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Objective:To evaluate the role of α7 nicotinic acetylcholine receptor (α7nAChR) in penehyclidine hydrochloride-induced reduction of endotoxin-induced acute lung injury (ALI) in mice.Methods:Forty SPF healthy male C57BL/6 mice, aged 6-8 weeks, weighing 18-25 g, were divided into 4 groups ( n=10 each) using a random number table method: control group (group C), ALI group, penehyclidine hydrochloride group (PHC group), and α7nAChR inhibitor MLA group (MLA group). ALI was induced by intraperitoneal injection of lipopolysaccharide 15 mg/kg in anesthetized animals, while normal saline was given instead in group C. In PHC group, penehyclidine hydrochloride 2 mg/kg was intraperitoneally injected at 30 min before developing the model. MLA 10 mg/kg was intraperitoneally injected at 10 min before administration of penehyclidine hydrochloride in MLA group. Mice were sacrificed at 6 h after lipopolysaccharide administration, and lung tissues were collected for microscopic examination of the pathological changes (by HE staining) and for determination of the wet/dry weight ratio (W/D ratio), content of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β) and IL-10 (by enzyme-linked immunosorbent assay) and expression of α7nAChR (by Western blot). Results:Compared with C group, the W/D ratio and contents of TNF-α and IL-1β were significantly increased, the content of IL-10 was decreased, and the expression of α7nAChR was up-regulated in ALI, PHC and MLA groups ( P<0.05). Compared with ALI group, the W/D ratio and contents of TNF-α and IL-1β were significantly decreased, the content of IL-10 was increased, and the expression of α7nAChR was up-regulated in PHC group ( P<0.05). Compared with PHC group, the W/D ratio and contents of TNF-α and IL-1β were significantly increased, the content of IL-10 was decreased, and the expression of α7nAChR was down-regulated in MLA group ( P<0.05). Compared with ALI group, the pathological changes of lung tissues were significantly mitigated in PHC group, while this effect of PHC was partially reversed by α7nAChR inhibitor MLA. Conclusions:α7nAChR is involved in penehyclidine hydrochloride-induced reduction of endotoxin-induced ALI in mice.
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Objective To investigate the expression of alpha 7 nicotinic acetylcholine receptor (α7 nAchR), cholinesterase (AChE), choline acetyl translocase (ChaT) after sevoflurane anesthesia. Methods A total of 120 healthy Sprague-Dawley rats with both two genders, aged 1 week, were randomly divided into 5 groups: blank group; air/O2 group; sevoflurane group (group SEV); α7 nAchR agonist group (group PUN); α7 nAchR antagonist group (group MLA), 24 in each group. Blank group received free feeding, air/O2 group was inhaled 60％ oxygen (carrier gas: 1 L/min O2+1 L/min air) 2 h; group SEV was inhaled 3.4％ sevoflurane and carrier gas for 2 h; group PUN and group MLA were injected with PNU-282987 and methyllycaconitine, respectively, after 24 h inhaled of 3.4％ sevoflurane and carrier gas for 2 h. After that, hippocampus dissection carried out in 2 h, 1 w, 4 w, and Western blot method was used to detect α7 nAchR, AChE, ChaT proteins expression. Results Two hours after anesthesia recovery, α7 nAchR in groups SEV, PNU and MLA was significantly lower than that in air/O2 group (P ＜ 0.05); AChE in groups PNU and MLA was significantly lower than that in air/O2 group (P ＜ 0.05); ChaT in groups SEV, PNU and MLA was significantly lower than that in air/O2 group (P ＜ 0.05). One week after anesthesia recovery, α7 nAchR in blank group and groups SEV and PNU was significantly higher than that in air/O2 group (P ＜ 0.05), α7 nAchR in group MLA was significantly lower than that in air/O2 group (P ＜ 0.05); AChE in blank group and and group PNU was significantly higher than that in air/O2 group (P ＜ 0.05), ChaT in blank group was significantly higher than that in air/O2 group (P ＜ 0.05), ChaT in group SEV was significantly lower than that in air/O2 group (P ＜ 0.05). Four weeks after anesthesia awake, AChE in each group was not statistically significant; α7 nAchR in group SEV was significantly higher than that in blank group (P ＜ 0.05), α7 nAchR in group PNU and MLA was significantly lower than that in blank group (P ＜ 0.05); ChaT in blank group and group PNU was significantly lower than that in air/O2 group (P ＜ 0.05), ChaT in group MLA was significantly higher than that in air/O2 group (P ＜ 0.05). Conclusion Sevoflurane inhalation can inhibit ChaT, α7 nAChR, which had no direct effect on AChE; α7 nAChR agonist can effectively help α7 nAChR and ChaT inhibition inhaled sevoflurane, and reached a peak at about 1 week; oxygen concentration around 60％ can increase α7 nAChR expression quantity, to a certain extent against sevoflurane inhibition.
