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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 study influence of acute hypoxia on the current of voltage-gated potassium channel (IK) in pulmonary artery smooth muscle cells (PASMC) of rats. Methods: A total of 20 male SD rats were randomly and equally divided into normoxic control group and acute hypoxia group. The rats in acute hypoxia group were kept in hypoxic chamber for 8 h before experiment. Whole cell patch-clamp technique was used to record IK in PASMC. Results: Acute hypoxia significantly decreased the IK density in PASMC of rats. During -60mV to -10mV of resting membrane potential（RMP）, acute hypoxia did not significantly decrease peak IK density in PASMC of rats, P>0.05; At 0 mV, acute hypoxia significantly decreased the peak IK density in PASMC [from（38.1 ± 5.2） pA / pF decreased to（9.82 ± 2.1） pA / pF ,P<0.05], then along with RMP increase in PASMC, the decreasing amplitude of peak IK density in PASMC gradually increased（P<0.05）; From + 30 mV to+ 60 mV, the decreasing amplitude of peak IK density in PASMC further significantly increased（P<0.01）; At + 60 mV the peak IK density decreased from（38.1 ± 5.2） pA / pF to（9.82 ± 2.1） pA / pF , and the decreasing amplitude reached (46.8±3.3)%. Conclusion: Acute hypoxia can decrease Kv current in PASMC of rats, leading to hypoxic pulmonary vasoconstriction.
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Objective To investigate the effect of dichloroacetate on the expression of Kv1.5 in a rat model of pulmonary arterial hypertension (PAH) .Methods Thirty-two male SD rats weighing 200-250 g were randomly divided into 4 groups ( n = 8 each): normal control group (group C), dichloroacetate control group (group D),PAH group, and PAH + dichloroacetate group (group PD). PAH was induced by left lung resection combined with subcutaneous injection of monocrotaline 60 mg/kg in PAH and PD groups. In group PD, dichloroacetate 80 mg/kg was given through a gastric tube into stomach once a day for 28 consecutive days after monocrotaline injection,while the equal volume of normal saline was given instead of dichloroacetate in group PAH. Group D only received dichloroacetate 80 mg/kg through a gastric tube into stomach once a day for 28 consecutive days. Pulmonary arterial pressure (PAP) was measured at day 28 after monocrotaline injection. The rats were then sacrificed and lung tissues were removed to calculate the percentage of thickness of the tunica media of pulmonary artery and right venicular hypertrophy index and to determine the proliferating cell nuclear antigen (PCNA) and Kv1.5 protein expression (by Western blot) and Kv1.5 mRNA expression (by RT-PCR).Results Compared with group C, the PAP,percentage of thickness of the tunica media, right ventricular hypertrophy index were significantly increased, Kv1.5 mRNA and protein expression was down-regulated and PCNA expression was up-regulated in groups PAH and PD ( P ＜ 0.05). Compared with group PAH, the PAP, percentage of thickness of the tunica media, right ventricular hypertrophy index were significantly decreased, Kv1.5 mRNA and protein expression was up-regulated and PCNA expression was down-regulated in group PD (P ＜ 0.05). There was no significant difference in the indexes mentioned above between group C and group D ( P ＞ 0.05). Conclusion Dichloroacetat alleviates PAH through upregulating Kv1.5 expression in lung tissues and inhibiting pulmonary vascular remodeling in rats.
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Objective To investigate the role of voltage-gated potassium channel in the human skin squamous cell carcinoma A431 cells and human keratinocyte HaCaT cells. Methods MTT assay was performed to detect the effect of different concentrations of tetraethylammonium (TEA) on the proliferation of cultured A431 cells and HaCaT cells. Besides, enzyme-linked immunosorbent assay (ELISA) was conducted to detect the expression of HERG channel protein in A431 cells, HaCaT cells and normal human skin tissue.Results TEA inhibited the proliferation of A431 cells and HaCaT cells in a dose- and time-dependent manner.After treated with TEA (≥ 10 mmol/L) for 24 or more hours, the proliferation of A431 cells and HaCaT cells was obviously suppressed. A significant difference was observed in the average concentration of HERG channel protein between A431 cells, HaCaT cells and normal human skin tissue (49.7114 ± 3.55696 pg/ml, 35.7471 ±4.14696 pg/ml, 36.8857 ± 3.47810 pg/ml, all P < 0.05). Conclusions The block of voltage-gated potassium channel could inhibit the proliferation of A431 cells and HaCaT cells, and the expression of voltage-gated potassium channel seems to be higher in human skin squamous cell carcinoma cells.
