OBJECTIVETo investigate whether the methanol extract of Berberis amurensis Rupr. (BAR) augments penile erection using in vitro and in vivo experiments.

METHODSThe ex vivo study used corpus cavernosum strips prepared from adult male New Zealand White rabbits. In in vivo studies for intracavernous pressure (ICP), blood pressure, mean arterial pressure (MAP), and increase of peak ICP were continuously monitored during electrical stimulation of Sprague-Dawley rats.

RESULTSPreconstricted with phenylephrine (PE) in isolated endotheliumintact rabbit corus cavernosum, BAR relaxed penile smooth muscle in a dose-dependent manner, which was inhibited by pretreatment with NG-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase inhibitor, and H-[1,2,4]-oxadiazole-[4,3-α]-quinoxalin-1-one, a soluble guanylyl cclase inhibitor. BAR significantly relaxed penile smooth muscles dose-dependently in ex vivo, and this was inhibited by pretreatment with L-NAME H-[1,2,4]-oxadiazole-[4,3-α]-quinoxalin-1-one. BAR-induced relaxation was significantly attenuated by pretreatment with tetraethylammonium (TEA, P<0.01), a nonselective K channel blocker, 4-aminopyridine (4-AP, P<0.01), a voltage-dependent K channel blocker, and charybdotoxin (P<0.01), a large and intermediate conductance Ca sensitive-K channel blocker, respectively. BAR induced an increase in peak ICP, ICP/MAP ratio and area under the curve dose dependently.

CONCLUSIONBAR augments penile erection via the nitric oxide/cyclic guanosine monophosphate system and Ca sensitive-K (BK and IK) channels in the corpus cavernosum.

Animals ; Area Under Curve ; Berberis ; chemistry ; Blood Pressure ; drug effects ; Cyclic GMP ; metabolism ; Epoprostenol ; pharmacology ; In Vitro Techniques ; Indomethacin ; pharmacology ; Male ; Models, Biological ; Muscle Relaxation ; drug effects ; Muscle, Smooth ; drug effects ; physiology ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitric Oxide ; metabolism ; Penile Erection ; drug effects ; Phenylephrine ; pharmacology ; Plant Extracts ; pharmacology ; Potassium Channel Blockers ; pharmacology ; Potassium Channels ; metabolism ; Pressure ; Rabbits

This study was designed to observe the differences between main pulmonary arteries and the third-order branches of pulmonary arteries in the contractile response to phenylephrine (Phen), endothelin-1 (ET-1) and potassium chloride (KCl). The vascular tension changes of main and the third-order branches of pulmonary arteries induced by KCl, ET-1 and Phen were recorded by traditional vascular tone detection methods and microvascular ring technique, respectively. The results showed that Phen could cause a significant contraction in main pulmonary arteries, but did not induce apparent contraction in the third-order branches of pulmonary arteries. Compared with main pulmonary arteries, ET-1 contracted the third-order branches of pulmonary arteries with reduced maximal response value and PDvalue. In comparison with the main pulmonary arteries, contraction caused by KCl was enhanced in the third-order branches of pulmonary arteries. The results suggest that the vascular reactivity of main and the third-order branches of pulmonary arteries is different and it is important to study the vascular function of small branches of pulmonary arteries. This study could provide an important experimental basis for the further study on vascular function of small branches of pulmonary arteries and the functional changes in pulmonary hypertension.
Animals ; Endothelin-1 ; pharmacology ; Male ; Phenylephrine ; pharmacology ; Potassium Chloride ; pharmacology ; Pulmonary Artery ; drug effects ; Rats ; Vasoconstriction

OBJECTIVETo study the effect of gastrodin on isolated thoracic aorta rings of rats and to investigate the potential mechanism.

METHODSA perfusion model of isolated thoracic aorta rings of rats was applied. The effect of cumulative gastrodin (5, 50, 100,150, 200, and 250 μmol/L) on endothelium-intact aorta rings was investigated. The same procedure was applied to observe the effect of gastrodin on endothelium-intact/denuded aorta rings pre-contracted with 10(-6) mol/L phenylephrine hydrochloride (PE). The aorta rings incubated by 200 mmol/L gastrodin in the Ca(2+)-free (K-H) solution was contracted by using PE. The effect of 200 mmol/L gastrodin on endothelium-denuded aorta rings pre-contracted with 60 mmol/L KCl was also observed.

