Determination of the equilibrium dissociation constants and number of glycine binding sites in several areas of the rat central nervous system, using a sodium-independent system

J Neurochem. 1981 Oct;37(4):1015-24. doi: 10.1111/j.1471-4159.1981.tb04489.x.


Parameters affecting the binding of [3H]glycine to membrane fractions isolated from the cerebral cortex, midbrain, cerebellum, medulla oblongata, and spinal cord of the rat were investigated in a Na+-free medium. A [3H]glycine binding assay was established in which the binding was specific, saturable, pH-sensitive, and reversible. Conditions were chosen in an effort to minimize binding to glycine uptake sites. From data on specific [3H]glycine binding Scatchard plots were prepared and the KD and Bmax values were calculated. Two glycine binding sites (high and low affinity) were identified only in the medulla (KD: 44, 211 nM; Bmax: 361, 1076 fmol/mg protein) and spinal cord (KD: 19, 104 nM; Bmax: 105, 486 fmol/mg protein). The ranges of the KD and Bmax values for the other three areas studied were 59 to 144 nM and 882 to 3401 fmol/mg protein, respectively. When the glycine content of each area, expressed as fmol/neuron, was plotted against the respective KD (high affinity), a negative correlation was found (r = --0.90; p less than 0.05). A similar negative correlation was found between the glycine content and Bmax (r = --0.88; p less than 0.05). Hill plots indicated a slope of essentially 1.0 for all areas. GABA, taurine, strychnine, diazepam, bicuculline, and imipramine had little or no effect on [3H]glycine binding.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acids / pharmacology
  • Animals
  • Brain / metabolism*
  • Cerebellum / metabolism
  • Cerebral Cortex / metabolism
  • Glycine / metabolism*
  • Kinetics
  • Male
  • Medulla Oblongata / metabolism
  • Mesencephalon / metabolism
  • Rats
  • Rats, Inbred Strains
  • Receptors, Cell Surface / metabolism*
  • Receptors, Glycine
  • Sodium / pharmacology
  • Spinal Cord / metabolism*
  • Tissue Distribution


  • Amino Acids
  • Receptors, Cell Surface
  • Receptors, Glycine
  • Sodium
  • Glycine