Effects of repetitive transcranial magnetic stimulation on neuronal excitability and ion channels in hindlimb unloading mice / 生物医学工程学杂志

Weightlessness in the space environment affects astronauts' learning memory and cognitive function. Repetitive transcranial magnetic stimulation has been shown to be effective in improving cognitive dysfunction. In this study, we investigated the effects of repetitive transcranial magnetic stimulation on neural excitability and ion channels in simulated weightlessness mice from a neurophysiological perspective. Young C57 mice were divided into control, hindlimb unloading and magnetic stimulation groups. The mice in the hindlimb unloading and magnetic stimulation groups were treated with hindlimb unloading for 14 days to establish a simulated weightlessness model, while the mice in the magnetic stimulation group were subjected to 14 days of repetitive transcranial magnetic stimulation. Using isolated brain slice patch clamp experiments, the relevant indexes of action potential and the kinetic property changes of voltage-gated sodium and potassium channels were detected to analyze the excitability of neurons and their ion channel mechanisms. The results showed that the behavioral cognitive ability and neuronal excitability of the mice decreased significantly with hindlimb unloading. Repetitive transcranial magnetic stimulation could significantly improve the cognitive impairment and neuroelectrophysiological indexes of the hindlimb unloading mice. Repetitive transcranial magnetic stimulation may change the activation, inactivation and reactivation process of sodium and potassium ion channels by promoting sodium ion outflow and inhibiting potassium ion, and affect the dynamic characteristics of ion channels, so as to enhance the excitability of single neurons and improve the cognitive damage and spatial memory ability of hindlimb unloading mice.

Voltage-gated sodium channels gene expression in Burning Mouth Syndrome: a case-control study

Abstract Burning mouth syndrome (BMS) is a condition characterized by painful symptoms of the oral mucosa, despite the absence of any clinical signs. Its etiology is unknown, and there is still no effective treatment to date. Current evidence has shown neuropathic impairment in BMS patients. Neuropathic pain can be related to the dysfunction of voltage-gated sodium channels, considering that these receptors regulate the induction of action potentials in nociceptive neurons. This study evaluated the gene expression of voltage-gated sodium channels Na v 1.7, Na v 1.8 and Na v 1.9 in these patients. The gene expressions of these channels were assessed by real time RT-PCR analysis of fresh-frozen tongue biopsies in a case-control study composed of 12 patients with BMS, and 5 healthy control patients, proportionally matched by sex and age, and analyzed using the 2^(-Delta Delta CT) method. There was no statistically significant difference between the analyzed groups, despite the increase in Na v 1.7 (fold-change = 3.13, p = 0.52) and decrease in Na v 1.9 (fold-change = 0.45, p = 0.36) gene expression in the BMS group. The Na v 1.8 gene was not expressed in any of the samples analyzed. Although the gene expression in the voltage-gated sodium channels in BMS under study seems to be comparable with that of the normal oral mucosa, the functionality of these channels in BMS has not yet been identified, thus suggesting that further research is needed to better understand these voltage-gated sodium channels.

Role of NALCN in hippocampal dentate gyrus in social behavior of mice / 中华麻醉学杂志

Objective:To evaluate the role of the sodium leak channel (NALCN) in the hippocampal dentate gyrus (DG) in the social behavior of mice.Methods:Thirty-nine male wild-type C57BL/6 mice, aged 6-8 weeks, weighing 18-22 g, were used in this study. Three mice were sacrificed to verify the expression and co-expression of NALCN with neuronal nuclear antigen (NeuN) in the hippocampal DG using the immunofluorescent staining. The remaining 36 mice were divided into 2 groups ( n=18 each) by the random number table method: control group (group C) and NALCN gene knockdown group (group KO). NALCN-shRNA virus was injected in group KO, and scrambled-shRNA virus was injected in group C. The three box social test and open field test were performed at 3 weeks after the virus injection. Mice were sacrificed under anesthesia after the behavioral test, hippocampal tissues were collected, and the injection location of the virus was verified with a fluorescence microscope, and the NALCN protein and mRNA expression in the hippocampal DG was detected by Western blot and real-time polymerase chain reaction, respectively. Results:NALCN and NeuN co-expressed a lot on the same neuron in the hippocampal DG of mice, indicating that NALCN was widely expressed on the neurons in the hippocampal DG. Compared with group C, the expression of NALCN and mRNA in the hippocampal DG was significantly down-regulated, and the social novelty preference disappeared ( P<0.05), and no significant change was found in the social ability and each parameter in the open field test in group KO ( P>0.05). Conclusions:NALCN in the hippocampal DG is involved in the regulation of social memory in mice, and the down-regulated expression of NALCN can lead to the loss of social novelty preference in mice.

