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Objectives: Centrally-acting antitussives with inhibitory effects on G protein-coupled inwardly rectifying potassium (GIRK) channels have been shown to also inhibit methamphetamine-induced hyperactivity in mice. In this study, we examined if cloperastine, which is the most potent inhibitor of the GIRK channels among antitussives, is sensitive to the expression levels of GIRK channels in the brain of methamphetaminetreated mice. Materials and Methods: The brain tissues have been removed and the total RNA has been extracted from tissues. The mRNA levels were evaluated using semiquantitative reverse transcription-polymerase chain reaction. Results: The concentration levels of the mRNA of GIRK channels within the ventral midbrain of methamphetamine-treated mice increased as compared with that in control and cloperastine reduced an upregulation in GIRK2, one of the subunits of the GIRK channels, by the injection of methamphetamine. Conclusion: These findings suggest that cloperastine might ameliorate hyperactivity by inhibiting the GIRK channels in the brain.
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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.
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Animals , Mice , Transcranial Magnetic Stimulation , Hindlimb Suspension , Neurons , Cognitive Dysfunction , BrainABSTRACT
Distal convoluted tubules (DCT), which contain the Na-Cl cotransporter (NCC) inhibited by thiazide diuretics, undergo complex modulation to preserve Na+ and K+ homeostasis. The lysine kinases 1 and 4 (WNK1 and WNK4), identified as hyperactive in the hereditary disease pseudohypoaldosteronism type 2, are responsible for activation of NCC and consequent hypokalemia and hypertension. WNK4, highly expressed in DCT, activates the SPAK/OSR1 kinases, which phosphorylate NCC and other regulatory proteins and transporters in the distal nephron. WNK4 works as a chloride sensor through a Cl- binding site, which acts as an on/off switch at this kinase in response to changes of basolateral membrane electrical potential, the driving force of cellular Cl- efflux. High intracellular Cl- in hyperkalemia decreases NCC phosphorylation and low intracellular Cl- in hypokalemia increases NCC phosphorylation and activity, which makes plasma K+ concentration a central modulator of NCC and of K+ secretion. The WNK4 phosphorylation by cSrc or SGK1, activated by angiotensin II or aldosterone, respectively, is another relevant mechanism of NCC, ENaC, and ROMK modulation in states such as volume reduction, hyperkalemia, and hypokalemia. Loss of NCC function induces upregulation of electroneutral NaCl reabsorption by type B intercalated cells through the combined activity of pendrin and NDCBE, as demonstrated in double knockout mice (KO) animal models, Ncc/pendrin or Ncc/NDCBE. The analysis of ks-Nedd-4-2 KO animal models introduced the modulation of NEDD4-2 by intracellular Mg2+ activity as an important regulator of NCC, explaining the thiazide-induced persistent hypokalemia.
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Objective:To investigate the clinical characteristics and outcome of patients with voltage-gated potassium channel complex (VGKCc) antibody associated clinical syndromes complicated with myasthenia gravis (MG) with thymoma.Methods:The clinical history, examinations and follow-up prognosis of 2 cases of VGKCc antibodies associated clinical syndromes with MG complicated with thymoma in Qilu Hospital (Qingdao), Cheeloo College of Medicine,Shandong University in September 2020 and December 2020 were reviewed. Related literatures were summarized at the same time.Results:Case 1, a 64-year-old female clinically presented with cognitive impairment, psychosis, and epilepsy seizures, whose serum autoimmune antibody testing showed positive leucine-rich glioma-inhibited 1 (LGI1) antibody, was diagnosed as anti-LGI1 encephalitis,and had history of MG with thymoma. Her symptoms were improved by immunotherapy. Case 2, a 67-year-old male, was diagnosed as MG, and developed cognitive impairment, myokymia and autonomic dysfunction later. His serum autoimmune antibody testing showed positive contactin associated protein-like 2 antibody. Therefore, Morvan syndrome complicated with MG with thymoma was definitely diagnosed. After admission, the patient was improved with immunotherapy and thymoma resection.Conclusions:Patients with VGKCc antibody-associated clinical syndromes complicated with MG have the clinical characteristics of the two diseases simultaneously, and there is also crossover. Immunotherapy and treatment for thymoma are generally effective.
