Brain Choline Acetyltransferase Research Articles

Protective effect of cholecalciferol against cobalt-induced neurotoxicity in rats: ZO-1/iFABP, ChAT/AchE and antioxidant pathways as potential therapeutic targets.

Cobalt (Co) toxicity has been reported to produce central nervous system and gastrointestinal abnormalities. This study assessed the therapeutic effect of cholecalciferol (Cho) supplementation against damages caused by sub-acute (14-day) cobalt chloride (CoCl2) exposure in the brain and intestines. Thirty-five male Wistar rats were divided equally into five groups: Group I (control) received no treatment; Group II received oral CoCl2 (100 mg/kg) only; Groups III, IV, and V received 1000, 3000 and 6000 IU/kg of cholecalciferol, respectively by oral gavage, and concurrently with CoCl2. Cobalt-treated rats showed neuronal vacuolation and presence of pyknotic nuclei in the cerebral cortex and hippocampus, depletion of Purkinje cells in the cerebellum, as well as inflammation and congestion in the intestinal mucosa. Cobalt also increased brain and intestinal hydrogen peroxide (H2O2) and malondialdehyde (MDA) concentrations, while simultaneously reducing glutathione (GSH) content, superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione S-transferase (GST) activities. Further, CoCl2 induced increases in brain acetylcholinesterase (AchE) activity and serum zonulin (ZO-1) levels. Conversely, Cho administration suppressed CoCl2-induced damages in the brain and intestines by reducing lipid peroxidation and increasing the activities of antioxidant enzymes. Remarkably, Cho produced stimulation of brain choline acetyltransferase (ChAT) and suppression of AchE activity, along with dose-dependent reduction in serum levels of ZO-1, intestinal fatty acid-binding protein (iFABP) and nitric oxide. In conclusion, the protective role of cholecalciferol against cobalt-induced toxicity occurred via modulation of cholinergic, intestinal permeability and antioxidant pathways. The results may prove significant in the context of the role of gut-brain connections in neuroprotection.

Effect of Ethyl Acetate Fraction from Eucommia ulmoides Leaves on PM2.5-Induced Inflammation and Cognitive Dysfunction.

This study aimed to evaluate the protective effect of the ethyl acetate from Eucommia ulmoides leaves (EFEL) on PM2.5-induced cognitive impairment in BALB/c mice. EFEL improved PM2.5-induced cognitive decline by improving spontaneous alternative behavioral and long-term memory ability. EFEL increased ferric reducing activity power (FRAP) in serum. In addition, EFEL increased superoxide dismutase (SOD) and reduced glutathione (GSH) contents and inhibited the production of malondialdehyde (MDA) in lung and brain tissues. EFEL also restored the mitochondrial function by regulating reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP) level, and ATP level in lung and brain tissues. EFEL ameliorated the cholinergic system by regulating the acetylcholine (ACh) content and acetylcholinesterase (AChE) activity in the brain tissue and the expression of AChE and choline acetyltransferase (ChAT) in the whole brain and hippocampal tissues. EFEL reduced PM2.5-induced excessive expression of inflammatory protein related to the lung, whole brain, olfactory bulb, and hippocampus. Physiological compounds of EFEL were identified as 5-O-caffeolyquinic acid, rutin, quercetin, and quercetin glycosides. As a result, EFEL has anti-inflammation and anti-amnesic effect on PM2.5-induced cognitive impairment by regulating the inflammation and inhibiting the lung and brain tissue dysfunction, and its effect is considered to be due to the physiological compounds of EFEL.

