Rottlerin protected dopaminergic cell line from cytotoxicity of 6-hydroxydopamine by inhibiting PKCδ phosphorylation

Objective

The present study aims to investigate the role of protein kinase C δ subtype (PKCδ) phosphorylation in the process of 6-hydroxydopamine (6-OHDA)-induced dopaminergic cell death, and demonstrate the molecular basis of neurological disorders, such as Parkinson’s disease.

Methods

The pheochromocytoma (PC12) cell line was employed in the present study. Cells were treated with 2 μmol/L PKCδ inhibitor Rottlerin, 10 nmol/L protein kinase C α subtype (PKCα) inhibitor bisindolylmaleimide I, or 5 nmol/L Gö6976 that could specifically inhibit the calcium-dependent PKC isoforms, respectively. PKCδ activator phorbol-12-myristate-13-acetate (PMA, 100 nmol/L) was also used in this study. All these agents were added to the medium before cells were incubated with 6-OHDA. Cells with no treatment served as control. The cytotoxicity of 6-OHDA was determined by methyl thiazolyl tetrazolium (MTT) reduction assay and PKCδ phosphorylation levels in various groups were measured by western blotting.

Results

Bisindolylmaleimide I and Gö6976 exerted no significant attenuation on the cytotoxicity of 6-OHDA, nor any effects on PKCδ phosphorylation in PC12 cells. However, Rottlerin could inhibit the phosphorylation of PKCδ and attenuate 6-OHDA-induced cell death, and the cell viability was raised to 69.6±2.63% of that in control group (P < 0.05). In contrast, PMA induced a significant increase in PKCδ phosphorylation and also strengthened the cytotoxic effects of 6-OHDA. The cell viability of PMA-treated PC12 cells decreased to 49.8±5.06% of that in control group (P < 0.001).

Conclusion

Rottlerin can protect PC12 cells from cytotoxicity of 6-OHDA probably by inhibiting PKCδ phosphorylation. The results suggest that PKCδ may be a key regulator of neuron loss in Parkinson’s disease.     

The construction of siRNA plasmid targeting mouse HIF-1α and in vitro study of its inhibition effect

Objective

To construct effective RNA-interference plasmids targeting mouse HIF-1α gene and testify their effects and specificities in interfering HIF-1α expression.

Methods

Three RNA-interference plasmids targeting mouse HIF-1α gene, pBS/U6/HIF-1α-siRNAI～III, were constructed and identified using double digestion method in the present study. RT-PCR, immunostaining and western blotting were employed to detect the expression alterations of HIF-1α in 293T cells following transfections of the three plasmids, respectively. The interference effect of pBS/U6/HIF1αi-II in SH-SY5Y cell line was further investigated.

Results

All the three RNA-interference plasmids, especially pBS/U6/HIF1αi-II, showed significant inhibition in HIF-1α expression in 293T cell line. pBS/U6/HIF1αi-II could also inhibit HIF-1α expression in SH-SY5Y cell line, in a dose-dependent way.

Conclusion

Plasmid pBS/U6/HIF1αi-II constructed in our study can effectively and specifically inhibit HIF-1α expression, and its role in neural tube development and dysfunction will be further investigated. Construct of pBS/U6/HIF1αi-II plasmid will provide a useful tool to study the role of HIF-1 pathway in embryogenesis, oncogenesis and ischemia development.     

Aβ31–35-induced neuronal apoptosis is mediated by JNK-dependent extrinsic apoptosis pathway

Objective

To investigate whether JNK-caspase-dependent apoptotic pathway is involved in Aβ_31–35-induced apoptosis of cultured cortical neurons.

Methods

Cultured cortical neurons were treated with Aβ_31–35 (25 µmol/L) for 4 h, 8 h, 16 h and 24 h, respectively. Caspase activities were measured using a spectrophotometer. Levels of c-Jun phosphorylation (p-c-Jun) and Fas ligand (FasL) expression were assessed by immunocytochemistry method and quantified using Image-pro plus11.0 image processing and analysis software.

