Regulation of [3H]nitrendipine binding by phospholipases A2 and C through direct and GTP-sensitive mechanisms

Mitchell S. Finkel, Theresa L. Hartsell, Carmine V. Oddis

Research output: Contribution to journalArticle

Abstract

We compared the effects of Phospholipases A2, C, B and D on [3H]nitrendipine binding to hamster cardiac membranes, in the absence and presence of ATP or GTP. Phospholipase A2, competitively inhibited [3H]nitrendipine binding to hamster cardiac membranes unchanged by ATP or GTP (Ki = 5 ng/ml); as evidenced by complete and reversible displacement of [3H]nitrendipine binding and increase in KD on Scatchard analyses. Phospholipase C also completely inhibited [3H]nitrendipine binding to hamster cardiac membranes (Ki = 5 ug/ml) with a decrease in Bmax and no change in KD on Scatchard analyses. The addition of GTP alone inhibited the PLC effect in EGTA-treated membranes. The addition of GTP with either CaCl2, or ATP or both resulted in an equal and opposite enhancement of the PLC effect. Phospholipases B and D had no effect on [3H]nitrendipine binding. These data support: (1) Direct effect of PLA2 on dihydropyridine binding. (2) Indirect regulation of dihydropyridine binding by Phospholipase C through a GTP and ATP-sensitive mechanism.

Original languageEnglish (US)
Pages (from-to)1031-1041
Number of pages11
JournalLife Sciences
Volume50
Issue number14
DOIs
StatePublished - 1992

ASJC Scopus subject areas

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

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