Digoxin Exhibits Neuroprotective Properties in a Rat Model of Dementia

Alzheimer's disease (AD) is by far the most common cause of cognitive impairment in older adults. Current treatments are entirely focused on the symptoms of AD. A complex etiology for AD has been proposed recently, in which AD leads in elevated levels of inflammation. We previously studied digoxin's involvement in the sporadic-AD intracerebroventricular (ICV)-streptozotocin (STZ) animal model due to its anti-inflammatory and neuroprotective characteristics. 18 adult sprague-dawley rats were split into three groups: control (n = 6), STZ + Saline (n = 6), and STZ + Digoxin (n = 6). Twelve AD-induced rats were split into two groups using stereotaxy five days after STZ injection (3mg/kg) into both lateral ventricles: one group got digoxin (0.1mg/kg/day, i.p.) for three weeks, while the other group received saline. Following treatment, each subject was subjected to a passive avoidance learning (PAL) test, followed by brain tissue harvesting. The levels of tumor necrosis factor-alpha (TNF-α) and choline acetyl transferase (ChAT) were measured in the brain, and neurons were counted using Cresyl violet staining in cornu ammonis-1 (CA1) and cornu ammonis-3 (CA3) cornu ammonis (CA3). ICV-STZ significantly shortened PAL latency, increased brain TNF-α levels, decreased brain ChAT activity, and decreased hippocampus neuron number. On the other hand, digoxin significantly reduced all of these STZ-induced deleterious effects. Digoxin significantly rescued rats from memory loss caused by ICV-STZ by decreasing hippocampal cell death, neuroinflammation, and cholinergic deficiency. These findings suggest that digoxin may be beneficial in treating cognitive impairment and Alzheimer's disease.

Neuroprotective effects of dexpanthenol on streptozotocin-induced neuronal damage in rats

Aim Although the most common age-related neurodegenerative disease defined by memory loss is Alzheimer's disease (AD), only symptomatic therapies are present. A complex pathway for the AD pathogenesis that includes an increase in inflammation has recently been suggested. Since in previous animal experiments dexpanthenol has anti-inflammatory and neuroprotective activities, effects and role of dexpanthenol in an intracerebroventricular (ICV)-streptozotocin (STZ) induced sporadic-AD(memory impairment) animal model have been examined. Design and methods In total, 18 adult sprague-dawley rats were classified into 3 groups; control (n = 6), STZ + Saline (n = 6) and STZ + Dexpanthenol (n = 6). Twelve AD-induced rats through STZ-injection (3 mg/kg) into both lateral ventricles via stereotaxy were separated into two groups five days after STZ administration: one of these groups was treated with dexpanthenol (1000 mg/kg/day, i.p.) for 3 weeks and the other with saline. A passive avoidance learning (PAL) test was used after treatment, followed by brain tissue extraction in all subjects. Brain levels of tumor necrosis factor-alpha (TNF-α) and choline acetyl transferase (ChAT) were measured and Cresyl violet staining was used to count neurons in cornu ammonis-1 (CA1) and cornu ammonis-3 (CA3). Results It was observed that ICV-STZ significantly shortened PAL latency, increased levels of TNF-α in brain, decreased activity of ChAT in brain, and number of hippocampal neurons. However, dexpanthenol significantly reduced all of those STZ-induced harmful effects. Conclusion Dexpanthenol significantly prevented the memory deficit induced by ICV-STZ through mitigating neuronal loss in hippocampus, cholinergic deficiency and neuroinflammation in rats. These findings suggest that dexpanthenol may be beneficial for treating memory impairment.

The neuroprotective effect of betanin in trimethyltin-induced neurodegeneration in mice.

Betanin, a natural food colorant with powerful antioxidative properties, has not been studied in terms of neurodegenerative disease intervention. Therefore, the present study aimed to investigate the neuroprotective effects of betanin against trimethyltin chloride (TMT) -induced neurodegeneration in mice. Forty male ICR mice were randomly divided into four groups: Sham-veh, TMT-veh, TMT-Bet50 and TMT-Bet100. In the TMT groups, neurodegeneration was induced with a one-time intraperitoneal injection of 2.6mg/kg TMT. Betanin-treated groups (Bet) were given oral doses of 50 or 100mg/kg dissolved in normal saline solution. Administrations were started 24h prior to TMT injection and continued for 2weeks. Anxious behavior and spatial cognition were evaluated, respectively. After behavioral tests, brain oxidative status, hippocampal histology and choline acetyltransferase (ChAT) activity were evaluated. Results showed that TMT significant induce anxious behavior and spatial learning and memory deficits (p < 0.05). These were found concurrently with significant decreases in CA1 ChAT activity, brain tissue catalase (CAT) and superoxide dismutase (SOD) activities with significant increase in hippocampal CA1 degeneration (p < 0.05). Betanin 100mg/kg exhibited significant anxiolytic effect, preventive effect on CA1 degeneration and CA1 ChAT activity alteration as well as improvement of spatial learning and memory deficits (p < 0.05). These were found concurrently with significant increases of reduced glutathione, CAT and SOD activities as well as the decrease in malondialdehyde (p < 0.05). We conclude that betanin 100mg/kg exhibits neuroprotective effects against TMT-induced neurodegeneration in mice via its anti-oxidative properties, protective against hippocampal CA1 degeneration and ChAT activity alteration. Therefore, betanin is interesting in further neurodegenerative therapeutic study and applications.