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Objective:To analyze clinical characteristics and genetic characteristics of children with ATP sensitive potassium passage (K ATP-HI). Methods:Forty-five children with genetically confirmed K ATP-HI and their families admitted to Beijing Children′s Hospital of Capital Medical University between February 2002 and December 2018 were selected as the study subjects. A detailed retrospective analysis of the patient's clinical characteristics, diagnosis and treatment process, disease-causing gene carrying status and later follow-up data was performed. ABCC8/KCNJ11 gene was sequenced by second-generation sequencing technology. Results:Among 45 children with K ATP-HI, 34 cases (75.6%) were neonatal onset, the first symptoms of 21 cases (46.7%) were convulsions. 39 cases had been treated with diazoxide, including 12 cases (30.8%) with good efficacy, 16 cases (41%) with poor efficacy and 11 cases with uncertain efficacy. Octreotide was further applied in 18 patients with uncertain or ineffective efficacy after diazoxide treatment, and 13 cases (72.2%) were effective, 3 cases were ineffective, and 2 cases were uncertain. 10 CHI patients who were ineffective to drug treatment or had clearly focal lesions confirmed by 18F-dopa positron emission by computed tomography ( 18F-DOPA PET) scans had undergone surgical treatment, 8 of which underwent partial pancreatectomy and blood glucose returned to normal after the operation; the other 2 cases underwent subtotal pancreatectomy and both had secondary diabetes after operation. Among 45 children with K ATP-HI, 1 case carried both ABCC8 and KCNJ11 mutations, 10 cases carried ABCC8 compound heterozygous mutations, and the remaining 34 cases carried ABCC8/KCNJ11 single genetic mutation. Among them, 21 cases had paternal inheritance, and 3 cases had maternal inheritance, 6 cases were identified with de novo mutations. Conclusions:Diazoxide treatment was ineffective for most K ATP-HI children, but octreotide had a higher effective rate. Partial pancreatectomy for focal type patients had a higher cure rate, and there was a risk of secondary diabetes after subproximal pancreatectomy, so it was very important to clarify the histological type of children before surgery. ABCC8 gene mutations and KCNJ11 gene mutations were the main pathogenic genes of K ATP-HI. Among patients carrying mutations in single ABCC8 or KCNJ11 gene mutation, K ATP-HI inherited by paternity were the majority. Some K ATP-HI children can relieve the hypoglycemia symptoms by themselves.
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Sulfonylureas are widely used oral anti-diabetic drugs. However, its long-term usage effects on patients' lifespan remain controversial, with no reports of influence on animal longevity. Hence, the anti-aging effects of chlorpropamide along with glimepiride, glibenclamide, and tolbutamide were studied with special emphasis on the interaction of chlorpropamide with mitochondrial ATP-sensitive K+ (mitoK-ATP) channels and mitochondrial complex II. Chlorpropamide delayed aging in Caenorhabditis elegans, human lung fibroblast MRC-5 cells and reduced doxorubicin-induced senescence in both MRC-5 cells and mice. In addition, the mitochondrial membrane potential and ATP levels were significantly increased in chlorpropamide-treated worms, which is consistent with the function of its reported targets, mitoK-ATP channels. Increased levels of mitochondrial reactive oxygen species (mtROS) were observed in chlorpropamide-treated worms. Moreover, the lifespan extension by chlorpropamide required complex II and increased mtROS levels, indicating that chlorpropamide acts on complex II directly or indirectly via mitoK-ATP to increase the production of mtROS as a pro-longevity signal. This study provides mechanistic insight into the anti-aging effects of sulfonylureas in C. elegans.