Results

Treatment with Aβ_31–35 (25 µmol/L) for 24 h induced significant increases in the activities of caspase-3 and caspase-8 in the cortical neurons. Besides, Aβ_31–35 could time-dependently enhance the expression of p-c-Jun protein. Moreover, SP600125 application (100 nmol/L) could completely abolish Aβ_31–35 neurotoxicity. The increase in FasL expression was detected at 8 h, 16 h and 24 h after Aβ_31–35 treatment, and SP600125 (100 nmol/L) significantly inhibited FasL expression.

Conclusion

JNK-c-Jun-FasL-caspase-dependent extrinsic apoptotic pathway plays a critical role in mediating Aβ_31–35-induced apoptosis of cultured neurons.     

TRPC通道阻断剂SKF-96365对蜜蜂毒肽诱发初级感觉细胞内向电流和胞内钙增高的作用(英文)

目的蜜蜂毒肽是蜜蜂粗毒中的主要物质。外周皮下注射蜜蜂毒肽可导致持续性自发痛和痛觉过敏。本研究旨在研究瞬时受体电势C(transient receptor potential canonical,TRPC)通道在蜜蜂毒肽诱致的初级感觉神经元活化中的介导作用。方法运用全细胞膜片钳和激光共聚焦测钙技术,检测TRPC通道抑制剂SKF-96365对蜜蜂毒肽诱致的急性分离大鼠背根神经节细胞胞内钙和内向电流升高的影响。结果电压钳记录的91个背根神经节细胞中,蜜蜂毒肽可诱发43.9%(40/91)的细胞产生内向电流,而不同浓度的SKF-96365(1,5,10μmol/L)均明显抑制了背根神经节细胞的内向电流,且呈剂量相关性。应用激光共聚焦钙成像技术记录的210个背根神经节细胞中,67.6%的细胞对蜜蜂毒肽敏感,产生胞内钙离子浓度的升高,而SKF-96365能抑制这种胞内钙浓度的升高,抑制率为46.5%。结论 SKF-96365能够抑制蜜蜂毒肽引起的背根神经节中小神经元的活化,提示TRPC通道介导了蜜蜂毒肽对初级感觉神经元的激活作用。     

Dose- and time-dependent α-synuclein aggregation induced by ferric iron in SK-N-SH cells

Objective

Intracellular formation of Lewy body (LB) is one of the hallmarks of Parkinson’s disease. The main component of LB is aggregated α-synuclein, present in the substantia nigra where iron accumulation also occurs. The present study was aimed to study the relationship between iron and α-synuclein aggregation.

Methods

SK-N-SH cells were treated with different concentrations of ferric iron for 24 h or 48 h. MTT assay was conducted to determine the cell viability. Thioflavine S staining was used to detect α-synuclein aggregation.

Results

With the increase of iron concentration, the cell viability decreased significantly. At the concentrations of 5 mmol/L and 10 mmol/L, iron induced α-synuclein aggregation more severely than at the concentration of 1 mmol/L. Besides, 48-h treatment-induced aggregation was more severe than that induced by 24-h treatment, at the corresponding iron concentrations.

Conclusion

Ferric iron can induce α-synuclein aggregation, which is toxic to the cells, in a dose- and time-dependent way.     

Lack of association between ADRA2B -4825 gene insertion/deletion polymorphism and migraine in Chinese Han population

Objective

The present study aimed to estimate the association between susceptibility to migraine and the 12-nucleotide insertion/deletion (indel) polymorphism in promoter region of α_2B-adrenergic receptor gene (ADRA2B).

Methods

A case-control study was carried out in Chinese Han population, including 368 cases of migraine and 517 controls. Genomic DNA was extracted from blood samples, and DNA fragments containing the site of polymorphism were amplified by PCR. Data were adjusted for sex, age, migraine history and family history, and analyzed using a logistic regression model.

Results

There was no association between indel polymorphism and migraine, at either the allele or the genotype level.