Cholinergic system and exploratory behavior are changed after weekly-binge ethanol exposure in zebrafish

Binge drinking is characterized by excessive alcohol consumption in a short period of time and is associated with a poor quality of life. Zebrafish are commonly used to investigate neurochemical, behavioral, and genetic parameters associated with ethanol (EtOH) exposure. However, few studies have used zebrafish as a model to investigate binge EtOH exposure. In order to elucidate the potential neurobehavioral impairments evoked by binge EtOH exposure in zebrafish, animals were immersed in 1.4% EtOH for 30 min three consecutive times with intervals of one week. Neurobehavioral parameters were analyzed immediately following the third exposure, as well as 2 and 9 days later. Brain choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities were reduced 9 days after the treatment. Thiobarbituric acid-reactive species and dichlorodihydrofluorescein levels were increased immediately after the treatment, but both returned to normal levels 2 days after the treatment. Catalase and glutathione reductase were impaired 2 and 9 days after the treatment. No alteration was observed in superoxide dismutase and glutathione peroxidase activities. EtOH treatment did not alter brain expression of inflammatory genes such as il-1β, il-10, and tnf-α. Zebrafish displayed anxiolytic-like behavior immediately after the last exposure, though there was no behavioral alteration observed 9 days after the treatment. Therefore, binge EtOH exposure in zebrafish leads to long lasting brain cholinergic alteration, probably related to oxidative stress immediately after the exposure, which is independent of classical inflammatory markers.

Exenatide reduces TNF-α expression and improves hippocampal neuron numbers and memory in streptozotocin treated rats

Recent studies suggest a possible link between type 2 diabetes and Alzheimer's disease (AD). Glucogan-like peptide 1 (GLP-1) facilitates insulin release from pancreas under hyperglycemic conditions. In addition to its metabolic effects, GLP-1 and its long-lasting analogs, including exenatide can stimulate neurogenesis and improve cognition in rodent AD model. The aim of the present study was to investigate the effects of exenatide on hippocampal cellularity, cognitive performance and inflammation response in a rat model of AD. Fourteen rats were used to create AD model using intracerebroventricular (ICV) streptozotocin (STZ) infusion while 7 rats were administered 0.9% NaCl only (sham-operated group). Following stereotaxic surgery, STZ received rats were randomly distributed into two groups, and treated with either saline or exenatide 20µgr/kg/day through intraperitoneally for two weeks. Then, cognitive performance (passive avoidance learning), brain tumor necrosis factor alpha (TNF-α) levels, choline acetyltransferase (ChAT) activity and hippocampal neuronal count were determined. While the brain TNF-α levels were significantly high in the saline-treated STZ group, exenatide treatment suppressed the increase in TNF-α levels. Saline-treated STZ group showed reduced ChAT activity compared to sham group. However, exenatide significantly preserved brain ChAT activity. The cognitive performance was also impaired in saline group while exenatide improved memory in rats. Moreover, exenatide treatment significantly prevented the decrease in hippocampal neurons. Overall, the results of the present study clearly indicated exenatide might have beneficial effects on impaired cognitive performance and hippocampal neuronal viability in AD by suppressing the inflammation response and increasing cholinergic activity.

Synthetic and endogenous cannabinoids protect retinal neurons from AMPA excitotoxicity in vivo, via activation of CB1 receptors: Involvement of PI3K/Akt and MEK/ERK signaling pathways

