Colonic Dysmotility in Murine Partial Colonic Obstruction Due to Functional Changes in Interstitial Cells

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.

Downregulation of large conductance calcium-activated potassium channels in paraventricular nucleus contributes to sympathoexcitation in rats with chronic heart failure / 中华心血管病杂志

Objective@#To elucidate the association between large conductance calcium-activated potassium channels (BKCa) in the paraventricular hypothalamic nucleus (PVN) and sympathetic outflow in rats with chronic heart failure (CHF) .@*Methods@#Male Wistar rats (6-7 weeks old) were randomized to sham operated group and CHF group (coronary artery ligation) . Two weeks after operation, BKCa inhibitor Iberiotoxin (IBTX) was infused into PVN by osmotic minipumps, rats were divided into following groups: sham+aCSF, CHF+aCSF, sham+low dose IBTX (0.125 nmol/nl) , CHF+low dose IBTX, sham+moderate dose IBTX (1.25 nmol/nl) , CHF+moderate dose IBTX, sham+ high dose IBTX (12.5 nmol/nl) , and CHF+high dose IBTX (n=6 each) . Additional rats were grouped as follows: sham+vehicle, sham+KCNMB4 knockdown (by rAAV2-KCNMB4 shRNA virus injection in PVN) , CHF+vehicle, CHF+ KCNMB4 knockdown group (n=6 each) . The cardiac function was determined by echocardiography, left ventricular hemodynamics were measured invasively, renal sympathetic nerve activity (RSNA) was recorded at 6 weeks after coronary artery ligation or sham operation. The contents of norepinephrine (NE) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) in plasma were determined by enzyme-linked immunosorbent assay. The protein and mRNA expression of KCNMB4 in PVN were measured by immunofluorescence staining, Western blot, and real-time PCR, mRNA expression of BKCa in PVN was detected by real-time PCR.@*Results@#Compared with the sham operation group, the cardiac function of the heart failure group was significantly reduced (P<0.05) , and the plasma NE and the serum NT-proBNP were significantly elevated (P<0.05) . The protein and mRNA expression of KCNMB4 in PVN were obviously down-regulated in CHF rats (P<0.05) . After perfusion of IBTX or KCNMB4 knockdown by microinjection of rAAV2-KCNMB4 shRNA virus,right ventricular weight/body weight and lung weight/body weight ratio as well as left ventricular end-diastolic diameter were increased and left ventricular ejection fraction was decreased (all P<0.05) , the sympathetic driving indexes was increased in sham rats, changes of these parameters further aggravated in CHF rats (P<0.05) . KCNMB4 knockdown further downregulated protein expression in PVN of CHF rats.@*Conclusion@#Downregulation and blunted function of BKCa in PVN may contribute to sympathoexcitation and deterioration of cardiac function in rats with chronic heart failure.

Different effects of remifentanil on basilar artery smooth muscle cells of normotensive and hypertensive rats / 临床麻醉学杂志

Objective To evaluate the effects of remifentanil (RMF)on large conductance cal-cium-activated potassium channel (BKCa)and voltage-gated potassium channel (KV)activition currents in basilar arterial smooth muscle cells (BASMCs)of normotensive and hypertensive rats. Methods Spontaneously hypertensive rats (SHR)and homologous normotensive wistar-kyoto (WKY)rats,were used in this study.BASMCs were obtained freshly by the method of enzymolysis. Six basilar artery smooth muscle cells of each rat were chosen and analyzed.Outward current ampli-tude was recorded by the whole-cell patch clamp technique.The outward current amplitude under all stimulation voltage in set of step stimulation protocol before (basal level)and after administration of RMF (3×10-7mol/L)were recorded respectively and net current was calculated (net current=cur-rent amplitude after administration-basic value).With administration by concentrations cumulative method,the current amplitude under +60 mV stimulation voltage was separately recorded before (basic value)and after application of different concentrations of RMF (10-10,10-9,10-8,10-7, 10-6,10-5mol/L),then calculated current increasing rate and the half effective concentration (EC50)of RMF increasing current amplitude in BASMCs.Another six basilar artery smooth muscle cells of each rat were chosen and given RMF (3×10-7mol/L),and separately treated with BKCa channel blocker (tetraethylammonium,TEA)and Kv channel blocker (4-aminopyridine,4-AP),and then administrated the corresponding RMF mixture.The current amplitude was recorded after each dose.Results At 0,+20,+40 and +60 mV,the net current generated by RMF on both BASMCs of rats was successively and significantly increased (P <0.05).The increment rate of outward currents in BASMCs generated by 10-10,10-9,10-8,10-7RMF successively and significantly went upward (P<0.05).Compared to WKY rats,the half-effective concentration(EC50)of RMF increas-ing the current amplitude in BASMCs of SHR significantly rose(P<0.05).Compared with the base-line,the current amplitude in BASMCs of the two kind rats was significantly increased after adminis-tration of RMF,and decreased after administration of TEA or 4-AP (P<0.05);Compared to ad-ministration of TEA or 4-AP,the current amplitude in BASMCs of the two kind rats was significantly in-creased after administration of TEA+RMF or 4-AP+RMF (P<0.05).Conclusion Bkcaand Kv currents in both BASMCs of SHR and WKY rats were activated by RMF in a voltage-dependent and dose-dependent manner,and the effect of RMF on BKCaand Kvactivition currents in BASMCs of SHR was weaker than WKY rats.