Conclusion

These findings do not support a functional significance of ADRA2B indel polymorphism at position -4825 relative to the start codon in the far upstream region of the promoter in the present migraine subjects.     

Effects of immune activation on the retrieval of spatial memory

Objective

It has been shown that there are extensive interactions between the central nervous system and the immune system. The present study focused on the effects of lipopolysaccharide (LPS) on memory retrieval, to explore the interaction between immune activation and memory.

Methods

C57BL/6J mice (8 weeks old) were first trained in the Morris water maze to reach asymptotic performance. Then mice were tested 24 h after the last training session and LPS was administered (1.25 mg/kg, i.p.) 4 h prior to the testing. The retrieval of spatial memory was tested by probe trial, and the time spent in the target quadrant and the number of platform location crosses were recorded. ELISA was performed to detect interleukin-1β (IL-1β) protein level in the hippocampus of mice tested in the water maze.

Results

Although LPS induced overt sickness behavior and a significant increase in the level of IL-1β in the hippocampus of mice, there was no significant difference in the time spent in the target quadrant or in the number of platform location crosses between LPS-treated and control groups in the probe trial testing.

Conclusion

Immune activation induced by LPS does not impair the retrieval of spatial memory.     

Comprehensive behavioral phenotyping of calpastatin-knockout mice

Background

In previous work, we investigated dieldrin cytotoxicity and signaling cell death mechanisms in dopaminergic PC12 cells. Dieldrin has been reported to be one of the environmental factors correlated with Parkinson's disease and may selectively destroy dopaminergic neurons.

Methods

Here we further investigated dieldrin toxicity in a dopaminergic neuronal cell model of Parkinson's disease, namely N27 cells, using biochemical, immunochemical, and flow cytometric analyses.

Results

In this study, dieldrin-treated N27 cells underwent a rapid and significant increase in reactive oxygen species followed by cytochrome c release into cytosol. The cytosolic cytochrome c activated caspase-dependent apoptotic pathway and the increased caspase-3 activity was observed following a 3 hr dieldrin exposure in a dose-dependent manner. Furthermore, dieldrin caused the caspase-dependent proteolytic cleavage of protein kinase C delta (PKCδ) into 41 kDa catalytic and 38 kDa regulatory subunits in N27 cells as well as in brain slices. PKCδ plays a critical role in executing the apoptotic process in dieldrin-treated dopaminergic neuronal cells because pretreatment with the PKCδ inhibitor rottlerin, or transfection and over-expression of catalytically inactive PKCδ^K376R, significantly attenuates dieldrin-induced DNA fragmentation and chromatin condensation.

Conclusion

Together, we conclude that caspase-3-dependent proteolytic activation of PKCδ is a critical event in dieldrin-induced apoptotic cell death in dopaminergic neuronal cells.     

Functional expression of P2X7 receptors in non-neuronal cells of rat dorsal root ganglia

The P2X7 receptor is an ATP-sensitive ligand-gated cation channel, expressed predominantly in cells with immune origin. Recent studies have demonstrated that P2X7 may play an important role in pain signaling. In the present study, the expression of P2X7 receptors in non-neuronal cells and neurons isolated from dorsal root ganglia was characterized using patch clamp, pharmacological and confocal microscopy approaches. In small diameter DRG neurons, 100 microM 2', 3'-O-(4-benzoylbenzoyl)-ATP (BzATP) evoked an inward current, which was inhibited completely by 1 microM A-317491, a potent and selective P2X3 receptor antagonist. In contrast, BzATP evoked concentration-dependent increases in inward currents in non-neuronal DRG cells with an EC50 value of 26 +/- 0.14 microM, which were resistant to the blockade by A-317491. The activity to evoke cationic currents by P2X receptor agonists in non-neuronal cells showed a rank order of BzATP > ATP > alpha,beta-meATP. Pyridoxal-phosphate-6-azophenyl-,2',4'-disulphonic acid (PPADS) and Mg2+ produced concentration-dependent inhibition of BzATP-evoked currents in non-neuronal cells. Confocal microscopy revealed positive immunoreactivity of anti-P2X7 receptor antibodies on non-neuronal cells. No anti-P2X7 immunoreactivity was observed on DRG neurons. Further electrophysiological studies showed that prolonged agonist activation of P2X7 receptors in non-neuronal cells did not lead to cytolytic pore formation. Taken together, the present study demonstrated functional expression of P2X7 receptors in non-neuronal but not in small diameter neurons from rat DRG. Modulation of P2X7 receptors in non-neuronal cells might have impact on peripheral sensory transduction under normal and pathological states.     