Cannabinoids have been suggested to protect retinal ganglion cells in different models of toxicity, but their effects on other retinal neurons are poorly known. We investigated the neuroprotective actions of the endocannabinoid N-arachidonoyl ethanolamine (Anandamide/AEA) and the synthetic cannabinoids R1-Methanandamide (MethAEA) and HU-210, in an in vivo retinal model of AMPA excitotoxicity, and the mechanisms involved in the neuroprotection. Sprague–Dawley rats were intravitreally injected with PBS or AMPA in the absence or presence of the cannabinoid agonists. Brain nitric oxide synthase (bNOS) and choline acetyltransferase (ChAT) immunoreactivity (IR), as well as TUNEL staining, assessed the AMPA-induced retinal amacrine cell loss and the dose-dependent neuroprotection afforded by cannabinoids. The CB1 receptor selective antagonist AM251 and the PI3K/Akt inhibitor wortmannin reversed the cannabinoid-induced neuroprotection, suggesting the involvement of CB1 receptors and the PI3K/Akt pathway in cannabinoids' actions. Experiments with the CB2 agonist JWH015 and [3H]CP55940 radioligand binding suggested that the CB2 receptor is not involved in the neuroprotection. AEA and HU-210 induced phosphorylation of Akt but only AEA induced phosphorylation of ERK1/2 kinases, as revealed by western blot analysis. To investigate the role of caspase-3 in the AMPA-induced cell death, the caspase-3 inhibitor Z-DEVD-FMK was co-injected with AMPA. Z-DEVD-FMK had no effect on AMPA excitotoxicity. Moreover, no difference was observed in the phosphorylation of SAPK/JNK kinases between PBS- and AMPA-treated retinas. These results suggest that endogenous and synthetic cannabinoids protect retinal amacrine neurons from AMPA excitotoxicity in vivo via a mechanism involving the CB1 receptors, and the PI3K/Akt and/or MEK/ERK1/2 signaling pathways.

Brain region-specific alterations in the gene expression of cytokines, immune cell markers and cholinergic system components during peripheral endotoxin-induced inflammation.

Inflammatory conditions characterized by excessive peripheral immune responses are associated with diverse alterations in brain function, and brain-derived neural pathways regulate peripheral inflammation. Important aspects of this bidirectional peripheral immune-brain communication, including the impact of peripheral inflammation on brain region-specific cytokine responses, and brain cholinergic signaling (which plays a role in controlling peripheral cytokine levels), remain unclear. To provide insight, we studied gene expression of cytokines, immune cell markers and brain cholinergic system components in the cortex, cerebellum, brainstem, hippocampus, hypothalamus, striatum and thalamus in mice after an intraperitoneal lipopolysaccharide injection. Endotoxemia was accompanied by elevated serum levels of interleukin (IL)-1β, IL-6 and other cytokines and brain region-specific increases in Il1b (the highest increase, relative to basal level, was in cortex; the lowest increase was in cerebellum) and Il6 (highest increase in cerebellum; lowest increase in striatum) mRNA expression. Gene expression of brain Gfap (astrocyte marker) was also differentially increased. However, Iba1 (microglia marker) mRNA expression was decreased in the cortex, hippocampus and other brain regions in parallel with morphological changes, indicating microglia activation. Brain choline acetyltransferase (Chat ) mRNA expression was decreased in the striatum, acetylcholinesterase (Ache) mRNA expression was decreased in the cortex and increased in the hippocampus, and M1 muscarinic acetylcholine receptor (Chrm1) mRNA expression was decreased in the cortex and the brainstem. These results reveal a previously unrecognized regional specificity in brain immunoregulatory and cholinergic system gene expression in the context of peripheral inflammation and are of interest for designing future antiinflammatory approaches.

Scopolamine 유도 치매동물모델에서 고려인삼(백삼, 홍삼 및 흑삼)의 기억력 개선 효과

본 연구에서는 백삼이나 홍삼의 기억력 개선 효과 연구를 기초로 흑삼의 기억력 개선효과 여부를 판단하고자 scopolamine으로 유도된 시험동물에게 7주간 시료 물질(백삼, WG; 홍삼, RG; 흑삼, BG) 추출액을 투여한 후, 행동학적인 평가 및 뇌 조직 내 malondialdehyde 농도, ChAT 활성 변<BR>화를 비교 분석하여 기억력 및 학습능력 손상에 대한 개선효과를 알아보고자 하였다. 수동회피시험에서 BG군과 RG군의 latency time이 scopolamine 투여한 PC군(positive control)에 비해서 유의적으로 길어지는 결과를 나타냈다. 수중미로시험에서도 BG군과 RG군의 scopolamine에 의한 기억 손상이 유의적으로 개선되어 NC군의 escape latency 수준 정도로 낮아짐을 확인할 수 있었다. 또한 probe test에서도 BG군과 RG군에서 장기 기억력 손상이 유의적으로 개선됨이 확인되었다. BG군과 RG군의 뇌조직 ChAT 효소 활성은 PC군에 비해 각각 42%, 71% 수준의 유의성 있는 활성증가를 보였다. 지질 과산화도 malondialdehyde 측정 결과에서 PC군 대비 RG군과 BG군에서 각각 37%, 33% 수준의 유의성 있는 감소를 보였다. 이상의 결과를 요약하면 시험물질 가운데 흑삼의 반복 경구투여는 scopolamine으로 유도된 흰쥐에서 기억력 감퇴를 개선하는 데 가장 효과적인 것으로 사료된다.

