title: L-tyrosine administration increases acetylcholinesterase activity in rats.
abstract: Tyrosinemia is a rare genetic disease caused by mutations on genes that codify enzymes responsible for tyrosine metabolism. Considering that tyrosinemics patients usually present symptoms associated with central nervous system alterations that ranges from slight decreases in intelligence to severe mental retardation, we decided to investigate whether acute and chronic administration of L-tyrosine in rats would affect acetylcholinesterase mRNA expression and enzymatic activity during their development. In our acute protocol, Wistar rats (10 and 30 days old) were killed one hour after a single intraperitoneal L-tyrosine injection (500 mg/kg) or saline. Chronic administration consisted of L-tyrosine (500 mg/kg) or saline injections 12 h apart for 24 days in Wistar rats (7 days old) and rats were killed 12 h after last injection. Acetylcholinesterase activity was measured by Ellman's method and acetylcholinesterase expression was carried out by a semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) assay. We observed that acute (10 and 30 days old rats) and chronic L-tyrosine administration increased acetylcholinesterase activity in serum and all tested brain areas (hippocampus, striatum and cerebral cortex) when compared to control group. Moreover, there was a significant decrease in mRNA levels of acetylcholinesterase in hippocampus was observed after acute protocol (10 and 30 days old rats) and in striatum after chronic protocol. In case these alterations also occur in the brain of the patients, our results may explain, at least in part, the neurological sequelae associated with high plasma concentrations of tyrosine seen in patients affected by tyrosinemia type II.
authors.affiliation: Laboratório de Bioenergética, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil.
authors.forename: Gabriela K
authors.initials: GK
authors.lastname: Ferreira
authors.forename: Milena
authors.initials: M
authors.lastname: Carvalho-Silva
authors.forename: Cinara L
authors.initials: CL
authors.lastname: Gonçalves
authors.forename: Júlia S
authors.initials: JS
authors.lastname: Vieira
authors.forename: Giselli
authors.initials: G
authors.lastname: Scaini
authors.forename: Fernando V
authors.initials: FV
authors.lastname: Ghedim
authors.forename: Pedro F
authors.initials: PF
authors.lastname: Deroza
authors.forename: Alexandra I
authors.initials: AI
authors.lastname: Zugno
authors.forename: Talita C B
authors.initials: TC
authors.lastname: Pereira
authors.forename: Giovanna M T
authors.initials: GM
authors.lastname: Oliveira
authors.forename: Luiza W
authors.initials: LW
authors.lastname: Kist
authors.forename: Maurício R
authors.initials: MR
authors.lastname: Bogo
authors.forename: Patrícia F
authors.initials: PF
authors.lastname: Schuck
authors.forename: Gustavo C
authors.initials: GC
authors.lastname: Ferreira
authors.forename: Emilio L
authors.initials: EL
authors.lastname: Streck
mesh_terms: D000110:Acetylcholinesterase / Q000096:biosynthesis* / Q000097:blood / Q000235:genetics; D000818:Animals; D000831:Animals, Newborn; D000833:Animals, Suckling; D001923:Brain Chemistry / Q000187:drug effects; D004195:Disease Models, Animal; D004334:Drug Administration Schedule; D004790:Enzyme Induction / Q000187:drug effects; D058851:GPI-Linked Proteins / Q000096:biosynthesis / Q000097:blood / Q000235:genetics; D007274:Injections, Intraperitoneal; D008297:Male; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014443:Tyrosine / Q000008:administration & dosage / Q000494:pharmacology*; D020176:Tyrosinemias / Q000201:enzymology
chemical_list: D058851:GPI-Linked Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D014443:Tyrosine; D000110:Acetylcholinesterase; C548245:Ache protein, mouse