The present study attempted to test a novel hypothesis that Ca(2+) sparks play an important role in arterial relaxation induced by tacrolimus. Recorded with confocal laser scanning microscopy, tacrolimus (10 µmol/L) increased the frequency of Ca(2+) sparks, which could be reversed by ryanodine (10 µmol/L). Electrophysiological experiments revealed that tacrolimus (10 µmol/L) increased the large-conductance Ca(2+)-activated K(+) currents (BKCa) in rat aortic vascular smooth muscle cells (AVSMCs), which could be blocked by ryanodine (10 µmol/L). Furthermore, tacrolimus (10 and 50 µmol/L) reduced the contractile force induced by norepinephrine (NE) or KCl in aortic vascular smooth muscle in a concentration-dependent manner, which could be also significantly attenuated by iberiotoxin (100 nmol/L) and ryanodine (10 µmol/L) respectively. In conclusion, tacrolimus could indirectly activate BKCa currents by increasing Ca(2+) sparks released from ryanodine receptors, which inhibited the NE- or KCl-induced contraction in rat aorta.
Animals ; Aorta ; cytology ; metabolism ; physiology ; Calcium Signaling ; Cells, Cultured ; Large-Conductance Calcium-Activated Potassium Channels ; metabolism ; Male ; Muscle, Smooth, Vascular ; drug effects ; metabolism ; physiology ; Myocytes, Smooth Muscle ; drug effects ; metabolism ; Norepinephrine ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Ryanodine ; pharmacology ; Tacrolimus ; pharmacology ; Vasoconstriction

OBJECTIVE: To explore the role of calpain in pulmonary vascular remodeling in hypoxia-induced pulmonary hypertension and the underlying mechanisms.
 METHODS: Sprague-Dawley rats were randomly divided into the hypoxia group and the normoxia control group. Right ventricular systolic pressure (RVSP) and mean pulmonary artery pressure (mPAP) were monitored by a method with right external jugular vein cannula. Right ventricular hypertrophy index was presented as the ratio of right ventricular weight to left ventricular weight (left ventricle plus septum weight). Levels of calpain-1, -2 and -4 mRNA in pulmonary artery were determined by real-time PCR. Levels of calpain-1, -2 and -4 protein were determined by Western blot. Primary rat pulmonary arterial smooth muscle cells (PASMCs) were divided into 4 groups: a normoxia control group, a normoxia+MDL28170 group, a hypoxia group and a hypoxia+MDL28170 group. Cell proliferation was detected by MTS and flow cytometry. Levels of Ki-67 and proliferating cell nuclear antigen (PCNA) mRNA were determined by real-time PCR.
 RESULTS: RVSP, mPAP and right ventricular remodeling index were significantly elevated in the hypoxia group compared to those in the normoxia group. In the hypoxia group, pulmonary vascular remodeling was significantly developed, accompanied by up-regulation of calpain-1, -2 and -4. MDL28170 significantly inhibited hypoxia-induced proliferation of PASMCs concomitant with the suppression of Ki-67 and PCNA mRNA expression.
 CONCLUSION Calpain mediates vascular remodeling via promoting proliferation of PASMCs in hypoxia-induced pulmonary hypertension.
Animals ; Calpain ; genetics ; physiology ; Cell Proliferation ; Dipeptides ; physiology ; Hypertension, Pulmonary ; chemically induced ; genetics ; physiopathology ; Hypertrophy, Right Ventricular ; Hypoxia ; Ki-67 Antigen ; drug effects ; Myocytes, Smooth Muscle ; physiology ; Proliferating Cell Nuclear Antigen ; drug effects ; Pulmonary Artery ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; Up-Regulation ; Vascular Remodeling ; genetics ; physiology

The aim of this study was to investigate the inhibitory effect of heparin/fibronectin (Hep/Fn) complexes on neointimal hyperplasia following endovascular intervention. Hep/Fn complexes were immobilized onto titanium (Ti) surfaces, with subsequent X-ray photoelectron spectroscopy (XPS), Toluidine Blue O (TBO) and immunohistochemistry methods were used to characterize surface properties. Smooth muscle cell (SMC) cultures were used to evaluate the effect of Hep/Fn complexes on SMC proliferation. Results showed that Hep/Fn complexes successfully immobilized onto Ti surfaces and resulted in an inhibition of SMC proliferation. This study suggests that Hep/Fn surface-immobilized biomaterials develop as a new generation of biomaterials to prevent neointimal hyperplasia, particularly for use in cardiovascular implants.
Biocompatible Materials ; Cell Proliferation ; drug effects ; physiology ; Cells, Cultured ; Fibronectins ; chemistry ; pharmacology ; Heparin ; chemistry ; pharmacology ; Humans ; Immobilized Proteins ; chemistry ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; drug effects ; physiology ; Surface Properties ; Titanium ; chemistry ; Umbilical Arteries

