Neuroprotective effects of the CTK 01512-2 toxin against neurotoxicity induced by 3-nitropropionic acid in rats.

The mitochondrial inhibitor 3-nitropropionic acid (3-NP) induces excitotoxicity. The authors hypothesized that CTK 01512-2, a recombinant peptide calcium channel N-type blocker, and the TRPA1 antagonist, could show neuroprotective effects. The male Wistar rats received 3-NP [25 mg/kg (i.p.) for 7 days], and a treatment of CTK 01512-2 was delivered intrathecally (i.t.), thrice a week. The neuroprotective effects were evaluated by [18F]FDG MicroPET analysis. The CTK 01512-2 toxin was able to reestablish similar glucose uptakes on the control animals. To detect the neurobehavioral effects from 3-NP, three protocols (6.25, 12.5, 18.75 mg/kg of 3-NP (i.p.), for 3, 4, and 6 days, respectively) were evaluated by performance tests (open field test, walk footprint, elevated plus-maze, Y-maze, and the object recognition test). Important disabilities in the gait of the rats were seen, as well as memory deficits, and anxious behavior in the animals that were treated with all 3-NP protocols. The dose of 18.75 mg/kg (for 3 days) showed the most pronounced behavioral effects and lethality, while the rats treated with 12.5 mg/kg (for 4 days) showed behavioral effects similar to the 6.25 mg/kg dose (for 6 days). The third protocol was then repeated and the rats were treated with the CTK 01512-2 toxin to be evaluated behaviorally again. The recombinant peptide prevented all of the gait-evaluated parameters that were induced by 3-NP at a 6.25 mg/kg dose, which displayed an improvement in the exploratory activities. Overall, these results have reinforced the positive effects of CTK 01512-2 against the behavioral changes that were induced by the mitochondrial inhibitor 3-NP.

Application of the UV-vis spectrophotometry method for the determination of glutamate in the cerebrospinal fluid of rats.

In experimental nociception models, there is an increase in the glutamate cerebrospinal fluid (CSF) and a decrease in its levels in analgesic treatments. For the determination of glutamate in CSF, an analytical UV spectrophotometric method was developed and validated. The measurements on the UV-vis spectrophotometer were performed after the derivatization reaction of the neurotransmitter, when reading in the ultraviolet (UV) region, at the maximum absorption wavelength of 265 nm. The technique presented excellent linearity, as well as good intraday and interday precision, with coefficients of variation less than 15 %, and a correlation coefficient close to 1.0 (lower dispersion of the experimental set points and lower uncertainty of the estimated regression coefficients). The analytical conditions that were established by the ultraviolet spectrophotometric method demonstrated selectivity, linearity, precision, specificity, robustness, and accuracy. This is suitable for the quantitative determination of glutamate in the CSF. The technique developed by UV-vis spectrophotometry for glutamate dosing was fast, efficient, easy to perform, and more economically accessible when compared to current standard techniques. When comparing the data obtained in this study with the results of the official methodology, in which HPLC and spectrofluorimetry were used, it was observed that the closest values of glutamate release occurred between the spectrofluorimeter and the UV-vis spectrophotometer. The UV-vis spectrophotometry method for the determination of CSF glutamate has been shown to be accurate, reproducible, and satisfactory, making it an extremely advantageous and a viable alternative for the determination of amino acid glutamate.