Pharmacological characteristics of NP-252, a new dihydropyridine slow Ca2+ channel blocker, in isolated rabbit vascular smooth muscle and guinea pig myocardium: vascular selectivity

Shoji Shibata, Nobuhiro Satake, Itsuo Kodama, R. Kelly Hester, Chang Gen Wang, Hiroshi Jino, Masakazu Hojo, Hiroshi Tatsumi, Vijayalakshmi Gandhi, David J. Jones

Research output: Contribution to journalArticle

3 Scopus citations

Abstract

NP-252, a new dihydropyridine derivative, and nifedipine non-competitively inhibited contractile responses to KCl and responses to Ca2+ in Ca2+-free medium containing KCl in rabbit aorta and renal, mesenteric, coronary and basilar arteries, mesenteric veins and vena cava. The effects of NP-252 in these smaller arteries and veins were much greater than those in aorta. However, a similar differential selectivity was not seen with nifedipine. In aorta, only NP-252 reduced total La3+ resistant 45Ca binding. However, the increases in bound 45Ca at La3+ resistant sites and 45Ca unidirectional influx due to KCl were inhibited by both NP-252 and nifedipine. The displacement of [3H]nitrendipine binding to rabbit aorta was monophasic for both NP-252 and nifedipine. In guinea-pig papillary muscles, NP-252 (> 10-7 M) slightly decreased action potential duration, developed tension and slow action potentials. The cardiac effects of NP-252 were much less prominent than those of nifedpine. These results indicate that NP-252 inhibits voltage-operated Ca2+ channels in small arteries and veins much more effectively than those in aorta, and this tissue selectivity is more apparent for NP-252 than nifedipine.

Original languageEnglish (US)
Pages (from-to)337-344
Number of pages8
JournalEuropean Journal of Pharmacology
Volume203
Issue number3
DOIs
StatePublished - Oct 22 1991

Keywords

  • (Slow response)
  • Ca binding
  • Ca channel blockers
  • Ca uptake
  • Cardiac muscle
  • Smooth muscle (vascular)
  • Tissue selectivity

ASJC Scopus subject areas

  • Pharmacology

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