L-pyroglutamic acid protects rat cortical neurons against sodium glutamate-induced injury.
OBJECTIVE
To evaluate the effects of L-pyroglutamic acid (L-PGA, L-5-oxo-2-pyrrolidinecaroxylic acid) on sodium glutamate-induced neurotoxicity in rat cortical neurons.


METHODS
In primary cortical cultures from 16-d-old fetal rat, neuronal viability and contents of nitrite in the bathing medium after transient exposure to sodium glutamate (Glu) were measured; with Fura 2-AM as an intracellular calcium indicator, AR-CM-MIC cation measurement system was used to examine cytosolic free calcium ([Ca2+]i).


RESULTS
L-PGA 10-80 mumol.L-1, inhibited Glu (500 mumol.L-1)-induced neuronal loss in a concentration-dependent manner with IC50 value of (41 +/- 9) mumol.L-1 (95% confidence limits: 30.3-54.7 mumol.L-1). L-PGA also attenuated Glu-induced NO release. L-PGA 1, 3, 10, 30, and 100 mumol.L-1 depressed Glu-caused [Ca2+]i elevation by 20.5%, 34.4%, 47.7%, 70.6%, and 80.4%, respectively.


CONCLUSIONS
L-PGA protects cortical neurons against Glu-induced neurotoxity which may be related to inhibition of NO formation or suppression of the rise in [Ca2+]i.
Xiao
X Q
XQ
Department of Pharmacology, China Pharmaceutical University, Nanjing.
Liu
G Q
GQ
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D005333:Fetus; D009474:Neurons / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism; D011761:Pyrrolidonecarboxylic Acid / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012970:Sodium Glutamate / Q000037:antagonists & inhibitors*
D018696:Neuroprotective Agents; D009569:Nitric Oxide; D002118:Calcium; D011761:Pyrrolidonecarboxylic Acid; D012970:Sodium Glutamate