nNav1.5 expression is associated with glutamate level in breast cancer cells

Abstract Background: Glutamate and voltage-gated sodium channels, both have been the target of intense investigation for its involvement in carcinogenesis and progression of malignant disease. Breast cancer with increased level of glutamate often metastasize to other organs (especially bone), whilst re-expression of 'neonatal' Nav1.5, nNav1.5 in breast cancer is known to promote cell invasion in vitro, metastasis in vivo and positive lymph node metastasis in patients. Methods: In this study, the role of nNav1.5 in regulating glutamate level in human breast cancer cells was examined using pharmacological approach (VGSCs specific blocker, TTX, glutamate release inhibitor, riluzole and siRNA-nNav1.5). Effect of these agents were evaluated based on endogenous and exogenous glutamate concentration using glutamate fluorometric assay, mRNA expression of nNav1.5 using qPCR and finally, invasion using 3D culture assay. Results: Endogenous and exogenous glutamate levels were significantly higher in aggressive human breast cancer cells, MDA-MB-231 cells compared to less aggressive human breast cancer cells, MCF-7 and non-cancerous human breast epithelial cells, MCF-10A. Treatment with TTX to MDA-MB-231 cells resulted in significant reduction of endogenous and exogenous glutamate levels corresponded with significant suppression of cell invasion. Subsequently, downregulation of nNav1.5 gene was observed in TTX-treated cells. Conclusions: An interesting link between nNav1.5 expression and glutamate level in aggressive breast cancer cells was detected and requires further investigation.

Relationship between Na + leak current channel in hippocampal dentate gyrus region and cognitive function in mice / 中华麻醉学杂志

Objective:To evaluate the relationship between Na + leak current channel (NALCN) in hippocampal dentate gyrus (DG) region and cognitive function in mice. Methods:Thirty-nine male wild type C57BL/6 mice, aged 6-8 weeks, weighing 18-22 g, were studied.Three mice were sacrificed to verify the expression of NALCN co-localized with neuronal nuclear antigen (NeuN) in the hippocampal DG region through immunofluorescence technique.The remaining 36 mice were divided into 2 groups ( n=18 each) by the random number table method: control group (group C) and NALCN gene knockout group (group KO). NALCN-shRNA virus was injected in hippocampal DG region in group KO, and scrambled-shRNA virus was injected in group C. Three weeks after virus injection, behavioral tests (Y maze test and open field test) were performed, then the animals were sacrificed, and the hippocampal tissues were removed for determination of the expression of NALCN protein and mRNA using Western blot and real-time polymerase chain reaction. Results:NALCN and NeuN colocalized a lot on the same neuron in the hippocampal DG region of mice, and NALCN was widely expressed in the hippocampal DG region.Compared with group C, the expression of NALCN protein and mRNA was significantly down-regulated, the times of entering the new arm were reduced, the duration of staying at the new arm was shortened ( P<0.05), and no significant change was found in the parameters mentioned above in the open field test in group KO ( P>0.05). Conclusions:NALCN in the hippocampal DG region is involved in the regulation of cognitive function in mice, and the down-regulation of NALCN may lead to cognitive decline.

