Activation of particulate guanylyl cyclase by endothelins in cultured SV-40 transformed cat iris sphincter smooth muscle cells

Ke Hong Ding, Andrew J. Latimer, Ata A. Abdel-Latif

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

We investigated the effects of endothelins (ETs) on cGMP production in cultured SV-40 transformed cat iris sphincter smooth muscle (SV-CISM-2) cells. ET-3 increased cGMP formation in a concentration-dependent manner (EC50 =-98nM), which was 2.5 times higher than that of ET-1. The ET(B)receptor agonists sarafotoxin-S6c and IRL 1620 also increased cGMP production, mimicking the effects of the ETs. The ETs receptor antagonist BQ 788, but not the ET(A) receptor antagonist BQ610, dose-dependently blocked ET-3-stimulated cGMP formation (IC50=10nM). The phorbol ester, Phorbol 12, 13 - dibutyrate (PDBu), which inhibits particulate guanylyl cyclase in smooth muscle, dose-dependently inhibited ET-3-stimulated cGMP accumulation (IC50=66nM). LY83583 and ODQ, inhibitors of soluble guanylyl cyclases, as well as inhibitors of the nitric oxide cascade and of intracellular Ca2+ elevation had no appreciable effect on ET-3-induced cGMP production. ET-3 markedly inhibited carbachol-induced intracellular Ca2+ mobilization. We conclude that ET-3 increases intracellular cGMP levels in SV-CISM-2 cells through activation of the ET(B) receptor subtype and subsequent stimulation of the membrane-bound guanylyl cyclase. Elevation of cGMP by ET and the subsequent inhibition of muscarinic stimulation of intracellular Ca2+ mobilization by the cyclic nucleotide could serve to modulate the contractile effects of Ca2+ -mobilizing agonists in the iris sphincter smooth muscle.

Original languageEnglish (US)
Pages (from-to)161-174
Number of pages14
JournalLife sciences
Volume64
Issue number3
DOIs
StatePublished - Dec 11 1998

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Keywords

  • Cyclic GMP
  • Endothelins
  • Guanylyl cyclase
  • Iris sphincter smooth muscle cells

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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