Specific binding of [3H]L-glutamate to cerebellar membranes: Evidence for recognition site heterogeneity

J. Slevin, J. Collins, K. Lindsley, J. T. Coyle

Research output: Contribution to journalArticlepeer-review

26 Scopus citations

Abstract

The kinetics of interaction of excitatory amino acid analogues and re puted antagonists with a specific binding site for [3H]l-glutamate, having a Kd of 600 nM, were examined in washed cerebellar membranes incubated at 37°C. Displacement curves were analyzed by an iterative computer program for a non-cooperative two-site competitive inhibition model. l-Glutamate, d-glutamate and d-aspartate exhibited simples, mass action kinetics with Hill coefficeents near unity and Kis of 1.1, 9.3 and 23.3 μM, respectively. Quisqualate, ibotenate and cyclopentylglutamate had Hill coefficients less than 0.85 and bound to an high affinity component with KHs of 0.4, 0.8 and 1.7 μM, respectively. Neither N-methyl-d-aspartate nor derivatives of kainate, with the exception of α-keto kainate, had KiS less than 0.1 mM. Linear analogues of glutamate with reputed antagonistic properties all exhibited shallow displacement curves with Hill coefficients less than 0.6 andKHS varying from 0.5 to 6.6 μM. Notably, 2-amino-6-phosphonocaproic acid had negligible affinity for the site in contrast to the valeric and pimelic phosphono analogues. The results indicate that [3H]l-glutamate labels a single class of sites that can be resolved into subpopulations by agonists and antagonists and provide additional evidence of excitatory amino acid receptor heterogeneity.

Original languageEnglish
Pages (from-to)353-360
Number of pages8
JournalBrain Research
Volume249
Issue number2
DOIs
StatePublished - Oct 14 1982

Keywords

  • cerebellum
  • excitatory amino acids
  • glutamic acid
  • kainic acid
  • N-methyl-d-aspartate
  • neurotransmitter receptrrs

ASJC Scopus subject areas

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

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