Application of lacosamide in sodium channel-related epilepsy in young infants / 中华神经科杂志

Objective:To report 2 young infants of sodium channel related epilepsy with SCN2A gene mutation, and to discuss the clinical characteristics of the disease and the efficacy and safety of lacosamide combined with the literature.Methods:Corresponding information of 2 children hospitalized in the Department of Neurology of Hunan Children′s Hospital in July 2021 and October 2021 was collected, including the symptoms, comprehensive physical examination, blood, cerebrospinal fluid, imaging, electrophysiological examination, diagnosis and treatment process, response to treatment and other clinical data, as well as the sequencing results of the whole exome of the children. The efficacy and safety of lacosamide were analyzed, and the related literatures of the Biomedical Literature Database, Wanfang Data Knowledge Service Platform and Chinese Knowledge Infrastructure Database were searched and reviewed.Results:Both of the 2 cases were girl. Their onset age was within 3 months. The initial symptoms were frequent convulsions and backward development. There was no structural abnormality in the head image. The convulsions could not be controlled according to conventional multidrug treatment. The seizures were quickly controlled with lacosamide. Now they have been followed up for 6 months. No obvious adverse reactions were found. Case 1 gene test results showed the SCN2A gene (chr2:166152333-166246334) heterozygous deletion, SCN1A gene (chr2:166847754-16693013) heterozygous deletion, the deletion size being about 5.72 Mb. Case 2 gene test results showed new missense mutation of SCN2A (c.1285G>A, p.Glu429Lys). There were dozens of seizures every day. They were treated with valproic acid, oxcarbazepine and levetiracetam successively. The seizures could not be controlled. Three focal seizures originated in the left temporal region were detected by electroencephalogram. There was no recurrence on the third day after adding lacosamide, and there was no attack after 5 months of follow-up. No obvious adverse reactions were found during follow-up.Conclusions:Sodium channel related epileptic encephalopathy often starts early, has frequent seizures, and can be accompanied by backward psychomotor development at the same time. The slow sodium channel blocker lacosamide has good efficacy and safety in the treatment of sodium channel-related epilepsy with SCN2A gene mutation or combined SCN1A gene mutation.

MS/MS analysis of four scorpion venoms from Colombia: a descriptive approach

Background: Scorpions are widely known for the neurotoxic effects of their venoms, which contain peptides affecting ionic channels. Although Colombia is recognized for its scorpion diversity, only a few studies are available describing the venom content. Methods: In this descriptive study, we analyzed the MS/MS sequence, electrophoretic and chromatographic profile linked to a bioinformatics analysis of the scorpions Chactas reticulatus (Chactidae), Opisthacanthus elatus (Hormuridae), Centruroides edwardsii (Buthidae) and Tityus asthenes (Buthidae) from Colombia. Results: Each scorpion showed a specific electrophoretic and chromatographic profile. The electrophoretic profiles indicate the presence of high molecular mass compounds in all venoms, with a predominance of low molecular mass compounds in the Buthidae species. Chromatographic profiles showed a similar pattern as the electrophoretic profiles. From the MS/MS analysis of the chromatographic collected fractions, we obtained internal peptide sequences corresponding to proteins reported in scorpions from the respective family of the analyzed samples. Some of these proteins correspond to neurotoxins affecting ionic channels, antimicrobial peptides and metalloproteinase-like fragments. In the venom of Tityus asthenes, the MSn analysis allowed the detection of two toxins affecting sodium channels covering 50% and 84% of the sequence respectively, showing 100% sequence similarity. Two sequences from Tityus asthenes showed sequence similarity with a phospholipase from Opisthacanthus cayaporum indicating the presence of this type of toxin in this species for the first time. One sequence matching a hypothetical secreted protein from Hottentotta judaicus was found in three of the studied venoms. We found that this protein is common in the Buthidae family whereas it has been reported in other families - such as Scorpionidae - and may be part of the evolutionary puzzle of venoms in these arachnids. Conclusion: Buthidae venoms from Colombia can be considered an important source of peptides similar to toxins affecting ionic channels. An interesting predicted antimicrobial peptide was detected in three of the analyzed venoms.(AU)

Voltage-gated sodium channel α2-subunit gene related epilepsy with autism spectrum disorder: a case report / 中华神经科杂志