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Objective:To evaluate the relationship between the euchromatic histone-lysine N-methyltransferase (G9a) and sodium-dependent activation of potassium channel (Slack) in the dorsal root ganglia (DRG) of rats with neuropathic pain (NP).Methods:Forty-eight clean-grade healthy male Sprague-Dawley rats, aged 1 month, weighing 100-120 g, were divided into 4 groups ( n=12 each) by a random number table method: sham operation group (S group), vector plus sham operation group (VS group), vector plus NP group (VN group), and G9a CRISPR/Cas9 knockout plus NP group (GN group). Sham operation was performed at the age of 2 months in group S. In group VS, AAV5 1 μl was microinjected into L 4 and L 5 DRG at the age of 1 month, and sham operation was performed at the age of 2 months.In VN group and GN group, AAV5 and G9a CRISPR/Cas9 knockout plasmid 1 μl were microinjected into L 4 and L 5 DRG at the age of 1 month, and NP model was established by spinal nerve ligation (SNL) at the age of 2 months.Six rats in each group were selected to measure the mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) before microinjection (T 0), before SNL (T 1), and at 3, 5 and 7 days after SNL (T 2-4). The animals were sacrificed after the last behavioral testing, the DRGs of lumbar segment (L 4, 5) were removed for determination of the expression of G9a, dimethylation of histone H3 at lysine 9(H3K9me2) and Slack (by Western blot). At 7 days after establishing the model, 6 rats from each group were selected to culture the primary DRG neurons.The frequency and amplitude of Slack current in DRG neurons and miniature excitatory post-synaptic currents (mEPSCs) in the spinal dorsal horn were measured by whole-cell patch-clamp technique. Results:Compared with group S, the TWL was significantly shortened and the MWT was decreased at T 2-4, the expression of G9a and H3K9me2 in the spinal dorsal horn was up-regulated, the expression of Slack was down-regulated, the amplitude and frequency of Slack currents in DRG neurons were decreased, and the frequency of mEPSCs was increased in group VN ( P<0.05), and no significant change was found in the parameters mentioned above in group VS ( P>0.05). Compared with group VN, the TWL was significantly prolonged and the MWT was increased at T 2-4, the expression of G9a and H3K9me2 in the spinal dorsal horn was down-regulated, the expression of Slack was up-regulated, the amplitude and frequency of Slack currents in DRG neurons were increased, and the frequency of mEPSCs was decreased in group GN ( P<0.05). Conclusion:The mechanism of NP is related to up-regulating the expression of G9a in DRG, thus inhibiting the expression and opening of Slack channels in rats.
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As a noninvasive neuromodulation technique, transcranial magnetic stimulation (TMS) is widely used in the clinical treatment of neurological and psychiatric diseases, but the mechanism of its action is still unclear. The purpose of this paper is to investigate the effects of different frequencies of magnetic stimulation (MS) on neuronal excitability and voltage-gated potassium channels in the
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Animals , Mice , Action Potentials , Magnetic Phenomena , Mental Disorders , Neurons , Patch-Clamp Techniques , Potassium Channels, Voltage-GatedABSTRACT
The tarantula Chilobrachys jingzhao is one of the largest venomous spiders in China. In previous studies, we purified and characterized at least eight peptides from C. jingzhao venom. In this report, we describe the purification and characterization of Jingzhaotoxin-X (JZTX-X), which selectively blocks Kv4.2 and Kv4.3 potassium channels. Methods: JZTX-X was purified using a combination of cation-exchange HPLC and reverse-phase HPLC. The amino-acid sequence was determined by automated Edman degradation and confirmed by mass spectrometry (MS). Voltage-gated ion channel currents were recorded in HEK293t cells transiently transfected with a variety of ion channel constructs. In addition, the hyperalgesic activity of JZTX-X and the toxin´s effect on motor function were assessed in mice. Results: JZTX-X contained 31 amino acids, with six cysteine residues that formed three disulfide bonds within an inhibitory cysteine knot (ICK) topology. In whole-cell voltage-clamp experiments, JZTX-X inhibited Kv4.2 and Kv4.3 potassium channels in a concentration- and voltage-dependent manner, without affecting other ion channels (Kv1.1, 1.2, 1.3, 2.1, delayed rectifier potassium channels, high- and low-voltage-activated Ca2+ channels, and voltage-gated sodium