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Objective To screen the difference of gene expression in dorsal root ganglia (DRG)of inflammatory visceral hypersensitivity rats and to explore the role of voltage gated calcium channel (VGCC) in inflammatory visceral hypersensitivity. Methods Total 180 male Sprague-Dawley rats were in this study,the weight varied from 200 gram to 300 gram. 2,4,6-trinitrobenzenesulfonic acid (TNBS) model group was maken by 2. 0% TNBS slowly injection,the dosage was 100mg per kilogram. The normal control group was only injected with same volume of 0. 9% sodium chloride solution. After the model had been maken for four days,gene expression profiles of L6-S2 DRGs were tested by rat cDNA microarray chips. And the result was verified by RT-PCR and Western blot. The changes of intracellular Ca2+ and the voltage gated calcium currents were recorded by patch-clamp.The special Ca2+ channel blockers were given by intrathecal injection,and then the changes of visceral sensitivity were observed. The visceral sensitivity was measured by abdominal withdrawal reflex (AWR). Results There were significant changes of 172 genes expression in L6-S2 DRGs of TNBS model rats,which included Ca2+ channel,membrane receptor and intracellular second messenger. Of those,L-type Ca2+ channel (Cav1. 2) and R-type Ca2+ channel (Cav2. 3) were significantly up-regulated. The results of gene microarray chips were further confirmed by RT-PCR and Western blot.The intracellular Ca2+ testing indicated that there was no statistical significant of resting intracellular Ca2+ in colonic special sensory neuron between TNBS group and normal control group (P＞0. 05);while the evoked transients [Ca2+] significantly increased compared with normal control group (P＜0. 05). The whole cell patch clamp recording showed that the L-type and R-type calcium current were significantly increased in colonic primary sensory neurons of TNBS group compared with normal control group (P＜0. 05). The inflammatory visceral hypersensitivity was significantly reduced by intrathecal injection of nimodipine and SNX-482 (P＜0. 05). Conclusion The up-regulation of Cav1. 2and Cav2. 3 play an important role in inflammatory visceral hyperalgesia,which may be the possible potential therapeutic targets for visceral inflammatory hyperalgesia.
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Objective To study the influence of 4-aminopyridine(4-AP)on proliferation,production,and apoptosis through inhibiting voltage-gated K+channel(Kv)in ovarian luteinized granulosa cells.nethods Ovarian luteinized granulosa cells were recovered from 25 women with regular menses who underwent in vitro fertilization programme.The cultured granulosa cells were divided into 4 groups:blank group,4-AP treated group,human chorionic gonadotropin(hCG)-induced group and hCG+4-AP cotreated group.The final concentrations of hCG and 4-AP were 1250 U/L and 5 nmol/L respectively.The progesterone production WaS detected by the chemoluminescence method.The expression of Kv mRNA on human ovarian luteinized granulosa cell was detected by RT.PCR The influence on the early apoptosis of gTanulosa cells bv 4-AP was observed by flow eytometry.Cellular caSpage-3 activities were observed with colorimetric method and the inhibition of the cell proliferation was studied using methyl thiazolyl tetrazolium(MTT)method.Results(1)Kv mRNA wag expressed in granulosa cell.(2)The progesterone production64),(206±32),(1991±172)and(763±79)nmol/L,respectively after24 hours culture.Exposure of the(3)The flow cytometry analysis and the cellular caapase-3 A405 showed that 4-AP increased the percentage ofearly phase apoptosis(P<0.01):4-AP treated group VS blank group[(40±5)%and 0.049 ±0.009]VS[(17±4)% and 0.029±0.008],hCG+4-AP CO-treated group VS hCG-induced group[(25±4)%and0.039 ±0.0081 VS[(15±3)%and 0.022 ±0.007].(4)24 hours after treated with 4-AP and hCG,theinhibitory rate of cultured granulosa cells of 4-AP treated group was higher than the blank group(19.7%VS0).and that of hCG+4-AP co-treated group was obviously higher than hCG-induced group(34.6% VS O,P<0.01).Conclusions The voltage-gated K+ channels expressed by ovarian luteinized granulosa cellplay an important role in cell proliferation,production,and apoptosis.4-AP may inhibit differentiation ofprogesterone in granulosa ceHs through the inhibition of proliferation and induction of apoptosis.