Objective:To summarize the clinical features and treatment of voltage-gated sodium channel α2-subunit (SCN2A) gene-related epilepsy.Methods:The clinical manifestion, video electroencephalography, head magnetic resonance imaging of a child diagnosed with epilepsy in Hebei Children′s Hospital were analyzed. Additionally, blood samples of the family were tested for the whole exome sequencing.Results:The boy aged 20 months,had been developed backward since childhood and accompanied by autism spectrum disorder manifestations. Seizures occurred at 19 months, manifested as isolated and clusters of spasms or generalized tonic seizures. The whole exome sequencing of the family revealed that the proband had c.4543C>T heterozygous mutation in the SCN2A gene, and both parents showed wild type. The effect of multiple anti-epileptic drugs on the children was not good, but the epilepsy was controlled after the final addition of perampane.Conclusions:The c.4543C>T heterozygous variant of SCN2A gene is the cause of disease in this child. This variant can cause epilepsy with autism spectrum disorder. The location and type of SCN2A mutations are strongly related with phenotypes, and a clear genetic etiology contributes to accurate treatment of children.

Lidocaine in oncological surgery: the role of blocking in voltage-gated sodium channels. A narrative review / Lidocaína em cirurgia oncológica: o papel do bloqueio dos canais de sódio dependentes de voltagem. Revisão narrativa

Abstract Background: The current evidence suggests that oncological surgery, which is a therapy used in the treatment of solid tumors, increases the risk of metastasis. In this regard, a wide range of tumor cells express Voltage-Gated Sodium Channels (VGSC), whose biological roles are not related to the generation of action potentials. In epithelial tumor cells, VGSC are part of cellular structures named invadopodia, involved in cell proliferation, migration, and metastasis. Recent studies showed that lidocaine could decrease cancer recurrence through its direct effects on tumor cells and immunomodulatory properties on the stress response. Objective: The aim of this narrative review is to highlight the role of VGSC in tumor cells, and to describe the potential antiproliferative effect of lidocaine during the pathogenesis of metastasis. Contents: A critical review of literature from April 2017 to April 2019 was performed. Articles found on PubMed (2000-2019) were considered. A free text and MeSH-lidocaine; voltage-gated sodium channels; tumor cells; invadopodia; surgical stress; cell proliferation; metastasis; cancer recurrence - for articles in English, Spanish and Portuguese language - was used. A total of 62 were selected. Conclusion: In animal studies, lidocaine acts by blocking VGSC and other receptors, decreasing migration, invasion, and metastasis. These studies need to be replicated in humans in the context of oncological surgery.

Resumo Justificativa: As evidências atuais sugerem que a cirurgia oncológica, usada no tratamento de tumores sólidos, aumenta o risco de metástase. Nesse sentido, uma ampla gama de células tumorais expressa Canais de Sódio Dependentes de Voltagem (CSDV), cujos papéis biológicos não estão relacionados à produção de potencial de ação. Nas células epiteliais tumorais, o CSDV é parte integrante de estruturas celulares denominadas invadópodes, que participam da proliferação, migração e metástase celular. Estudos recentes mostraram que a lidocaína pode diminuir a recorrência do câncer através de efeitos diretos nas células tumorais e de propriedades imunomoduladoras na resposta ao estresse. Objetivo: O objetivo desta revisão narrativa é analisar o papel do CSDV nas células tumorais e descrever o possível efeito antiproliferativo da lidocaína na patogênese das metástases. Conteúdo: Foi realizada uma revisão crítica da literatura de Abril de 2017 a Abril de 2019. Os artigos encontrados no PubMed (2000 − 2019) foram analisados. Pesquisamos textos de linguagem livre e descritores MeSH-lidocaína; canais de sódio dependentes de voltagem; células tumorais; invadópodes; estresse cirúrgico; proliferação celular; metástase; recorrência do câncer − em artigos publicados em inglês, espanhol e português. Foram selecionadas 62 publicações. Conclusão: Em estudos empregando animais, a lidocaína atua bloqueando o CSDV e outros receptores, diminuindo a migração, invasão e metástase. Esses estudos precisam ser replicados em humanos submetidos a cirurgia oncológica.