Effects of Temperature on the Antipredator Behaviour and on the Cholinergic Expression in the European Sea Bass (Dicentrarchus labrax L.) Juveniles

AbstractIn this paper, an experimental approach was used to test for the parallel effects of temperature (T) increase on the antipredator behaviour and the cholinergic expression in the juvenile European sea bass (Dicentrarchus labrax L.). The effects of three T treatments (18, 22 and 26°C) were tested on the main behavioural components of the antipredator response towards live aquatic predators and aerial simulated attacks, whereas brain cholinergic expression was evaluated by choline acetyltransferase (ChAT) immunoblotting (Western blot) at the extreme values of the thermal range (18 and 26°C). Antipredator responses towards a live fish were analysed over pre‐exposure and exposure phases within a short temporal scale (20 s before and after the stimulus). The results suggest that T modulates several quantitative components of the antipredator behaviour. The mean shoaling index (shoal cohesiveness) was higher at 22°C than at 18 and 26°C during both the pre‐stimulus and the exposure phase. Conversely, the mean distances from the predator and the tank bottom were, respectively, lower and higher at 26°C than in the other two treatments. In regard to the antipredator response on the aerial stimulus, comparisons across treatments revealed statistically significant differences between fish performing freezing or latency to recovery, suggesting that the fright reaction has a higher persistence at the coldest T (18°C) than at 22 and 26°C. Western blot analysis revealed a reduction in brain ChAT expression in fish acclimated to 26°C compared to those at 18°C. Results were discussed in the light of the relationships between behavioural traits, metabolism and their consequences on the population level, as a response to climate change in coastal habitats.

Effect of western and high fat diets on memory and cholinergic measures in the rat

Recent evidence shows an association between obesity and cognitive decline. The present study aimed to determine whether a very high fat (60%) or western diet can affect working or spatial memory in rats and whether the diet-induced cognitive impairment is linked to the level of acetylcholine in the brain. Three groups of male Long Evans rats were fed either chow, western diet (21% fat, 0.15% cholesterol) or a high fat diet (60% fat) for 12 weeks (n=12 per group). Body weight, food intake and blood pressure were measured weekly. Behavioural testing, novel object recognition and Y-maze were carried out at 12 weeks. At the end of the study brain choline acetyltransferase and acetylcholinesterase levels were estimated. Results showed that consumption of a western diet for twelve weeks impaired a rat's spatial memory (p<0.05), and increased body weight, calorie intake, blood pressure and triglyceride levels. Conversely our high fat diet also impaired spatial memory (p<0.05) but this effect was independent of the rat's body weight or blood pressure. No significant changes in brain acetylcholine markers were observed. In conclusion, diets with higher fat content impaired hippocampal-dependant memory, even when hypertension and obesity are absent; however the mechanism is still unclear.

Single dose exposure of sarin and physostigmine differentially regulates expression of choline acetyltransferase and vesicular acetylcholine transporter in rat brain

Choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) are the key components of cholinergic system apart from acetylcholinesterase. Effects of subcutaneous exposures of 0.25 and 0.5 LD50 sarin and 0.75mg/kg physostigmine on immunoreactivity levels of these two proteins (ChAT and VAChT) were studied. Immunoreactivity levels of ChAT decreased significantly after 1 and 3days in cortex and 3days of 0.25 LD50 sarin administration in cerebellum. While 0.5 LD50 sarin exposure caused significant down regulation after 2.5h to 7days in cortex and 1 and 3days in cerebellum with respect to controls. Physostigmine at 0.75mg/kg dose showed enhanced levels of ChAT after 1day which decreased significantly after 3 and 7days both in cortex and cerebellum compared to controls. VAChT level decreased significantly after 1day in cortex and 3 and 7days in cerebellum after 0.25 LD50 sarin administration, while 0.5 LD50 sarin significantly lowered VAChT immunoreactivity level after 2.5h and 7days in cortex and 2.5h and 1day in cerebellum. Physostigmine at 0.75mg/kg dose showed significant enhanced immunoreactivity levels of VAChT after 1, 3, and 7days in cortex and 3days in cerebellum. Results show that acetylcholinesterase inhibition by sarin caused reduction in cholinergic neurotransmission at cholinergic proteins expression levels, while physostigmine caused differential expression of key cholinergic proteins. Moreover, cortex, which receives greater cholinergic innervations, is more susceptible to anticholinesterase effect on cholinergic gene expression. These changes can explain delayed neurocognitive changes during anticholinesterases induced chronic neurotoxicity.