channels Nav1.5 and 1.7). JZTX-X also shifted the voltage-dependent channel activation to more depolarized potentials, whereas extreme depolarization caused reversible toxin binding to Kv4.2 channels. JZTX-X shifted the Kv4.2 and Kv4.3 activities towards a resting state, since at the resting potential the toxin completely inhibited the channels, even in the absence of an applied physical stimulus. Intrathecal or intraplantar injection of JZTX-X caused a long-lasting decrease in the mechanical nociceptive threshold (hyperalgesia) but had no effect on motor function as assessed in the rotarod test. Conclusions: JZTX-X selectively suppresses Kv4.2 and Kv4.3 potassium channel activity in a concentration- and voltage-dependent manner and causes long-lasting mechanical hyperalgesia.(AU)
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Animals , Spider Venoms , Spiders , Shal Potassium ChannelsABSTRACT
G protein-gated inward rectifier potassium(GIRK)channels are widely distributed in the central nervous system and play important roles in maintaining the resting membrane potential of neurons,adjusting neuronal excitability,and regulating the release of neurotransmitter.Studies have shown that addictive behavior is closely related to the expression and activity of the GIRK channels in the brain reward system and the GIRK channels may be a potential target for addiction treatment.This article summarizes the recent research advances in GIRK channels in terms of structure,intracranial tissue distribution,and especially substance addiction.
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Objective To observe the protective effects of fluoxetine on working memory impairment induced by chronic cerebral ischemia and further explore its mechanism in rats. Methods The rat model of chronic cerebral ischemia was made by surgical ligation of the bilateral carotid artery. 44 male Sprague Dawley rats were divided into sham group (n = 10) , ischemic model group (ra = 12), ischemic + fluoxetine group (n = 12) , and sham + fluoxetine group (n = 10). Fluoxetine was administered by gavage after 1 week of ischemic surgery and continued for 4 weeks. The sham group and the ischemic model group were given the same volume of 0. 9% saline. The performance of working memory was tested by a modified Morris water maze experiment that lasted for 4 days. The expression of neuronal nuclei (NeuN) , S-100(3, G protein gated inwardly rectifying K channels 1,2, and 3 ( GirKl , 2 , and 3 ) , and sorting nexin 27 ( SNX27 ) in the prefrontal cortex ( PFC) of rats were tested by Western blot, and compare between groups. Results (1) There was no significant difference in swimming speed among the four groups ( P > 0.05 ). In the training experiment, there was no significant difference among the four groups in the escape latency and the swimming distance ( both P > 0.05 ). In the memory retention test, the escape latency of rats in the ischemic model group was significantly increased on 2nd, 3rd and 4th day compared with the sham group (day2: [48.2 ±6. 3] s vs. [27.4±4.0]s, day 3 :[53.9 ±6.4] s vs. [29.4±6.3]s, day4: [41.4± 4. 9] s vs. [23.8 ±3.7] s; all P 0.05). (3) There was no significant difference in the membrane expression of GirKl protein among the four groups (P > 0. 05). Taking the sham group as a reference and the relative grey value of GirK2 and GirK3 is defined as 1, the relative grey values of GirK2 in the ischemia model group and the ischemia + fluoxetine group were 1. 27 ± 0. 07 and 1. 06 ±0.06, the relative grey values of GirK3 in the ischemia model group and the ischemia + fluoxetine group were 1.23 ±0.08 and 1.00 ±0.06. The membrane expression of GirK2 and GirK3 in the ischemic model group was higher than that in the sham group. The membrane expression of GirK2 and GirK3 in the ischemic + fluoxetine group was down-regulated compared with the ischemic model group ( both P < 0. 05). (4) Taking the sham group as a reference and the relative grey value of SNX27 in the sham group is defined as 1, the relative grey values of SNX27 in the ischemia model group, the ischemia + fluoxetine group, and the sham + fluoxetine group were 0. 78 ± 0.09, 0.97 ± 0.04, and 0. 94 ±0.05, respectively. The expression of SNX27 in the ischemic model group was lower than that in the sham group, and the down-regulation of SNX27 expression in the ischemic model group was reversed after fluoxetine treatment (P<0. 05). Conclusion Fluoxetine can ameliorate working memory impairment of rats induced by chronic cerebral ischemia, which may partly reverse the increase of surface expression of GirK2 and GirK3 in the prefrontal cortex through acting on SNX27.
