Objective To re-confirm and characterize the biophysical and pharmacological properties of endogenously expressed human acid-sensing ion channel 1a (hASIC1a) current in HEK293 cells with a modified perfusion methods...
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Objective To re-confirm and characterize the biophysical and pharmacological properties of endogenously expressed human acid-sensing ion channel 1a (hASIC1a) current in HEK293 cells with a modified perfusion methods. Methods With cell floating method, which is separating the cultured cell from coverslip and putting the cell in front of perfusion tubing, whole cell patch clamp technique was used to record hASICla currents evoked by low pH external solution. Results Using cell floating method, the amplitude of hASICla currents activated by pH 5.0 in HEK293 cells is twice as large as that by the conventional method where the cells remain attached to coverslip. The time to reach peak at two different recording conditions is (21±5) ms and (270±25) ms, respectively. Inactivation time constants are (496±23) ms and (2284±120) ms, respectively. The cell floating method significantly increases the amiloride potency of block on hASIC 1 a [IC50 is (3.4± 1.1 ) μmol/L and (2.4± 0.9) μmol/L, respectively]. Both recording methods have similar pH activation ECs0 (6.6±0.6, 6.6±0.7, respectively). Conclusion ASICs channel activation requires fast exchange of extracellular solution with the different pH values. With cell floating method, the presence of hASIC la current was re-confirmed and the biophysical and pharmacological properties of hASIC la channel in HEK293 cells was precisely characterized. This method could be used to study all ASICs and other ligand-gated channels that require fast extracellular solution exchange.
目的研究突变型人胰高血糖素样肽-1(mutated human glucagon-like peptide-1,mGLP-1)对谷氨酸诱导的人神经母细胞瘤细胞SH-SY5Y细胞损伤的影响。方法环磷酸腺苷(cAMP)试剂盒检测细胞内cAMP含量,比较mGLP-1和天然人胰高血糖素样肽-1(natu...
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目的研究突变型人胰高血糖素样肽-1(mutated human glucagon-like peptide-1,mGLP-1)对谷氨酸诱导的人神经母细胞瘤细胞SH-SY5Y细胞损伤的影响。方法环磷酸腺苷(cAMP)试剂盒检测细胞内cAMP含量,比较mGLP-1和天然人胰高血糖素样肽-1(natural human glucagon-like peptide-1,nGLP-1)与GLP-1受体结合的能力;以谷氨酸诱导SH-SY5Y细胞损伤,同时用mGLP-1处理SH-SY5Y细胞,采用MTT法检测细胞存活率;乳酸脱氢酶(LDH)试剂盒检测细胞LDH的释放量;DAPI染色法观察细胞凋亡形态学特征;钙流法检测胞内钙离子浓度变化;通过检测丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性、总谷胱甘肽(total GS)含量的变化判断细胞氧化损伤程度。结果 mGLP-1与nGLP-1类似,都能提高细胞内cAMP水平;mGLP-1能缓解谷氨酸诱导的细胞损伤,增加细胞存活率,降低LDH释放量;mGLP-1对谷氨酸导致的细胞内钙离子变化没有修复作用;mGLP-1能抑制氧化损伤指标MDA含量升高,促进抗氧化系统指标SOD活性增强和total GS含量增加。结论 mGLP-1可导致细胞内cAMP含量增加。mGLP-1对谷氨酸所致神经细胞损伤具有保护作用,这可能是mGLP-1通过对神经细胞的抗氧化损伤作用实现的,而不是改善谷氨酸导致的钙稳态失衡。mGLP-1的保护作用与nGLP-1类似,而mGLP-1在体内稳定性更强,半衰期更长;提示mGLP-1可能对相关神经退行性疾病的治疗具有更佳的潜在价值。
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