Pharmacological characterisation and autoradiographic distribution of polyamine-sensitive [3H]ifenprodil binding sites in the rat brain.
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.
Dana
C
C
Synthélabo Recherche (LERS), Biology Department, Bagneux, France.
Benavides
J
J
Schoemaker
H
H
Scatton
B
B
D000818:Animals; D001345:Autoradiography; D001665:Binding Sites; D001921:Brain / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009928:Organ Specificity; D010880:Piperidines / Q000378:metabolism*; D011073:Polyamines / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D014316:Tritium
D010880:Piperidines; D011073:Polyamines; D016194:Receptors, N-Methyl-D-Aspartate; D014316:Tritium; C010739:ifenprodil