Effects of WNK3 kinase on regulation of large-conductance calcium-activated potassium channels and its mechanisms / 中华肾脏病杂志

Objective To investigate the effects of WNK3 kinase on the regulation of large-conductance calcium-activated potassium channels (Maxi K channels) on African green monkey kidney fibroblast-like cells (Cos-7 cells) and its mechanisms.Methods (1) Cos-7 cells were transfected with 0,0.6,1.2,1.8 μg WNK3 plasmid+0.5 μg Maxi K plasmid.The total protein expression of Maxi K channel and the phosphorylation of mitogen-activated protein kinase (MAPK) extracellular regulated kinase-1 and-2 (ERK1/2) were detected by Western blotting.(2) Cos-7 cells were divided into the control group (2.5 μg Maxi K plasmid) and the experimental group (2.5 μg WNK3 plasmid+2.5 μg Maxi K plasmid).Cell surface biotinylation was used to investigate the cell surface protein expression of Maxi K channel in Cos-7 cells.Immunoprecipitation and Western blotting were used to detect the ubiquitination of Maxi K channel protein.(3) WNK3 kinase was knocked down by WNK3 siRNA.The lysosomal degradation pathway was blocked by the proton pump inhibitor (Baf-A1).Cos-7 cells were divided into Maxi K+negative control siRNA group,Maxi K+WNK3 siRNA group and Maxi K+WNK3 siRNA+Baf-A1 group.The protein expression of Maxi K channel protein was detected by Western blotting.Results (1) Compared with those in 0 μg WNK3 plasmid groups,in 0.6,1.2,1.8 μg WNK3 plasmid groups the total protein expression of the Maxi K channel increased and the phosphorylation level of MAPK ERK1/2 reduced on a dose-dependent manner (all P ＜ 0.01).(2)Compared with those in the control group,the total protein expression and cell surface membrane protein expression of the Maxi K channel increased in the experimental group (P ＜ 0.01),while the ubiquitination of the Maxi K channel protein reduced (P ＜ 0.01).(3) Compared with the Maxi K +negative control siRNA group,the expression of Maxi K protein reduced in the Maxi K+WNK3 siRNA group (P ＜ 0.01),but did not change in the Maxi K+WNK3 siRNA + Bar-A1 group (P ＞ 0.05).The expression of Maxi K protein in Maxi K+WNK3 siRNA+Baf-A1 group was higher than that in Maxi K+WNK3 siRNA group (P ＜ 0.01).Conclusions WNK3 kinase inhibits the lysosomal degradation pathway of Maxi K channel protein by reducing the ubiquitination of Maxi K channel,and promotes the expression of Maxi K channel protein in cells and on cell membrane.These effects may be achieved by suppressing MAPK ERK1/2 signal transduction pathway.

