Brief isoflurane anesthesia regulates striatal AKT-GSK3 beta signaling and ameliorates motor deficits in a rat model of early-stage Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative movement disorder primarily affecting the nigrostriatal dopaminergic system. The link between heightened activity of glycogen synthase kinase 3 beta (GSK313) and neurodegenerative processes has encouraged investigation into the potential disease-modifying effects of novel GSK3 beta inhibitors in experimental models of PD. Therefore, the intriguing ability of several anesthetics to readily inhibit GSK3 beta within the cortex and hippocampus led us to investigate the effects of brief isoflurane anesthesia on striatal GSK3 beta signaling in nave rats and in a rat model of early-stage PD. Deep but brief (20-min) isoflurane anesthesia exposure increased the phosphorylation of GSK3 beta at the inhibitory Ser9 residue, and induced phosphorylation of AKT(Thr308) (protein kinase B; negative regulator of GSK3 beta) in the striatum of naive rats and rats with unilateral striatal 6-hydroxydopamine (6-OHDA) lesion. The 6-OHDA protocol produced gradual functional deficiency within the nigrostriatal pathway, reflected as a preference for using the limb ipsilateral to the lesioned striatum at 2 weeks post 6-OHDA. Interestingly, such motor impairment was not observed in animals exposed to four consecutive isoflurane treatments (20-min anesthesia every 48 h; treatments started 7 days after 6-OHDA delivery). However, isoflurane had no effect on striatal or nigral tyrosine hydroxylase (a marker of dopaminergic neurons) protein levels. This brief report provides promising results regarding the therapeutic potential and neurobiological mechanisms of anesthetics in experimental models of PD and guides development of novel disease-modifying therapies.Peer reviewe

Sleep-State Dependent Alterations in Brain Functional Connectivity under Urethane Anesthesia in a Rat Model of Early-Stage Parkinson's Disease

Parkinson's disease (PD) is characterized by the gradual degeneration of dopaminergic neurons in the substantia nigra, leading to striatal dopamine depletion. A partial unilateral striatal 6-hydroxydopamine (6-OHDA) lesion causes 40-60% dopamine depletion in the lesioned rat striatum, modeling the early stage of PD. In this study, we explored the connectivity between the brain regions in partially 6-OHDA lesioned male Wistar rats under urethane anesthesia using functional magnetic resonance imaging (fMRI) at 5 weeks after the 6-OHDA infusion. Under urethane anesthesia, the brain fluctuates between the two states, resembling rapid eye movement (REM) and non-REM sleep states. We observed clear urethane-induced sleep-like states in 8/19 lesioned animals and 8/18 control animals. 6-OHDA lesioned animals exhibited significantly lower functional connectivity between the brain regions. However, we observed these differences only during the REM-like sleep state, suggesting the involvement of the nigrostriatal dopaminergic pathway in REM sleep regulation. Corticocortical and corticostriatal connections were decreased in both hemispheres, reflecting the global effect of the lesion. Overall, this study describes a promising model to study PD-related sleep disorders in rats using fMRI.Peer reviewe

Alcohol Co-Administration Changes Mephedrone-Induced Alterations of Neuronal Activity

Mephedrone (4-MMC), despite its illegal status, is still a widely used psychoactive substance. Its effects closely mimic those of the classical stimulant drug methamphetamine (METH). Recent research suggests that unlike METH, 4-MMC is not neurotoxic on its own. However, the neurotoxic effects of 4-MMC may be precipitated under certain circumstances, such as administration at high ambient temperatures. Common use of 4-MMC in conjunction with alcohol raises the question whether this co-consumption could also precipitate neurotoxicity. A total of six groups of adolescent rats were treated twice daily for four consecutive days with vehicle, METH (5 mg/kg) or 4-MMC (30 mg/kg), with or without ethanol (1.5 g/kg). To investigate persistent delayed effects of the administrations at two weeks after the final treatments, manganese-enhanced magnetic resonance imaging brain scans were performed. Following the scans, brains were collected for Golgi staining and spine analysis. 4-MMC alone had only subtle effects on neuronal activity. When administered with ethanol, it produced a widespread pattern of deactivation, similar to what was seen with METH-treated rats. These effects were most profound in brain regions which are known to have high dopamine and serotonin activities including hippocampus, nucleus accumbens and caudate-putamen. In the regions showing the strongest activation changes, no morphological changes were observed in spine analysis. By itself 4-MMC showed few long-term effects. However, when co-administered with ethanol, the apparent functional adaptations were profound and comparable to those of neurotoxic METH.Peer reviewe

Nigrostriatal 6-hydroxydopamine lesions increase alpha-synuclein levels and permeability in rat colon

Increasing evidence suggests that the gut-brain axis plays a crucial role in Parkinson's disease (PD). The abnormal accumulation of aggregated alpha-synuclein (aSyn) in the brain is a key pathological feature of PD. Intracerebral 6-hydroxydopamine (6-OHDA) is a widely used dopaminergic lesion model of PD. It exerts no aSyn pathology in the brain, but changes in the gut have not been assessed. Here, 6-OHDA was administered unilaterally either to the rat medial forebrain bundle (MFB) or striatum. Increased levels of glial fibrillary acidic protein in the ileum and colon were detected at 5 weeks postlesion. 6-OHDA decreased the Zonula occludens protein 1 barrier integrity score, suggesting increased colonic permeability. The total aSyn and Ser129 phosphorylated aSyn levels were elevated in the colon after the MFB lesion. Both lesions generally increased the total aSyn, pS129 aSyn, and ionized calcium-binding adapter molecule 1 (Iba1) levels in the lesioned striatum. In conclusion, 6-OHDA-induced nigrostriatal dopaminergic damage leads to increased aSyn levels and glial cell activation particularly in the colon, suggesting that the gut-brain axis interactions in PD are bidirectional and the detrimental process may start in the brain