Pharmacological modulation of brain Nav1.2 and cardiac Nav1.5 subtypes by the local anesthetic ropivacaine

Objective

The present study was aimed to investigate the pharmacological modulatory effects of ropivacaine, an amide-type local anesthetic, on rat Nav1.2 (rNav1.2) and rNav1.5, the two Na⁺ channel isoforms heterologously expressed in Xenopus oocytes and in HEK293t cell line, respectively.

Methods

Two-electrode voltage-clamp (TEVC) and whole-cell patchclamp recordings were employed to record the whole-cell currents.

Results

Ropivacaine induced tonic inhibition of peak Na⁺ currents of both subtypes in a dose- and frequency-dependent manner. rNav1.5 appeared to be more sensitive to ropivacaine. In addition, for both Na⁺ channel subtypes, the steady-state inactivation curves, but not the activation curves, were significantly shifted to the hyperpolarizing direction by ropivacaine. Use-dependent blockade of both rNav1.2 and rNav1.5 channels was induced by ropivacaine through a high frequency of depolarization, suggesting that ropivacaine could preferentially bind to the 2 inactivated Na⁺ channel isoforms.

Conclusion

The results will be helpful in understanding the pharmacological modulation by ropivacaine on Nav1.2 subtype in the central nervous system, and on Nav1.5 subtype abundantly expressed in the heart.     

Changes in P2X receptor responses of sensory neurons from P2X3-deficient mice

Dorsal root ganglion (DRG) neurons respond to ATP with transient, persistent or biphasic inward currents. In contrast, the ATP responses in nodose neurons are persistent. These sustained currents are also heterogeneous, with one component being accounted for by P2X2/3 receptors, and the residual response probably mediated by P2X2 receptors, although the direct evidence for this has been lacking. In the present study, we examined the P2X receptors on DRG and nodose neurons from P2X3-deficient (P2X3-/-) mice, using whole cell voltage-clamp recording and immunohistochemistry. We found that all P2X3-/- DRG neurons lacked rapidly desensitizing response to ATP, and both DRG and nodose neurons from P2X3-null mutant mice no longer responded to alpha,beta-methylene ATP (alphabetameATP). In contrast, ATP evoked persistent inward current in 12% of DRG neurons and 84% of nodose neurons from P2X3-/- mice. This retained persistent response to ATP on nodose neurons had an EC50 for ATP of 77 microm, was antagonized by Cibacron blue and pyridoxal-5-phosphate-6-azophenyl-2',4'-disulphonic acid, potentiated by Zn2+ and acidification, but not enhanced by ivermectin or diinosine pentaphosphate. 2',3'-O-Trinitrophenyl-ATP antagonized this response with an IC50 of 8 microm. All these properties are consistent with those of recombinant P2X2 homomeric receptors. Furthermore, specific P2X2 receptor immunoreactivity detected in wild-type sensory neurons was unaltered in null mutant mice. Therefore, the alphabetameATP-insensitive persistent responses on nodose neurons are likely to be mediated by P2X2 homomers, which contribute to 60% of currents evoked by 100 microm ATP in the wild type.     