Effects of docosahexenoic acid on large conductance Ca+-activated K+ channels in retinal smooth muscle cells / 中华眼底病杂志

Objective To investigate the effects ofdocosahexenoic acid (DHA) on large conductance Ca2+-activated K+ (BK) channels in normal retinal artery smooth muscle cells (RASMCs).Methods Cultured human RASMCs (6 th-8 th generations) were used to patch clamp experiment.The open probabihties (NP0) in BK channels with different concentrations (0.0,1.0,3.0,5.0,7.5,10.0 μmol/L) of DHA were recorded by patch clamp technique in single channel configuration.RASMCs were intervened by different concentrations (0.0,1.0,5.0 μmol/L) of DHA as control group,low and high doses of DHA groups,respectively.The protein expressions of β subunit of BK channels in RASMCs from three groups were measured by Western blot.Results The NP0 of BK channels were 0.044 4±0.001 2,0.081 2±0.004 2,0.209 0±0.006 1,0.310 5±0.005 3,0.465 0±0.007 8 and 0.497 7±0.014 5 with perfusate of 0.0,1.0,3.0,5.0,7.5,10.0 μtmol/L DHA.DHA activated BK channels in a dose-dependent manner (F=2.621,P＜0.05).There was no significant difference in the protein expression of control group,low and high doses of DHA groups (F=1 1.657,P＞0.05).Conclusion DHA can directly activate BK channels,no increasing in subunit expression of BK channels.

Large Calcium-Activated Potassium Channels Contribute to Neuronal Abnormal Firing in the Medial Vestibular Nucleus Following Hypoxia / 听力学及言语疾病杂志

Objective To investigate the effects of BKCa channel on electrophysiology excitatory regulation in MVN neuron following hypoxia and to reveal its molecular mechanism.Methods C57BL/6 mices were performed MVNs hypoxia mice model,and randomly allowed to normal oxgen group and hypoxia group.The hypoxia group, according to the application of NS1 6 1 9 ,was further divided into the no NS1 6 1 9 pretreatment group and NS1 6 1 9 pre-treatment group.Using the patch clamp experiment technology,we recorded the effects of the MVN abnormal neu-ronal firing and the change of the BKCa currents.Using immunohistochemical technique,the changes of BKCa in the hypoxic MVNs detected were.Results Acute hypoxia increased neuronal activities.NS1619 pretreatment de-creased hypoxia-induced firing rate,and increased and postponed the maximum increase by hypoxia(P<0.05),al-so alleviated 10-min-hypoxia-induced depolarization(P<0.05).Perfusion with hypoxic significantly reduced the BKCa positive neurons(P<0.05).Conclusion These findings suggest that acute hypoxia increases neuronal activi-ties.The decreased MVN BKCa channels contribute to hypoxia-induced abnormal neuronal activities.

Effect of cardiac shock wave therapy on human cardiac microvascular endothelial cells and its signal con-duction pathway / 医学研究生学报

[Abstract ] Objective Cardiac shock wave therapy (CSWT) can promote arteriogenesis in ischemic myocardia , but the mo-lecular mechanism remains unclear .The study aimed to explore the effect of CSWT on arteriogenesis in human cardiac microvascular endothelial cells ( HCMEC ) and the role of focal adhesion kinase (FAK) and Calcium-activated potassium channels (KCa) in the sig-nal conduction pathway of CSWT arteriogenesis . Methods HC-MEC cells cultured in vitro were randomly divided into control group , CSWT group , CSWT +T ( FAK inhibitor PF-573228 ) group and CSWT+F( SCa inhibitor iberiotoxin ) group.Each group received one CSWT(0.09 mJ/mm2, 200Times) 48 h after added stimulant.24 hours'conventional culture later , tests were made on the levels of endothelial nitric oxide synthase ( eNOS ) and vascular endothelial growth factor ( VEGF) mRNA as well as the changes of related protein expression . Results ①QPCR test showed that eNOS , VEGF mRNA expressions increased in CSWT group compared with control group (4.61 ±0.19 vs 3.99 ±0.17, P<0.05), while compared with CSWT group, eNOS, VEGF mRNA expressions in CSWT +T group were decreased (0.62 ±0.10 vs 0.40 ±0.02, P<0.05), eNOS, VEGF mRNA expressions in CSWT +F group were also decreased (0.53 ±0.02 vs 0.64 ±0.02, P<0.05), all the differ-ences were of statistical significance .②Western blot showed that eNOS , VEGF protein expressions increased in CSWT group compared with control group(0.63 ±0.02 vs 0.43 ±0.02, P<0.05), while compared with CSWT group , eNOS, VEGF protein expressions in CSWT+T group were decreased (0.36 ±0.01 vs 0.29 ±0.02, P<0.05), eNOS, VEGF protein expressions in CSWT +F group were also decreased (0.37 ±0.02 vs 0.30 ±0.02, P<0.05), all the differences were of statistical significance . Conclusion CSWT can improve eNOS , VEGF mRNA and protein expressions in HCMEC cells and FAK and KCa may participate in the signal conduction pathway of CSWT arteriogenesis .

