CHAPS solubilization of a G-protein sensitive 5-HT1A receptor from bovine hippocampus.
The binding of [3H] 8-OH-DPAT to membrane-bound 5-HT1A receptors from bovine hippocampus was saturable and corresponded to a single high-affinity state. Solubilization of the bovine hippocampal membranes with 10 mM CHAPS containing 200 mM NaCl, renders a preparation which binds [3H] 8-OH-DPAT with high-affinity (Kd = 1.9 nM) and is guanine nucleotide sensitive and ketanserin insensitive. 50% of [3H] 8-OH-DPAT binding activity is solubilized. The presence of GMP-P(NH)P promotes a low-affinity (Kd = 9.6 nM) state which is characteristic of receptors coupled to G-proteins. GMP-P(NH)P markedly accelerates the dissociation [3H] 8-OH-DPAT from solubilized membranes while having negligible effects on association. Thus, the agonist can activate the terniary complex rather than to promote its formation. 8-OH DPAT, WB 4101 and 5-carboxamidotryptamine dose responsively inhibit soluble [3H] 8-OH-DPAT binding with IC(50) values of 16.1, 15.6 and 1.3 nM, respectively. The CHAPS solubilized membrane preparation retains many of the [3H] 8-OH-DPAT binding characteristics of the membrane bound form.
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Dept. of Pharmacology, Mt. Sinai School of Medicine, CUNY, N.Y. 10029.
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Meyerson
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D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000032:analysis / Q000378:metabolism; D002793:Cholic Acids; D003902:Detergents; D019204:GTP-Binding Proteins / Q000502:physiology*; D006150:Guanine Nucleotides / Q000494:pharmacology; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D006624:Hippocampus / Q000032:analysis*; D011985:Receptors, Serotonin / Q000187:drug effects / Q000302:isolation & purification* / Q000378:metabolism; D013764:Tetrahydronaphthalenes / Q000378:metabolism
D002793:Cholic Acids; D003902:Detergents; D006150:Guanine Nucleotides; D011985:Receptors, Serotonin; D013764:Tetrahydronaphthalenes; D006165:Guanylyl Imidodiphosphate; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D019204:GTP-Binding Proteins; C028213:3-((3-cholamidopropyl)dimethylammonium)-1-propanesulfonate