OBJECTIVETo investigate the effects of inward rectifier potassium channel blockers (BaCl2, CsCl) on the functions of endothelial progenitor cells (EPCs).

METHODSDensity gradient centrifugation-isolated rat hone marrow mononuclear cells were cultured in vitro. EPCs were harvested and seeded on six culture dish when cells grew to 3-5 passages. Before testing the EPCs were synchronized with M199, which contain 2% fetal calf serum. In the end, EPCs were treated with different intervention. The experiment mainly included two parts: (1) BaCl2 (100 micromol/L) and free BaC2 of Tyrodes solution; (2) CsCl (1 mmol/L) and control. Cell pretreated with blockers above mentioned for 12 h, then the gene expression of stromal cell-derived factor-1 (SDF-1), epoprotenol (PGI2) were assessed, beyond that the ability of adhesion, migration were assayed with different tests. In addition, the medium was collected when EPCs were treated for 3 days. The levels of SDF-1 were measured by sandwich enzyme-linked immunosorbent assay (ELISA). Going even further, EPCs were treated with the signal pathway blockers in advance, after repeat the above steps, in order to analyze the change of SDF-1 and then discuss its mechanism.

RESULTSCompared with control group, BaCl2, CsCl could increase EPC adhesion and migration to same extent. Moreover, the gene expression of SDF-1, PGI2 was significantly up-regulated and the production of SDF-1 increased evidently. Furthermore, the mechanism of SDF-1 secretion increasing mainly was associated with eNOS signaling pathways.

CONCLUSIONBa2+ and Cs+ play important roles in increasing EPCs functions, such as adhesion, migration and secretion.

Animals ; Barium Compounds ; pharmacology ; Cells, Cultured ; Cesium ; pharmacology ; Chemokine CXCL12 ; metabolism ; Chlorides ; pharmacology ; Endothelial Cells ; cytology ; Enzyme-Linked Immunosorbent Assay ; Potassium Channels, Inwardly Rectifying ; antagonists & inhibitors ; physiology ; Rats ; Stem Cells ; cytology

OBJECTIVE: To investigate the expression of Kv1.3 and Kir2.1 during human monocyte-derived macrophages differentiation into foam cells and their function in foam cells formation. METHODS: The human macrophage-derived foam cells were obtained by incubating macrophages with ox-LDL (30 mg/L) for 60 h. The expression of Kv1.3 and Kir2.1 channels were examined by immunocytochemistry, RT-PCR and Western blot. Effects of channel blockers (rMargatoxin and BaCl2) on the cellular cholesterol metabolism were studied by measuring the cellular contents of total cholesterol (TC), free cholesterol (FC), and cholesterol ester (CE) in the presence or absence of the channel blockers. RESULTS: After incubating macrophages with 30 mg/L ox-LDL for 60 h, the cellular contents of TC, FC and CE were markedly increased and the ratio of CE/TC was raised from (14.4+/-6.8)% to (57.9+/-3.5)% (P<0.05), which indicated that the cells had differentiated into foam cells. The expression of Kv1.3 and Kir2.1 channels appeared no obvious difference when differentiating into foam cells (P>0.05); After being blocked specifically (rMargatoxin: 0.1, 10 nmol/L; BaC(12): 75, 125 micromol/L), the cellular contents of TC and CE were markedly reduced without exception and the ratios of CE/TC were all less than 50% (P<0.05). CONCLUSION Both Kv1.3 and Kir2.1 channels play a critical role in differentiation of macrophages into foam cells and blockage of corresponding potassium channels would prevent the formation of the foam cells.
Barium Compounds ; pharmacology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Chlorides ; pharmacology ; Cholesterol Esters ; metabolism ; Foam Cells ; cytology ; Humans ; Kv1.3 Potassium Channel ; antagonists & inhibitors ; Macrophages ; cytology ; Monocytes ; cytology ; Potassium Channels, Inwardly Rectifying ; antagonists & inhibitors ; Scorpion Venoms ; pharmacology

OBJECTIVETo study the effects of resvaratrol derivatives on spontaneous HR and CF of isolated guinea pig atrium.

METHODThe dose-effect curve of resvaratrol was observed. The possible mechanism of potassium channels responsible for changes of CF and HR after administering with resvaratrol was measured.

RESULTResvaratrol reduced the spontaneous HR and weakened the CF in a dose-dependent manner ranging from 10(-6) to 3 x 10(-4) mol x L(-1) (P < 0.05). As compared with Res group, the effects were partly blocked by Gli (P < 0.05) and TEA (P < 0.01), but not blocked by 4-AP, BaCl2, Atropine.