阿尔茨海默病APPswe/PS1dE9双转基因小鼠的病理生化和行为学研究(英文)

目的阿尔茨海默病(Alzheimer’sdisease,AD)APPswe/PS1dE9双转基因小鼠已被广泛运用于各种实验研究。AD小鼠脑内产生过量的β淀粉样蛋白(Aβ),后者会影响突触功能和中枢神经系统的发育。然而,该转基因小鼠模型的生化和行为学特征却未见报道。本研究旨在对该小鼠模型的病理从生化和行为学角度进行检测。方法对6月和12月龄转基因和野生型小鼠取血约100μL,1200g离心后,分离血清。在小鼠6月和12月龄时,进行为期15天的辐射状六臂水迷宫实验。ELISA法检测血清和大脑中Aβ1-40和Aβ1-42的含量,以及血清中8-羟基脱氧鸟苷的含量。比较转基因和野生型小鼠大脑不同部位中α-,β-和γ-分泌酶活性的差异。结果在6月龄之前,APP-swe/PS1dE9双转基因小鼠的死亡率约为35%,这些死亡的小鼠脑内Aβ1-40和Aβ1-42水平较高,两者比例约为1:10。在6月和12月龄时,转基因小鼠血清中Aβ1-40水平均显著高于Aβ1-42水平,Aβ1-40与Aβ1-42比例为2.37:1。在12月龄时,转基因小鼠大脑中Aβ1-42水平显著高于Aβ1-40水平,两者比例约为2.17:1,并且在不同脑区中,Aβ1-42和Aβ1-40含量变化较大。在小脑、前、后部皮质层以及海马中,Aβ1-42水平显著高于Aβ1-40。分泌酶活性在转基因和野生型小鼠之间以及在不同脑部位之间没有很大的差异,这提示PS1转基因并没有导致高γ-分泌酶活性,该基因可能使γ-分泌酶更有效的切割和产生Aβ1-42。此外,转基因小鼠血清中8-羟基脱氧鸟苷含量较野生型小鼠升高,但没有显著性差异。行为学结果显示,在6月龄时,转基因小鼠与野生型相比呈现出显著的记忆障碍,到12月龄时,这种障碍变得更为严重,表现为水迷宫实验中产生更多的错误。结论 APPswe/PS1dE9双转基因小鼠最早在6月龄时就能很好地模拟早发性AD,可用于实验研究。     

Potentiation of the P2X3 ATP receptor by PAR-2 in rat dorsal root ganglia neurons, through protein kinase-dependent mechanisms, contributes to inflammatory pain

Proinflammatory agents trypsin and mast cell tryptase cleave and activate protease-activated receptor-2 (PAR-2), which is expressed on sensory nerves and causes neurogenic inflammation. P2X3 is a subtype of the ionotropic receptors for adenosine 5'-triphosphate (ATP), and is mainly localized on nociceptors. Here, we show that a functional interaction of the PAR-2 and P2X3 in primary sensory neurons could contribute to inflammatory pain. PAR-2 activation increased the P2X3 currents evoked by α, β, methylene ATP in dorsal root ganglia (DRG) neurons. Application of inhibitors of either protein kinase C (PKC) or protein kinase A (PKA) suppressed this potentiation. Consistent with this, a PKC or PKA activator mimicked the PAR-2-mediated potentiation of P2X3 currents. In the in vitro phosphorylation experiments, application of a PAR-2 agonist failed to establish phosphorylation of the P2X3 either on the serine or the threonine site. In contrast, application of a PAR-2 agonist induced trafficking of the P2X3 from the cytoplasm to the plasma membrane. These findings indicate that PAR-2 agonists may potentiate the P2X3, and the mechanism of this potentiation is likely to be a result of translocation, but not phosphorylation. The functional interaction between P2X3 and PAR-2 was also confirmed by detection of the α, β, methylene-ATP-evoked extracellular signal-regulated kinases (ERK) activation, a marker of neuronal signal transduction in DRG neurons, and pain behavior. These results demonstrate a functional interaction of the protease signal with the ATP signal, and a novel mechanism through which protease released in response to tissue inflammation might trigger the sensation to pain through P2X3 activation.     