The quantitative determination of BKCa channels in placental arteriole smooth muscle cells of hypertensive disorder complicating pregnancy / 重庆医学

Objective To observe the change of protein levels of large conductance calcium activated potassium channel (BK‐Ca) in placental arteriole smooth muscle cells from hypertensive disorder complicating pregnancy and discuss its role .Methods Western blot analysis was used to examine protein expression of α subunit andβ1 subunit of BKCa channels in placental arteriole smooth muscle cells from hypertensive disorder complicating pregnancy .Results The relative protein expression level of α‐subunit in the HDCP group was 1 .001 2 ± 0 .169 8(n=15) ,and the NT group was 1 .028 2 ± 0 .180 6 (n=15) .There was no significant differences between the two groups (P> 0 .05);the relative protein expression level of β1 subunit in the HDCP group was 0 .418 1 ± 0 .080 8 (n=15) ,and the NT group was 1 .616 8 ± 0 .012 6 (n=15) ,theβ1‐subunit protein expression levels of HDCP group were significantly lower (P<0 .05) .Conclusion The protein expression ofβ1‐subunit ,but notα‐subunit ,was reduced in pla‐cental arteriole smooth muscle cells from hypertensive disorder complicating pregnancy .Therefore ,BKCa channel activity may have been involved in hypertensive disorder complicating pregnancy ;and the abnormal expression ofβ1 subunit maybe an important basis in hypertensive disorder complicating pregnancy .

Role of large conductance calcium-activated potassium channels in vascular hyporesponsiveness in rats with obstructive jaundice / 中华麻醉学杂志

Objective To evaluate the role of large conductance calcium-activated potassium (BKCa) channels in vascular hyporesponsiveness in rats with obstructive jaundice.Methods Eighteen male Sprague-Dawley rats,weighing 180-200 g,were randomly divided into 3 groups (n =6 each) using a random number table:control group (group C),sham operation group (group S),and bile duct ligation group (group BDL).Obstructive jaundice was produced by common bile duct ligation.At 7 days after surgery,blood samples were collected for determination of the levels of serum total bilirubin (TBL),direct bilirubin (DBL),indirect bilirubin (IBL),alanine aminotransferase (ALT),and aspartate aminotransferase (AST).Thoracic aortic rings were prepared,and the endothelium was removed.The aortic rings were sequentially perfused with different concentrations of norepinephrine (NE) and sodium nitroprusside (SNP),and the maximum amplitude of contraction and dilatation of aortic rings was recorded.The aortic rings were then perfused with BKCa channel blocker Chtx with the final concentration of 10 7 mol/L,followed by perfusion with different concentrations of NE and SNP again,and the maximum amplitude of contraction and dilatation of aortic rings was recorded under each concentration.The percentage of maximum contraction and dilatation (maximum amplitude after Chtx administration÷maximum amplitude before Chtx administration× 100％) was calculated.Results Compared with C and S groups,the levels of TBL,DBL,IBL,ALT and AST in serum were significantly increased,the maximum amplitude of NE-induced contraction of aortic rings was decreased,and the percentage of the maximum NE-induced dilatation of aortic rings was increased,the maximum amplitude of SNP-induced contraction of aortic rings was increased,and the percentage of the maximum SNP-induced dilatation of aortic rings was decreased in group BDL.Conclusion Excessivc opening of BKCa channels may be involved in the mechanism of vascular hyporesponsiveness in rats with obstructive jaundice.

