Objective To investigate the role of externally regulated kinase (ERK) in a rat model of levodopa-induced motor complications. Methods The hemi-parkinsonian rat model was produced by injecting stereotaxically 6-OHDA to right medial forebrain bundle(MFB). First, rats were intraperitoneally treated with levodopa (50 mg/kg with benserazide 12.5 mg/kg, twice daily) for 22 days. On day 23, rats were treated with ERK inhibitor, PD98059 before levodopa administration. Rotational duration and peak rotation were estimated. After sacrificed, ERK1/2 phosphorylation was observed by Western blot. Results Our study showed that chronic treatment of lesioned rats with levodopa markedly upregulated the ERK1/2 phosphorylation of in lesioned striatum(155.6%±6.5%). PD98059 could reduce hyperphosphorylation of ERK1/2(85.4%±5.6%). Meanwhile, PD98059 reversed both the shortened rotational duration and increased peak rotation induced by chronic levodopa treatment. Moreover, PKC inhibitor could partly downregulated the ERK1/2 phosphorylation(101.2%±6.2%, compared with levodopa+vehide, t=3.2, P<0.05). Conclusions These results indicated that the development of motor complications could be associated with activation of ERK pathway. And more, activation of ERK was partly dependent on PKC. Pharmaceuticals which act to inhibit ERK pathway may be useful in the treatment of parkinsonism related motor complications.

Objective To examine the caregivers' burden and quality of life (QOL) of main caregivers of patients with Parkinson's disease by analyzing caregiver and patient-related factors. Methods A total of 53 cases with Parkinson's disease seen from October 2012 to December 2013 in Yantaishan hospital of Yantai City were selected. Assessments: (a) EuroQol-5 questionnaires, including: EQ-5 dimensions (EQ -5d) and visual analogue scale (VAS). (b) Unified Parkinson's Disease Rating Scale. (c) Hoehn-Yahr(H-Y) stage; (d) Parkinson's disease sleep scale (PDSS), 15 items; (e) Hamilton Anxiety Rating Scale (HAMD-14), Hamilton Depression Rating Scale (HAMA-24); (f) Chinese version of Zarit caregiver burden interview. Results Spearman correlation analysis showed that the EQ-5D index and EQ-VAS negatively correlated with HAMD-14 of caregivers of Parkinson diseasepatients (r=- 0.318, - 0.046) (P<0.05), and negatively correlated with H-Y staging (r=-0.592, -0.531), UPDRSI (r=-0.434, -0.316) , UPDRS Ⅱ (r=0.521, 0.513) , UPDRS Ⅲ (r=0.520, 0.534), UPDRS Ⅳ (r=0.564, 0.509), PDSS in patients with Parkinson's disease (r=0.547, 0.490), HAMD-14 (r=0.315, 0.350), HAMA-24 (r=0.413, 0.401) of Parkinson's disease patients (P<0.05). Caregiver burden was related with HAMD-14 (r=0.496), HAMA-24 (r=0.551),H-Y stage (r=0.697), PDSS (r=0.659), UPDRS Ⅰ-Ⅳ (r=0.538, 0.668, 0.696, 0.600), EQ-5D index of Parkinson disease patients (r=0.682), EQ-VAS of Parkinson disease patients (r=0.670) (P<0.05); and positively related with anxiety of caregivers (r=0.275) , and a negative correlation with the caregivers' quality of lives (r=0.665) (P<0.05). Bivariate analyses showed significant correlations between caregiver burden and patients' sleep, scores of Parkinson's motor symptoms, and caregivers' depression. Based on multiple regression analysis, Zarit score proved to be the main predictor of caregivers' QOL. Caregivers' age, total numbers of caregivers and H-Y stage also proved to be a relevant factor. Conclusion Improvement of patient's sleep, motor symptoms anddepression might alleviate caregivers' strain. There is a correlation between caregivers' burden and QOL. QOL of caregivers can be improved through reducing their care-burden.