Ensheathing cells utilize dynamic tiling of neuronal somas in development and injury as early as neuronal differentiation

Background

Glial cell ensheathment of specific components of neuronal circuits is essential for nervous system function. Although ensheathment of axonal segments of differentiated neurons has been investigated, ensheathment of neuronal cell somas, especially during early development when neurons are extending processes and progenitor populations are expanding, is still largely unknown.

Methods

To address this, we used time-lapse imaging in zebrafish during the initial formation of the dorsal root ganglia (DRG).

Results

Our results show that DRG neurons are ensheathed throughout their entire lifespan by a progenitor population. These ensheathing cells dynamically remodel during development to ensure axons can extend away from the neuronal cell soma into the CNS and out to the skin. As a population, ensheathing cells tile each DRG neuron to ensure neurons are tightly encased. In development and in experimental cell ablation paradigms, the oval shape of DRG neurons dynamically changes during partial unensheathment. During longer extended unensheathment neuronal soma shifting is observed. We further show the intimate relationship of these ensheathing cells with the neurons leads to immediate and choreographed responses to distal axonal damage to the neuron.

Conclusion

We propose that the ensheathing cells dynamically contribute to the shape and position of neurons in the DRG by their remodeling activity during development and are primed to dynamically respond to injury of the neuron.

     

Activation of TRPM2 and TRPV1 Channels in Dorsal Root Ganglion by NADPH Oxidase and Protein Kinase C Molecular Pathways: a Patch Clamp Study

Despite considerable research, the mechanisms of neuropathic pain induced by excessive oxidative stress production and overload calcium ion (Ca²⁺) entry in dorsal root ganglion (DRG) remain substantially unidentified. The transient receptor potential melastatin 2 (TRPM2) and vanilloid 1 (TRPV1) channels are activated with different stimuli including oxidative stress. TRPM2 and TRPV1 have been shown to be involved in induction of neuropathic pain. However, the activation mechanisms of TRPM2 and TRPV1 via NADPH oxidase and protein kinase C (PKC) pathways are poorly understood. In this study, I investigated the roles of NADPH oxidase and PKC on Ca²⁺ entry through TRPM2 and TRPV1 channels in in vitro DRG neurons of rats. Rat DRG neurons were used in whole-cell patch clamp experiments. The H₂O₂-induced TRPM2 current densities were decreased by N-(p-amylcinnamoyl)anthranilic acid (ACA), and dose-dependent capsaicin (CAP) and H₂O₂-induced TRPV1 currents were inhibited by capsazepine (CPZ). The TRPV1 channel is activated in the DRG neurons by 0.01 mM capsaicin but not 0.001 mM or 0.05 mM capsaicin. TRPM2 and TRPV1 currents were increased by the PKC activator, phorbol myristate acetate (PMA), although the currents were decreased by ACA, CPZ, and the PKC inhibitor, bisindolylmaleimide I (BIM). Both channel currents were further increased by PMA + H₂O₂ as compared to H₂O₂ only. In the combined presence of PMA + BIM, no TRPM2 or TRPV1 currents were observed. The CAP and H₂O₂-induced TRPM2 current densities were also decreased by the NADPH oxidase inhibitors apocynin and N-Acetylcysteine. In conclusion, these results demonstrate a protective role for NADPH oxidase and PKC inhibitors on Ca²⁺ entry through TRPM2 and TRPV1 channels in DRG neurons. Since excessive oxidative stress production and Ca²⁺ entry are implicated in the pathophysiology of neuropathic pain, the findings may be relevant to the etiology and treatment of neuropathology in DRG neurons.     

RETRACTED ARTICLE: Pro-protein convertase-2/carboxypeptidase-E mediated neuropeptide processing of RGC-5 cell after in vitro ischemia

Objective

To observe the change of the neuropeptide pro-protein processing system in the ischemic retina ganglion cell-5 (RGC-5) cells, pro-protein convertase-2 (PC2), carboxypeptidase-E (CPE) and preproneuropeptide Y (preproNPY) protein levels in the ischemic RGC-5 cells and conditioned medium were analyzed.

