PURPOSE: To investigate the effects of brimonidine, an alpha-2-adrenergic agonist, on barrier function in ARPE-19 cells by measuring transepithelial resistance (TER). METHODS: ARPE-19 cells were cultured into a confluent monolayer on a microporous filter. Brimonidine was added to the apical medium, and the barrier function of the cells was evaluated by measuring TER. A subset of cells was treated under hypoxic conditions, and the TER changes observed upon administration of brimonidine were compared to those observed in cells in normoxic conditions. RESULTS: The ARPE cell membrane reached a peak resistance of 29.1+/-7.97 Omega cm2 after four weeks of culture. The TER of the cells treated under normoxic conditions increased with brimonidine treatment; however, the TER of the cells treated under hypoxic conditions did not change following the administration of brimonidine. CONCLUSIONS: Barrier function in ARPE-19 cells increased with brimonidine treatment. Understanding the exact mechanism of this barrier function change requires further investigation.
Adrenergic alpha-Agonists/*pharmacology ; Cell Hypoxia/drug effects/physiology ; Cell Line ; Electric Impedance ; Humans ; Quinoxalines/*pharmacology ; Receptors, Adrenergic, alpha-2/*drug effects ; Retinal Pigment Epithelium/*drug effects/*physiology

Doxazosin, a high selective alpha1-adrenoceptor antagonist, is considered as the first-line therapy for the patients with benign prostatic hyperplasia (BPH) and also produce several side effects in cardiovascular system. In this study, we observed the isometric vasoconstrictive responses of the rabbit isolated arterial rings to electric field stimulation and noradrenaline ( NA ) to study the effects of R-doxazosin ( R-DOX ) and S-doxazosin ( S-DOX ) on the alpha1-adrenoceptor-regulated vasoconstrictive responses in the rabbit isolated ear artery, mesenteric artery and pulmonary artery, and the effects of higher concentration of S-DOX and R-DOX on presynaptic alpha2-adrenoceptor-regulated purinergic vasoconstriction in the rabbit isolated saphenous artery. We found that R-DOX and S-DOX competitively inhibited the vasoconstriction induced by NA in the rabbit isolated ear artery, mesenteric artery and pulmonary artery. The pA2 values of R-DOX and S-DOX against NA in the rabbit isolated ear artery, mesenteric artery and pulmonary artery were 7. 91 +/- 0. 03 and 7. 53 +/- 0. 05, 7. 80 +/- 0. 05 and 7. 29 +/-0. 07, 8. 32 +/- 0. 06 and 7. 97 +/- 0. 07, respectively. The pA2 values of R-DOX in the three arterial preparations were significantly higher than those of S-DOX (P < 0. 01). R-DOX and S-DOX at the concentrations of 0. 1 - 10 micromol x L (-1) did not affect the vasoconstriction induced by electric stimulation in the rabbit isolated saphenous artery. R-DOX and S-DOX at 100 micromol x L(-1) in the rabbit isolated saphenous artery completely inhibited the vascular responses to exogenous NA, but did not affect the vascular responses to exogenous adenosine triphosphate (1 mmol x L(-1) ). It is reasonable to suggest that R-DOX and S-DOX competitively inhibit the vasoconstriction induced by NA in the rabbit ear artery, mesenteric artery and pulmonary artery, and the pA2 values of S-DOX are significantly lower than those of R-DOX. The higher concentration (10 micromol x L(-1)) of R-DOX and S-DOX does not affect the presynaptic alpha2-adrenoceptors at sympathetic nerve terminals of the rabbit saphenous artery.
Adrenergic alpha-2 Receptor Antagonists ; Adrenergic alpha-Antagonists ; chemistry ; pharmacology ; Animals ; Blood Vessels ; drug effects ; physiology ; Dose-Response Relationship, Drug ; Doxazosin ; chemistry ; pharmacology ; Electric Stimulation ; In Vitro Techniques ; Male ; Mesenteric Arteries ; drug effects ; physiology ; Norepinephrine ; pharmacology ; Pulmonary Artery ; drug effects ; physiology ; Rabbits ; Receptors, Adrenergic, alpha-2 ; physiology ; Stereoisomerism ; Vasoconstriction ; drug effects

OBJECTIVETo elucidate the relationship between rat hepatic stellate cells (HSC) and sympathetic neurotransmitter norepinephrine (NE) during liver fibrosis.

