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Solubilization of Rat Brain Phencyclidine Receptors in an Active Binding Form That Is Sensitive to N ‐Methyl‐d‐Aspartate Receptor Ligands
Author(s) -
Ambar Ifat,
Kloog Yoel,
Sokolovsky Mordechai
Publication year - 1988
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1988.tb04846.x
Subject(s) - phencyclidine , nmda receptor , receptor , chemistry , metabotropic receptor , glutamate receptor , binding site , biochemistry
Phencyclidine (PCP) receptors were successfully solubilized from rat forebrain membranes with 1% sodium cholate. Approximately 58% of the initial protein and 20–30% of the high‐affinity PCP binding sites were solubilized. The high affinity toward PCP‐like drugs, the stereo‐selectivity of the sites, and the sensitivity to N ‐methyl‐d‐aspartate (NMDA) receptor ligands were preserved. Binding of the potent PCP receptor ligand N‐ [ 3 H][l‐(2‐thienyl)cyclohexyl] piperidine ([ 3 H]TCP) to the soluble receptors was saturable ( K D = 35 n M ), and PCP‐like drugs inhibited [ 3 H]TCP binding in a rank order of potency close to that observed for the membrane‐bound receptors; the most potent inhibitors were TCP ( K i = 31 n M ) and the anticonvulsant MK‐801 ( K i = 50 n M ). The NMDA receptor antagonist 2‐amino‐5‐phosphonovaleric acid inhibited‐binding of [ 3 H]TCP to the soluble receptors; glutamate or NMDA diminished this inhibition in a dose‐dependent manner. Taken together, the results indicate that the soluble PCP receptor preparation contains the glutamate recognition sites and may represent a single receptor complex for PCP and NMDA, as suggested by electrophysiological data. The successful solubilization of the PCP receptors in an active binding form should now facilitate their purification.