Pisamai PratumtanPiyarat GovitrapongBoonsirm WithyachumnarnkulBoonserm PoolsanguanMahidol University2018-08-102018-08-101991-01-01Life Sciences. Vol.48, No.1 (1991), 19-26002432052-s2.0-0025924367https://repository.li.mahidol.ac.th/handle/123456789/22000Membrane preparation from the optic lobe of the giant freshwater prawn, Macrobrachium rosenbergii de Man, was examined for the presence of specific L-(3H) glutamate binding. The optic lobes were isolated from live animals. The tissue was homogenized and the membrane fraction isolated by differential centrifugation. The membrane suspension was incubated with 10-1,000 nM of L-(3H) glutamate at 37 ° C for 60 min. Nonspecific binding was determined by incubating the mixture with 100 μM L-glutamate. L-(3H) glutamate specifically bound to the membrane fraction with a dissociation equilibrium constant (Kd) of 205 nM and maximum number of binding sites (Bmax) of 2.04 n mol/mg protein. By using LIGAND computerized program, the saturation isotherm binding pattern indicates a single type of binding. To determine the type of glutamate receptors, competitive inhibition and IC50of several glutamate agonists and antagonists were determined. The study reveals a metabotropic type of binding site. © 1991.Mahidol UniversityBiochemistry, Genetics and Molecular BiologyMedicinePharmacology, Toxicology and PharmaceuticsArticleSCOPUS10.1016/0024-3205(91)90421-7