Characterization by [3H]resiniferatoxin binding of a human vanilloid (capsaicin) receptor in post-mortem spinal cord.
Membranes obtained from post-mortem human spinal cord specimens bound [3H]resiniferatoxin (RTX) with an affinity of 11 nM in a non-cooperative fashion. This binding behaviour contrasted with the high affinity [3H]RTX binding (Kd = 24 pM) to rat spinal cord membranes which displayed apparent positive cooperativity (cooperativity index = 1.8) but was in accord with the low affinity (Kd = 5 nM) non-cooperative RTX binding to guinea pig spinal cord preparations. We conclude that the [3H]RTX binding assay utilizing post-mortem human spinal cord membranes affords a novel biochemical approach to explore structure-activity relations at human vanilloid receptors.
Department of Pharmacology, Menarini Ricerche Sud, Pomezia (Roma), Italy.
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Szallasi
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Goso
D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D002211:Capsaicin / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D004224:Diterpenes / Q000378:metabolism*; D006168:Guinea Pigs; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008566:Membranes / Q000378:metabolism; D009498:Neurotoxins / Q000378:metabolism*; D015240:Phorbol 12,13-Dibutyrate / Q000493:pharmacokinetics; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D011955:Receptors, Drug / Q000378:metabolism*; D013116:Spinal Cord / Q000378:metabolism*
D004224:Diterpenes; D009498:Neurotoxins; D011955:Receptors, Drug; D015240:Phorbol 12,13-Dibutyrate; C024353:resiniferatoxin; D011493:Protein Kinase C; C071423:capsazepine; D002211:Capsaicin