Characterisation of [3H]MK-801 binding and its cooperative modulation by pig brain membranes.
Cooperative modulation of [3H]MK-801 binding to extensively washed pig cortical brain membranes in the presence of various concentrations of L-glutamate, glycine, spermine, CPP and DCKA was evaluated in association experiments. In saturation experiments [3H]MK-801 labelled a homogeneous population of binding sites with a Kd-value of 1.26 +/- 0.18 nmol 1(-1) and a Bmax-value of 2130 +/- 200 fmol/mg protein. The pharmacological profile of this site was further evaluated in competition experiments with known NMDA receptor channel blockers. In nonequilibrium binding experiments EC50-values of reference compounds acting at the L-glutamate, at the glycine, and at the polyamine site, were determined by increasing or decreasing [3H]MK-801 binding. Ifenprodil reduced [3H]MK-801 binding in a biphasic manner. All the data obtained are in agreement with results from [3H]MK-801 binding to rodent as well as human brain membranes. This study therefore strongly suggests, that pig cortical membranes are a suitable alternative to rodent brain membranes, and an acceptable substitute for human brain membranes in [3H]MK-801 binding experiments.
Höfner
G
G
Institut fùr Pharmazie und Lebensmittelchemie, München, Germany.
Wanner
K T
KT
D000818:Animals; D001667:Binding, Competitive; D002540:Cerebral Cortex / Q000378:metabolism*; D016291:Dizocilpine Maleate / Q000378:metabolism*; D018691:Excitatory Amino Acid Antagonists / Q000378:metabolism*; D018698:Glutamic Acid / Q000494:pharmacology; D005998:Glycine / Q000494:pharmacology; D007700:Kinetics; D007736:Kynurenic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D010879:Piperazines / Q000378:metabolism; D010880:Piperidines / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D013096:Spermine / Q000494:pharmacology; D013552:Swine
D018691:Excitatory Amino Acid Antagonists; D010879:Piperazines; D010880:Piperidines; D016194:Receptors, N-Methyl-D-Aspartate; C065286:SDZ EAA 494; D013096:Spermine; D018698:Glutamic Acid; D016291:Dizocilpine Maleate; D007736:Kynurenic Acid; C010739:ifenprodil; C066192:5,7-dichlorokynurenic acid; D005998:Glycine