Human peripheral monocytes express putative receptors for neuroexcitatory amino acids.
Human peripheral mononuclear cells responded chemotactically to 4-carboxyl-L-glutamic acid. The maximal chemotactic response occurred at 0.1 nM. No chemotactic response was found with neutrophils or fetal bovine fibroblasts. Glutamic acid, a neuroexcitatory dicarboxylic amino acid and the parent compound of 4-carboxyglutamic acid, did not stimulate chemotaxis in any of the cells tested. However, it functioned as an antagonist to 4-carboxyglutamic acid (ED50 approximately 2 pM; ED100 approximately 10 pM). In contrast to the lack of response to glutamic acid, its dicarboxylic cyclic analogue, kainic acid, excited a chemotactic response in mononuclear cells. The data suggest that mononuclear phagocytes have receptors for dicarboxylic neuroexcitatory amino acids, and we speculate that 4-carboxyglutamic acid, a tricarboxylic acid, may have a previously unrecognized role as a neuroexcitatory amino acid.
Malone
J D
JD
Richards
M
M
Kahn
A J
AJ
D015055:1-Carboxyglutamic Acid / Q000378:metabolism*; D002628:Chemoreceptor Cells / Q000502:physiology; D002630:Chemotactic Factors / Q000502:physiology*; D005971:Glutamates / Q000378:metabolism* / Q000494:pharmacology / Q000502:physiology*; D006801:Humans; D007608:Kainic Acid / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D009000:Monocytes / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000502:physiology*
D002630:Chemotactic Factors; D005971:Glutamates; D018377:Neurotransmitter Agents; D011956:Receptors, Cell Surface; D015055:1-Carboxyglutamic Acid; D007608:Kainic Acid