L-beta-methylaminoalanine inhibits [3H]glutamate binding in the presence of bicarbonate ions. 1989

K E Richter, and E E Mena
Department of Neuroscience, Pfizer Inc., Groton, CT 06340.

We examined the ability of the neurotoxin, L-beta-methylaminoalanine (L-BMAA), to inhibit [3H]glutamate binding to rat brain synaptic junctions. In a tris(hydroxymethyl)aminomethane acetate buffer, L-BMAA did not affect [3H]glutamate binding (IC50 greater than 10 mM). However, in the presence of ammonium bicarbonate (20 mM) L-BMAA blocked [3H]glutamate binding with an IC50 of 1 mM. This inhibition was not caused by ammonium ion since other ammonium salts were inactive. Furthermore, identical inhibition was obtained in the presence of potassium bicarbonate. Bicarbonate ion did not alter the ability of N-methyl-D-aspartic acid to block glutamate binding. These results indicate that bicarbonate ion is required for the interaction of L-BMAA with the glutamate receptor and may account for the observation that beta-methylaminoalanine is neurotoxic in vitro only in the presence of bicarbonate.

UI MeSH Term Description Entries
D009498 Neurotoxins Toxic substances from microorganisms, plants or animals that interfere with the functions of the nervous system. Most venoms contain neurotoxic substances. Myotoxins are included in this concept. Alpha-Neurotoxin,Excitatory Neurotoxin,Excitotoxins,Myotoxin,Myotoxins,Neurotoxin,Alpha-Neurotoxins,Excitatory Neurotoxins,Excitotoxin,Alpha Neurotoxin,Alpha Neurotoxins,Neurotoxin, Excitatory,Neurotoxins, Excitatory
D005625 Frontal Lobe The part of the cerebral hemisphere anterior to the central sulcus, and anterior and superior to the lateral sulcus. Brodmann Area 8,Brodmann's Area 8,Frontal Cortex,Frontal Eye Fields,Lobus Frontalis,Supplementary Eye Field,Area 8, Brodmann,Area 8, Brodmann's,Brodmanns Area 8,Cortex, Frontal,Eye Field, Frontal,Eye Field, Supplementary,Eye Fields, Frontal,Frontal Cortices,Frontal Eye Field,Frontal Lobes,Lobe, Frontal,Supplementary Eye Fields
D005971 Glutamates Derivatives of GLUTAMIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain the 2-aminopentanedioic acid structure. Glutamic Acid Derivatives,Glutamic Acids,Glutaminic Acids
D000087522 Cyanobacteria Toxins Toxic secondary metabolites produced CYANOBACTERIA. Cyanobacterial Neurotoxin,Cyanobacterial Neurotoxins,Cyanobacterial Toxins,Cyanotoxins,Neurotoxin, Cyanobacterial
D000599 Amino Acids, Diamino Amino Acids, Dibasic,Diamino Amino Acids,Dibasic Amino Acids,Acids, Diamino Amino,Acids, Dibasic Amino
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D001639 Bicarbonates Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the pH of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity. Bicarbonate,Bicarbonate Ions,Hydrogen Carbonates,Bicarbonate Ion,Carbonic Acid Ions,Hydrogen Carbonate,Carbonate, Hydrogen,Carbonates, Hydrogen,Ion, Bicarbonate,Ions, Bicarbonate,Ions, Carbonic Acid
D017470 Receptors, Glutamate Cell-surface proteins that bind glutamate and trigger changes which influence the behavior of cells. Glutamate receptors include ionotropic receptors (AMPA, kainate, and N-methyl-D-aspartate receptors), which directly control ion channels, and metabotropic receptors which act through second messenger systems. Glutamate receptors are the most common mediators of fast excitatory synaptic transmission in the central nervous system. They have also been implicated in the mechanisms of memory and of many diseases. Excitatory Amino Acid Receptors,Glutamate Receptors,Receptors, Excitatory Amino Acid,Excitatory Amino Acid Receptor,Glutamate Receptor,Receptor, Glutamate
D051381 Rats The common name for the genus Rattus. Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus
D017981 Receptors, Neurotransmitter Cell surface receptors that bind signalling molecules released by neurons and convert these signals into intracellular changes influencing the behavior of cells. Neurotransmitter is used here in its most general sense, including not only messengers that act to regulate ion channels, but also those which act on second messenger systems and those which may act at a distance from their release sites. Included are receptors for neuromodulators, neuroregulators, neuromediators, and neurohumors, whether or not located at synapses. Neurohumor Receptors,Neuromediator Receptors,Neuromodulator Receptors,Neuroregulator Receptors,Receptors, Neurohumor,Receptors, Synaptic,Synaptic Receptor,Synaptic Receptors,Neuromediator Receptor,Neuromodulator Receptor,Neuroregulator Receptor,Neurotransmitter Receptor,Receptors, Neuromediators,Receptors, Neuromodulators,Receptors, Neuroregulators,Receptors, Neurotransmitters,Neuromediators Receptors,Neuromodulators Receptors,Neuroregulators Receptors,Neurotransmitter Receptors,Neurotransmitters Receptors,Receptor, Neuromediator,Receptor, Neuromodulator,Receptor, Neuroregulator,Receptor, Neurotransmitter,Receptor, Synaptic,Receptors, Neuromediator,Receptors, Neuromodulator,Receptors, Neuroregulator

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