The purpose of the present study is to investigate the effect of isoliquiritigenin (ISL) on the cerebral basilar artery in spontaneously hypertensive rats (SHR). The change of SHR systolic pressure was measured by tail artery pressure measurement instrument before and after ISL intervention. After perfusion with 1 × 10(-5) mol/L phenylephrine (PE), 1 × 10(-5) mol/L PE + 1 × 10(-4) mol/L ISL and 1 × 10(-5) mol/L PE, the diameter of the cerebral basilar artery separated from SHR was measured by pressure myograph. The current of large-conductance calcium-activated potassium (BKCa) channel of SHR single vascular smooth muscle cell (VSMC) was recorded by whole-cell patch-clamp technique and the cGMP levels of basilar artery was evaluated by ELISA. The results showed that 1) after intervention with ISL for 14 days, the systolic pressure of SHR was decreased from (218.3 ± 1.6) mmHg to (119.2 ± 1.9) mmHg (P < 0.01), but there was no difference in systolic pressure between ISL-treated SHR and Wistar-Kyoto (WKY) rat; 2) 1 × 10(-4) mol/L ISL relaxed the SHR cerebral basilar artery (P < 0.01); 3) ISL significantly increased the outward current density of VSMC from SHR cerebral basilar artery (P < 0.01, n = 6), and the effect could be reversed by 1 × 10(-3) mol/L TEA (a BKCa channel inhibitor), but 3 × 10(-4) mol/L 4-AP (a Kv channel inhibitor) had no effect on the enhanced current density induced by ISL in VSMC; 4) 1 × 10(-5) mol/L Methylene blue (a sGC inhibitor) significantly inhibited the ISL-enhanced current density in VSMC (P < 0.05, n = 6); 5) ISL significantly increased the cGMP level of SHR basilar artery (P < 0.05, n = 6). The results suggest that the role of the ISL in relaxing the SHR cerebral basilar artery may be related to its effect in enhancing BKCa current by increasing the levels of cGMP in the VSMC.
Animals ; Basilar Artery ; drug effects ; Blood Pressure ; Cerebral Arteries ; drug effects ; Chalcones ; pharmacology ; Cyclic GMP ; physiology ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; physiology ; Patch-Clamp Techniques ; Potassium Channels, Calcium-Activated ; physiology ; Rats ; Rats, Inbred SHR ; Rats, Inbred WKY ; Systole

OBJECTIVETo explore the effects of NF-κB on proliferation of rat pulmonary artery smooth muscle cells (PASMC) inhibited by simvastatin.

METHODSPASMC isolated from rats and cultured in vitro were randomly divided into four groups (n=6 each): control, platelet-derived growth factor (PDGF) treatment, PDGF+simvastatin treatment, and PDGF+simvastatin+parthenolide (NF-κB inhibitor) treatment. MTT colorimetric assay and flow cytometry were performed to detect cell proliferation and cell cycle distribution. Immunohistochemistry was performed to detect the expression of NF-κB protein. Real-Time PCR was performed to detect NF-κB mRNA expression.

RESULTSCompared with the control group, MTT values of PASMC at all time points, cell proportion at the S phase and G2+M phase, NF-κB protein and mRNA expression increased significantly in the PDGF group (P<0.05). With the intervention of simvastatin, the levels of above indexes decreased compared with the PDGF group (P<0.05). With the intervention of simvastatin and parthenolide, the levels of above indexes decreased more obviously, but were not significantly different from those in the simvastatin intervention group.

CONCLUSIONSSimvastatin can inhibit proliferation of PASMC and cell cycle process. NF-κB may play an important role in the inhibitory effect of simvastatin on the proliferation of PASMC.

Animals ; Cell Proliferation ; drug effects ; Hydroxymethylglutaryl-CoA Reductase Inhibitors ; pharmacology ; Male ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; physiology ; NF-kappa B ; analysis ; genetics ; physiology ; Pulmonary Artery ; cytology ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Simvastatin ; pharmacology

