Pharmacological characterisation and autoradiographic distribution of polyamine-sensitive [3H]ifenprodil binding sites in the rat brain

Neurosci Lett. 1991 Apr 15;125(1):45-8. doi: 10.1016/0304-3940(91)90127-f.

Abstract

Saturation studies with [3H]ifenprodil (in the presence of 3 microM (+)-3-PPP and 10 microM GBR 12909) demonstrated the presence of a high-affinity (Kd = 0.45 microM) population of binding sites in sagittal rat brain sections. This binding was inhibited by spermine (IC50 = 69 microM) and spermidine (IC50 = 623 microM) but not by putrescine (1 mM). Ifenprodil displaced this binding in a biphasic fashion with a high affinity component (IC50 = 0.992 microM) accounting for approximately 50% of the spermine-displaceable [3H]ifenprodil binding. The polyamine-sensitive [3H]ifenprodil binding sites were heterogenously distributed in the rat brain, the highest binding densities being found in the hippocampus and in the nucleus accumbens. The anatomical distribution of [3H]ifenprodil binding sites closely matches that previously reported for the N-methyl-D-aspartate (NMDA) receptor.

MeSH terms

  • Animals
  • Autoradiography
  • Binding Sites
  • Brain / metabolism*
  • Kinetics
  • Male
  • Organ Specificity
  • Piperidines / metabolism*
  • Polyamines / pharmacology*
  • Rats
  • Rats, Inbred Strains
  • Receptors, N-Methyl-D-Aspartate / metabolism*
  • Tritium

Substances

  • Piperidines
  • Polyamines
  • Receptors, N-Methyl-D-Aspartate
  • Tritium
  • ifenprodil