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Scorpion venoms are natural sources of molecules that have, in addition to their toxic function, potential therapeutic applications. In this source the neurotoxins can be found especially those that act on potassium channels. Potassium channels are responsible for maintaining the membrane potential in the excitable cells, especially the voltage-dependent potassium channels (Kv), including Kv1.3 channels. These channels (Kv1.3) are expressed by various types of tissues and cells, being part of several physiological processes. However, the major studies of Kv1.3 are performed on T cells due its importance on autoimmune diseases. Scorpion toxins capable of acting on potassium channels (KTx), mainly on Kv1.3 channels, have gained a prominent role for their possible ability to control inflammatory autoimmune diseases. Some of these toxins have already left bench trials and are being evaluated in clinical trials, presenting great therapeutic potential. Thus, scorpion toxins are important natural molecules that should not be overlooked in the treatment of autoimmune and other diseases.(AU)
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Animals , Scorpion Venoms/toxicity , Potassium Channels , Immunosuppression Therapy/methodsABSTRACT
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.
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OBJECTIVE To investigate the effect and mechanisms of doxorubicin (DOX) on isolated thoracic aorta and carotid artery of rats. METHODS The cumulative dosing method was used to add DOX every 10 min to reach the final concentrations of 1, 3, 10, 30 and 100 μmol·L-1, and the tension of isolated thoracic aorta and carotid artery in basal tension, precontracted by phenylephrine (PE) 1 μmol ·L-1 and KCI 60 mmol ·L-1, was respectively recorded in vitro vascular ring perfusion apparatus. Furthermore, No-nitro-L-arginine methyl ester (L-NAME), tetraethylammonium (TEA), 4-aminopyridine (4-AP), BaCI2, glibenclamide (Gli), indometacin (Indo) and proparanolol were used to explore the mechnisms of the vasodilating effect of DOX. RESULTS DOX had no effect on the thoracic aorta and carotid artery in basal tension and precontracted by KCI. However, DOX induced concentration-dependent relaxation in both the thoracic aorta and carotid artery precontracted by PE (P<0.05), and it had stronger vasodilating effect on the endothelium-intact thoracic aorta than on the endothelium-denuded thoracic aorta (P<0.05). After the treatment with nitric oxidase inhibitor, L-NAME 0.1 mmol·L-1, calcium activated potassium channel (KCa) inhibitor, TEA 1 mmol·L-1, voltage-dependent potassium channel (KV) inhibitor, 4-AP 1 mmol·L-1 and inward rectifier potassium channel (KIR) inhibitor, BaCI2 1 mmol·L-1, the vasodilating effect of DOX was obviously decreased (P<0.05), but the application of Indo 0.01 mmol ·L-1 Gli 0.01 mmol ·L-1 and β-adrenregic receptor blocker propranolol 0.01 mmol·L-1 had no effect on the vasodilating effect of DOX. Additionally, DOX 1, 10 and 100 μmol·L-1 significantly reduced PE-induced contraction of the thoracic aorta in Ca2+-free solution, and the concentration-effect curve of CaCI2 could be shifted to the right in the presence of DOX (P<0.05). CONCLUSION These results have demonstrated that DOX vasodilating effects on the thoracic aorta and carotid artery are concentration-dependent. The mechanisms are likely to be related to nitric oxide/cGMP pathway, KV, KCa, K1R, intracellular calcium release and extracellular calcium influx.
