Effects of endothelin on phospholipases and generation of second messengers in cat iris sphincter and SV-CISM-2 cells

Ata A. Abdel-Latif, Ke Hong Ding, Rashid A. Akhtar, Sardar Y.K. Yousufzai

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

In both immortalized cat iris sphincter smooth muscle cells (SV-CISM-2 cells) and cat iris sphincter, endothelin-1 (ET-1) markedly increased the activities of phospholipase A2 (PLA2), as measured by the release of arachidonic acid (AA), phospholipase C (PLC), as measured by the production of inositol trisphosphate (IP3), and phospholipase D (PLD), as measured by the formation of phosphatidylethanol (PEt). In SV-CISM-2 cells, ET-1 induced AA release, IP3 production and PEt formation in a dose- and time-dependent manner. The dose-response studies showed that the peptide is more potent in activating PLD (EC50 = 1.2 nM) than in activating PLC (EC50 = 1.5 nM) or PLA2 (EC50 = 1.7 nM). The time course studies revealed that ET-1 activated the phospholipases in a temporal sequence in which PLA2 was stimulated first (t( 1/4 ) = 12 s), followed by PLC (t( 1/4 ) = 48 s) and lastly PLD (t( 1/4 ) = 106 s). In SV-CISM-2 cells, in contrast to the intact iris sphincter, sarafotoxin-c, an ET(B) receptor agonist, had no effect on the phospholipases, and indomethacin, a cyclooxygenase inhibitor, had no effect on the stimulatory effect of ET-1 on the phospholipases. These results suggest that in this smooth muscle cell line, ET-1 interacts with the ET(A) receptor subtype to activate, via G proteins, phospholipases A2, C and D in a temporal sequence.

Original languageEnglish (US)
Pages (from-to)147-155
Number of pages9
JournalJournal of Lipid Mediators and Cell Signalling
Volume14
Issue number1-3
DOIs
Publication statusPublished - Sep 1996

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Keywords

  • ET(A) receptor subtype
  • SV-CSM-2 cells
  • cat iris sphincter
  • endothelin
  • phospholipases A, C, D
  • second messengers

ASJC Scopus subject areas

  • Immunology
  • Pharmacology

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