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A lesão pulmonar aguda (LPA) é caracterizada por inflamação pulmonar de início súbito com recrutamento de polimorfonucleares e liberação de mediadores próinflamatórios. É uma condição grave que evolui com óbito em aproximadamente 40% dos casos. Diversos estudos que elucidaram a fisiopatologia da LPA, o tratamento ainda é insatisfatório. O sistema colinérgico anti-inflamatório foi descrito no pulmão e está relacionado a um reflexo via nervo vago que inibe a liberação de citocinas inflamatórias por efeitos relacionados a ação da acetilcolina em receptores nicotínicos. Nossa hipótese é de que a redução de VAChT, que está relacionada ao déficit na liberação de ACh, module a resposta inflamatória pulmonar em modelo de LPS. Objetivo: 1. Avaliar se a deficiência de VAChT modula a resposta pulmonar em animais geneticamente modificados; 2. Avaliar se a deficiência colinérgica induzida por redução de VAChT está envolvida na resposta pulmonar ao LPS e elucidar alguns mecanismos envolvidos; 3. Avaliar o potencial terapêutico do PNU, um agonista de alfa7nAChR nas alterações funcionais e histopatológicas em modelo de LPA em animais C57Bl6. Metodologia: Foram utilizados camundongos machos geneticamente modificados mutante (VAChT KDHOM) ou selvagem (WT) e C57BL/6. Inicialmente avaliamos a função pulmonar e a histopatologia pulmonar em animais VAChT KDHOM. Após, animais WT e VAChT KDHOM receberam instilação intranasal de LPS ou salina e a resposta inflamatória foi avaliada de 1,5h até 72 horas após. Ainda, foi avaliado a resposta pulmonar em VAChT KDHOM e WT após a instilação de LPS intraperitoneal. Por fim, animais C57BL/6 instilados com LPS intranasal, receberam tratamento prévio ou após com PNU, agonista do receptor nicotínico alfa7. Resultados: Animais mutante apresentaram maior quantidade de células recuperadas no lavado bronco alveolar (LBA) e aumento de citocinas próinflamatórias, aumento de edema peribrônquico e piora da função pulmonar. Ainda,...
Acute lung injury (ALI) is characterized by acute lung inflammation with recruitment of polymorphonuclear and release of proinflammatory mediators. It is a severe condition since leads to death 40% of the cases. Several studies have elucidated the pathophysiology of ALI, however the treatment is still unsatisfactory. The anti-inflammatory cholinergic system was described in the lung and is related to a vagal nerve reflex that inhibits the release of inflammatory cytokines by the action o ACh on nicotinic receptors. Our hypothesis is that the VAChT reduction, which is related to the deficit in the release of ACh, modulates the pulmonary inflammatory response in a model of LPS. Aim: 1. To assess whether VAChT deficiency modulates the pulmonary response in genetically modified animals; 2. Assess whether cholinergic deficiency induced reduction VAChT is involved in pulmonary response to LPS and elucidate some mechanisms involved; 3. To evaluate the therapeutic potential of PNU, an agonist alfa7nAChR, in functional and histological changes in C57BL6 mice with LPA. Methods: Mutant genetically modified male mice (VAChT KDHOM) or wild (WT) and C57BL/6 were used. First, we evaluated lung function and lung histopathology in VAChT KDHOM animals. After, WT animals and VAChT KDHOM received intranasal instillation of LPS or saline and the inflammatory response was assessed 1.5 hours to 72 hours. Moreover, the pulmonary response was evaluated in WT and VAChT KDHOM after instillation of LPS intraperitoneally. Finally, C57BL6 instilled with intranasal LPS received prior or post-treatment with PNU, an alfa7 nicotinic receptor agonist. Results: Mutant animals had higher number of cells recovered in brochoalveolar lavage (BAL) and increased pro-inflammatory cytokines, peribronchial edema and worsening of lung function. Still, there was an increase of NF_kB expression and reduction of JAK2. The VAChT deficiency induced increase in inflammatory cells...