Objective To explore the relationship between motor complications of Parkinson's disease(PD)with chronic L-dopa treatment and striatal phosphorylated GluR1Ser845.Methods The hemi-parkinsonian rat model was produced by injecting stereotaxically 6-OHDA to right medial forebrain bundle(MFB).Then the hemi-parkinsonian rat was treated intraperitoneally with L-dopa methylester(25 mg?kg-1?d-1,twice one day)for 22 days and rotational duration and frequency of off period were respectively estimated.After they were sacrificed,their subcellualr distribution of GluR1 and GluR1Ser845 phosphorylation was observed with immunofluorescence and Western blot.Results After the chronic treatment with L-dopa methylester,PD rats displayed shortened rotational duration and increased frequency of off period,which was similar to fluctuations of the symptoms and on-off phenomenon in PD patients.In the lesioned striatum of PD rats,the amount of GluR1 and phosphorylated GluR1Ser845 in striatal membrane was reduced to 73.0%?4.8% and 42.0%?5.6%,respectively,compared with those non-lesioned.After chronic treatment of PD rats with L-dopa,the amount of GluR1 and phosphorylated GluR1Ser845 in striatal membranes were increased to 104.0%?5.5% and 112.0%?3.4%.These unique changes occurred only in parvalbumin-positive interneurons.Conclusions These findings suggest that subcellular distribution and phosphorylation state of GluR1Ser845 in parvalbumin-positive interneurons may play a significant role in the pathogenesis of motor complications of chronic L-dopa treatment for PD.

Objective To investigate cellular and behavioral effects of adenosine A2A receptor antagonist in a rat model of levodopa-induced motor complications.Methods The hemi-parkinsonian rat model was produced by stereotaxically injecting 6-OHDA to right medial forebmin bundle(MFB).Animals were intraperitoneally treated with levodopa 50 mg/kg plus benserazide 12.5 mg/kg twice a day for 22 days levodopa + vehicle.Rotational duration was estimated.After they were sacrificed,the expression of adenosine A2A receptor was observed by immunohistochemistry and Western blot.Results CSC,reversing the shortened rotational duration induced by levodopa,prolonged the rotational duration.This effect was maintained fil the end of the treatment.The chronic levedopa treatment induced an upregulation of adenosine A2A receptor expression in the lesioned striatum (IOD,(11.55±2.75)×104).The subsequent CSC treatment decreased the adenosine A2A receptor expression to the level of control (IOD,(6.02±1.29)× 104) and PD group (IOD,(5.60±1.83)×104>,F=33.31,P<0.05).Conclusion These results suggest that adenosine A2A receptor is probably involved in the development of levodopa induced motor complications and adenosine A2A receptor antagonist could be useful in the treatment of motor comphcations in parkinsonian patients.

Objective To investigate the alteration of phosphorylated GluR1Ser831 and behavioural effects in a rat model of levodopa-induced motor complications after Ca2 +/calmodulin-dependent protein kinase Ⅱ (CaMKⅡ) inhibitor KN-93 treatment. Methods The hemi-parkinsonian rat model was produced by injecting stereotaxically 6-OHDA to right medial forebrain bundle. Then, rats were intraperitoneally treated with levodopa ( 50 mg/kg with benserazide 12.5 mg/kg,twice daily) for 22 days. On day 23 ,rats received KN-93 before levodopa administration. Rotational duration was estimated. After sacrificed, subcellualr distribution of GluR1 and phosphorylated GluR1Ser831 were observed by western blot. Results The study showed that CaMKⅡ inhibitor KN-93 prolonged rotational duration. Moreover, KN-93 could regulate subcellular distribution of GluR1 and reduce hyperphosphorylation of GluR1 Ser831, which was closely associated with levodopa-induced motor complications. The expression of membrane GluR1 and phosphorylated GluR1Ser831 was (83.4 ±4.2)% and (47.2 ±5.2)% ,respectively. Conclusions These results indicated that activation of CaMKⅡ contributed to development of motor complications, through a mechanism that involved an increase in phosphorylated GluR1 Ser831. Pharmaceuticals which act to inhibit CaMKⅡ may be useful in the treatment of the motor complications in parkinsonian patients.

