Efeito da ingestão de café sobre a liberação de glutamato sinaptossomal, estimulda por toxina escorpiônica, em ratos

Abstract

The goal of the present work is, therefore, to evaluate coffee intake effect on the glutamatergic system stimulated by tityustoxin gamma (TiTX-g), from escorpion venom Tityus serrulatus, in rats. Six groups of Wistar rats were utilized: WNG (Wellnourished control group) received rat lab chow diet, enriched with dog food; WCOF (Wellnourished group coffee) fed WNG diet, supplemented with aqueous coffee extract; MNG (Malnourished group) fed 60% of the amount given to WNG; MCOF (Malnourished coffee) fed 60% of the amount given to WCOF; MREC (Malnourished group feed recovered) fed as MNG up to 60 days of life and thereafter fed ad libitum; MRECOF (Malnourished group coffee and feed recovered) fed as MREC supplemented with aqueous coffee extract. The animals were decapitated at 120 days of life and the cortical synaptosomal fraction was prepared. Glutamate released was evaluated by fluorimetric method and the synaptosomes were incubated in Krebs-Ringer-Hepes medium containing 0.05ìM tityustoxin gamma. The model of food restriction promoted a decrease in body weight (in g ± SEM): WNG = 463.5 ± 12.7, WCOF = 429.0 ± 11.5, MNG = 294.8 ± 4.9,MCOF = 293.3 ± 5.1, MREC = 397.7 ± 9.1 and MRECOF = 398.5 ± 9.2 (P<0,05). Glutamate released after stimulus by the toxin was significantly less in the malnourished and feed recovered malnourished groups compared to wellnourished control (nmol/mg protein ± SEM): WNG = 3.11 ± 0.55, WCOF = 1.99±0.27, MNG = 1.69 ± 0.24, MCOF = 2.07 ± 0.64, MREC = 1.96 ± 0.36 e MRECOF = 1.44 ± 0.10 (P<0,05). It was concludedthat neonatal malnutrition decreased irreversibly glutamate release from synaptosomes after scorpion toxin stimulus and that coffee presented similar effects, indicating probable modulation in the central nervous system.