ABSTRACT
Aim To investigate the mechanism of high salt-induced cerebral artery remodeling in mice by up-regulating TMEM16A. Methods Forty C57BL/6J mice were randomly divided into four groups (10 per group, 8 weeks of intervention), namely, blank control group (normal diet), low-salt group (2% high salt diet), medium-salt group (4% high salt diet) and high-salt group (8% high salt diet). HE staining was used to observe the morphological changes of cerebral arteries; blood vessel permeability test was used to compare the color and absorbance value of brain tissue. Immunofluorescence was employed to detect TMEM16A expression in cerebral arteries of mice in each group; PCR and Western blot were applied to detect the mRNA and protein expression of TMEM16A in cerebral arterial tissues; whole-cell patch clamp was use to record the calcium-activated chloride channel (CaCC) currents of mouse cerebral artery smooth muscle cells in each group. Results HE results showed that 2%, 4%, and 8% high salt diet could concentra-tion-dependently induce cerebral arterial wall thickening and lumen stenosis in C57BL/6J mice. The permeability test found that compared with the control group, the absorbance value of the brain tissue of the mice in the 2%, 4% and 8% high salt groups increased significantly. The results of isolated muscle tension showed that compared with the control group, the systolic response of isolated cerebral arteries to 60 mmol • L
ABSTRACT
Objective: To investigate the mechanisms of electroacupuncture (EA) at Zusanli (ST 36), Liangmen (ST 21) and Sanyinjiao (SP 6) in intervening diabetic gastroparesis (DGP) based on calcium-activated chloride channel. Methods: Forty Sprague-Dawley rats were randomly divided into four groups, including a normal control group (group A), a model group (group B), an EA group (group C) and a metoclopramide group (group D), with 10 rats in each group. A single intraperitoneal injection of 2％ streptozotocin (STZ) combined with 8-week high-glucose high-fat diet was used to establish a DGP rat model. After intervention, gastrointestinal propulsive rate was observed; the expression level of transmembrane protein 16A (TMEM16A) was examined by immunohistochemistry; the Ca2+ concentration in interstitial cells of Cajal (ICCs) was detected by immunofluorescence; and whole-cell patch-clamp technique was applied to detect the current intensity of calcium-activated chloride channel (ICaCC) in ICCs in gastric antrum. Results: After modeling, the blood glucose levels in group B, group C and group D were significantly increased compared with group A (all P<0.01); after intervention, compared with group B, the blood glucose levels in group C and group D were significantly decreased (P<0.05, P<0.01); the intra-group comparison of blood glucose level between after modeling and after intervention found significant difference only in group C (P<0.01). The gastrointestinal propulsive rates in group B, group C and group D were significantly different from that in group A (P<0.01 or P<0.05); the gastrointestinal propulsive rates were markedly higher in group C and group D than in group B (P<0.01, P<0.01). The expressions of TMEM16A in group B and group C were decreased compared with group A (P<0.01, P<0.05); the expressions of TMEM16A in group C and group D were increased compared with group B (P<0.01, P<0.05). The fluorescence intensity of Ca2+ was significantly lower in group B than in group A (P<0.01); the fluorescence intensity of Ca2+ was significantly higher in group C and group D than in group B (P<0.01, P<0.05). ICaCC in ICCs in group B was significantly decreased compared with group A; ICaCC in group C and group D were increased compared with group B. Conclusion: EA at Zusanli (ST 36), Liangmen (ST 21) and Sanyinjiao (SP 6) can significantly improve gastrointestinal motility in DGP rats by up-regulating the ICaCC in ICCs.
ABSTRACT
Objective To establish a cell model based on calcium-activated chloride channel (CaCC) that could sensitively detect the second messenger Ca
ABSTRACT
To foster communication and interactions amongst international scholars and scientists in the field of ion channel research, the 6th International Ion Channel Conference (IICC-2017) was held between June 23-27, 2017 in the eastern coastal city of Qingdao, China. The meeting consisted of 450 attendees and 130 speakers and poster presenters. The program consisted of research progress, new findings and ongoing studies that were focused on (1) Ion channel structure and function; (2) Ion channel physiology and human diseases; (3) Ion channels as targets for drug discovery; (4) Technological advances in ion channel research. An insightful overview was presented on the structure and function of the mechanotransduction channelNOMPC (No mechanoreceptor potential C), a member of the transient receptor potential (TRP) channel family. Recent studies on Transmembrane protein 16 or Anoctamin-1 (TMEM16A, a member of the calcium-activated chloride channel [CaCC] family) were summarized as well. In addition, topics for ion channel regulation, homeostatic feedback and brain disorders were thoroughly discussed. The presentations at the IICC-2017 offer new insights into our understanding of ion channel structures and functions, and ion channels as targets for drug discovery.