RESULTSCompared with the denuded gastrodin group, the intact gastrodin group could significantly relax the PE-contracted aorta rings (P<0.01). In Ca(2+)-free (K-H) solution KHS, the PE-induced contraction rate of aorta rings pre-incubated by gastrodin was 6.5%±0.7%, which was significantly less than the control group (11.8%±0.9%,P<0.01). However, after 3 mmol/L CaCl2 was added, the Ca(2+)-induced contraction in the gastrodin group (51.7%±2.4%) was similar to that in the control group (49.8%±2.8%). The contractile rate of rings in the KCl-contracted gastrodin group (96.3%±0.6%) was not significantly different from that in the control group (96.8%±1.2%).

CONCLUSIONSGastrodin has the effect of vasorelaxation on isolated thoracic aorta rings of rats. The mechanism of the vasorelaxation of gastrodin may mainly work through the inhibition of inositol 1, 4, 5-trisphosphosphate receptor on the sarcoplasmic reticulum of the arterial smooth muscle, which leads to the reduction of the Ca(2+) released from the sarcoplasmic reticulum.

Animals ; Aorta, Thoracic ; drug effects ; physiology ; Benzyl Alcohols ; pharmacology ; Calcium ; metabolism ; Endothelium, Vascular ; physiology ; Female ; Glucosides ; pharmacology ; In Vitro Techniques ; Male ; Phenylephrine ; pharmacology ; Rats ; Rats, Wistar ; Vasodilation ; drug effects

OBJECTIVETo investigate the acute effects of aldosterone (ALD) on mesenteric resistance vessels in normal or heart failure (HF) rats and its mechanism.

METHODSHF model was adopted by in vivo ligation of left anterior descending coronary artery in SD rats; segments of third-order branches of mesenteric artery were isolated and dissected into about 2 mm rings for isometric force recording.

RESULTSPretreated with ALD for 10 min,phenylephrine (PE)-induced contraction of normal mesenteric artery decreased first and then increased compared to control group along with the increase of the concentration of PE while decreased in HF rats. This effect was attenuated by ALD receptor-special antagonist eplerenone partially. ALD increased Ach-induced endothelial-dependent vascular relaxation significantly compared to control group both in normal and HF rats. Pretreated with ALD and dexamethasone (DEX) for 10 min, the effects of ALD on PE-induced contraction were weakened in mesenteric artery both of normal and HF rats. And this reaction of DEX to ALD-treated mesenteric in normal rats was attenuated by RU486 partially.

CONCLUSIONALD has biphasic effect in PE-induced response on mesenteric artery of normal rats, while reduces the sensitivity of mesenteric artery to PE in HF rats. DEX attenuates the biphasic effect of ALD on artery of normal rat partially but has no significant effect on that of HF rats.

Aldosterone ; pharmacology ; Animals ; Heart Failure ; physiopathology ; Male ; Mesenteric Arteries ; drug effects ; physiology ; Phenylephrine ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Vasoconstriction ; drug effects

Animals ; Botulinum Toxins, Type A ; pharmacology ; Capsaicin ; pharmacology ; Carbachol ; pharmacology ; Humans ; Keratoconjunctivitis ; surgery ; Phenylephrine ; pharmacology ; Saliva ; drug effects ; Submandibular Gland ; drug effects ; transplantation ; Translational Medical Research

Cinnamyl alcohol (CAL) is known as an antipyretic, and a recent study showed its vasodilatory activity without explaining the mechanism. Here we demonstrate the vasodilatory effect and the mechanism of action of CAL in rat thoracic aorta. The change of tension in aortic strips treated with CAL was measured in an organ bath system. In addition, vascular strips or human umbilical vein endothelial cells (HUVECs) were used for biochemical experiments such as Western blot and nitrite and cyclic guanosine monophosphate (cGMP) measurements. CAL attenuated the vasoconstriction of phenylephrine (PE, 1 microM)-precontracted aortic strips in an endothelium-dependent manner. CAL-induced vasorelaxation was inhibited by pretreatment with NG-nitro-L-arginine methyl ester (L-NAME; 10(-4) M), methylene blue (MB; 10(-5) M) and 1 H-[1,2,4]-oxadiazolole-[4,3-a] quinoxalin-10one, (ODQ; 10(-6) or 10(-7) M) in the endothelium-intact aortic strips. Atrial natriuretic peptide (ANP; 10(-8) or 10(-9) M) did not affect the vasodilatory effect of CAL. The phosphorylation of endothelial nitric oxide synthase (eNOS) and generation of nitric oxide (NO) were stimulated by CAL treatment in HUVECs and inhibited by treatment with L-NAME. In addition, cGMP and PKG1 activation in aortic strips treated with CAL were also significantly inhibited by L-NAME. Furthermore, CAL relaxed Rho-kinase activator calpeptin-precontracted aortic strips, and the vasodilatory effect of CAL was inhibited by the ATP-sensitive K+ channel inhibitor glibenclamide (Gli; 10(-5) M) and the voltage-dependent K+ channel inhibitor 4-aminopyridine (4-AP; 2 x 10(-4) M). These results suggest that CAL induces vasorelaxation by activating K+ channels via the NO-cGMP-PKG pathway and the inhibition of Rho-kinase.
Animals ; Aorta/drug effects/metabolism/physiology ; Atrial Natriuretic Factor/pharmacology ; Cyclic GMP/*metabolism ; Cyclic GMP-Dependent Protein Kinases/*metabolism ; Dipeptides/pharmacology ; Human Umbilical Vein Endothelial Cells/drug effects/metabolism ; Humans ; Male ; Methylene Blue/pharmacology ; NG-Nitroarginine Methyl Ester/pharmacology ; Nitric Oxide/*metabolism ; Nitric Oxide Synthase/metabolism ; Oxadiazoles/pharmacology ; Phenylephrine/pharmacology ; Phosphorylation ; Potassium Channel Blockers/pharmacology ; Potassium Channels/*agonists ; Propanols/*pharmacology ; Quinoxalines/pharmacology ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Vasoconstriction/*drug effects ; Vasodilation/drug effects ; rho-Associated Kinases/antagonists & inhibitors/*metabolism