Role of large-conductance Ca2+-activated K+ channels and protein kinase G in ketamine-induced isolated tracheal smooth muscle relaxation in rats with asthma / 中华麻醉学杂志

Objective To investigate the role of large-conductance Ga2+-activated K+ (BKCa) channels and protein kinase G (PKG) in ketamine-induced isolated tracheal smooth muscle relaxation in rats with asthma.Methods Healthy Sprague-Dawley rats,weighing 250-300 g,were used in this study.Asthma was induced with egg albumin.Thirty-six tracheal rings of 15 rats in which asthma model was successfully established were randomly divided into 3 groups (n =12 each):ketamine treatment group (group AK),IBTX (BKCa channel blocker) +ketamine treatment group (group AKI),and KT-58232 (PKG inhibitor) + ketamine treatment group (group AKK).Tracheal rings were suspended in an organ bath filled with oxygenated Kreb's solution at 36.5-37.5 ℃.In group AK,the tracheal rings were precontracted with acetyleholine 0.1 mmol/L,and the rings were then exposed to ketamine 0.4 g/L for 15 min.In group AKI,before acetyleholine and ketamine were added to the solution,the rings were pretreated with IBTX 3μmol/L for 30 min.In group AKK,before acetyleholine and ketamine were added to the solution,the rings were pretreated with KT-5823 2μmol/L for 30 min.The tension of rings was measured by using a force-displacement transducer.Results The amplitude of relaxation of isolated tracheal smooth muscle was significantly decreased in groups AKI and AKK as compared with group AK (P ＜ 0.05).Conclusion Ketamine induces isolated tracheal smooth muscle relaxation through activating BKCa channels and PKG signaling pathway in rats with asthma.

Intermediate-conductance-Ca2+activated K+channels are involved in regulating cell cycle of endometrial cancer cells / 第二军医大学学报

Objective To study the expression of intermediate? conductance? Ca2+-activatedK+ (KCa3.1) channelsin Endometrial cancer tissues and their role in regulating cell cycle of endometrial cancer cells.Methods Real?time PCR and Western blotting analysis were used to examine the expression of KCa3.1 channels in 25 normal endometrial specimens,26 atypical hyperplasia specimens and 25 endometrial cancer specimens.Clotrimazole (an inhibitor of KCa3.1 channel)and RNA interference (RNAi) targeting KCa3.1 channel were used to block KCa3.1, so as to explore the role of KCa3.1 channels in regulating the cell cycle of endometrial cancercells.Results The expression levels of KCa3.1 mRNA and protein in endometrial carcinoma were significantly higher than those in the typical hyperplasia endometrial and normal endometrial tissues (P<0.01).Clotrimazole retarded cell cycle at G0-G1 phase in a dose-dependent manner and reduced HEC-1-Acells of S phase.KCa3.1 protein level in cells transfected with target-KCa3.1 siRNA was only (40.27±6.09)%that of cells transfected with negative control.Transfection with target?KCa3.1 siRNA also retarded cell cycle of HEC-1A cells atG0-G1phase,and reduced cells of S phase compared with negative control siRNA. Meanwhile,transfection with target=-KCa3.1 siRNA also reduced cyclinD1 protein expression in HEC-1A cells. Conclusion The expressions of KCa3.1 channels are elevated in endometrial cancer tissues,and KCa3.1 channels may influence cell cycle through regulating cyclinD1.

Effects of remifentanil on large-conductance Ca2+ -activated potassium channels in human mesenteric arterial smooth muscle cells / 中华麻醉学杂志

Objective To investigate the effects of remifentanil on large-conductance Ca2+ -activated potassium channel (BKCa) in human mesenteric arterial smooth muscle cells (MASMCs) and the mechanism of the vasorelaxant effect of remifentanil. Methods Human MASMCs were obtained freshly by the method of enzymolysis. BKCa current (IBKCa) was recorded by the whole-cell patch clamp technique. The changes in IBKC. produced by different concentrations of remifentanil (1.2, 4.8, 19.4, 77.4 and 310.0 nmol/L) with the holding potential of + 80 mV were observed. BKCa activation rate was calculated. Results Remifentanil significantly increased IBKCa,moved Ⅰ-Ⅴ curve upward and had no effect on the threshold of activation for IBKCa . With the increase in the concentration of remifentanil, BKCa activation rate increased gradually (P ＜ 0.01), and it remained stable when the concentration reached 19.4 nmol/L. There was no significant difference in the peak time of IBKCa after different concentrations of remifentanil were given (P ＞ 0.05). Logarithmic curve was found to suit the relationship between the concentration of remifentanil and BKCa activation rate and the IC50 concentration was (118 ± 7) nmol/L. Conclusion Remifentanil results in vasorelaxation by activating BKCa in MASMCs in a concentration-dependent manner.