Pseudo hypoaldosteronism type 1B due to novel deletion mutation in SCNN1A gene

Pseudo hypoaldosteronism type 1B (PHA1B) is a systemic form of salt wasting. Children present after the first week of life with typical symptoms of an adrenal crisis. PHA1B is caused by autosomal recessive homozygous mutations in genes encoding epithelial sodium channels (ENaC) subunits ?, ? and ?. ENaC are widespread and present in renal tubules, airways, colon, sweat and salivary glands. Electrolyte imbalance is significant with severe hyponatremia, hyperkalemia and metabolic acidosis. In early life until approximately one year of age electrolytes remain unstable despite active management but then gradually improve. The mainstay of treatment is high dose salt replacement, sodium bicarbonate and sodium polystyrene therapy. The adequate treatment and monitoring can result in normal physical and psychomotor development. We present a case of PHA1B with severe intractable electrolyte imbalances in neonatal period. The genetic sequence revealed a novel homozygous deletion mutation in exon 4 of the SCNN1A gene (c.942delC, p.N315Tfs*16).

Progress in Study on Ion Channel and Pathogenesis of Irritable Bowel Syndrome / 胃肠病学

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder, mainly manifested as recurrent abdominal pain, abdominal discomfort and/or changes of defecation habits and stool character, its pathogenesis has not been fully clarified. The pathophysiology is characterized by visceral hypersensitivity, abnormal intestinal motility, and so on. Abnormality of ion channels may be in involved in the pathophysiological mechanism of IBS. This article reviewed the progress in study on ion channels and pathogenesis of IBS.

Voltage-gated sodium channel and painful diabetic neuropathy / 中国医师杂志

Sodium channel provides a new idea for the study of painful diabetic neuropathy.Based on the research status of sodium channel and painful diabetic neuropathy at home and abroad,five sodium channels with high correlation with diabetic painful neuropathy were selected,and the characteristics of these sodium channels were summarized.The expression status of sodium channel in diabetic painful neuropathy model was summarized,and the role of sodium channel in the pathogenesis of diabetic painful neuropathy was summarized.The relationship between sodium channel and diabetic painful neuropathy was analyzed,as well as the difficulties facing the current research,in order to provide references for the research and application of sodium channel in the treatment of diabetic painful neuropathy.

Role of protein kinase C in maintenance of chronic inflammatory pain in rats: the relationship with expression of Nav1.8 in dorsal root ganglion / 中华麻醉学杂志

Objective To evaluate the role of protein kinase C in the maintenance of chronic inflammatory pain in rats and the relationship with the expression of Nav1.8 in the dorsal root ganglion (DRG).Methods Thirty pathogen-free healthy female Sprague-Dawley rats,weighing 180-220 g,were divided into 3 groups using a random number table:control group (group C),chronic inflammatory pain group (group CIP) and PKC inhibitor group (group P).Normal saline 20 μl was injected into the plantar surface of the right hindpaw every day for 14 consecutive days in group C.Prostaglandin E2 100 ng was injected into the plantar surface of the right hindpaw every day for 13 consecutive days to establish the model of chronic inflammatory pain,and dimethyl sulfoxide 20μl was injected into the plantar surface of the right hindpaw on 14th day in group CIP.Prostaglandin E2 100 ng was injected into the plantar surface of the right hindpaw every day for 13 consecutive days,and PKC inhibitor GF1O9203X 100 nmol/20 μl was injected into the plantar surface of the right hindpaw on 14th day in group P.The mechanical paw withdrawal threshold (MWT) was measured at 1 day before injection (T0) and 1,3,7 and 14 days after the last injection (T1-4).The DRGs of the lumbar segment (L4.5) were removed for determination of Nav1.8 expression using immunofluorescence and Western blot.Results Compared with group C,the MWT was significantly decreased at T1-4 in CIP and P groups,and the expression of Nav1.8 in DRGs was significantly up-regulated in group CIP (P＜0.05).Compared with group CIP,the MWT was significantly increased at T4,and the expression of Nav1.8 in DRGs was down-regulated in group P (P＜0.05).Conclusion Up-regulated expression of Nav1.8 after PKC activation in DRGs is involved in the maintenance of chronic inflammatory pain in rats.

