Motor disturbances and thalamic electrical power of frequency bands' improve by grape seed extract in animal model of Parkinson's disease

Previous studies showed that grape seed extract [GSE] is an excellent natural substance with potent antioxidant effect and free radical scavenger. This study aimed to evaluate the effect of GSE on motor dysfunctions and thalamic local Electroencephalography [EEG] frequency bands' powers in rats with Parkinson's disease [PD]. In this study 8 micro g 6-hydroxydopamine [6-OHDA] dissolved in 2 micro l normal saline containing 0.01% ascorbic acid was infused into right medial forebrain bundle [MFB] to make an animal model of PD. Rats with PD received four weeks GSE [100 mg/kg, p.o.] after apomorphine-induced rotation test. Spontaneous motor tests and also thalamic ventroanterior nucleus [AV] local EEG recording were done in freely moving rats in all groups. Chronic treatment of PD rats with GSE could influence potentially frequency bands' powers of thalamic VA and improve post-lesion motor dysfunctions significantly [p<0.05 and p<0.01, respectively]. Our findings suggest that GSE modulates the CNS function and has beneficial effects on the direct and indirect striato-thalamo-cortical pathways in PD. GSE acts as a new and potent natural free radical scavenger which removes oxidants produced by neurotoxin 6-OHDA in brain. Therefore, it reinforces electrical power of remained thalamic VA neurons and thereby improves post-lesion motor disorders

Effect of dexamethasone on striatal neurotransmissions in the rats subjected to Parkinson's disease animal model

The aim of this study was to evaluate the effects of dexamethasone on striatal dopaminergic, glutamatergic and gamma amino butyric acid [GABA] ergic neurotransmission in normal and parkinsonian rats. Dexamethasone [0.15, 0.30, 0.60 and 0.8 mg/kg] was administered to normal or parkinsonian rats [i.p.] followed by the analysis of the striatal neurotransmitters concentrations. Additionally, the effect of dexamethasone on the damaged Substantian nigra pars compata [SNc] neurons has been investigated. Dexamethasone resulted in decreased level of striatum glutamatergic-GABAergic and enhanced dopaminergic neurotransmission in normal and parkinsonian rats. In addition, acute treatment with dexamethasone did not improve the lesion at all. These findings suggest the new therapeutic mechanism of action for dexamethasone in Parkinson's disease animal model

[Neuroprotective effect of aqueous extract of Berberis vulgaris L. in a model of parkinson's disease in rat]

Parkinson's disease is a neurodegenerative disease of dopaminergic neurons in substancia nigra. Superoxides formation is one of the main etiologies of the disease, and angiotensin converting enzyme inhibitors [ACEIs] are able to suppress superoxide formation. Berberis vulgaris is an ACE inhibitor and considered for this purpose. Male rats [n=32] were divided in 4 groups: Sham, Neurotoxin [injection of 6-hydroxydopamine into left hemisphere SNC], Berberis vulgaris aqueous extract [10 mg/kg] and captopril. Berberis and captopril were injected i.p. 7 days before and 3 days after 6-hydroxydopamine injection. Muscle rigidity, apomorphine test, brain protein oxidation and lipid peroxidation as well as serum and brain ACE activity were assayed in all 4 groups. Rotation test with apomorphine in captopril and Berberis groups were significantly lower than neurotoxin group [p=0.002]. Lipid peroxidation in captopril was significantly lower than neurotoxin [p=0.013]. Captopril and Berberis both inhibited serum ACE activity respectively, but Berberis inhibited brain ACE too. Berberis vulgaris aqueous extract is an ACE inhibitor with anti-parkinsonism effect and should be studied more