Characterization of a Human NK1 Tachykinin Receptor in the Astrocytoma Cell Line U 373 MG |
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Authors: | E Heuillet J Ménager V Fardin O Flamand M Bock C Garret A Crespo A M Fallourd A Doble |
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Institution: | Biology, Centre de Recherche de Vitry-Alfortville, Rhône-Poulenc Rorer, Vitry-sur-Seine, France;Biotechnology Departments, Centre de Recherche de Vitry-Alfortville, Rhône-Poulenc Rorer, Vitry-sur-Seine, France |
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Abstract: | Abstract: The human NK1 tachykinin receptor in the astrocytoma cell line U 373 MG was characterized using selective agonists and antagonists described for this receptor in the rat. Specific 3H]substance P binding sites were present on cell homogenates, whereas 3H]neurokinin A or 3H]-senktide binding sites were absent. The binding was saturable and reversible. The binding of 3H]substance P was inhibited by very low concentrations of L-Pro9]substance P and Sar9,Met(O2)11]substance P; septide was ~ 1,000-fold less potent. The most potent peptide antagonist was trans -4-hydroxy-1-(1 H -indol-3-ylcarbonyl)-L-prolyl- N -methyl- N -(phenylmethyl)-L-tyrosineamide. The rank order of potency for the nonpeptide antagonists was ( S , S )-CP 96,345 > (±)-CP 96,345 > (±)-2-chlorobenzylquinuclidinone > ( R , R )-CP 96,345 > RP 67580 > RP 68651. In 3H]-inositol-labeled cells, substance P stimulated phosphatidylinositol turnover. A good correlation was found when the abilities of NK1 receptor agonists for stimulating inositol phosphate production and for inhibiting 3H]substance P binding were compared. Similarly, the binding and functional assays were well correlated for the antagonists. As a result of its high sensitivity and selectivity, the U 373 MG cell line thus appears an excellent tool for investigating the pharmacology of the human NK1 receptor. |
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Keywords: | Human NK1 tachykinin receptor U 373 MG cell line NK1-selective agonists and antagonists Phospholipase C Binding studies Functional studies |
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