ObjectiveTo investigate the role of N-methyl-D-aspartate receptor subunit 2B (NR2B) antagonist CP-101.606 in behaviour and expression of related signal proteins in a rat model of levodopa-induced motor complications.MethodsThe hemi-parkinsonian rat model was produced by injecting stereotaxically 6-OHDA to right medial forebrain bundle.Then,rats were intraperitoneally treated with levodopa (50 mg/kg with benserazide 12.5 mg/kg,twice daily) for 22 days.On 23th day,rats received CP-101.606 before levodopa administration.Rotational duration was estimated.After sacrificed,phosphorylated NR2B and Ca2+/calmodulin-dependent protein kinase Ⅱ (CaMKⅡ) and glutamate receptor 1 ( GluR1S831 ) were observed by western blot.ResultsThe results showed that NR2B antagonist CP-101.606 reversed the levodopa-induced shortened rotational duration.Chronic levodopa treatment increased abundance of the phosphorylated NR2B and downstream related signal proteins CaMKⅡ and GluR1S831 to (145.3±6.5)％ and (132.5±5.7)％ and (105.6±6.3)％,respectively.Moreover,CP-101.606 could reduce hyperphosphorylation of NR2B and CaMKⅡ and GluR1 S831 to (102 ± 4.9 )％,(98.4±3.9)％ and (49.5 ± 4.2 )％,respectively.ConclusionsThese results indicate that the enhancement of N-methyl-D-aspartate (NMDA) receptor function mediated by NR2B phosphorylation contribute to development of motor complications,through a mechanism that involved the downstream signal mediators of NMDA receptor overactivation.Pharmaceuticals which act to inhibit NR2B may be useful in the treatment of the motor complications in parkinsonian patients.

BACKGROUND:Pathogenesis of Parkinson’s disease is not completely understood, and there is yet no effective therapy that can prevent the neurodegenerative process of the disease fundamentaly. OBJECTIVE:To explore the effects of pituitary adenylate cyclase-activating polypeptide (PACAP) on lactacystin-induced Parkinson’s disease dopaminergic PC12 cel apoptosis and its molecular mechanism. METHODS: Under induction by nerve growth factors, PC12 cels differentiated into dopaminergic neurons, and then were treated with different concentrations of lactacystin for different time. When the cel survival rate was about 50%,the concentration and action time oflactacystin were selected to establish cel models of Parkinson’s disease. In the study, there were control group, lactacystin group, PACAP1-27 group (intervention group 1) and PACAP1-27+PACAP6-27 co-intervention group (intervention group 2). Changes of cel morphology were observed under inverted microscope; cel viability was detected with MTT method; the expression of endoplasmic reticulum stress specific protein caspase-12 was detected by western blot. Then the action of PACAP1-27 and PACAP6-27 to the cytoxicity of lactacystin was observed. RESULTS AND CONCLUSION: With different concentrations and action time of lactacystin, the viability of PC12 cels presented a concentration- and time-dependent decline. When the lactacystin at 20μmol/L acted for 24 hours, the cel viability was declined by about 50%. Under same conditions of lactacystin concentration and action time (20 μmol/L, 24 hours), the cels in the lactacystin group appeared to have damaged changes, declined cel viability, and increased caspase-12 activity in comparison with the control group (P< 0.01). Compared with the lactacystin group, the cel damage was relieved and cel viability was increased significantly in the intervention group 1 as wel as the expression of caspase-12 was decreased (P < 0.01). Experimental findings in the intervention group 2 were similar to those in the lactacystin group. These results suggest that lactacystin, an ubiquitin proteasome inhibitor, can lead to cel damage; PACAP1-27 plays a protective role by regulating the above-mentioned signal pathway. As one PACAP1-27 receptor antagonist, PACAP6-27 can attenuate this effect of PACAP1-27.

Objective To study the association between serum homocysteine (Hcy) level and cognitive impairment in PD patients.Methods Eighty-one PD patients admitted to our hospital were divided into normal cognition group (n=25),mild cognitive impairment group (n=32) and dementia group (n=24) with 19 healthy persons undergoing physical examination served as a control group.Their cognitive impairment was assessed according to their medical history,detailed physical examination data,Hoehn-Yahr scale score,MMSE score,and CDR score.Their serum levels of Hcy,folic acid and vitamin B12 were measured.The association of serum Hcy,folic acid and vitamin B12 levels with cognitive impairment was analyzed.Results The serum Hcy level was significantly higher in normal cognition group,mild cognitive impairment group and dementia group than in control group (P＜0.05,P＜0.01) and in dementia group than in normal cognition group (14.8±3.9 μmol/L vs 12.5±3.3 μmol/L,P＜0.05).The serum Hcy level was associated with oral levodopa and oral benserazide daily dose,oral levodopa and oral benserazide taking time,course of PD and age (r=0.298,P=0.000;r=0.280,P=0.000;r=0.301,P=0.000;r=0.184,P=0.019) but not associated with the severity of PD.Conclusion High serum Hcy level is one of the risk factors for cognitive impairment in PD patients,and control of oral levodopa dose contributes to the prevention and treatment of dementia in PD patients.