Memory defect induced by beta-amyloid plus glutamate receptor agonist is alleviated by catalpol and donepezil through different mechanisms

Our previous studies demonstrate that a non-cholinesterase inhibitor (AChEI) compound catalpol, purified from a traditional Chinese medicinal herb Rehmannia glutinosa, could improve the symptoms and pathological changes in animal and cellular models of memory related neurodegenerative diseases. In this study, we compared catalpol with the most commonly used AChEI donepezil in respect to their mechanism of action on the neurodegenerative changes in an animal model induced by beta-amyloid (Aβ) plus glutamate receptor agonist. It was found that the model mice showed significant deficit in the learning ability and memory in Y maze avoidance test, and meanwhile both donepezil and catalpol greatly improve the learning ability and memory after 2 to 3months' administration. At the selected doses, donepezil only partially raised the declined brain muscarinic acetylcholine receptor (M receptor) density and choline acetyltransferase (ChAT) activity resulting in these levels still lower than normal control, while catalpol completely retrieved these two parameters. ELISA revealed that catalpol, instead of donepezil, possessed the capability of elevating the declined brain BDNF level of the animal model. The ELISA results on the BDNF protein level was confirmed by quantitative RT-PCR measurement of BDNF mRNA in Aβ25–35-treated primary culture of forebrain neurons. In combination with our previous work, we think the neuroprotective effects of donepezil and catalpol are mediated through different mechanisms. Since BDNF has been proved to be an important intrinsic factor in protecting neurodegenerative diseases, catalpol may be a hopefully effective compound against neurodegenerative changes induced by Aβ and glutamate receptor agonist.

The Relationship between Choline Acetyltransferase and Nitric Oxide Synthase Isoform Expression in Alzheimer’s Disease

Nitric oxide (NO) plays an important role in cholinergic neurotransmission and has been implicated in the progression of Alzheimer’s disease (AD). Cholinergic neurotransmission has been associated with regulation of NO synthase (NOS) expression, and we determined previously that NO modulates choline acetyltransferase (ChAT) expression. In spite of the important links identified between NOS and ChAT, little is known about the relationship between these two enzymes in AD. Therefore in the present study, we compared the expression levels of ChAT and NOS in necropsy brain of individuals with AD and non-demented controls. ChAT and NOS levels were assessed in control and AD caudate, nucleus basalis of Meynert (nbM), cortex and hippocampus by radioenzymatic assay, immunoblot analysis and RT-PCR. We detected a significant decrease in ChAT activity in the cortex of AD cases, but no alterations in NOS activity were observed in any of the brain regions examined. At the mRNA level, no significant decrease in total ChAT mRNA was detected but the decrease in M-ChAT mRNA levels approached significance in the nbM. No difference in nNOS and iNOS mRNA and protein levels was observed between control and AD tissue in any of the four brain regions sampled, but a statistically significant decrease in eNOS mRNA levels was detected in both the cortex and hippocampus of AD brain. Finally, the levels of ChAT and NOS activity, protein or mRNA isoforms did not correlate in most of the brain regions examined, but a reduction in ChAT activity and eNOS mRNA in basal forebrain projection regions was observed. These data suggest that in general, there is no correlation between the levels of NOS and ChAT in control or AD subjects, but a reduction in eNOS levels in the hippocampus and cortex indicates there could be an interaction between eNOS containing cells and basal forebrain projections neurons in AD.

Brain choline acetyltransferase: influence of thyroidectomy and thyroxine in the adult rat.

