridine 5'-triphosphate (UTP), a potent vasoconstrictor that activates phospholipase C, shifted Ca2+ signaling from sparks to waves in the smooth muscle cells of rat cerebral arteries. UTP decreased the frequency of Ca2+ sparks and transient Ca2+-activated K-- (K(Ca)) currents and increased the frequency of Ca2+ waves. The UTP-induced reduction in Ca2+ spark frequency did not reflect a decrease in global cytoplasmic Ca2+, Ca2+ influx through voltage-dependent Ca2+ channels (VDCC), or Ca2+ load of the sarcoplasmic reticulum (SR), since global Ca2+ was elevated, blocking VDCC did not prevent the effect, and SR Ca2+ load did not decrease. However, blocking protein kinase C (PKC) with bisindolylmaleimide I did prevent UTP reduction of Ca2+ sparks and transient K(Ca) currents. UTP decreased the effectiveness of caffeine, which increases the Ca2+ sensitivity of ryanodine-sensitive Ca2+ release (RyR) channels, to activate transient K(Ca) currents. This work supports the concept that vasoconstrictors shift Ca2+ signaling modalities from Ca2+ sparks to Ca2+ waves through the concerted actions of PKC on the Ca2+ sensitivity of RyR channels, which cause Ca2+ sparks, and of inositol trisphosphate (IP3) on IP3 receptors to generate Ca2+ waves.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Cell Physiology
Volume279
Issue number5 48-5
StatePublished - Dec 7 2000
Externally publishedYes

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Uridine Triphosphate
Cerebral Arteries
Smooth Muscle Myocytes
Ryanodine
Sarcoplasmic Reticulum
Vasoconstrictor Agents
Protein Kinase C
Inositol 1,4,5-Trisphosphate Receptors
Type C Phospholipases
Inositol
Caffeine

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cell Biology

Cite this

Differential regulation of Ca2+ sparks and Ca2+ waves by UTP in rat cerebral artery smooth muscle cells. / Jaggar, Jonathan; Nelson, Mark T.

In: American Journal of Physiology - Cell Physiology, Vol. 279, No. 5 48-5, 07.12.2000.

Research output: Contribution to journalArticle

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