Estrogen deficiency reduces maximal running capacity and affects serotonin levels differently in the hippocampus and nucleus accumbens in response to acute exercise

IntroductionEstrogen deficiency is associated with unfavorable changes in body composition and metabolic health. While physical activity ameliorates several of the negative effects, loss of ovarian function is associated with decreased physical activity levels. It has been proposed that the changes in brain neurochemical levels and /or impaired skeletal muscle function may underlie this phenomenon.MethodsWe studied the effect of estrogen deficiency induced via ovariectomy (OVX) in female Wistar rats (n = 64). Rats underwent either sham or OVX surgery and were allocated thereafter into four groups matched for body mass and maximal running capacity: sham/control, sham/max, OVX/control, and OVX/max, of which the max groups had maximal running test before euthanasia to induce acute response to exercise. Metabolism, spontaneous activity, and maximal running capacity were measured before (PRE) and after (POST) the surgeries. Three months following the surgery, rats were euthanized, and blood and tissue samples harvested. Proteins were analyzed from gastrocnemius muscle and retroperitoneal adipose tissue via Western blot. Brain neurochemical markers were measured from nucleus accumbens (NA) and hippocampus (HC) using ultra-high performance liquid chromatography.ResultsOVX had lower basal energy expenditure and higher body mass and retroperitoneal adipose tissue mass compared with sham group (p ≤ 0.005). OVX reduced maximal running capacity by 17% (p = 0.005) with no changes in muscle mass or phosphorylated form of regulatory light chain (pRLC) in gastrocnemius muscle. OVX was associated with lower serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) level in the NA compared with sham (p = 0.007). In response to acute exercise, OVX was associated with low serotonin level in the HC and high level in the NA (p ≤ 0.024).DiscussionOur results highlight that OVX reduces maximal running capacity and affects the response of brain neurochemical levels to acute exercise in a brain region-specific manner. These results may offer mechanistic insight into why OVX reduces willingness to exercise

Moottoroidun polkupyörän takahaarukan suunnittelu

Insinöörityössä oli tavoitteena suunnitella takahaarukka sähkömoottoroituun polkupyörään olemassaolevien osien ympärille. Ensin selvitettiin, miten pyörän muut osat vaikuttavat takahaarukkaan. Seuraavaksi takahaarukka mallinnettiin 3D-suunnitteluohjelmalla. Määritettiin ja arvioitiin kolme kuormitustapausta, joita käytettiin laskettaessa takahaarukan lujuutta ohjelmallisesti elementtimenetelmällä neljä kierrosta. Jokaisen kierroksen jälkeen laskentamallia tarkennettiin tai malliin tehtiin muutoksia tulosten perusteella. Huomattiin, että haarukkaa taka-akselin olakkeita vasten puristavilla muttereilla on suuri vaikutus haarukan lujuuteen kaikissa kuormitustapauksissa. Työpiirustuksia ei vielä tehty, koska havaittiin, että laskentamallia on syytä tarkentaa edelleen ainakin iskunvaimentimen osalta, jotta iskunvaimentimen kiinnityskohtaan muodostuvat jännitykset saadaan laskettua tarkemmin.The aim of this Bachelor’s thesis was to design a swing arm around the existing parts of a motorized bicycle. The study was carried out as follows. Firstly, the existing parts, their interaction and requirements for the swing arm were studied. Secondly, the swing arm was designed with a 3D CAD program. Thirdly, three load cases were decided and described. Finally, the load cases and the 3D model were used to calculate the strength of the swing arm with a FEM calculation program. On the basis of the results, the model was enhanced or made more accurate after each of the four rounds of calculation. The calculations point out that the nuts clamping the halves of the swing arm against the shoulders of the rear axle play a remarkable part in the strength of the swing arm structure. In conclusion, it was discovered that further improvements of the calculation model are necessary before finalizing the manufacturing drawings

Systemic inflammation elevates cytosolic prolyl oligopeptidase protein expression but not peptidase activity in the cerebral cortices of familial Alzheimer`s disease modeling mice

Changes in brain prolyl oligopeptidase (PREP) expression and activity have been associated with neuroinflammation and Alzheimer`s disease (AD). The role of PREP in AD, which onset can be contributed by peripheral infection-induced inflammation, is unknown. The aim of the study was to elucidate further the association of PREP with AD pathology and inflammation. Here, we quantitated PREP protein expression by liquid chromatography-tandem mass spectrometry-based quantitative targeted absolute proteomics and determined PREP peptidase activity in the cerebral cortices of familial AD (APdE9) and lipopolysaccharide (LPS)-induced inflammation mouse models. PREP activity was investigated using the fluorogenic substrate Suc-Gly-Pro-AMC. PREP expression was significantly increased (by 2-fold) in the brain cytosolic fraction of LPS treated APdE9 mice, while the peptidase activity remained unaltered. In the cortical crude membrane fraction, the PREP expression and activity were decreased by 35–40% in the LPS treated APdE9 mice. In conclusion, cortical cytosolic and membrane-bound PREP expression levels and enzyme activities were altered due to LPS-induced inflammation in the AD mouse model. Since the cytosolic protein expression increased without any concomitant increase in the peptidase activity, it is likely that PREP activity is affected by other factors than protein expression alone.Peer reviewe