Summary The choline acetyltransferase (ChAT) activity of the cerebral cortex, cerebellum, hypothalamus, hippocampus, amygdala, midbrain, pons and medulla oblongata was determined in adult intact, thyroidectomized and thyroxine (T4)-treated thyroidectomized rats. The results show that thyroidectomy decreased ChAT activity in most brain areas while T4 restored ChAT activity to control levels only in the cerebral cortex and amygdala. Zusammenfassung Cholinacetyltransferase im Gehirn: Einfluß der Thyreoidektomie und des Thyroxins bei der adulten Ratte Bei adulten, intakten, thyreoidektomierten und Thyroxin (T4)-behandelten thyreoidektomierten Ratten wurde die Aktivität der Cholinacetyltransferase (ChAT) in folgenden Abschnitten des Gehirns bestimmt: Cerebraler Cortex, Cerebellum, Hypothalamus, Hippocampus, Amygdala, Zwischenhirn, Pons und Medulla oblongata. Die Ergebnisse zeigen, daß nach Thyreoidektomie die ChAT-Aktivität in den meisten Gehirnbezirken abnahm und daß nach Substitution von T4 die ChAT-Aktivität nur im cerebralen Cortex und in der Amygdala wieder auf die Kontrollwerte anstieg. Résumé Cholinestérase-transférase dans le cerveau: Influence d'une thyreoidectomie et de la thyroxine chez des rats adultes L'activitü de la cholinestérase (ChAT) a été déterminée chez des rats adultes, intacts, thyreoidectomiés avec et sans traitement à la thyroxine (T4) dans les parties suivantes du cerveau: cortex cérébral, cervelet, hypothalamus, hippocampe, amygdale, diencéphale, Pons et Medulla oblongata. Les résultats ont montré que ChAT-activité diminue dans la plupart des régions du cerveau après thyreoidectomie et que cette activité remonte aux valeurs de contrôle seulement dans le cortex cérébral et l'amygdale après une substitution de T4. Resumen La acetilcolinatransferasa en el cerebro: El influjo de la tiroidectomía y de la tiroxina en la rata adulta Se valoró en ratas adultas intactas, tiroidectomizadas y tiroidectomizadas tratadas con tiroxina (T 4) la actividad de la acetilcolinatransferasa (ChAT) en los tramos del cerebro siguientes: corteza cerebral, cerebelo, hipotálamo, hipocampo, tonsila, diencéfalo, puente de Varolio y medula oblongada. Los resultados señalan que tras la tiroidectomía disminuía la actividad ChAT en la mayoría de las áreas cerebrales y que tras la substitución de T 4 solo volvió a aumentar la actividad ChAT en la corteza cerebral y en la tonsila hasta alcanzar los niveles de control.

Gender and folate intake affect choline dynamics and gene expression in mice consuming isotopically labeled choline.

This study investigated the effects of folate intake, Mthfr deficiency, and gender on the fate of orally consumed choline and on the transcript levels of choline metabolizing genes. Mthfr +/+ or +/− mice (n=40; 20 nonpregnant female, 20 male; age 10 wk) were randomized to a folate sufficient or folate deficient diet for 8 wk during which modest amounts of labeled choline (d9‐choline; 1.6 mM), added to the drinking water, were consumed. Based on the concentrations of deuterium labeled choline metabolites in liver, gender robustly (P&lt;0.01) affected choline flux. Compared to males, females had higher concentrations of d9‐phosphatidylcholine (PC, 1.5 times), d3‐PC (2 times), d9‐glycerophosphocholine (GPC, 4 times), d9‐betaine (2 times) and d6‐dimethylglycine (2 times). Female mice also expressed more PEMT in liver and kidney, more BHMT in kidney, and less BHMT in liver. Folate deficiency also influenced (P&lt;0.05) choline dynamics in female mice with lower hepatic concentrations of d3‐PC and d9‐GPC. Increased expression (~3 times) of hepatic choline dehydrogenase and brain choline acetyltransferase was also observed in both genders. In contrast, Mthfr deficiency had subtle effects on choline metabolism; none of which achieved statistical significance. Taken together, these data show enhanced choline cycling and greater sensitivity to folate intake in nonpregnant female than male mice.Grant Funding Source: Funded in part by NIH Grant No. S06GM053933 and the California Agricultural Research Initiative

Effects of Systemic Nicotine, Alcohol or Their Combination on Cholinergic Markers in the Frontal Cortex and Hippocampus of Rat