Effect of sufentanil on calcium-activated potassium currents in rat abdominal aortic smooth muscle cells / 第二军医大学学报

Objective: To investigate the influence of sufentanil on calcium-activated K+ channels (IKCa) in rat abdominal aortic smooth muscle cells, and to investigate its role in dilation of blood vessels. Methods: Rat abdominal aortic smooth muscle cells (AASMCs) were freshly obtained by enzymatic digestion. Whole-cell voltage-clamp technique was used to assess the effect of sufentanil (1 × 10-8, 3 × 10-8, 1 × 10-7 mol/L) on IKCa. Results: Sufentanil significantly increased the amplitude of IKc compared with the control group (P < 0.05 or P < 0.01). The effect of sufentanil was reversible and in a concentration-dependent manner. Conclusion: Sufentanil can promote the activation of KCa channel in rat AASMCs, which might be related to the vasodilatory effect of sufentanil observed in clinical practice.

Alterations in Calcium-Activated Potassium Channel Expressions in Human Prostate Cancer / 대한비뇨기과학회지

PURPOSE: Recent studies have shown that potassium (K+) and sodium channels are involved in prostate cell growth. However, a great many of the studies have been done in prostate cancer cell lines and there are only scant studies on prostate cancer and benign prostatic hypertrophy (BPH) tissue. The present study was aimed to evaluate the alterations of the calcium-activated K+ channel (KCa) expression in prostate cancer, and to compare them with the expression profiles in human BPH tissue to understand their potential role in the progression of prostate cancer. MATERIALS AND METHODS: The prostate tissues obtained from radical prostatectomy (n=10) and transurethral resection of the prostate (n=18) were quickly frozen in liquid nitrogen for the RNA measurements. The protein and mRNA levels of the KCa subtypes and connexins were measured by performing immunoblot analysis and reverse-transcription polymerase chain reaction, respectively. RESULTS: The mRNA levels of type 2 (SK2) and type 3 (SK3) small-conductance and large-conductance (BK) KCas in the prostate cancer tissues were decreased more than 50% compared with those in the BPH samples. In addition, the BK and SK2 protein levels in prostate cancer were also significantly lower than those in the BPH. As reported previously, the connexin 26 and 43 transcript signals in the prostate cancer were significantly reduced compared with those in the BPH samples. CONCLUSIONS: These results suggest that the impaired expression of KCas may have a role in tumor progression via aberrant and uncontrolled prostate cell growth.

Different mRNA expressions of calcium activated channels in normal and instable detrusors / 第三军医大学学报

Objective To study the different mRNA expressions of big and small conductance calcium activated potassium channels (Bkca and Skca), and calcium activated chloride channels (Clca) in normal and instable detrusors. Methods Model of bladder outlet obstruction (BOO) of female Wistar rats was prepared by ligating the proximal urethra in the perineum. Detrusor instability (DI) was confirmed by conscious cystometry. The mRNA was extracted from the detrusors of normal and DI rats for the detection of the expressions of Bkca, Skca2, Skca3, and Clca by RT PCR. The different channel expression between normal and instable detrusors was identified by gel imaging. Results The incidence of DI in BOO rats was 76.17%. Bladder capacity and the maximal detrusor pressure increased significantly ( P

The effect of ketamine on the large conductance Ca~(2+)-activated potassium channels / 中华麻醉学杂志

Objecitve:To study the effects of ketamine on the large conductance Ca~(2+)-activated potassium (BK)channels in cultured newborn rat hippocampal neurons. Method:All experiments were carried out on 3-7 days old neurons. Single channel current signals were recorded in symmetrical high K~+ solution(140mM) under cell-attached patch and inside-out patch. Result:(1)In inside-out patch, with the unitary conductance being 176.5?16.5pS,the BK channel activity was markedly activated by internal Ca~(2+) but was blocked by potassium channel blocker (TEA). (2) In cellattached patch,when the concentration of ketamine was 0.01,0.05,0.20mmol/L and membrane potential kept at?60mV,the open probability (Po) decreased from 0.042?0.011 at baseline to 0.027?0.008,0.030?0.015,0.032?0.021 respectively(P0.05). Conclusion:Ketamine has dual effects on the BK channels,the inhibition may be related to its side effects,and the activation to the mechanism in anesthesia.