METHODSUsing immunofluorescence and RT-PCR, the expressions of a1 and b2-adrenoceptors in activated HSC were detected. Methyl thiazolyl tetrazolium (MTT) was adopted to investigate the effect of NE on the proliferation of HSC. Meanwhile, the expressions of collagen-1, transforming growth factor beta (TGFb) and smooth muscle a-actin (a-SMA) in NE-stimulated HSC were detected by RT-PCR. The contents of NE in HSC were determined by high performance liquid chromatography-electrochemical detector (HPLC-ECD).

RESULTSThe a1 and b2-adrenoceptors were expressed in HSC. NE markedly stimulated the proliferation of HSC in a concentration-dependent manner (F = 140.464, P less than 0.05). NE induced the mRNA expressions of collagen-1, TGFb and a-SMA in HSC (t= -4.160; t= -8.763; t= -17.651, P less than 0.05). HSC were synthesizing and releasing NE, especially when stimulated with platelet-derived growth factor (PDGF) (10 ng/ml) (t= -32.907, P less than 0.05).

CONCLUSIONOur findings show that HSC are direct targets of NE and HSC are hepatic neuroglial cells that produce and respond to sympathetic neurotransmitter norepinephrine, suggesting that interrupting sympathetic nervous system signaling may be useful in the treatment of liver fibrosis.

Actins ; metabolism ; Animals ; Cell Proliferation ; drug effects ; Cells, Cultured ; Collagen Type I ; metabolism ; Hepatic Stellate Cells ; drug effects ; metabolism ; Liver Cirrhosis ; Norepinephrine ; pharmacology ; Rats ; Receptors, Adrenergic, alpha-1 ; metabolism ; Receptors, Adrenergic, beta-2 ; metabolism ; Transforming Growth Factor beta ; metabolism

OBJECTIVE: To evaluate whether dexmedetomidine hydrochloride, an α(2)-adrenergic receptor agonist, can prevent H(2)O(2)-induced oxidative stress and inflammatory response in Kupffer cells.
 METHODS: H(2)O(2)-induced oxidative damage model of Kupffer cell was established. Kupffer cells were pre-conditioned by dexmedetomidine hydrochloride or Yohimbine for 24 h. MTT colorimetry was used to demonstrate the survival rate of Kupffer cells. The levels of lactate dehydrogenase (LDH), malonaldehyde (MDA) and TNF-α in the culture medium were assessed by corresponding kits.
 RESULTS: Dexmedetomidine hydrochloride protected Kupffer cells from H(2)O(2)-induced oxidative damage, showing an increase in the cell survival rate while a decrease in LDH, MDA and TNF-α release in the culture supernatant. Yohimbine, an α(2)-adrenergic receptor antagonist, completely neutralized the protective effect of Dexmedetomidine hydrochloride on Kupffer cells. Yohimbine itself had no effect on H(2)O(2)-induced oxidative damage and inflammatory response.
 CONCLUSION Dexmedetomidine hydrochloride can prevent H(2)O(2)-induced oxidative stress and inflammatory response in Kupffer cells through activation of α(2)-adrenergic receptors.
Adrenergic alpha-2 Receptor Antagonists ; pharmacology ; Cell Survival ; Cells, Cultured ; Dexmedetomidine ; pharmacology ; Humans ; Hydrogen Peroxide ; pharmacology ; Kupffer Cells ; cytology ; drug effects ; L-Lactate Dehydrogenase ; metabolism ; Malondialdehyde ; metabolism ; Oxidative Stress ; drug effects ; Receptors, Adrenergic, alpha-2 ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism ; Yohimbine ; pharmacology

