In vivo binding of nimodipine in the brain: II. Binding kinetics in focal cerebral ischemia

Matthew J. Hogan, Albert Gjedde, Antoine M. Hakim

Research output: Contribution to journalArticle

Abstract

We report the binding characteristics of [3H]nimodipine to normal and ischemic brain in vivo. We used the 1,4-dihydropyridine, nimodipine, to label the L-type voltage-sensitive calcium channel in focal cerebral ischemia after occlusion of both the middle cerebral and ipsilateral common carotid arteries in rats. Varying concentrations of [3H]nimodipine were infused 3.5 h after the onset of ischemia and circulated for 30 min before the brain was obtained for autoradiography and determination of regional nimodipine content. In separate sets of experiments, the metabolites of nimodipine were determined and the conditions for equilibrium of nimodipine distribution were established. Increased nimodipine uptake was observed in ischemic regions. This increased binding was saturable and specific with an affinity constant, KD, of 0.45 nM and a maximal regional binding capacity, Bmax ranging from 3.1 to 10.9 pmol/g. Only binding to ischemic tissue was specific and saturable whereas that in nonischemic tissue was nonspecific. In vivo binding of nimodipine may be used to identify cell membrane depolarization and calcium channel activation in focal cerebral ischemia.

Original languageEnglish (US)
Pages (from-to)771-778
Number of pages8
JournalJournal of Cerebral Blood Flow and Metabolism
Volume11
Issue number5
DOIs
StatePublished - 1991

Keywords

  • Autoradiography
  • Binding kinetics
  • Calcium channels
  • Focal cerebral ischemia
  • Nimodipine

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine

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