Solubilization and characterization of binding sites for [3H]NE-100, a novel and potent sigma 1 ligand, from guinea pig brain.
The binding sites for [3H]NE-100, a newly defined sigma 1 ligand, was solubilized from guinea pig brain, using zwitterionic detergent 3-[(3-c holamidopropyl) dimethylamino]-1-propanesulfonate (CHAPS), and the properties of the solubilized binding sites were compared to those for [3H](+)-pentazocine, a selective sigma 1 ligand. The pharmacological selectivity of solubilized sites for both [3H]NE-100 and [3H](+)-pentazocine was identical to that obtained from membrane preparations. Stereoselectivity of benzomorphan such as pentazocine and SKF10,047 was preserved in displacing [3H]NE-100 binding in solubilized preparations as observed in membrane preparations. The inhibitory potencies of several sigma ligands on [3H]NE-100 binding were similar to those on [3H](+)-pentazocine binding, indicating that the pharmacological characteristics of the binding sites for [3H]NE-100 are retained after solubilization. Phenytoin augmented the binding of [3H](+)-3-(3-hydroxyphenyl)-N-(1-propyl) piperidine hydrochloride (3-PPP) to solubilized sigma binding sites while it had no effect on the binding of [3H]NE-100. Furthermore, the inhibitory effect of putative sigma receptor agonists such as (+)-3-PPP and dextromethorphan were enhanced by phenytoin; the effects of haloperidol, a putative sigma receptor antagonist, were unaltered. Molecular weight of [3H]NE-100 binding protein was estimated to be 440KDa by Sepharose CL-6B gel filtration chromatography, and the value was identical to that of [3H](+)-pentazocine binding protein, a putative sigma 1 binding protein. These findings indicate that [3H]NE-100 binding sites are putative sigma 1 binding sites, and that NE-100 may act as an antagonist at sigma 1 binding sites.
Chaki
S
S
1st Laboratory, Taisho Pharmaceutical Co. Ltd., Saitama, Japan.
Okuyama
S
S
Ogawa
S
S
Tanaka
M
M
Muramatsu
M
M
Nakazato
A
A
Tomisawa
K
K
D000818:Animals; D000840:Anisoles / Q000378:metabolism*; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism*; D003915:Dextromethorphan / Q000378:metabolism; D006168:Guinea Pigs; D008024:Ligands; D008297:Male; D010423:Pentazocine / Q000378:metabolism; D010672:Phenytoin / Q000378:metabolism; D011437:Propylamines / Q000378:metabolism*; D011869:Radioligand Assay; D017480:Receptors, sigma / Q000378:metabolism*; D014316:Tritium
D000840:Anisoles; D008024:Ligands; D011437:Propylamines; D017480:Receptors, sigma; D014316:Tritium; C083832:N,N-dipropyl-2-(4-methoxy-3-(2-phenylethoxy)phenyl)ethylamine monohydrochloride; D010672:Phenytoin; D003915:Dextromethorphan; D010423:Pentazocine