Treatment with conotoxin, an 'N-type' calcium channel blocker, in neuronal hypoxic-ischemic injury

Ken P. Madden, Wayne M. Clark, Frank W. Marcoux, Albert W. Probert, Mark L. Weber, Jean Rivier, Justin A. Zivin

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

Therapeutic efficacy of calcium channel blockers in stroke remains controversial, but previously used agents bind almost exclusively to L-type calcium channels. The newly-discovered N-type calcium channel is specific to neurons, and therapy involving blockade of this site has not been previously attempted. We assessed the neuroprotective effect of omega-conotoxin GVIA (CgTx), a blocker of N-type calcium channels, using both in vitro hypoxic injury to rat cortical neurons and an in vivo model of reversible spinal cord ischemia in the rabbit. In cell cultures, CgTx inhibited hypoxia-induced 45Ca accumulation and neuronal injury minimally, compared to the NMDA antagonist ketamine. In vivo, the duration of spinal cord ischemia which produced permanent paraplegia in 50% of control animals (ET50) was 24.0 ± 2.6 min. Animals treated 2 h prior to ischemia with 0.5 nmol CgTx in the subarachnoid space had an ET50 of 26.9 ± 1.8 min (P = 0.36). Animals treated 24 h prior to ischemia (all had persistent systemic tremor) had a ET50 of 28.9 ± 1.8 min (P = 0.13). We conclude that pharmacologic modulation of the N-type calcium channel does not provide a significant protective effect against neuronal hypoxic-ischemic injury.

Original languageEnglish (US)
Pages (from-to)256-262
Number of pages7
JournalBrain research
Volume537
Issue number1-2
DOIs
StatePublished - Dec 24 1990

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Keywords

  • Calcium
  • Conotoxin
  • Hypoxia
  • Ischemia
  • Ketamine
  • Nimodipine
  • Spinal cord
  • Subarachnoid

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

Cite this

Madden, K. P., Clark, W. M., Marcoux, F. W., Probert, A. W., Weber, M. L., Rivier, J., & Zivin, J. A. (1990). Treatment with conotoxin, an 'N-type' calcium channel blocker, in neuronal hypoxic-ischemic injury. Brain research, 537(1-2), 256-262. https://doi.org/10.1016/0006-8993(90)90366-J