In vivo neuroprotective effects of the novel imidazolyl nitrone free-radical scavenger (Z)-alpha-[2-thiazol-2-yl)imidazol-4-yl]-N-tert-butylnitrone (S34176)

The Main Molecular Mechanisms Underlying Methamphetamine- Induced Neurotoxicity and Implications for Pharmacological Treatment

Methamphetamine (METH) is a popular new-type psychostimulant drug with complicated neurotoxicity. In spite of mounting evidence on METH-induced damage of neural cell, the accurate mechanism of toxic effect of the drug on central nervous system (CNS) has not yet been completely deciphered. Besides, effective treatment strategies toward METH neurotoxicity remain scarce and more efficacious drugs are to be developed. In this review, we summarize cellular and molecular bases that might contribute to METH-elicited neurotoxicity, which mainly include oxidative stress, excitotoxicity, and neuroinflammation. We also discuss some drugs that protect neural cells suffering from METH-induced neurotoxic consequences. We hope more in-depth investigations of exact details that how METH produces toxicity in CNS could be carried out in future and the development of new drugs as natural compounds and immunotherapies, including clinic trials, are expected.

Design and synthesis of (4E)-4-(4-substitutedbenzylideneamino)-3-substituted-2,3-dihydro-2-thioxothiazole-5-carbonitrile as novel A2A receptor antagonists

Novel 2-thioxothiazole derivatives (6-19) as potential adenosine A2A receptor (A2AR) antagonists were synthesized. The strong interaction of the compounds (6-19) with A2AR in docking study was confirmed by high binding affinity with human A2AR expressed in HEK293T cells using radioligand-binding assay. The compound 19 demonstrated very high selectivity for A2AR as compared to standard A2AR antagonist SCH58261. Decrease in A2AR-coupled release of endogenous cAMP in treated HEK293T cells demonstrated in vitro A2AR antagonist potential of the compound 19. Attenuation in haloperidol-induced impairment (catalepsy) in Swiss albino male mice pre-treated with compound 19 is evocative to explore its prospective in therapy of PD.

Radical trapping properties of imidazolyl nitrones

The ability of ten imidazolyl nitrones to directly scavenge free radicals (R(*)) generated in polar ((*)OH, O(*)(2)(-), SO(*)(3)(-) cysteinyl, (*)CH(3)) or in apolar (CH(3)-(*)CH-CH(3)) media has been studied. When oxygen or sulfur-centered radicals are generated in polar media, EPR spectra are not or weakly observed with simple spectral features. Strong line intensities and more complicated spectra are observed with the isopropyl radical generated in an apolar medium. Intermediate results are obtained with (*)CH(3) generated in a polar medium. EPR demonstrates the ability of these nitrones to trap radicals to the nitrone C(alpha) atom (alpha radical adduct) and to the imidazol C(5) atom (5-radical adduct). Beside the nucleophilic addition of the radical to the C(alpha) atom, the EPR studies suggest a two-step mechanism for the overall reaction of R(*) attacking the imidazol core. The two steps seem to occur very fast with the (*)OH radical obtained in a polar medium and slower with the isopropyl radical prepared in benzene. In conclusion, imidazolyl nitrones present a high capacity to trap and stabilize carbon-centered radicals.

Interactions between methamphetamine and environmental stress: role of oxidative stress, glutamate and mitochondrial dysfunction

AIMS

Methamphetamine is an amphetamine derivative that is abused increasingly world-wide at an alarming rate over the last decade. Pre-clinical and human studies have shown that methamphetamine is neurotoxic to brain dopamine and serotonin. Other lines of study indicate that stress enhances the vulnerability to drug abuse. The purpose of this review is to shed light on the biochemical similarities between methamphetamine and stress in an effort to highlight the possibility that prior exposure to stress may interact with methamphetamine to exacerbate neurotoxicity.

METHODS

A review of the literature on methamphetamine and stress was conducted that focused on the common neurotoxic and biochemical consequences of methamphetamine administration and stress exposure.

RESULTS

Experimental findings of a large number of studies suggest that there are parallels between stress and methamphetamine with regard to their ability to increase glutamate release, produce a metabolic compromise and cause oxidative damage.

CONCLUSION

A combination of methamphetamine administration and stress can act synergistically and/or additively to cause or augment toxicity in brain regions such as striatum and hippocampus.