Expression and Role of Voltage-Gated Sodium Channels in Human Dorsal Root Ganglion Neurons with Special Focus on Nav1.7, Species Differences, and Regulation by Paclitaxel / 神经科学通报·英文版

Voltage-gated sodium channels (Navs) play an important role in human pain sensation. However, the expression and role of Nav subtypes in native human sensory neurons are unclear. To address this issue, we obtained human dorsal root ganglion (hDRG) tissues from healthy donors. PCR analysis of seven DRG-expressed Nav subtypes revealed that the hDRG has higher expression of Nav1.7 (~50% of total Nav expression) and lower expression of Nav1.8 (~12%), whereas the mouse DRG has higher expression of Nav1.8 (~45%) and lower expression of Nav1.7 (~18%). To mimic Nav regulation in chronic pain, we treated hDRG neurons in primary cultures with paclitaxel (0.1-1 μmol/L) for 24 h. Paclitaxel increased the Nav1.7 but not Nav1.8 expression and also increased the transient Na currents and action potential firing frequency in small-diameter (<50 μm) hDRG neurons. Thus, the hDRG provides a translational model in which to study "human pain in a dish" and test new pain therapeutics.

Differential Inhibition of Nav1.7 and Neuropathic Pain by Hybridoma-Produced and Recombinant Monoclonal Antibodies that Target Nav1.7 : Differential activities of Nav1.7-targeting monoclonal antibodies / 神经科学通报·英文版

The voltage-gated Na channel subtype Nav1.7 is important for pain and itch in rodents and humans. We previously showed that a Nav1.7-targeting monoclonal antibody (SVmab) reduces Na currents and pain and itch responses in mice. Here, we investigated whether recombinant SVmab (rSVmab) binds to and blocks Nav1.7 similar to SVmab. ELISA tests revealed that SVmab was capable of binding to Nav1.7-expressing HEK293 cells, mouse DRG neurons, human nerve tissue, and the voltage-sensor domain II of Nav1.7. In contrast, rSVmab showed no or weak binding to Nav1.7 in these tests. Patch-clamp recordings showed that SVmab, but not rSVmab, markedly inhibited Na currents in Nav1.7-expressing HEK293 cells. Notably, electrical field stimulation increased the blocking activity of SVmab and rSVmab in Nav1.7-expressing HEK293 cells. SVmab was more effective than rSVmab in inhibiting paclitaxel-induced mechanical allodynia. SVmab also bound to human DRG neurons and inhibited their Na currents. Finally, potential reasons for the differential efficacy of SVmab and rSVmab and future directions are discussed.

Preliminary study on the role of voltage-gated sodium channel subtype Nav1.5 in lymph node metastasis of oral squamous cell carcinoma / 中华口腔医学杂志

Objective@#To investigate the relationship between the expression of voltage-gated sodium channel subtype Nav1.5 in oral squamous cell carcinoma (OSCC) and the occurrence and lymph node metastasis of OSCC.@*Methods@#Totally 10 samples of normal oral mucosa tissue as control group, 26 samples of OSCC as the experimental group was divided into non-metastatic group (n=16) and metastatic group (n=10) according to the presence or absence of lymph node metastasis. Quantitative real-time PCR (qPCR), Western blotting, immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA) were used to detect the expression of Nav1.5 in control group and experimental groups at mRNA and protein levels. The data were analyzed by one-way analysis.@*Results@#The expression of Nav1.5 mRNA in the experimental group (non-metastatic group: 2.311±0.134, metastatic group: 4.462±0.362) was higher than those in the control group (1.054±0.162) (P=0.037; P=0.029), and the metastasis group was significantly higher than the non-metastasis group (P=0.031). Western blotting showed the expression of Nav1.5 in experimental groups (non-metastatic: 0.143±0.005, metastatic: 0.253±0.015) was up-regulated significantly compared with control group (0.080±0.010) (P=0.034, P=0.026), and the metastasis group was significantly higher than the non-metastasis group (P=0.033). The immunohistochemistry show the positive expression rates of Nav1.5 in normal and OSCC tissues were 1/10 and 92% (24/26). The differences were statistically significant (P=0.016), and the metastasis group was significantly higher than the non-metastasis group (P=0.028). The ELISA results revealed that the level of Nav1.5 in control was control group (0.834±0.103) μg/L, in non-metastasis group was (1.578±0.167) μg/L, in metastasis group was (3.882±0.422) μg/L (P=0.041; P=0.032), and the metastasis group was significantly higher than the non-metastasis group (P=0.030).@*Conclusions@#Nav1.5 was highly expressed in poorly differentiated OSCC and the expression was significantly different with or without lymph node metastasis. Nav1.5 may be involved in the occurrence and metastasis of OSCC.

