目的:探讨酸敏感离子通道(acid-sensing ion channels，ASICs)的四种亚型即ASIC1a、ASIC1b、ASIC2a和ASIC3是否表达于大鼠岩神经节(petrosal ganglion)神经元。方法:采用常规免疫组化法(PV法)，观察正常大鼠岩神经节神经元是否表达ASIC1a、ASIC1b、ASIC2a和ASIC3。结果:在正常大鼠岩神经节神经元，可见ASIC1a、ASIC1b、ASIC2a和ASIC3表达;ASIC1a与ASIC2a，ASIC3与ASIC1b，ASIC3与ASIC1a，ASIC3与ASIC2a在岩神经节神经元上共表达。结论:正常生理情况下，大鼠岩神经节神经元均表达ASIC1a、ASIC1b、ASIC2a和ASIC3;ASICs亚型之间的共表达提示,在岩神经节可能存在ASICs异聚体的方式。
Ion channels are involved in the mechanism of anesthetic action and side effect. The transcription and expression of ion channel genes can be modulated by general anesthetics. The adverse effect of continuous infusion of etomidate has been concerned. However, the effects of etomidate on mRNA expressions of ion channel genes remain unclear. In this study, we exposed Daphnia pulex in 250 μmol/L of etomidate for 240 min and observed the change of heart rate, phototactic behavior and blood glucose during the period of exposure, as well as the mRNA expressions of 120 ion channel genes at the end of the experiment. Compared to the controls, heart rate, phototactic behavior and blood glucose were not influenced by 250 μmol/L of etomidate. According to the quantitative PCR results, 18 of 120 Daphnia pulex ion channel genes transcripts were affected by persistent 240 min exposure to 250 μmol/L of etomidate: 2 genes were upregulated and 16 genes were down-regulated, suggesting that etomidate showed effects on many different ion channels in transcription level. Systematical exploration of transcriptional changes of ion channels could contribute to understanding of the pharmacological mechanism of etomidate.
【摘要】 目的 探讨慢性缺氧对大鼠岩神经节神经元酸敏感离子通道（acid-sensing ion channels，ASICs）亚型3（ASIC3）和亚型2a（ASIC2a）表达的影响。 方法 将12只健康成年SD大鼠随机分为正常组和缺氧组。用免疫组织化学法（PV）观察正常和慢性缺氧大鼠岩神经节神经元ASIC3和ASIC2a的表达。 结果 给予慢性缺氧刺激后，岩神经节ASIC3阳性表达神经元数目增多（Plt;0.05），灰度值降低（Plt;0.05）；而ASIC2a阳性表达神经元数目和灰度值无明显变化（Pgt;0.05）。 结论 慢性缺氧可上调大鼠岩神经节神经元ASIC3的表达，而对ASIC2a的表达无明显影响，提示ASIC3和ASIC2a可能在岩神经节对缺氧的反应中起着不同的作用。【Abstract】 Objective To investigate the effects of chronic hypoxia on expression of acid-sensing ion channels (ASIC) 3 and ASIC2a in neurons of petrosal ganglions of rats. Methods A total of 12 SD rats were randomly assigned to control group and hypoxia group. The expressions of ASIC3 and ASIC2a of the neurons in the petrosal ganglions in the two groups were investigated with the immunohistochemical technique. Results The level of positive ASIC3 expression in the petrosal ganglions was higher in the hypoxia group than that in the control group (Plt;0.05); the difference of positive ASIC2a expression levels between the control group and the hypoxia group was not statistically significant (Pgt;0.05). Conclusion Chronic hypoxia can significantly increase the expression of ASIC3, but not that of ASIC2a, of the neurons in the petrosal ganglions, suggesting their different roles in mediating a cellular response to chronic hypoxia.
Mutations in the BEST1 gene are associated with a range of retinal diseases collectively referred to as "Best diseases", including Best vitelline macular dystrophy. More than 300 mutations at different sites of the BEST1 gene have been found, which may cause a series of functional disorders such as the mistransport of the calcium-activated anion channel protein-1 protein encoded by it, protein oligomerization defects, and abnormal anion channel activity, leading to different clinical phenotypes. Although it has been established that the BEST1 gene mutation is associated with at least one different type of Best disease, the relationship between the specific gene mutation site and the specific clinical phenotype has not been fully defined. For the time being. Drugs and gene therapy for the Best diseases are still in the basic research stage, which provides a broad development space for future treatment exploration. In the future, when selecting gene therapy in clinical applications, it is necessary to combine the clinical phenotype and molecular diagnosis of patients, and clearly define their mutation types and pathogenic mechanisms in order to achieve better personalized treatment effects.
