The removal of excess glutamate from brain fluids after acute insults such as closed head injury (CHI) and stroke is expected
to prevent excitotoxicity and the ensuing long lasting neurological deficits. Since blood glutamate scavenging accelerates
the removal of excess glutamate from brain into blood and causes neuroprotection, we have evaluated here whether the neuroprotective
properties of pyruvate could be partly accounted to its blood glutamate scavenging activity. The neurological outcome of rats
after CHI improved significantly when treated with intravenous pyruvate (0.9 mmoles/100 g) but not with pyruvate administered
together with glutamate. Pyruvate, at 5 μmole/100 g rat was neither protective not able to decrease blood glutamate but displayed
the latter two properties when combined with 60 μg/100 g of glutamate-pyruvate transaminase. Since the neurological recovery
from CHI was correlated with the decrease of blood glutamate levels, we conclude that pyruvate blood glutamate scavenging
activity contributes to the spectrum of its neuroprotective mechanisms.
Keywords Glutamate - Excitotoxicity - Blood glutamate levels - Blood glutamate scavenging - Oxaloacetate - Pyruvate - Glutamate-pyruvate transaminase - Closed head injury - Stroke - Neuroprotection - Brain to blood glutamate efflux - Neurological outcome - Antioxidant activity - Intravenous injection