Role of AT1 R-CaN signaling pathway in regulation of Nav1.5 protein ex-pression in hypertrophic ventricular myocytes from neonatal rats / 中国病理生理杂志

AIM:To investigate the effect of angiotensin II type 1 receptor (AT1R)-calcineurin (CaN) signa-ling pathway on the expression of sodium current channel Nav 1.5 at mRNA and protein levels in the hypertrophic ventricu-lar myocytes from neonatal rats .METHODS:The ventricular myocytes were isolated from the ventricles of 1-day-old neo-natal Sprague-Dawley rats and were divided into 4 groups according to different drug intervention as control group , pheny-lephrine (PE) group, losartan (Los)+PE group and cyclosporin A (CsA)+PE group.The method of RNA interference mediated by adenovirus carrying short hairpin RNA ( shRNA) was used to knock down the gene which encodes the beta subtype of CaN A subunit (CnAβ) and the cells were divided into 4 groups as Ad-Null group, Ad-Null+PE group, Ad-CnAβshRNA1 group and Ad-CnAβshRNA1+PE group.The mRNA expression of brain natriuretic peptide ( BNP) ,β-my-osin heavy chain (β-MHC) and Nav1.5 was detected by RT-qPCR.The protein levels of CnAβand Nav1.5 in the whole-cell extracts were determined by Western blot analysis .RESULTS:Treatment of the neonatal rat ventricular myocytes with PE for 24 h increased the protein-to-DNA ratio and the mRNA expression of BNP and β-MHC.The size of the cell surface was also increased after PE treatment .Treatment of the cells with PE increased the protein expression of CnAβ, and re-duced the protein expression of Nav 1.5.Both Los and CsA prevented those effects of PE .The mRNA expression of Nav1.5 was reduced by PE , and no significant difference of Nav 1.5 mRNA expression among PE group , Los+PE group and CsA+PE group was observed .Silencing of CnAβin the neonatal rat ventricular myocytes using Ad-CnAβshRNA1 inhibited the ability of PE to increase the mRNA expression of BNP , and diminished the ability of PE to reduce the protein expression of Nav1.5.CONCLUSION:AT1 R-CaN signaling pathway participates in regulating protein expression of Nav 1.5 in the hy-pertrophic ventricular myocytes from neonatal rats .

Renal intercalated cells and blood pressure regulation

Type B and non-A, non-B intercalated cells are found within the connecting tubule and the cortical collecting duct. Of these cell types, type B intercalated cells are known to mediate Cl⁻ absorption and HCO₃⁻ secretion largely through pendrin-dependent Cl⁻/HCO₃⁻ exchange. This exchange is stimulated by angiotensin II administration and is also stimulated in models of metabolic alkalosis, for instance after aldosterone or NaHCO₃ administration. In some rodent models, pendrin-mediated HCO₃⁻ secretion modulates acid-base balance. However, the role of pendrin in blood pressure regulation is likely of more physiological or clinical significance. Pendrin regulates blood pressure not only by mediating aldosterone-sensitive Cl⁻ absorption, but also by modulating the aldosterone response for epithelial Na⁺ channel (ENaC)-mediated Na⁺ absorption. Pendrin regulates ENaC through changes in open channel of probability, channel surface density, and channels subunit total protein abundance. Thus, aldosterone stimulates ENaC activity through both direct and indirect effects, the latter occurring through its stimulation of pendrin expression and function. Therefore, pendrin contributes to the aldosterone pressor response. Pendrin may also modulate blood pressure in part through its action in the adrenal medulla, where it modulates the release of catecholamines, or through an indirect effect on vascular contractile force. This review describes how aldosterone and angiotensin II-induced signaling regulate pendrin and the contributory role of pendrin in distal nephron function and blood pressure.

