title: Interference of ethanol and methylmercury in the developing central nervous system.
abstract: Studies involving alcohol and its interactions with other neurotoxicants represent the focus of several works of research due to the fact that the use of alcohol can sometimes leads to serious health problems. Fetal exposure to alcohol and mercury has a high incidence in some regions of Brazil, where there are pregnant women who are alcoholics and live in mining areas. This work was conducted to examine the effects of combined exposure to ethanol (EtOH) and methylmercury (MeHg) in rats during the development of the central nervous system (CNS). Experimental behavioral animal models/tests were used in order to examine locomotion, anxiety, depression and memory. Pregnant rats received tap water or EtOH 22.5% w/v (6.5 g/kg per day), by gavage) during pregnancy and breast-feeding. On the 15th day of pregnancy, some groups received 8 mg/kg of MeHg (by gavage). The groups were as follows: control, EtOH, MeHg and EtOH+MeHg. The experimental results showed that the EtOH, MeHg and EtOH+MeHg groups reduced the percentage of frequency and time spent in the open arms entries of the elevated plus-maze (EPM) test, when compared to the control group. This result suggests an anxiogenic behavioral response. The MeHg group increased locomotor activity in the arena and the immobility time in the forced swimming test, suggestive of depression-like behavior. The EtOH+MeHg group showed greater reductions in the percentages of frequency and time spent in the open arms entries in the EPM test, suggesting a sedative-behavior since the frequency of enclosed arm entries was affected. In the inhibitory avoidance task, the EtOH+MeHg group reduced the latency of the step-down response onto the grid floor, suggesting a cognitive and behavior dysfunctions. Taken together, the results suggest that EtOH and/or MeHg intoxication during the developing CNS may be a risk for deficits related to locomotor impairment, anxiety, depression and neurocognitive functions. There is a possibility that EtOH may prevent some of the MeHg responses, but the precise mechanism of action involved in this process needs to be considered for future research.
authors.affiliation: Faculdade de Ciências da Saúde, Curso de Ciências Farmacêuticas, Universidade de Brasília, Distrito Federal 70910-900, Brazil. crismaia@unb.br
authors.forename: Cristiane do Socorro Ferraz
authors.initials: CS
authors.lastname: Maia
authors.forename: Greice Maria Rodrigues de Souza
authors.initials: GM
authors.lastname: Lucena
authors.forename: Pollyanna Barbosa Farias
authors.initials: PB
authors.lastname: Corrêa
authors.forename: Raphael Borges
authors.initials: RB
authors.lastname: Serra
authors.forename: Robson Willian de Melo
authors.initials: RW
authors.lastname: Matos
authors.forename: Flávia da Cunha
authors.initials: FC
authors.lastname: Menezes
authors.forename: Setsuko Noro dos
authors.initials: SN
authors.lastname: Santos
authors.forename: João Batista de
authors.initials: JB
authors.lastname: Sousa
authors.forename: Edmar Tavares da
authors.initials: ET
authors.lastname: Costa
authors.forename: Vania Maria Moraes
authors.initials: VM
authors.lastname: Ferreira
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D002490:Central Nervous System / Q000187:drug effects* / Q000196:embryology*; D004347:Drug Interactions; D000431:Ethanol / Q000008:administration & dosage / Q000633:toxicity*; D005260:Female; D008297:Male; D008431:Maternal-Fetal Exchange; D018782:Maze Learning / Q000187:drug effects; D008767:Methylmercury Compounds / Q000008:administration & dosage / Q000032:analysis / Q000633:toxicity*; D009043:Motor Activity / Q000187:drug effects; D011247:Pregnancy; D011270:Pregnancy, Animal; D051381:Rats; D013550:Swimming
chemical_list: D008767:Methylmercury Compounds; D000431:Ethanol; C004925:methylmercuric chloride