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Background@#The pathogenesis of obstructive sleep apnea (OSA) remains not fully understood. This study aimed to explore the mechanism of OSA by assessing the association between the human tandem of P domains in a weak inwardly rectifying K+ channel (TWIK)-related acid-sensitive K+ channel-1 (TASK-1) gene and OSA.@*Methods@#A total of 164 patients with severe OSA and 171 patients without OSA were recruited from the Center for Hypertension of People’s Hospital of Xinjiang Uygur Autonomous Region (China) from April to December in 2016. Two single nucleotide polymorphisms (rs1275988 and rs2586886) in the TASK-1 gene were selected and genotyped using a kompetitive allele specific polymerase chain reaction genotyping system. Clinical-pathological characteristics and genotype data were compared between the severe and non-OSA groups to explore the association between TASK-1 gene polymorphism and severe OSA.@*Results@#There were no significant differences in genotype distribution, allele frequency, and the recessive and dominant model of the two selected single nucleotide polymorphisms (rs1275988 and rs2586886) between the severe and non-OSA groups in the total population (P < 0.05). However, for patients with a body mass index (BMI) ≥28 kg/m2, the distribution of genotypes and alleles, and the recessive model (GG + GA vs. AA) exhibited significant differences between the severe and non-OSA group (for genotypes: P = 0.014 and P = 0.026; for alleles: P = 0.006 and P = 0.011; for the recessive model: P = 0.005 and P = 0.009, respectively). The simple logistic regression analysis revealed that the GG genotype was a risk factor for OSA. The odds ratio (OR) and 95% confidence intervals (CI) were 4.902 (1.582–15.186, P = 0.006) for rs1275988 and 4.420 (1.422–13.734, P = 0.010) for rs2586886, respectively. In multivariate logistic regression analysis, the combination of GG genotypes of rs1275988 with BMI ≥28 kg/m2 increased the risk of severe OSA (OR = 8.916, 95% CI 4.506–17.645, P < 0.001).@*Conclusion@#Both the GG genotype of rs1275988 and GG genotype of rs2586886 in the TASK-1 gene may play as potential risk factors in obese patients with OSA.
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Objective@#The aging model of guinea pigs induced by D-galactose was set up to investigate the changes of BKCa expression and function on cochlear pericytes and their relationship with age-related hearing loss.@*Methods@#Thirty healthy 8-week-old guinea pigs were randomly divided into three groups, with 10 in each group: D-galactose aging model group, subcutaneous injection of D-galactose (500 mg/kg) daily for 6 weeks; saline control group, the same amount of saline was injected into the neck of the aging model group for 6 weeks; the blank control group, no treatment was performed. The threshold of auditory brainstem response (ABR) was detected. The content of BKCa in the perivascular cells of the guinea pig cochlear cells was detected by immunofluorescence technique. The changes of peripheral current density and BKCa current were detected by patch clamp technique. The data were analyzed by GraphPad Prism software.@*Results@#Compared with the saline group and the control group, the ABR threshold and the amplitude of the wave I were significantly decreased in the aging model group, and the difference was statistically significant (P<0.01). Compared with the control group, the expression of BKCa in the vascular pericytes of guinea pigs in the aging model group was significantly reduced (1.00±0.08 vs 0.27±0.03,the difference was statistically significant P<0.01), and the cell current density and BKCa net current value were also significantly reduced with statistically significant (P<0.01).@*Conclusions@#D-galactose can successfully induce guinea pig aging model, in which BKCa expression decreases and net current value decreases in pericytes of cochlear striavascularis, and changes in BKCa expression and function may be related to age-related hearing loss.
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Epilepsy is one of the commonest neurological disorder,and genetic factors play a major role in the etiology of epilepsy disorders.In recent years,more and more attention has been paid on the study of potassium channel and epilepsy.The classification of potassium channels is complex,and variants in these genes can lead to a variety of phenotypes from the severest to the mildest,from early infantile epileptic encephalopathy (EIEE) to benign familial neonatal convulsion (BFNC).Moreover,patients with mutations in the same gene may exhibit with distinctive clinical manifestations,the channel dysfunction caused by the variants is correlated with the severity of the disorder.To achieve accurate treatment,the change of channel function is needed to be studied,and more attention should be paid on the development of targeted drugs.