Subject(s)
Animals , Male , Mice , Acetylcholine , Acute Lung Injury , Mice , Models, Animal , Pneumonia , Vesicular Acetylcholine Transport ProteinsABSTRACT
<p><b>OBJECTIVE</b>To observe the influence of electroacupuncture (EA) at lower-sea points of stomach, large intestine, small intestine and gallbladder on interleukin-1β (IL-1β), high mobility group protein 1 (HMGB 1) and alpha 7 nicotinic acetylcholine receptor (nAchR α7) in rats with acute gastric mucosal lesion (AGML), so as to explore whether there is relative specificity in treating gastric viscera disease by stimulating Zusanli (ST 36).</p><p><b>METHODS</b>Sixty healthy SD rats were randomly assigned into a blank group, a model group, a Zusanli group, a Shangjuxu group, a Xiajuxu group and a Yanglingquan group, ten rats in each one (half male and half female). The WRS method was applied to induce the AGML model except the rats in the blank group. The rats in the blank group were treated with routine diet; the rats in the model group were treated with immobilization at rat platform, 30 min per time; the rats in the Zusanli group, Shangjuxu group, Xiajuxu group and Yanglingquan group were treated with acupuncture and connected with EA device (dilatational wave 10 Hz/50 Hz, positive electrode on the left side and negative electrode on the right side, intensity was appropriate when rat hind leg slightly shook), 30 min per time. The treatment was given once a day. After consecutive 10-day treatment, the gastric tissue was collected and the damage of gastric mucosa was evaluated; ELISA method was applied to measure the content of serum IL-1β and tissue HMGB 1; the Western blot method was applied to measure the expression of nAchR α7 receptor.</p><p><b>RESULTS</b>(1) Compared with the model group, the ulcer index (UI) of gastric mucosa, serum IL-1β and tissue HMGB 1 were lower, and the expression of nAchR α7 was increased in the remaining groups (<0.05,<0.01). (2) Compared with the Zusanli group, the UI of gastric tissue, serum IL-1β and tissue HMGB 1 were higher in the Shangjuxu group, Xiajuxu group and Yanglingquan group (<0.05,<0.01), and the expression of nAchRα7 was reduced in the Yanglingquan group (<0.01).</p><p><b>CONCLUSIONS</b>(1) EA at digestive system-related lower-sea points, through IL-1β, HMGB 1 and nAchR α7, could regulate immune response, lighten inflammatory reaction and reduce mucosal injury, which could realize the intervention effect on AGML rats. (2) From the comparison, it is concluded the intervention effect of Zusanli group is superior to the other groups, partly indicating the relative specificity between Zusanli and stomach.</p>
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Berberine (BBR) is an isoquinoline alkaloid extracted from Rhizoma coptidis and has been used for treating type 2 diabetes mellitus (T2DM) in China. The development of T2DM is often associated with insulin resistance and impaired glucose uptake in peripheral tissues. In this study, we examined whether BBR attenuated glucose uptake dysfunction through the cholinergic anti-inflammatory pathway in HepG2 cells. Cellular glucose uptake, quantified by the 2-[N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)-amino]-2-deoxy-D-glucose (2-NBDG), was inhibited by 21% after HepG2 cells were incubated with insulin (10(-6) mol/L) for 36 h. Meanwhile, the expression of alpha7 nicotinic acetylcholine receptor (α7nAChR) protein was reduced without the change of acetylcholinesterase (AChE) activity. The level of interleukin-6 (IL-6) in the culture supernatant, the ratio of phosphorylated I-kappa-B kinase-β (IKκβ) Ser181/IKKβ and the expression of nuclear factor-kappa B (NF-κB) p65 protein were also increased. However, the treatment with BBR enhanced the glucose uptake, increased the expression of α7nAChR protein and inhibited AChE activity. These changes were also accompanied with the decrease of the ratio of pIKKβ Ser181/IKKβ, NF-κB p65 expression and IL-6 level. Taken together, these results suggest that BBR could enhance glucose uptake, and relieve insulin resistance and inflammation in HepG2 cells. The mechanism may be related to the cholinergic anti-inflammatory pathway and the inhibition of AChE activity.
Subject(s)
Humans , Berberine , Pharmacology , Glucose , Metabolism , Hep G2 Cells , Hypoglycemic Agents , Pharmacology , I-kappa B Kinase , Metabolism , I-kappa B Proteins , Metabolism , Insulin , Metabolism , Insulin Resistance , Interleukin-6 , Metabolism , Transcription Factor RelA , Metabolism , alpha7 Nicotinic Acetylcholine Receptor , Genetics , MetabolismABSTRACT
PURPOSE: To investigate the role of alpha3 and alpha7 nicotinic acetylcholine receptor subunits (nAChRs) in the bladder, using a rat model with detrusor overactivity induced by partial bladder outlet obstruction (BOO). METHODS: Forty Sprague-Dawley rats were used: 10 were sham-operated (control group) and 30 were observed for 3 weeks after partial BOO. BOO-induced rats were further divided into 3 groups: Two groups of 10 rats each received intravesicular infusions with hexamethonium (HM group; n=10) or methyllycaconitine (MLC group; n=10), which are antagonists for alpha3 and alpha7 nAChRs, respectively. The remaining BOO-induced rats received only saline infusion (BOO group; n=10). Based on the contraction interval measurements using cystometrogram, the contraction pressure and nonvoiding bladder contractions were compared between the control and the three BOO-induced groups. Immunofluorescent staining and Western blotting were used to analyze alpha3 and alpha7 nAChRs levels. RESULTS: The contraction interval of the MLC group was higher than that of the BOO group (P<0.05). Nonvoiding bladder contraction almost disappeared in the HM and MLC groups. Contraction pressure increased in the BOO group (P<0.05) compared with the control group and decreased in the HM and MLC groups compared with the BOO group (P<0.05). Immunofluorescence staining showed that the alpha3 nAChR signals increased in the urothelium, and the alpha7 nAChR signals increased in the urothelium and detrusor muscle of the BOO group compared with the control group. Western blot analysis showed that both alpha3 and alpha7 nAChR levels increased in the BOO group (P<0.05). CONCLUSIONS: Alpha3 and alpha7 nAChRs are associated with detrusor overactivity induced by BOO. Furthermore, nAChR antagonists could help in clinically improving detrusor overactivity.