Serotonin (5-hydroxytryptamine (5-HT)) is a neurotransmitter that regulates a variety of functions in the nervous, gastrointestinal and cardiovascular systems. Despite such importance, 5-HT signaling pathways are not entirely clear. We demonstrated previously that 4-aminopyridine (4-AP)-sensitive voltage-gated K+ (Kv) channels determine the resting membrane potential of arterial smooth muscle cells and that the Kv channels are inhibited by 5-HT, which depolarizes the membranes. Therefore, we hypothesized that 5-HT contracts arteries by inhibiting Kv channels. Here we studied 5-HT signaling and the detailed role of Kv currents in rat mesenteric arteries using patch-clamp and isometric tension measurements. Our data showed that inhibiting 4-AP-sensitive Kv channels contracted arterial rings, whereas inhibiting Ca2+-activated K+, inward rectifier K+ and ATP-sensitive K+ channels had little effect on arterial contraction, indicating a central role of Kv channels in the regulation of resting arterial tone. 5-HT-induced arterial contraction decreased significantly in the presence of high KCl or the voltage-gated Ca2+ channel (VGCC) inhibitor nifedipine, indicating that membrane depolarization and the consequent activation of VGCCs mediate the 5-HT-induced vasoconstriction. The effects of 5-HT on Kv currents and arterial contraction were markedly prevented by the 5-HT2A receptor antagonists ketanserin and spiperone. Consistently, alpha-methyl 5-HT, a 5-HT2 receptor agonist, mimicked the 5-HT action on Kv channels. Pretreatment with a Src tyrosine kinase inhibitor, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine, prevented both the 5-HT-mediated vasoconstriction and Kv current inhibition. Our data suggest that 4-AP-sensitive Kv channels are the primary regulator of the resting tone in rat mesenteric arteries. 5-HT constricts the arteries by inhibiting Kv channels via the 5-HT2A receptor and Src tyrosine kinase pathway.
4-Aminopyridine/pharmacology ; Action Potentials ; Animals ; Calcium Channel Blockers/pharmacology ; Calcium Channels/metabolism ; Cells, Cultured ; Ketanserin/pharmacology ; Male ; Mesenteric Arteries/drug effects/*metabolism/physiology ; Muscle Contraction ; Muscle, Smooth, Vascular/cytology/drug effects/metabolism/physiology ; Myocytes, Smooth Muscle/drug effects/metabolism/physiology ; Nifedipine/pharmacology ; Potassium Channel Blockers/pharmacology ; Potassium Channels, Voltage-Gated/antagonists & inhibitors/*metabolism ; Protein Kinase Inhibitors/pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptor, Serotonin, 5-HT2A/*metabolism ; Serotonin/*pharmacology ; Serotonin 5-HT2 Receptor Antagonists/pharmacology ; Spiperone/pharmacology ; *Vasoconstriction ; src-Family Kinases/antagonists & inhibitors/*metabolism

The aim of the present study was to investigate whether protein kinase C (PKC) was involved in the effect of mesenteric lymph duct ligation or mesenteric lymph drainage on vascular calcium sensitivity in hemorrhagic shock rats. Male Wistar rats were randomly divided into Sham, Shock (hemorrhagic shock), Shock+Ligation (mesenteric lymph duct ligation plus shock) and Shock+Drainage (mesenteric lymph drainage plus shock) groups. After being in shock (hypotension 40 mmHg) for 3 h, the tissue of superior mesenteric artery (SMA) was taken out for detecting the PKC expression and phospho-PKC (p-PKC) activity, and the vascular rings of SMA were prepared and used to measure the response to gradient calcium concentration for assaying the calcium sensitivity, the parameters of which including tension, maximum tension (E(max)) and negative logarithm of EC(50), called the pD(2). Other vascular rings from Shock+Ligation and Shock+Drainage groups were incubated with PKC regulator PMA or Staurosporine before the measurement of calcium sensitivity. The results showed that, PKC expression, p-PKC activity and calcium sensitivity of SMA in Shock group was significantly lower than that of Sham group, whereas the above-mentioned indexes were significantly elevated in Shock+Ligation and Shock+Drainage groups compared with those in Shock group. PKC agonist PMA enhanced the contractile activity of vascular rings to gradient calcium ions, and increased E(max) of SMA in Shock+Ligation and Shock+Drainage groups. On the contrary, PKC inhibitor Staurosporine significantly decreased the response to gradient calcium ions and E(max) of SMA in Shock+Ligation and Shock+Drainage groups. These results suggest that PKC plays a role in the improvement of vascular calcium sensitivity by blockade of mesenteric lymph return in hemorrhagic shock rats.
Animals ; Calcium ; pharmacology ; Drainage ; Ligation ; Lymph ; physiology ; Lymphatic Vessels ; physiology ; Male ; Mesenteric Artery, Superior ; drug effects ; physiology ; Mesentery ; Muscle, Smooth, Vascular ; drug effects ; metabolism ; Protein Kinase C ; metabolism ; physiology ; Rats ; Rats, Wistar ; Shock, Hemorrhagic ; physiopathology ; Vasoconstriction ; drug effects ; physiology

OBJECTIVETo investigate effects of dahuang zhechong pill ( DHZCP) on the cell cycle and the related signal pathways in vascular smooth muscle cells (VSMCs) stimulated by platelet-derived growth factor (PDGF) with the method of serum pharmacology.

METHODSDNA synthesis in VSMCs was examined by detecting 5'-bromo-2'-deoxyuridine incorporation with the immunocytochemical method. The cycle of VSMCs was evaluated with flow cytometry. Expressions of cyclin D1, p27, protein kinase Cα (PKCα), and phosphorylated extracellular signal regulated kinase 1/2 (ERK1/2) were quantified by Western blot method.