Renal intercalated cells and blood pressure regulation

Type B and non-A, non-B intercalated cells are found within the connecting tubule and the cortical collecting duct. Of these cell types, type B intercalated cells are known to mediate Cl⁻ absorption and HCO₃⁻ secretion largely through pendrin-dependent Cl⁻/HCO₃⁻ exchange. This exchange is stimulated by angiotensin II administration and is also stimulated in models of metabolic alkalosis, for instance after aldosterone or NaHCO₃ administration. In some rodent models, pendrin-mediated HCO₃⁻ secretion modulates acid-base balance. However, the role of pendrin in blood pressure regulation is likely of more physiological or clinical significance. Pendrin regulates blood pressure not only by mediating aldosterone-sensitive Cl⁻ absorption, but also by modulating the aldosterone response for epithelial Na⁺ channel (ENaC)-mediated Na⁺ absorption. Pendrin regulates ENaC through changes in open channel of probability, channel surface density, and channels subunit total protein abundance. Thus, aldosterone stimulates ENaC activity through both direct and indirect effects, the latter occurring through its stimulation of pendrin expression and function. Therefore, pendrin contributes to the aldosterone pressor response. Pendrin may also modulate blood pressure in part through its action in the adrenal medulla, where it modulates the release of catecholamines, or through an indirect effect on vascular contractile force. This review describes how aldosterone and angiotensin II-induced signaling regulate pendrin and the contributory role of pendrin in distal nephron function and blood pressure.

Behavior of ion channels controlled by electric potential difference and of Toll-type receptors in neuropathic pain pathophysiology / O comportamento dos canais iônicos controlados por diferença de potencial elétrico e dos receptores do tipo Toll na fisiopatologia da dor neuropática

ABSTRACT BACKGROUND AND OBJECTIVES: Neuropathic pain is a severe and refractory medical condition, for which only partially effective treatments are currently available. Recent experimental data on the role of voltage-gated ion channels, particularly sodium and potassium channels, have been described. In this brief review, we aimed at addressing the role of sodium and potassium channels in the pathophysiology of neuropathic pain and recent evidences about their role as a new therapeutic target in painful conditions. CONTENTS: Pharmacological and biophysical studies have shown that voltage-gated sodium channels, particularly Nav1.3, Nav1.7, Nav1.8, and Nav1.9 isoforms are important in the pathophysiology of neuropathic pain. Similarly, the involvement of voltage-gated potassium channels, especially KV1 and KV7 isoforms, has been clearly shown in the establishment of chronic painful conditions. Recent evidences that ion sodium and potassium channels dysfunction is involved in the development of chronic painful conditions corroborate the possibility of pharmacologically modulate them as new therapeutic strategies. CONCLUSION: Recent evidences suggest that selective sodium channel blockers and potassium channels activating of modulating drugs are important and promising targets in the search for new options to treat neuropathic pain.

RESUMO JUSTIFICATIVA E OBJETIVOS: A dor neuropática constitui-se em uma condição clínica grave e refratária, para a qual apenas tratamentos com eficácia parcial estão disponíveis. Estudos experimentais recentes sobre o papel relevante de canais iônicos controlados por diferença de potencial elétrico ou voltagem, especialmente canais de sódio e potássio, tem sido descritos. Nesta breve revisão, objetivou-se abordar o papel dos canais de sódio e potássio na fisiopatologia da dor neuropática e as recentes evidências a respeito do seu papel como novo alvo terapêutico em quadros dolorosos. CONTEÚDO: Estudos farmacológicos e biofísicos tem demonstrado que os canais de sódio dependentes de voltagem, particularmente as isoformas Nav1.3, Nav1.7, Nav1.8 e Nav1.9 são relevantes na fisiopatologia da dor neuropática. De forma similar, o envolvimento dos canais de potássio dependentes de voltagem, especialmente as isoformas Kv1 e Kv7, tem sido claramente demonstrado no estabelecimento de quadros dolorosos crônicos. As evidências recentes de que a disfunção de canais iônicos de sódio e potássio está envolvida no desenvolvimento de quadros dolorosos crônicos evidenciam a capacidade de modulá-los farmacologicamente em novas estratégias terapêuticas. CONCLUSÃO: Evidências recentes sugerem que bloqueadores seletivos de canais de sódio e fármacos ativadores ou moduladores dos canais de potássio representam um alvo relevante e promissor na busca por novas opções no tratamento da dor neuropática.