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OBJECTIVE To study the relationship between potassium channel and ADAR1 in Hep-2 cell line. METHODS The potassium current was recorded by the whole-cell recording technique of perforated membrane clamp. Using semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) , the expressions of ADAR1 mRNA in the Hep-2cell line were detected. RESULTS The similar membrane current was observed when cells were held at -40 mV and test potentials ranged from -80 mV to +80 mV. The current exhibited properties of voltage-dependent, outward rectification. It exhibited complete activation after alatency of 25ms and no or little inactivation over the 800ms voltage pulse. It could be blocked by potassium channel blockers TEA. The relative intensities of ADAR1 mRNA of t he Hep-2 cell line were different before and after its potassium channel was blocked. CONCLUSION Delayed rectifier potassium channel exist in human laryngeal carcinoma cell line Hep-2.The potassium channel is voltage-dependent. There is a correlation between the potassium channel and ADAR1 mRNA in Hep-2 cell line.
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AIM: To determine the effect of hydrogen peroxide(H_2O_2) on voltage-gated potassium channel currents(IKv) in pulmonary vascular smooth muscle cells(PASMCs).METHODS: Using whole cell patch-clamp technique,IKv was recorded in freshly isolated rat PASMCs with acute enzymatic digestion method.The effect of hydrogen peroxide on IKv in PASMCs was investigated in normoxia.RESULTS: IKv in PASMCs was increased significantly by H_2O_2 and the increase depended on the concentration in normoxia.Current-voltage relationship curve shifted to the left.CONCLUSION: Hydrogen peroxide is an important K~+ channel opener.
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Objective To study the effects of sevoflurane on voltage-gated Na~+, K~+ and Ca~(2+) channels in rat dorsal root ganglion(DRG) cells.Methods Dorsal root ganglions were dissected from thoracic and upper lumbar segments of the spinal cord. DRG cells were prepared by digestion with collagenase and trypsin at 32-34℃ The whole cell Na~+, K~+ and Ca~(2+) currents were recorded by standard patch clamp technique. The changes in the currents from holding potential of-70 mV to test potential of 0 mV were recorded in a 10 mV increments in the presence and absence of sevoflurane. Results 0.4, 0.9 and 1.8 mmol?L~(-1) sevoflurane had no effect on Na~+ or K~+ currents but Ca~(2+) currents could be significantly suppressed by 0.4 mmol?L~(-1) sevoflurane. Conclusion Na~+ and K~+ channels in DRG cells are not involved in the spinal mechanism of sevoflurane. The inhibition of Ca~(2+) current in DRG cells by sevoflurane could be associated with the antinociceptive effect of sevoflurane at the spinal cord level.
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AIM: The aim of this study is to investigate the possible role of potassium channel in hypoxic pulmonary vasoconstriction (HPV). METHODS: Fresh human lung tissues were obtained from the Division of Chest Surgery to establish a human model of HPV in vitro. Three groups, control group, COPD group and COPD plus chronic hypoxia group were divided. Human isolated pulmonary artery rings and specific blocking agent corresponding to K_V, K_ Ca, K_ ATP were used to investigate the possible role of the potassium channel in HPV. RESULTS: (1) In acute hypoxia, the vascular ring tension in three groups all increased (P