Chronic administration of nifedipine induces upregulation of dihydropyridine receptors in rabbit heart

G. E.C. De Cingolani, S. M. Mosca, M. V. Petroff, H. E. Cingolani

Research output: Contribution to journalArticlepeer-review

Abstract

In rabbits chronically pretreated with nifedipine (20 mg/day for 25 days), we demonstrate upregulation of Ca2+ channels in mammalian heart (maximal binding capacity = 222 ± 14 and 421 ± 55 fmol/mg protein for control and treated, respectively; P < 0.05) without significant changes in dissociation constant. No changes in calcium sensitivity or maximal force were detected by pretreatment with nifedipine in chemically skinned fibers. Cardiac contractility at different extracellular Ca2+ concentrations was similar in control and pretreated animals. This upregulation of Ca2+ channels in mammalian heart offers an explanation for the lack of significant negative inotropic effect after chronic administration of nifedipine.

Original languageEnglish (US)
Pages (from-to)H1222-H1226
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume267
Issue number3 36-3
DOIs
StatePublished - 1994

Keywords

  • calcium channels
  • contractile proteins
  • force-pCa relationship
  • heart contractility

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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