Monosodium glutamate neonatal treatment as a seizure and excitotoxic model.
Monosodium glutamate (MSG) subcutaneously administrated to neonatal rats induces several neurochemical alterations in the brain, which have been associated with an excitotoxic process triggered by an over activation of glutamate receptors; however there are few systematic studies about initial changes in intracerebroventricular (i.c.v.) Glu levels produced by MSG in the brain. Thus, to characterize these changes, rat pups were injected with a MSG solution at 1, 3, 5 and 7 postnatal days (PD), and i.c.v. Glu levels and hippocampal total content of related amino acids (Asp, Glu, Gln, Gly, Tau, Ala and GABA) were estimated before, immediately and after each injection. Behavioral and EEG responses were also monitored after MSG administrations. Significant rise in i.c.v. Glu levels were found, mainly in response to the first and second injection. Moreover, the total content of all amino acids evaluated also increased during the first hour after the first MSG administration but only Glu and GABA remained elevated after 24 h. These biochemical modifications were accompanied with behavioral alterations characterized by: screeching, tail stiffness, head nodding, emprosthotonic flexion episodes and generalized tonic-clonic convulsions, which were associated with electroencephalographic pattern alterations. Altered behavior found in animals treated with MSG suggests an initial seizure situation. Although four MSG administrations were used, the most relevant findings were observed after the first and second administrations at PD1 and PD3, suggesting that only two MSG injections could be sufficient to resemble a seizure and/or excitotoxic model.
López-Pérez
Silvia Josefina
SJ
Departamento de Biología Celular y Molecular, Centro Universitario de Ciencias Biológicas y Agropecuarias, Universidad de Guadalajara, Jalisco, Mexico. tmx36722245@prodigy.net.mx
Ureña-Guerrero
Mónica Elisa
ME
Morales-Villagrán
Alberto
A
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D015374:Biosensing Techniques; D002552:Cerebral Ventricles / Q000187:drug effects / Q000378:metabolism; D004195:Disease Models, Animal; D004569:Electroencephalography; D018698:Glutamic Acid / Q000134:cerebrospinal fluid / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000503:physiopathology; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009498:Neurotoxins / Q000633:toxicity*; D051381:Rats; D017208:Rats, Wistar; D012640:Seizures / Q000139:chemically induced* / Q000503:physiopathology; D012970:Sodium Glutamate / Q000633:toxicity*; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D000596:Amino Acids; D009498:Neurotoxins; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D012970:Sodium Glutamate