Methods

The RGC-5 cell was differentiated in 0.1 μmol/L staurosporine for 24 h and then stressed by different doses of oxygen and glucose deprivation (OGD). The acute or chronic OGD-induced cell death rates were obtained by using PI or TUNEL staining. The protein expression levels were determined by using the Western blot method and PC2 activity analysis.

Results

The ischemia caused substantial cell death in an OGD dose-dependent manner. In the cells, proPC2 and preproNPY protein levels gradually increased whereas proCPE gradually decreased. After OGD, PC2 activity was decreased. In the conditioned medium, proPC2 and PC2 proteins gradually decreased whereas proCPE, CPE, and preproNPY proteins gradually increased.

Conclusion

These results demonstrated that OGD inhibited the neuropeptide pro-protein processing system by reducing PC2 activity and the maturation of proPC2. The aggregation of the pro-proteins and the increase of the active CPE excision adversely exacerbated the cell injury. The pro-protein processing system might play a critical role in the ischemic stress of RGC-5 cells.     

Progressive changes of orexin system in a rat model of 6-hydroxydopamineinduced Parkinson’s disease

Objective

Sleep disturbance, which is characterized by excessive daytime sleepiness and sleep attacks, is frequently observed in patients with Parkinson’s disease (PD). Loss of orexin neurons in hypothalamus and the resultant decreased level of orexin in cerebrospinal fluid (CSF) found in narcolepsy patients may also play an essential role in the pathogenesis of sleep disturbance. The present study aimed to investigate the possible changes in the orexin system during PD progression.

Methods

After the establishment of a rat PD model by injecting 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle, the numbers of orexin-A- and tyrosine hydroxylase (TH)-positive neurons, and the levels of orexin-A fibers and orexin-A in CSF were examined by immunohistochemistry and ELISA assay, respectively.

Results

Compared to the TH-containing neurons that exhibited fast degeneration in response to 6-OHDA, orexin-A-containing neurons were less sensitive to 6-OHDA. The number of orexin-A-positive neurons began to decrease at day 21 after operation, and at day 49, it decreased by 30% of the initial level. The orexin-A level in CSF of PD rats did not show any obvious fluctuations compared to the control, and there was no obvious reduction in the density of orexin-A-positive fibers in brain areas such as tuberomammillary nucleus.

Conclusion

These results reveal for the first time the dynamic changes of orexin system during the progression of PD. This may provide valuable information for drug development to reverse the loss of orexin neurons and sleep disturbance in PD patients.     

The changes of blood glucose control and lipid profiles after short-term smoking cessation in healthy males

Objective

Our aim was to evaluate the changes in blood glucose control and lipid profiles after 2-months of smoking cessation in healthy males.

Methods

Smoking abstinence was evaluated through self-report and urine cotinine levels. 12 individuals who succeeded in quitting smoking were analyzed. Fasting values of glucose and insulin were used to estimate the β-cell activity and insulin resistance was evaluated using the Homeostasis Model Assessment (HOMA) and Quantitative Insulin Sensitivity Check Index (QUICKI).

Results

The data showed that the subjects had a significant increase in weight, body mass index and fasting plasma glucose levels after smoking cessation. The HOMA-Insulin Resistance and the HOMA β-cell function increased significantly (p=0.005, p=0.047 respectively). The QUICKI showed a significant decrease (p=0.005). In addition, the low-density lipoprotein cholesterol levels decreased significantly (p=0.028); however, changes in the high-density lipoprotein cholesterol, the triglyceride and total cholesterol levels were not significant (p=0.284, p=0.445 respectively).

Conclusion

During the initial stage of smoking abstinence, insulin resistance increased and insulin sensitivity decreased due to elevated body weight and fat composition. Therefore, it is important to educate individuals that stop smoking about the necessity of weight control during smoking cessation programs.