Objective To study the influence of ischemia-reperfusion on the expression of the hyperpolarization activated cycl icnucleotide gated cation channel 4 (HCN4) and to discuss the mechanism of functional disturbance of sinoatrial node tissue (SANT) after ischemia reperfusion injury (IRI). Methods Eighty five healthy adult rabbits, weighing 2-3 kg, were randomly divided into 3 groups: control group [a suture passed under the root section of right coronary artery (RCA) without l igation, n=5], experimental group A (occluding the root section of RCA for 30 minutes, then loosening the root 2,4, 8 and 16 hours, n=10), experimental group B (occluding the root section of RCA for 1 hour, then loosening the root 2, 4,8 and 16 hours, n=10). At the end of the reperfusion, the SANT was cut off to do histopathological, transmission electronmicroscopical and immunohistochemical examinations and semi-quantitative analysis. Results The result of HE stainingshowed that patho-injure of sinoatrial node cell (SANC) happened in experimental groups A and B after 2 hours of reperfusion, the longer the reperfusion time was, the more serious patho-injure of SANC was after 4 and 8 hours of reperfusion, SANC reached peak of damage after 8 to 16 hours of reperfusion; patho-injure of SANC was more serious in experimental group B than in experimental group A at the same reperfusion time. Immunohistochemical staining showed that the expression of HCN4 located in cellular membrane and cytoplasm in the central area of SANC and gradually decreased from the center to borderl ine. The integral absorbance values of HCN4 expression in the control group (397.40 ± 34.11) was significantly higher than those in the experimental group A (306.20 ± 35.77, 216.60 ± 18.59, 155.40 ± 19.11 and 135.00 ± 12.30) and in the experimental group B (253.70 ± 35.66, 138.70 ± 13.28, 79.10 ± 9.60 and 69.20 ± 8.42) after 2, 4, 8 and 16 hours of reperfusion (P lt; 0.05). With reperfusion time, the expression of HCN4 of SANC decreased, which was lowest after 8 hours of reperfusion; showing significant difference among 2, 4 and 8 hours after reperfusion (P lt; 0.05) and no significant difference between 8 and 16 hours after reperfusion (P gt; 0.05). At the same reperfusion time, the expression of HCN4 was higher in the experimental group A than in the experimental group B. The result of transmission electron microscope showed that ultramicrostructure of SANC was damaged after reperfusion in experimental groups A and B. The longer the reperfusion time was, the more serious ultramicrostructure damage of SANC was, and reached the peak of damage after 8 hours of reperfusion. Ultramicrostructure of SANC was not different between 8 and 16 hours of reperfusion. At the same reperfusion time, the ultramicrostructure damage of SANC was moreserious in experimental group B than in experimental group A. Conclusion IRI is harmful to the morphous and structure ofSANC, and effects the expression of HCN4 of SANC, which is concerned with functional disturbance and arrhythmia.
Objective To summarize the role of Piezo mechanosensitive ion channels in the osteoarticular system, in order to provide reference for subsequent research. Methods Extensive literature review was conducted to summarize the structural characteristics, gating mechanisms, activators and blockers of Piezo ion channels, as well as their roles in the osteoarticular systems. Results The osteoarticular system is the main load-bearing and motor tissue of the body, and its ability to perceive and respond to mechanical stimuli is one of the guarantees for maintaining normal physiological functions of bones and joints. The occurrence and development of many osteoarticular diseases are closely related to abnormal mechanical loads. At present, research shows that Piezo mechanosensitive ion channels differentiate towards osteogenesis by responding to stretching stimuli and regulating cellular Ca2+ influx signals; and it affects the proliferation and migration of osteoblasts, maintaining bone homeostasis through cellular communication between osteoblasts-osteoclasts. Meanwhile, Piezo1 protein can indirectly participate in regulating the formation and activity of osteoclasts through its host cells, thereby regulating the process of bone remodeling. During mechanical stimulation, the Piezo1 ion channel maintains bone homeostasis by regulating the expressions of Akt and Wnt1 signaling pathways. The sensitivity of Piezo1/2 ion channels to high strain mechanical signals, as well as the increased sensitivity of Piezo1 ion channels to mechanical transduction mediated by Ca2+ influx and inflammatory signals in chondrocytes, is expected to become a new entry point for targeted prevention and treatment of osteoarthritis. But the specific way mechanical stimuli regulate the physiological/pathological processes of bones and joints still needs to be clarified. Conclusion Piezo mechanosensitive ion channels give the osteoarticular system with important abilities to perceive and respond to mechanical stress, playing a crucial mechanical sensing role in its cellular fate, bone development, and maintenance of bone and cartilage homeostasis.
Objective To explore the effect of hydrostatic pressure on intracellular free calcium concentration ([Ca2+]i) and the gene expression of transient receptor potential vanilloid (TRPV) in cultured human bladder smooth muscle cells (hb-SMCs), and to prel iminarily probe into the possible molecular mechanism of hb-SMCs prol iferation stimulated by hydrostatic pressure. Methods The passage 6-7 hb-SMCs were loaded with Ca2+ indicator Fluo-3/AM. When the hb-SMCs were under 0 cm H2O (1 cm H2O=0.098 kPa) (group A) or 200 cm H2O hydrostatic pressure for 30 minutes (group B) and then removing the 200 cm H2O hydrostatic pressure (group C), the [Ca2+]i was measured respectively by inverted laser anningconfocal microscope. When the hb-SMCs were given the 200 cm H2O hydrostatic pressure for 0 hour, 2 hours, 6 hours, 2 hours, and 24 hours, the mRNA expressions of TRPV1, TRPV2, and TRPV4 were detected by RT-PCR technique. Results The [Ca2+]i of group A, group B, and group C were (100.808 ± 1.724), (122.008 ± 1.575), and (99.918 ± 0.887) U, respectively; group B was significantly higher than groups A and C (P lt; 0.001). The [Ca2+]i of group C decreased to the base l ine level of group A after removing the pressure (t=0.919, P=0.394). The TRPV1, TRPV2, and TRPV4 genes expressed in hb-SMCs under 200 cm H2O hydrostatic pressure at 0 hour, 2 hours, 6 hours, 12 hours, and 24 hours, but the expressions had no obvious changes with time. There was no significant difference in the expressions of TRPV1, TRPV2, and TRPV4 among 3 groups (P gt; 0.05). Conclusion The [Ca2+]i of hb-SMCs increases significantly under high hydrostatic pressure. As possible genes in stretch-activated cation channel, the TRPV1, TRPV2, and TRPV4 express in hb-SMCs under 200 cm H2O hydrostatic pressure. It is possible that the mechanical pressure regulates the [Ca2+]i of hb-SMCs by opening the stretch-activated cation channel rather than up-regulating its expression.