Acute alcohol (Alc) intoxication has been shown to decrease choline acetyltransferase (ChAT) in the rat brain. The present study extends that finding by examining the effects of nicotine (Nic), Alc, and their combination on ChAT and acetylcholinesterase (AChE) in the frontal cortex and hippocampus of rat. The samples were collected at 30 and 120 min after intraperitoneal administration of saline (0.9%, control), Nic (1 mg/kg), Alc (1 g/kg), and Nic + Alc and analyzed by RT-PCR, Western blot and colorimetry. Alc alone considerably reduced ChAT mRNA expression, whereas Nic alone decreased AChE mRNA expression. In contrast, Nic + Alc exposure had resulted in no significant change in the parameters. These findings are consistent with the results of the Western blot and AChE activity analysis. The results, therefore, indicate that Nic and Alc alone may interact with the central cholinergic system. This interactive effect may contribute to a frequent association of tobacco and Alc consumption.

Polymorphisms at the Paraoxonase 1 L55M and Q192R Loci Affect the Pathophysiology of Alzheimer’s Disease: Emphasis on the Cholinergic System and Beta-Amyloid Levels

Background: Paraoxonase 1 (PON1) functions to protect the cholinergic system against nerve gases and the organophosphate family of pesticides. Recent studies have shown that polymorphisms at the PON1 L55M and Q192R loci might affect individual susceptibility to experience-derived and environmental events such as the exposure to inhibitors of cholinesterase (ChEIs). Objective: ChEI therapy being the treatment of choice for mild-to-moderate Alzheimer’s disease (AD) patients, we determined whether genetic variations in the PON1 loci are associated with AD risk and whether they affect brain choline acetyltransferase (CHAT) activity, nicotinic receptor density, and β-amyloid (Aβ) levels in different regions of AD and age-matched control subjects. Methods: This pilot genetic study used a small cohort of brains from autopsy-confirmed AD patients and age-matched controls from the Douglas Hospital Brain Bank, Quebec, Canada. Results: The frequency of the M55M genotype at the PON1 L55M locus was found to be significantly increased in AD patients relative to age-matched controls (p < 0.05). Significant associations were observed between the PON1 L55M and Q192R polymorphisms and frontal cortex Aβ levels as well as CHAT activity and nicotinic receptor density in the temporal cortex. Conclusions: Our results suggest a prominent role for PON1 in the pathophysiology of common AD with a marked impact on the cholinergic system and Aβ levels in the brain.

Dicholine salt of succinic acid, a neuronal insulin sensitizer, ameliorates cognitive deficits in rodent models of normal aging, chronic cerebral hypoperfusion, and beta-amyloid peptide-(25-35)-induced amnesia.

BackgroundAccumulated evidence suggests that insulin resistance and impairments in cerebral insulin receptor signaling may contribute to age-related cognitive deficits and Alzheimer's disease. The enhancement of insulin receptor signaling is, therefore, a promising strategy for the treatment of age-related cognitive disorders. The mitochondrial respiratory chain, being involved in insulin-stimulated H2O2 production, has been identified recently as a potential target for the enhancement of insulin signaling. The aim of the present study is to examine: (1) whether a specific respiratory substrate, dicholine salt of succinic acid (CS), can enhance insulin-stimulated insulin receptor autophosphorylation in neurons, and (2) whether CS can ameliorate cognitive deficits of various origins in animal models.ResultsIn a primary culture of cerebellar granule neurons, CS significantly enhanced insulin-stimulated insulin receptor autophosphorylation. In animal models, CS significantly ameliorated cognitive deficits, when administered intraperitoneally for 7 days. In 16-month-old middle-aged C57Bl/6 mice (a model of normal aging), CS enhanced spatial learning in the Morris water maze, spontaneous locomotor activity, passive avoidance performance, and increased brain N-acetylaspartate/creatine levels, as compared to the age-matched control (saline). In rats with chronic cerebral hypoperfusion, CS enhanced spatial learning, passive avoidance performance, and increased brain N-acetylaspartate/creatine levels, as compared to control rats (saline). In rats with beta-amyloid peptide-(25–35)-induced amnesia, CS enhanced passive avoidance performance and increased activity of brain choline acetyltransferase, as compared to control rats (saline). In all used models, CS effects lasted beyond the seven-day treatment period and were found to be significant about two weeks following the treatment.ConclusionThe results of the present study suggest that dicholine salt of succinic acid, a novel neuronal insulin sensitizer, ameliorates cognitive deficits and neuronal dysfunctions in animal models relevant to age-related cognitive impairments, vascular dementia, and Alzheimer's disease.