OBJECTIVETo investigate the vasorelaxation effect of crocetin (CCT) and its mechanism.

METHODSIsolated aortic rings from Sprague-Dawley rats were mounted in the organ bath system. The tension of the aorta was recorded.

RESULTCCT significantly provoked concentration-dependent relaxation in both endothelium-intact and-denuded aortic rings pre-constricted by phenylephrine (10⁻⁵ mol/L), and the vasorelaxation in endothelium-intact aortic rings was stronger than that in endothelium-denuded ones. CCT had no significant effects on aortic rings pre-constricted with KCl (6 × 10⁻² mol/L). Pretreatment with eith L-NAME (10⁻⁴ mol/L), an inhibitor of nitric oxide synthase (NOS), or indomethacin (10⁻⁵ mol/L), an inhibitor of cyclooxygenase, for 30 min significantly attenuated the relaxation of endothelium-intact aortic rings induced by CCT. Besides, both tetraethylammonium (a Ca²(+)-activated K(+) channel inhibitor, 5 × 10⁻³ mol/L) and 4-aminopyridine (a voltage-sensitive K(+) channel inhibitor, 10⁻³ mol/L), but not the ATP-sensitive K(+) channel inhibitor glibenclamide (3 × 10⁻⁶ mol/L), significantly attenuated CCT-induced relaxation in endothelium-denuded aortic rings.

CONCLUSIONCCT had partial endothelium-dependent relaxation in rat aortas, which may be mediated by activating the endothelial NOS-NO and cyclooxygenase-prostacyclin pathways. The endothelium-independent relaxation in rat aortas induced by CCT may be mediated by Ca²(+)-activated K(+) channels and voltage-sensitive K(+) channels.

Animals ; Aorta, Thoracic ; drug effects ; metabolism ; physiology ; Carotenoids ; pharmacology ; Endothelium, Vascular ; drug effects ; metabolism ; In Vitro Techniques ; Male ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase ; metabolism ; Phenylephrine ; pharmacology ; Potassium Channel Blockers ; metabolism ; Rats ; Rats, Sprague-Dawley ; Vasodilation ; drug effects ; Vasodilator Agents ; pharmacology

OBJECTIVETo study the relaxant effects of glycyrrhizinate and salvianolic acid B on rat portal vein in vitro.

METHODSHealthy female Wistar rats were canalized from hepatic artery, portal vein and hepatic vein in vitro. Remained blood in liver was eliminated with heparinized Krebs-Henseleit solution through hepatic artery, then the liver was isolated under infusing manner. Being constricted with phenylephrine and relaxed with acetylcholine, and infused with glycyrrhizinate or salvianolic acid B, the portal pressures of infused rat livers were consistently monitored by BL-420S physiological experiment system. The median effective concentration (EC50) of the two agents were analyzed with non-linear various slope regression using Prism-4 software.

RESULTSEC50 of glycyrrhizinate in relaxing the phenylephrine-contracted portal was 1.5556 x 10(-9) mol/L, suggesting one of the mechanism of action of diammonium glycyrhizinate for the treatment of portal hypertension was direct relaxation. Salvianolic acid B showed constrictive action on the phenylephrine-retracted portal vein, the EC50 was 1.4639 x 10(-9) mol/L, indicating that its indirect control action was took part in the portal hypertension therapy synergistically.

CONCLUSIONUnder the mode with both controlled-velocity and monitored pressure, glycyrrhizinate showed relaxation and salvianolic acid B showed constriction on portal pressure in vitro.