ABSTRACT
Calcium-activated chloride channel (CaCC) is an anion channel, widely distributed in the human body, taking a part in cell functions including secretion, heart muscle repolarization, nerve signal transmission and several physiological activities. The anoctamin 1 (ANO1) protein is the molecular basis of CaCC and the modification of ANO1 protein will produce a variety of pharmacological effects, such as analgesia, treating dysentery and asthma, even tumor proliferation and migration inhibition. In the past decade, many methods in screening of ANO1 regulators have been developed. Although a series of the ANO1-based CaCC regulatory molecules have been identified, the pharmacological effects of these molecules are not consistent. In this review, we introduce ANO1 protein regulators from many aspects including bio-test methods, structure-activity relationships, and the potential applications.
ABSTRACT
Neuronal firing patterns and frequencies determine the nature of encoded information of the neurons. Here we discuss the molecular identity and cellular mechanisms of spike-frequency adaptation in central nervous system (CNS) neurons. Calcium-activated potassium (K(Ca)) channels such as BK(Ca) and SK(Ca) channels have long been known to be important mediators of spike adaptation via generation of a large afterhyperpolarization when neurons are hyper-activated. However, it has been shown that a strong hyperpolarization via these KCa channels would cease action potential generation rather than reducing the frequency of spike generation. In some types of neurons, the strong hyperpolarization is followed by oscillatory activity in these neurons. Recently, spike-frequency adaptation in thalamocortical (TC) and CA1 hippocampal neurons is shown to be mediated by the Ca²⁺-activated Cl- channel (CACC), anoctamin-2 (ANO2). Knockdown of ANO2 in these neurons results in significantly reduced spike-frequency adaptation accompanied by increased number of spikes without shifting the firing mode, which suggests that ANO2 mediates a genuine form of spike adaptation, finely tuning the frequency of spikes in these neurons. Based on the finding of a broad expression of this new class of CACC in the brain, it can be proposed that the ANO2-mediated spike-frequency adaptation may be a general mechanism to control information transmission in the CNS neurons.
Subject(s)
Action Potentials , Brain , Central Nervous System , Fires , Neurons , Potassium , Potassium Channels, Calcium-ActivatedABSTRACT
Objective To study the modulation alterations of calcium activated potassium channel (Kca) and calcium activated chloride channels (Clca) on detrusor instability(DI) and their roles in DI. Methods The detrusor instability (DI) animal model was established using female Wistar rats. Detrusor strips were obtained from normal and DI rats. The contraction frequency and amplitude of the strips were measured by an in vitro tension test. The actions of channel openers and blockers were studied. Results Spontaneous contraction frequency and amplitude of DI increased significantly. The block of big conductance calcium activated potassium channel(Bkca) by Iberiotoxin resulted in decrease of frequency but increase of amplitude in the control, but only increase of frequency in DI. The opener, NS1619, resulted in decreases of frequency and amplitude in the control, but only decreases of frequency in DI. The block of small conductance Kca (Skca) by apamin resulted in increases of frequency and amplitude in both control and DI groups, but the opener, Chlorzoxazone, resulted in decreases of frequency and amplitude in the control, but only decrease of frequency in DI. The contraction alterations of DI were significantly lower than those of the control no matter Kca was blocked or opened. NFA, a selective Clca blocker, resulted in no significant frequency and amplitude alteration in the control, but significant decrease in DI. Conclusion These results suggested that Kca and Clca play a critical role in the modulation of detrusor contraction, and the down regulation of Kca and up regulation of Clca suggests that disorder of calcium related regulation may play an important role in DI.
ABSTRACT
Objective To evaluate the ability of goblet cell in the airway in rat with asthma to synthesize granulocyte-macrophage colony-stimulating factor (GM-CSF),and the role of calcium-activated chloride channel (CLCA) in the synthesis. Methods A model of asthma was replicated in male BALB/c mice with ovalbumin sensitization. The goblet cells in small bronchi were identified with AB-PAS staining,and the expression of GM-CSF in the same airway was assessed with immunohistochemistry staining. The recombinant plasmid of pIRES2-EFGP/hCLCA1 was transfected stably into the human mucoepidermoid cell NCI-H292. The expression and transcription levels of GM-CSF in transfected cells were determined with immunohistochemistry staining and RT-PCR assay. The non-transfected cell and the transfected cell exposed to niflumic acid (NFA),which was a CLCA inhibitor,were designated as two control groups. Results Positive staining of GM-CSF expression could be seen in the goblet cells of small bronchi. The cells with expression of hCLCA1 showed much higher levels of GM-CSF expression and transcription than those of two control groups. It was also found that NFA could effectively reduce the levels of GM-CSF in transfected cells. Conclusion The goblet cell of asthmatic airway can synthesize GM-CSF,and one of mechanisms is the increased expression of CLCA.