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.

Tissue accumulation of microplastics in mice and biomarker responses suggest widespread health risks of exposure

“…Previous studies have been demonstrated that MPs exposure could affect AChE in aquatic organisms2545. Here we observed that MPs treatments increased the activity of AChE, which may lead to a reduction of cholinergic neurotransmission efficiency50. Corresponding to a potentially neurotoxic response, MPs exposure also caused increases of threonine, aspartate and taurine in serum.…”

Anti-Alzheimer Activity of Tacrine Loaded Methoxypoly (Ethylene Glycol) Poly (Caprolactone) Nanoparticles

“…In brain activities changes of antioxidant enzymes, glutathione and thiobarbituric acid reactive substances contents in all the experimental groups of rat [28]. In intense organizations of L-tyrosine in 10 and 30-day-old rats indicated expanded AChE action in serum and all assessed cerebrum zones when contrasted with control bunch [29]. The impact of zinc chloride, cadmium acetic acid derivation, mercury chloride, and lead acetic acid derivation was examined.…”

Ecotoxicological Effect of Single and Combined Exposure of Carbamazepine and Cadmium on Female Danio rerio: A Multibiomarker Study

“…Interestingly, the present study showed that AChE activity in zebrafish was enhanced when exposed to combined stress of Cd and CBZ. The increase of AChE activity has been related to the production of free radicals [48] and to the apoptotic processes occurring in the organism [49,50]. AChE activity increase leads to fast acetylcholine degradation and downregulation of acetylcholine receptors, influencing the cognitive functions of the organism [51].…”