Determination of amino acid levels in the rat striatum, after administration of ethanol alone and associated with ketamine, a glutamatergic antagonist.
The main goal of this study was to determine the amino acids (glutamate, aspartate, glutamine and tyrosine) levels in the rat striatum, after ethanol administration alone and/or associated with ketamine. In protocol 1 (Et+ketamine-1), ethanol was administered to male Wistar rats until the 7th day, and at the next day the group received only ketamine (25mg/kg, i.p.) up to the 14th day. In protocol 2 (Et+ketamine-2), ethanol was also administered up to the 7th day, and was associated with ketamine from the 8th up to the 14th day. In other groups, animals were treated daily with ethanol (4 g/kg, p.o.), for 7 or 14 days or ketamine daily for 7 days. Controls were administered with distilled water for 7 days. Results showed that, in protocol 1, aspartate (ASP) levels increased after ketamine administration, as compared to the controls. This effect was inhibited in the group Et+ketamine-1. Ethanol (7 days) increased glutamate (GLU) levels, as compared to control, and this effect did not differ significantly from that observed in the ketamine group. When ketamine was administered after the ethanol withdrawal (protocol 1), no alterations in those amino acid concentrations were seen, as compared to the control and ketamine groups. A tendency for increasing GLU levels was observed, after administration of ethanol (14 days) or ketamine alone or associated (protocol 2), when compared to control values. In protocol 2, TYR levels decreased as related to controls and to the 14-day ethanol-treated group. We can assume that ketamine presents only an antagonist effect, in animals pretreated with ethanol, followed by ketamine administered from the 8th day on. This is due to the fact that NMDA receptors are already sensitized, leading to a decrease in these receptors functions and consequently to ASP and GLU releases.
Vasconcelos
Silvânia Maria Mendes
SM
Department of Physiology and Pharmacology, Federal University of Ceará, Rua Cel. Nunes de Melo 1127, CEP 60431-270, Fortaleza, Brazil. silvania.vasconcelos@yahoo.com.br
Sales
Gabriel Teixeira Montezuma
GT
Lima
Natália Martins
NM
Soares
Paula Matias
PM
Pereira
Elaine Cristina
EC
Fonteles
Marta Maria França
MM
Sousa
Francisca Cléa Florenço de
FC
Viana
Glauce Socorro de Barros
GS
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001479:Basal Ganglia / Q000187:drug effects* / Q000378:metabolism; D002492:Central Nervous System Depressants / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D004347:Drug Interactions; D000431:Ethanol / Q000008:administration & dosage*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D007649:Ketamine / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
D000596:Amino Acids; D002492:Central Nervous System Depressants; D018691:Excitatory Amino Acid Antagonists; D000431:Ethanol; D007649:Ketamine