RESULTSDHZCP containing serum significantly inhibited DNA synthesis of PDGF-stimulated VSMCs, arrested the cells in G G(1) phase, modulated the protein expressions of cyclin D D(1) and p27, and suppressed the activation of PKCα and ERK1/2.

CONCLUSIONDHZCP containing serum inhibits VSMCs proliferation via modulating the expressions of cell cycle proteins to arrest the cell in G G(1) phase, which is attributed to, at least in part, suppressing PKCα-ERK1/2 signaling in VSMCs.

Animals ; Aorta, Thoracic ; cytology ; Blood Proteins ; pharmacology ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cyclin D1 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; DNA ; biosynthesis ; Drugs, Chinese Herbal ; pharmacology ; G1 Phase ; drug effects ; physiology ; MAP Kinase Signaling System ; physiology ; Male ; Muscle, Smooth, Vascular ; cytology ; drug effects ; enzymology ; Platelet-Derived Growth Factor ; pharmacology ; Protein Kinase C-alpha ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo investigate the contribution of mitochondrial pathway in the apoptosis induced by puerarin (PUE) in pulmonary artery smooth muscle cells.

METHODCultured rat pulmonary artery smooth muscle cells (PASMC) were intervened by high, middle and low dose of puerarin (1.5 x 10(-3), 1.5 x 10(-4), 1.5 x 10(-5) mol x L(-1)). The change of mitochondrial membrane potential was observed. Western blot detected the expression of apoptosis-related gene Caspase-9, Bax and Bcl-2 protein.

RESULTCompared with the control group, mitochondrial membrane potential significantly decreased in puerarin groups. Puerarin can enhance the expression of Caspase-9 and Bax protein, decrease the expression of Bcl-2 protein. Puerarin also has a concentration-dependent on the induction of PASMC.

CONCLUSIONPuerarin can induce PASMC apoptosis through mitochondrial pathway.

Animals ; Apoptosis ; drug effects ; Caspase 9 ; metabolism ; Cells, Cultured ; Isoflavones ; pharmacology ; Male ; Mitochondria ; drug effects ; Muscle, Smooth, Vascular ; cytology ; drug effects ; Myocytes, Smooth Muscle ; drug effects ; physiology ; Proto-Oncogene Proteins c-bcl-2 ; analysis ; Pulmonary Artery ; cytology ; drug effects ; Rats ; Rats, Wistar

BACKGROUNDRhoA/Rho kinase (ROCK) pathway is involved in pulmonary arterial hypertension (PAH) and pulmonary artery smooth muscle cell (PASMC) proliferation. Inhibition of ROCK has been proposed as a treatment for PAH. But the mechanism of RhoA/ROCK pathway and its downstream signaling in proliferation of human PASMCs is unclear. We investigated the effect of fasudil, a selective ROCK inhibitor, on platelet-derived growth factor (PDGF) induced human PASMC proliferation, and the possible association between RhoA/ROCK and extracellular signal-regulated kinase (ERK), p27(Kip1).

METHODSHuman PASMCs were cultured with the stimulation of 10 ng/ml PDGF, and different concentrations of fasudil were added before the addition of mitogen. Cell viability and cell cycle were determined with MTT and flow cytometry respectively. ROCK activity, ERK activity and protein expression of proliferating cell nuclear angigen (PCNA) and p27(Kip1) were measured by immunoblotting.

RESULTSBy MTT assay, PDGF significantly increased the OD value that represented human PASMC proliferation, and pretreatment with fasudil significantly reversed this effect in a dose-dependent manner. After PDGF stimulation, the percentage of cells in S phase increased dramatically from 15.6% to 24.3%, while the percentage in G(0)/G(1) phase was reduced from 80.6% to 59%. And pretreatment with fasudil reversed the cell cycle effect of PDGF significantly in a dose-dependent manner. PDGF markedly induced ROCK activity and ERK activity with a peak at 15 minutes, which were significantly inhibited by fasudil. In addition, fasudil significantly inhibited PDGF-induced PCNA expression and fasudil also upregulated p27(Kip1) expression in human PASMCs, which decreased after PDGF stimulation.

CONCLUSIONRhoA/ROCK is vital for PDFG-induced human PASMC proliferation, and fasudil effectively inhibited PDGF-induced human PASMC proliferation by up-regulation of p27(Kip1), which may be associated with inhibition of ERK activity.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine ; analogs & derivatives ; pharmacology ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Humans ; MAP Kinase Signaling System ; physiology ; Muscle, Smooth, Vascular ; cytology ; Platelet-Derived Growth Factor ; pharmacology ; Protein Kinase Inhibitors ; pharmacology ; Pulmonary Artery ; cytology ; Up-Regulation