A novel selective NMDA agonist, N-phthalamoyl-L-glutamic acid (PhGA).
Ionic currents elicited by N-phthalamoyl-L-glutamic acid (PhGA) were investigated on freshly isolated hippocampal neurons with the whole-cell voltage clamp and concentration clamp techniques. PhGA elicited desensitizing inward currents in Mg(2+)-free salines only in the presence of glycine. The dose-response relationship for PhGA was close to a Langmuir isotherm with Kd = 3.7 mM and saturating level 0.75 of that for L-aspartate (L-Asp). PhGA-activated currents were blocked by Mg2+, D-2-amino-5-phosphonovalerate and kynurenate, and had the same reversal potential as L-Asp-activated currents. Complete cross-desensitization was obtained between the responses to PhGA and L-Asp. We conclude that PhGA is a new selective 'superacidic' agonist of the N-methyl-D-aspartate type of glutamate receptor.
Department of Physico-chemical Biology of Cellular Membranes, Academy of Sciences of the Ukrainian SSR, Kiev.
N I
NI
Kiskin
Tsyndrenko AYa
M A
MA
Dumpis
L B
LB
Piotrovsky
O A
OA
Krishtal
D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D016202:N-Methylaspartate / Q000502:physiology*; D009474:Neurons / Q000378:metabolism; D009994:Osmolar Concentration
D005971:Glutamates; D001224:Aspartic Acid; D018698:Glutamic Acid; C034741:N-phthaloylglutamic acid; D016202:N-Methylaspartate; D008274:Magnesium