sitagliptin-phosphate and Parkinsonian-Disorders

L-dopa is still considered as the gold standard therapy for Parkinson's disease (PD); however, L-dopa-induced dyskinesia (LID) is a serious complication of long-term L-dopa treatment. The present study investigated the therapeutic potential of sitagliptin and liraglutide in comparisons with L-dopa against PD. In addition, their capacity to modulate L-dopa dose and/or side effects was investigated, too. Rats were injected with rotenone (3 mg/kg/day, s.c.) for 10 consecutive days to induce the experimental PD. The rotenone-treated rats were administered sitagliptin (30 mg/kg/day, p.o.) and liraglutide (50 μg/kg, s.c.) for 16 days either alone or together with L-dopa/carbidopa (50/25 mg/kg/day, i.p.). Scoring of LID was done on days 2, 4, 8, 12, and 16 in all L-dopa-treated groups. Twenty-four hours after the last administered dose of tested drugs, the behavior of rats in each group was screened by using the open-field test. Sitagliptin and liraglutide revealed marked attenuation of LID scores; in addition, they markedly increased animals' motor performance. Moreover, they preserved substantia nigra pars compacta (SNpc) tyrosine hydroxylase (TH) and vesicular monoamine transporter 2-positive (VMAT2) cells with prominent increase of the striatal dopamine (DA) content. On the other hand, they significantly decreased nigral neuromelanin (NM)-positive cells, activated microglia, gliosis, and other pathological changes. In conclusion, sitagliptin and liraglutide could be a promising therapeutic challenger in PD, modifying L-dopa effect and/or allowing the use of L-dopa with fewer side effects.

Topics: Animals; Antiparkinson Agents; Carbidopa; Corpus Striatum; Dopamine; Drug Combinations; Dyskinesia, Drug-Induced; Levodopa; Liraglutide; Male; Motor Activity; Parkinsonian Disorders; Pars Compacta; Random Allocation; Rats, Wistar; Rotenone; Sitagliptin Phosphate

Parkinson's disease (PD) is a neurodegenerative disease with high morbidity among adults worldwide that causes tremendous trouble to people's lives. The purpose of this study was to investigate the impact of sitagliptin on PD and its potential mechanism.. First, the memory of rats in each group was evaluated with the Morris water maze (MWM) test and the passive avoidance test. Then, both brain-derived neurotrophic factor (BDNF) protein and mRNA levels were detected by ELISA and qPCR assays, respectively. Then, rapid Golgi impregnation was used to observe the density of dendritic spines in the hippocampal CA1 area. Finally, k252a, an antagonist of Trk receptors, was used to block the binding of BDNF with its receptors, and the effects of sitagliptin on PD improvement were detected.. Our study showed that sitagliptin improved memory deficits in PD rats. Meanwhile, the expression level of BDNF and tyrosine hydroxylase (TH) was upregulated, and the density of dendritic spine was increased by sitagliptin administration. Moreover, K252a administration blocked the positive effects of sitagliptin on memory in PD rats.. Sitagliptin rescued the memory deficits, which was achieved by upregulating BDNF to prevent neuronal death and dendritic spine loss. Our findings indicate that sitagliptin might be a promising potential drug for PD treatment in the future.

Topics: Animals; Antiparkinson Agents; Avoidance Learning; Brain-Derived Neurotrophic Factor; Carbazoles; Enzyme Inhibitors; Indole Alkaloids; Male; Maze Learning; Memory Disorders; Neurons; Neuroprotective Agents; Nootropic Agents; Parkinsonian Disorders; Random Allocation; Rats, Wistar; Sitagliptin Phosphate; Tyrosine 3-Monooxygenase; Up-Regulation