Animals ; Benzofurans ; pharmacology ; Blood Pressure ; drug effects ; Female ; Glycyrrhizic Acid ; pharmacology ; Hypertension, Portal ; physiopathology ; Phenylephrine ; pharmacology ; Portal Vein ; physiology ; Rats ; Rats, Wistar ; Vasoconstrictor Agents ; pharmacology ; Vasodilator Agents ; pharmacology ; Vasomotor System ; drug effects

The hypothalamic paraventricular nucleus (PVN) is a central site for integration of the endocrine system and the autonomic nervous system. Despite a number of studies have pointed out the importance of the PVN in the central regulation of cardiovascular functions, the chemical mediators in the PVN responsible for mediating baroreflex are not well understood. In the present study, we used the conscious rats to investigate the possible involvement of glycine (Gly) in PVN in the central regulation of baroreflex induced by intravenous injection of phenylephrine (0.8 mug/0.04 mL, in 3 min). Then, the microdialysis sampling was performed in the PVN and the concentration of Gly in the microdialysate was measured by high performance liquid chromatography (HPLC) combined with electrochemical techniques, and mean arterial pressure (MAP) and heart rate (HR) were recorded simultaneously. Injection of phenylephrine elicited a significant increase (P<0.01) in MAP from the baseline of (99.5+/-14.2) mmHg to the maximum of (149.8+/-19.5) mmHg and a decrease (P<0.01) in HR from the baseline of (400.8+/-33.1) beats/min to the minimum of (273.4+/-40.8) beats/min, respectively. Synchronously, the injection of phenylephrine increased the level of Gly in the microdialysate from the PVN to (162.9+/-27.3)% of the basal level (P<0.05). Perfusion of strychnine (100 mumol/L), an antagonist of Gly receptor, into the PVN enhanced the pressor response and attenuated the bradycardic response during the baroreflex, resulting in a decrease in baroreflex sensitivity (P<0.001). Whereas, the perfusion of Gly (1 mmol/L) into the PVN did not affect the pressor response but enhanced the bradycardic response during the baroreflex, resulting in an increase in baroreflex sensitivity (P<0.001). These results suggest that endogenous Gly in the PVN may act via strychnine-sensitive Gly receptor to produce a facilitative effect on baroreflex.
Animals ; Baroreflex ; drug effects ; Glycine ; pharmacology ; Heart Rate ; Microinjections ; Paraventricular Hypothalamic Nucleus ; physiology ; Phenylephrine ; pharmacology ; Rats

OBJECTIVETo determine whether matrine, a kind of traditional Chinese medicinal alkaloid, can relax the aortic smooth muscles isolated from guinea pigs and to investigate the mechanism of its relaxant effects.

METHODSPhenylephrine or potassium chloride concentration-dependent relaxation response of aortic smooth muscles to matrine was studied in the precontracted guinea pigs.

RESULTSMatrine (1 x 10(-4) mol/L -3.3 x 10(3) mol/L) relaxed the endothelium-denuded aortic rings pre-contracted sub-maximally with phenylephrine, in a concentration-dependent manner, and its pre-incubation (3.3 x 10(-3) mol/L) produced a significant rightward shift in the phenylephrine dose-response curve, but had no effects on the potassium chloride-induced contraction. The anti-contractile effect of matrine was not reduced by the highly selective ATP-dependent K+ channel blocker glibenclamide (10(-5) mol/L), either by the non-selective K+ channel blocker tetraethylammonium (10(-3) mol/L), or by the beta-antagonist propranolol (10(-5) mol/L). In either "normal" or "Ca(2+)-free" bathing medium, the phenylephrine-induced contraction was attenuated by matrine (3.3 x 10(-3) mol/L), indicating that the vasorelaxation was due to inhibition of intracellular and extracellular Ca2+ mobilization.

CONCLUSIONMatrine inhibits phenylephrine-induced contractions by inhibiting activation of alpha-adrenoceptor and interfering with the release of intracellular Ca2+ and the influx of extracellular Ca2+.

Alkaloids ; chemistry ; pharmacology ; Animals ; Aorta ; drug effects ; physiology ; Calcium ; pharmacology ; Culture Media ; pharmacology ; Dose-Response Relationship, Drug ; Glyburide ; pharmacology ; Guinea Pigs ; In Vitro Techniques ; Male ; Muscle Contraction ; drug effects ; Muscle Relaxation ; drug effects ; Muscle, Smooth, Vascular ; drug effects ; physiology ; Phenylephrine ; pharmacology ; Potassium Chloride ; pharmacology ; Propranolol ; pharmacology ; Quinolizines ; chemistry ; pharmacology ; Tetraethylammonium ; pharmacology