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Epilepsy is one of the commonest neurological disorder, and genetic factors play a major role in the etiology of epilepsy disorders. In recent years, more and more attention has been paid on the study of potassium channel and epilepsy. The classification of potassium channels is complex, and variants in these genes can lead to a variety of phenotypes from the severest to the mildest, from early infantile epileptic encephalopathy (EIEE) to benign familial neonatal convulsion (BFNC). Moreover, patients with mutations in the same gene may exhibit with distinctive clinical manifestations, the channel dysfunction caused by the variants is correlated with the severity of the disorder. To achieve accurate treatment, the change of channel function is needed to be studied, and more attention should be paid on the development of targeted drugs.
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AIM:To investigate the protective effect of zacopride (ZAC) on the pressure-overload left ventricular remodeling in the rats induced by coarctation of abdominal aorta.METHODS:Male Sprague-Dawley (SD) rats with pressure overload were induced by the coarctation of abdominal aorta.The model rats were intraperitoneally administered with ZAC, chloroquine (Chlor) , and zacopride+chlorquine (ZAC+Chlor).The study duration was 8 weeks.The cardiac structure and function were assessed by echocardiography.The heart weight/body weight (HW/BW) ratio and the left ventricular weight/body weight (LVW/BW) ratio were calculated.The changes of structure and shape in myocardial tissue were observed with HE staining.The ultrastructure of the myocytes was observed under transmission electron microscope.The inward rectifier potassium channel (IK1) protein expression was determined by Western blot.The mRNA expression of Kir2.1 was detected by RT-PCR.RESULTS:Compared with vehicle group, ZAC improved cardiac function, as indicated by the decreased left ventricular end-diastolic dimension (LVEDD) and left ventricular end systolic dimension (LVESD) (P<0.05) , and the increased left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) (P<0.01).The HW/BW and LVW/BW ratios were significantly decreased, and the cross-sectional area of the cardiomyocytes was significantly less in ZAC group than that in vehicle group (P<0.01).The ultrastructure of the myocytes was significantly improved.Chlor blocked the protective effect of zacopride on the pressure-overload left ventricular remodeling.The protein level ofmRNA expression of Kir2.1 in the cardiac tissues in ZAC group were significantly increased compared with vehicle group (P<0.01).CONCLUSION:ZAC significantly attenuates pressure overload-induced ventricular remodeling in rats.
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BACKGROUND/AIMS: Interstitial cells play important roles in gastrointestinal (GI) neuro-smooth muscle transmission. The underlying mechanisms of colonic dysmotility have not been well illustrated. We established a partial colon obstruction (PCO) mouse model to investigate the changes of interstitial cells and the correlation with colonic motility. METHODS: Western blot technique was employed to observe the protein expressions of Kit, platelet-derived growth factor receptor-α (Pdgfra), Ca²⁺-activated Cl⁻ (Ano1) channels, and small conductance Ca²⁺- activated K⁺ (SK) channels. Colonic migrating motor complexes (CMMCs) and isometric force measurements were employed in control mice and PCO mice. RESULTS: PCO mice showed distended abdomen and feces excretion was significantly reduced. Anatomically, the colon above the obstructive silicone ring was obviously dilated. Kit and Ano1 proteins in the colonic smooth muscle layer of the PCO colons were significantly decreased, while the expression of Pdgfra and SK3 proteins were significantly increased. The effects of a nitric oxide synthase inhibitor (L-NAME) and an Ano1 channel inhibitor (NPPB) on CMMC and colonic spontaneous contractions were decreased in the proximal and distal colons of PCO mice. The SK agonist, CyPPA and antagonist, apamin in PCO mice showed more effect to the CMMCs and colonic smooth muscle contractions. CONCLUSIONS: Colonic transit disorder may be due to the downregulation of the Kit and Ano1 channels and the upregulation of SK3 channels in platelet-derived growth factor receptor-α positive (PDGFRα⁺) cells. The imbalance between interstitial cells of Cajal-Ano1 and PDGFRα-SK3 distribution might be a potential reason for the colonic dysmotility.