High affinity specific [3H] (+)PN 200-110 binding to dihydropyridine receptors associated with calcium channels in rat cerebral cortex and heart

Howard R. Lee, William R. Roeske, Henry I. Yamamura

Research output: Contribution to journalArticlepeer-review

102 Scopus citations

Abstract

The binding properties of the 1,4-dihydropyridine calcium channel antagonist, [3H](+)PN 200-110, were studied in rat cerebral cortical and cardiac homogenates (37°C, Krebs phosphate buffer). Specific binding of [3H](+)PN 200-110 was saturable, reversible, and of high affinity (Kd values are 35 and 64 pM for the cerebral cortex and heart, respectively). In parallel studies with [3H](+)PN 200-110, the dissociation constant of [3H]nitrendipine was 10-12 times higher. Substituted dihydropyridine calcium channel antagonists and agonists competitively inhibited specific [3H](+)PN 200-110 binding, but d-cis diltiazem enhanced and verapamil incompletely inhibited [3H](+)PN 200-110 binding in both the cerebral cortex and the heart. The effects of diltiazem and verapamil on [3H](+)PN 200-110 binding were due mainly to alterations in the dissociation constant (Kd), without alterations in the binding density (Bmax). The new [3H](+)PN 200-110 receptor binding assay is remarkable for its low degree of nonspecific binding as compared to [3H]nitrendipine at physiological temperatures. [3H(+)PN 200-110 is a useful ligand for the further analysis of the dihydropyridine binding sites associated with calcium channels.

Original languageEnglish (US)
Pages (from-to)721-732
Number of pages12
JournalLife Sciences
Volume35
Issue number7
DOIs
StatePublished - Aug 13 1984

ASJC Scopus subject areas

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

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