Subject(s)
Animals , Rats , alpha7 Nicotinic Acetylcholine Receptor , Blotting, Western , Fluorescent Antibody Technique , Hexamethonium , Models, Animal , Rats, Sprague-Dawley , Receptors, Nicotinic , Urinary Bladder , Urinary Bladder Neck Obstruction , Urinary Bladder, Overactive , UrotheliumABSTRACT
The cholinergic anti-inflammatory pathway (CAP) is a new neurophysiologic mechanism regulating the immune system, with alpha7 nicotinic acetylcholine receptor (α7nAChR) being its potential pharmacological target. Cumulative studies have demonstrated that activation of α7nAChR can inhibit inflammation through modulating pro-inflammatory cytokines. The role of α7nAChR has been confirmed in a series of inflammatory diseases. This review is aimed to provide new insights for using a7nAChR against inflammatory diseases.
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OBJECTIVE: Agonists of alpha7-nicotinic acetylcholine receptors (nAChRs) have been developed as potential therapeutic drugs for neuropsychiatric diseases such as schizophrenia and Alzheimer's disease. Positron emission tomography (PET) is a noninvasive brain imaging technique to measure receptor occupancy in the living human brain. Although much effort has been expended to create specific PET radioligands for alpha7-nAChRs in the brain, only 4-[11C]methylphenyl-1,4-diazabicyclo[3.2.2.]nonane-4-carboxylate ([11C]CHIBA-1001) is currently available for clinical studies. In contrast, two 5-hydroxytryptamine-3 (5-HT3) receptor antagonists, tropisetron and ondansetron, have been used to treat patients with chemotherapy-induced or postoperative nausea and vomiting. Furthermore, tropisetron, but not ondansetron, possesses high affinity for alpha7-nAChRs. In the present study, we evaluated the receptor occupancy in the human brain after a single oral administration of tropisetron and ondansetron using [11C]CHIBA-1001 and PET. METHODS: Two serial dynamic PET scans using [11C]CHIBA-1001 in healthy non-smoking male subjects were performed before and after receiving an oral administration of these medications. RESULTS: A single oral administration of tropisetron, but not ondansetron, decreased the total distribution volume of [11C]CHIBA-1001 in the human brain. CONCLUSION: This study shows that tropisetron, but not ondansetron, could bind to alpha7-nAChRs in the human brain after a single oral administration. Therefore, [11C]CHIBA-1001 may be a useful PET radioligand to measure the occupancy of alpha7-nAChRs in the human brain.
Subject(s)
Humans , Male , Administration, Oral , Alzheimer Disease , Brain , Electrons , Indoles , Neuroimaging , Ondansetron , Positron-Emission Tomography , Postoperative Nausea and Vomiting , Receptors, Cholinergic , Receptors, Nicotinic , SchizophreniaABSTRACT
Objective To investigate whether CD4~+ CD25~+ regulatory T cells (Treg) from C57BL/6J mice express alpha7 nicotinic acetylcholine receptor (α7nAChR). Methods CD4~+ CD25~+ regulatory T cells were isolated from mouse splenocytes with a CD4~+ CD25~+ regulatory T Cell isolation kit (Mihenyi Bio-tee). The purity of isolated Tregs was analyzed by flow eytometry. Expressions of α7nAChR in mouse CD4~+ CD25~+ Tregs were examined by immunofluorescence staining, Western blotting, and reverse transeription-PCR, respectively. Results It was revealed by flow cytometry that Tregs could bind alpha-bungarotoxin (α-BGT)-F/TC, a specific α7 nAChR antagonist. Moreover, a positive binding to α-Bgt was also observed on the cell surface of Treg, as viewed by fluorescent confoeal microscopy. In addition, a clear band of a7nAChR with a molecular mass of approximately 55 kD was found from Tregs by Western blotting analysis, and α7nAChR mRNA was expressed with the expected size of 199 bp from Tregs by reverse transcription-PCR. Conclusion Natural CD4~+ CD25~+ Tregs from mice express α7nAChR.