CONCLUSIONResvaratrol can induce negative chronotropic action and negative (inotropic action. The mechanism(s) may relate to the opening of K(ATP) and Kc(Ca).

Animals ; Barium Compounds ; pharmacology ; Cardiotonic Agents ; administration & dosage ; isolation & purification ; pharmacology ; Chlorides ; pharmacology ; Dose-Response Relationship, Drug ; Female ; Glyburide ; pharmacology ; Guinea Pigs ; Heart Rate ; drug effects ; In Vitro Techniques ; KATP Channels ; antagonists & inhibitors ; Male ; Myocardial Contraction ; drug effects ; Plants, Medicinal ; chemistry ; Potassium Channel Blockers ; pharmacology ; Potassium Channels, Calcium-Activated ; antagonists & inhibitors ; Potassium Channels, Inwardly Rectifying ; antagonists & inhibitors ; Stilbenes ; administration & dosage ; isolation & purification ; pharmacology ; Tetraethylammonium ; pharmacology

PURPOSE: This study examined the expression and function of inward rectifier K+ channels in cultured rat hepatic stellate cells (HSC). MATERIALS AND METHODS: The expression of inward rectifier K+ channels was measured using real-time RT-PCR, and electrophysiological properties were determined using the gramicidin-perforated patch-clamp technique. RESULTS: The dominant inward rectifier K+ channel subtypes were K(ir)2.1 and K(ir)6.1. These dominant K+ channel subtypes decreased significantly during the primary culture throughout activation process. HSC can be classified into two subgroups: one with an inward-rectifying K+ current (type 1) and the other without (type 2). The inward current was blocked by Ba2+ (100micrometer) and enhanced by high K+ (140mM), more prominently in type 1 HSC. There was a correlation between the amplitude of the Ba2+-sensitive current and the membrane potential. In addition, Ba2+ (300micrometer) depolarized the membrane potential. After the culture period, the amplitude of the inward current decreased and the membrane potential became depolarized. CONCLUSION: HSC express inward rectifier K+ channels, which physiologically regulate membrane potential and decrease during the activation process. These results will potentially help determine properties of the inward rectifier K+ channels in HSC as well as their roles in the activation process.
Animals ; Barium/pharmacology ; Blotting, Western ; Cells, Cultured ; Electrophysiology ; Liver/cytology/*metabolism ; Male ; Membrane Potentials/drug effects ; Potassium/pharmacology ; Potassium Channels, Inwardly Rectifying/genetics/metabolism/*physiology ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVE: The purpose of this study was to establish a minimally invasive and reproducible protocol for estimating the gastrointestinal (GI) transit time in mice using barium and radiopaque markers. MATERIALS AND METHODS: Twenty 5- to 6-week-old Balb/C female mice weighing 19-21 g were used. The animals were divided into three groups: two groups that received loperamide and a control group. The control group (n = 10) animals were administered physiological saline (1.5 mL/kg) orally. The loperamide group I (n = 10) and group II (n = 10) animals were administered 5 mg/kg and 10 mg/kg loperamide orally, respectively. Thirty minutes after receiving the saline or loperamide, the mice was administered 80 microL of barium solution and six iron balls (0.5 mm) via the mouth and the upper esophagus by gavage, respectively. Afterwards, the mice were continuously monitored with fluoroscopic imaging in order to evaluate the swallowing of the barium solution and markers. Serial fluoroscopic images were obtained at 5- or 10-min intervals until all markers had been excreted from the anal canal. For analysis, the GI transit times were subdivided into intestinal transit times (ITTs) and colon transit times (CTTs). RESULTS: The mean ITT was significantly longer in the loperamide groups than in the control group (p < 0.05). The mean ITT in loperamide group II (174.5 +/- 32.3) was significantly longer than in loperamide group I (133.2 +/- 24.2 minute) (p < 0.05). The mean CTT was significantly longer in loperamide group II than in the control group (p < 0.05). Also, no animal succumbed to death after the experimental procedure. CONCLUSION: The protocol for our study using radiopaque markers and barium is reproducible and minimally invasive in determining the GI transit time of the mouse model.
Analysis of Variance ; Animals ; Barium Sulfate/pharmacology ; Contrast Media/administration & dosage ; Female ; Fluoroscopy ; Gastrointestinal Transit/*physiology ; Iron ; Loperamide/administration & dosage ; Mice ; Mice, Inbred BALB C ; Microscopy, Electron, Scanning ; Prostheses and Implants ; Reproducibility of Results ; Sodium Chloride/administration & dosage ; Surface Properties