Determination of N-methyl-d-aspartate in tissues of bivalves by high-performance liquid chromatography

Molecular Characterization of NMDA-Like Receptors inAplysiaandLymnaea:Relevance to Memory Mechanisms

“…For example, NMDA can be ineffective in the mimicking of glutamategated currents or can even be an antagonist (as was described for the leech [Mat Jais et al, 1984]). Surprisingly, NMDA was also found as an endogenous compound in tissues of some bivalve molluscs (Sato et al, 1987;Todoroki et al, 1999;Shibata et al, 2001). …”

d-Aspartate—An important bioactive substance in mammals: A review from an analytical and biological point of view

“…Since then, NMDA has been detected in various organisms, such as mollusks, cephalopods, crustaceans, cephalochordates, tunicates, fishes, amphibians, birds and mammals [89][90][91][92][93][94]. In mammalian tissues, the synthesis of NMDA from d-Asp has been reported [90].…”

Determination of d-aspartate N-methyltransferase activity in the starfish by direct analysis of N-methyl-d-aspartate with high-performance liquid chromatography

“…Our method reported in the previous studies using (+)-FLEC is able to separate of NMDA from the other N-methylamino acids [3,4]. On the basis of the method [2], we report here the development of a direct and reliable assay method for d-aspartate N-methyltransferase activity using a simple HPLC system, and its application in starfish tissues, in which we found a large amount of NMDA together with other acidic N-methylamino acids. d-Aspartate oxidase was purified as previously reported [10] and had a specific activity of 450 nmol/min per mg protein.…”

“…This was performed according to our previous report [2] with minor modifications as follows: the residue, resulting from the procedure described above, was dissolved in 100 l of 0.1 M sodium borate buffer (pH 9.0). A 10 l volume of this sample solution was mixed, in a 1.5-ml Eppendorf tube, with 40 l of OPA solution (50 mg/ml) in acetonitrile and was kept at 50 • C for 15 min to remove d-aspartate unreacted in the enzyme reaction.…”

“…NMDA, first known as an artificial compound, was discovered to be a natural product since it was isolated from the bivalve Scapharca broughtonii in 1987 [1]. We developed a simple and easy method for the determination of NMDA by high-performance liquid chromatography (HPLC) of their (+)-1-(9-fluorenyl)ethyl chloroformate [(+)-FLEC] fluorescent derivatives, after removal of primary amino acids by treatment with o-phthalaldehyde (OPA) [2], and demonstrated occurrence of NMDA in the several bivalves [3]. During these studies, we also found some other compounds that were similar to NMDA in HPLC behavior.…”