OBJECTIVE: To evaluate whether dexmedetomidine hydrochloride, an α2-adrenergic receptor agonist, can prevent oxidative damage to alveolar macrophages induced by H2O2. METHODS: We used methyl thiazolyl tetrazolium (MTT) colorimetry to test the effect of different concentrations and action time of H2O2 on the survival rate of alveolar macrophages, and then we chose the appropriate H2O2 concentration and action time to build NR8383 cell oxidative damage model. After pre-conditioning of 0.01, 0.10, and 1.00 μmol/L dexmedetomidine hydrochloride for 24 hours, MTT colorimetry was used to demonstrate the survival rate of NR8383 cells damaged by H2O2, and the release of lactate dehydrogenase (LDH) and TNF-α by H2O2-damaged NR8383 cells was detected by corresponding kit. RESULTS: At 50-300 μmol/L, H2O2 caused concentration-dependent oxidative damage in the alveolar macrophages, decreased the cell survival rate, and increased LDH and TNF-α release. At 0.01-1.00 μmol/L dexmedetomidine hydrochloride concentration-dependently protected NR8383 cells from oxidative damage induced by H2O2, significantly increased the cell survival rate, decreased LDH and TNF-α release, and this effect of dexmedetomidine hydrochloride was dose-dependent. Yohimbine, an α2 - adrenergic receptor antagonist, completely neutralized the protective effect of dexmedetomidine hydrochloride on NR8383 cells without affecting the oxidative damage of NR8383 cells. CONCLUSION Dexmedetomidine hydrochloride can prevent alveolar macrophages from oxidative damage induced by H2O2, which may play a protective role through α2 - adrenergic receptors.
Animals ; Cell Line ; Cell Survival ; Dexmedetomidine ; pharmacology ; Hydrogen Peroxide ; L-Lactate Dehydrogenase ; metabolism ; Macrophages, Alveolar ; drug effects ; Oxidative Stress ; Rats ; Receptors, Adrenergic, alpha-2 ; metabolism ; Tumor Necrosis Factor-alpha ; metabolism

OBJECTIVETo demonstrate the inhibitory effect of kappa-opioid receptor activation by U50488H on hypertrophy induced by NE in cultured neonatal rat cardiac myocytes and compare its effect with that of prazosin and propranolol.

METHODSThe cellular proliferation was determined with crystal violet staining. The protein content was assayed with Lowry's method. The cardiomyocytes volumes were measured by computer photograph analysis system. The protein synthesis was assayed with [3H]-lencine incorporation method.

RESULTS(1) NE significantly induced the increase of protein content, [3H]-leucine incorporation and cell size without a concomitant increase in cell number in low serum medium. OThese responses were partially suppressed by prazosin or propranolol alone and completely abolished by both in combination. U50488H significantly inhibited the NE-induced increase of protein content, [3H]-leucine incorporation and cell size. The inhibitory effects of U50488H on NE-induced cardiac hypertrophy were greater than either prazosin or propranolol, but comparable to combination of both.

CONCLUSIONNE, acting via both alpha1- and beta-adrenergic pathway, stimulates myocyte hypertrophy. Stimulating kappa-opioid receptor significantly inhibits NE-induced cardiac hypertrophy, which may be related with alpha1- and beta1-adrenergic pathway.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer ; pharmacology ; Adrenergic alpha-1 Receptor Antagonists ; pharmacology ; Adrenergic beta-Antagonists ; pharmacology ; Animals ; Animals, Newborn ; Cardiomegaly ; chemically induced ; pathology ; prevention & control ; Cell Enlargement ; drug effects ; Cells, Cultured ; Female ; Male ; Myocytes, Cardiac ; cytology ; Norepinephrine ; Prazosin ; pharmacology ; Propranolol ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Receptors, Opioid, kappa ; agonists

AIMTo investigate the molecular mechanisms of saponins from the rhizome of Anemarrhena asphodeloides Bunge.

METHODSOligonucleotide microarrays consisting of 87 probes representing 87 human cardiovascular disease-related genes were constructed. Effects of saponins on gene expression in human umbilical vein endothelial cells were analyzed by comparing hybridization of Cy 5-labeled cDNAs from saponins-treated human umbilical vein endothelial cells and Cy 3-labeled cDNAs from untreated human umbilical vein endothelial cells.

RESULTSThe results indicate that angiotensinogen gene, alpha 2A-adrenoceptor gene and endothelin-converting enzyme 1 gene were downregulated 2.8, 1.9 and 3.1 folds respectively after human umbilical vein endothelial cells were incubated in medium containing 80 mg.L-1 saponins.

CONCLUSIONThese results suggest that saponins may have beneficial effect on cardiovascular diseases by modulating the function of vein endothial cells and microarray can be used to investigate the biological action of extracts from traditional Chinese medicine.

Anemarrhena ; chemistry ; Angiotensinogen ; genetics ; metabolism ; Aspartic Acid Endopeptidases ; genetics ; metabolism ; Cells, Cultured ; Down-Regulation ; drug effects ; Endothelin-Converting Enzymes ; Endothelium, Vascular ; cytology ; metabolism ; Gene Expression ; drug effects ; Humans ; Metalloendopeptidases ; Oligonucleotide Array Sequence Analysis ; Plants, Medicinal ; chemistry ; Receptors, Adrenergic, alpha-2 ; genetics ; metabolism ; Rhizome ; chemistry ; Saponins ; isolation & purification ; pharmacology ; Umbilical Veins ; cytology ; metabolism