The Effect of Neurotoxin MPTP and Neuroprotector Isatin on the Profile of Ubiquitinated Brain Mitochondrial Proteins.

Mitochondria are a crucial target for the actions of neurotoxins, causing symptoms of Parkinson's disease in various experimental animal models, and also neuroprotectors. There is evidence that mitochondrial dysfunction induced by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) influences functioning of the ubiquitin-proteasomal system (UPS) responsible for selective proteolytic degradation of proteins from various intracellular compartments (including mitochondria) and neuroprotective effects of certain anti-Parkisonian agents (monoamine oxidase inhibitors) may be associated with their effects on the UPS. In this study, we have investigated the effect of the neurotoxin MPTP and neuroprotector isatin, and their combination on the profile of ubiquitinated brain mitochondrial proteins. The development of movement disorders induced by MPTP administration caused dramatic changes in the profile of ubiquitinated proteins associated with mitochondria. Pretreatment with the neuroprotector isatin decreased manifestations of MPTP-induced Parkinsonism, and had a significant impact on the profile of ubiquitinated mitochondrial proteins (including oxidative modified proteins). Administration of isatin alone to intact mice also influenced the profile of ubiquitinated mitochondrial proteins, and increased the proportion of oxidized proteins carrying the ubiquitination signature. These alterations in the ubiquitination of mitochondrial proteins observed within 2 h after administration of MPTP and isatin obviously reflect immediate short-term biological responses to these treatments.

Evolution of anti-parkinsonian activity of monoterpenoid (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol in various in vivo models.

It has been found recently that monoterpenoid (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol (Diol) demonstrates high antiparkinsonian activity in some animal models. We carried out an extended study of the antiparkinsonian activity of Diol in a set of relevant animal models. Diol (20mg/kg) exhibited an anticataleptogenic effect in the haloperidol-induced catalepsy model and restored motor activity in animals in the reserpine-induced model of oligokinesia. The ability of Diol singly administered before MPTP injection to reduce rigidity comparable to that of activity of L-DOPA (100mg/kg) was found using the model of Parkinsonian syndrome (PS) induced by single injection of MPTP (30mg/kg) to C57BL/6 mice. In the model of PS induced by subchronic administration of MPTP (4 × 20mg/kg), Diol at a dose of 20mg/kg reduced rigidity with effectiveness comparable to that of L-DOPA, while being superior to L-DOPA in terms of its effect on motor activity. It was found using the model of PS induced by systemic administration of rotenone that subchronic daily oral administration of Diol prior to rotenone injection reduced severity of PS in rats. Assessment of the effects of chronic administration of Diol (20mg/kg) and L-DOPA to animals with 6-OHDA-induced PS showed that administration of Diol alleviated the symptoms of sensorimotor deficit in right limbs in rats. Thus, the potent antiparkinsonian activity of Diol was demonstrated in all the used rodent models experiments. Diol (20mg/kg) is as effective as the comparator agent L-DOPA administered at doses of 50-100mg/kg.

The effect of short-term administration of (-)-deprenyl and isatin on the expressions of some genes in the mouse brain cortex.

BACKGROUND: Isatin (indoledione 2,3) is an endogenous indole found in the mammalian brain, peripheral tissues, and body fluids. It exhibits many neurophysiological and neuropharmacological effects. It shares some common molecular targets with (-)-deprenyl, a neuroprotective pharmacological drug. Some isatin effects imply a possible influence of gene expression; however, no isatin-responsive genes have yet been identified. MATERIAL/METHODS: In this study the effects of a three-week administration of isatin (20 mg/kg) or (-)-deprenyl (1 mg/kg) on the expressions of several putative isatin/deprenyl-responsive genes in the mouse cortex were compared using real-time PCR. RESULTS: Both treatments caused similarly significant decreases in superoxide dismutase (SOD) mRNA. Treatment of mice with either drug decreased glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA, although only in the deprenyl-treated mice was this significant (p<0.01). No significant changes were found in cortex mRNA content of monoamine oxidase A or monoamine oxidase B. CONCLUSIONS: The results suggest that isatin and (-)-deprenyl have some common target genes and this supports the idea that isatin may be an endogenous partial functional agonist of (-)-deprenyl. Since GAPDH mRNA expression is sensitive to the pharmacological treatments, these results also question the applicability of GAPDH as a reference gene in gene expression studies.