Animals ; Humans ; Pyrazines ; pharmacology ; Vasodilator Agents

Nicardipine is a potent coronary and systemic vasodilator without depression of ventricular function. We investigated the changes in local myocardial perfusion (LMP) according to the nicardipine administration after coronary reperfusion in a beating canine model. A Doppler probe was placed around the left anterior descending coronary artery (LAD) and thermal diffusion microprobe was implanted in the myocardium perfused by the exposed LAD. To define the nicardipine effects, we compared the two groups (control group, n=7 vs nicardipine group, n=7). In nicardipine group, 5 microgram/kg/min nicardipine was infused continuously. After the release of the LAD occlusion, LAD blood flow were increased compared to the baseline of both groups. However, there was no difference between groups in the LAD blood flow. The LMP after LAD reperfusion did not recover to the baseline level until 30 min after LAD reperfusion in control group (74%, 52% and 70% at 10, 20 and 30 min after LAD reperfusion, respectively). In nicardipine group, however, the LMP recovered to the baseline level at 20 min (99%), and increased more than the baseline level at 30 min (141%) after LAD reperfusion. Our findings suggest that the nicardipine augments the LMP following the release of a coronary occlusion.
Animals ; Coronary Circulation/drug effects* ; Dogs ; Drug Evaluation, Preclinical ; Myocardial Reperfusion* ; Myocardial Reperfusion Injury/prevention & control* ; Nicardipine/pharmacology* ; Nicardipine/therapeutic use ; Vasodilator Agents/pharmacology* ; Vasodilator Agents/therapeutic use

The favorable effects of estrogen on cardiovascular diseases can be explained by several mechanisms such as changes in serum lipid profiles and thrombogenecity. Estrogen also affects the vascular tone, but there has been no report in which the effect of estrogen was tested comprehensively for several vasoactive substances, especially after long-term administration. Two weeks after bilateral ovariectomy in 8-week old female Sprague-Dawley rats, placebo or 17 beta-estradiol (E2) pellets (0.5 mg; released over 3 weeks) were implanted subcutaneously. Two weeks after pellet implantation, organ chamber experiments were performed using aortae. Compared with control, E2-treated vessels showed impaired endothelium-dependent relaxation to acetylcholine. E2 enhanced the contraction to norepinephrine and U46619 and had no effect on endothelin-1-induced contraction. In contrast, the contraction to angiotensin (AT)-II was inhibited by E2. Northern blot analysis for AT1 receptor expression using cultured aortic smooth muscle cells showed no difference between control and E2-treated cells, suggesting that AT1 receptor downregulation is not the likely mechanism. These results suggest that E2 affects the vascular tone variably according to vasoactive substances.
Animal ; Estradiol/pharmacology* ; Female ; In Vitro ; Ovariectomy* ; Rats ; Rats, Sprague-Dawley ; Vasoconstrictor Agents/pharmacology* ; Vasodilator Agents/pharmacology* ; Vasomotor System/drug effects*

OBJECTIVETo investigate the vasodilating effects of pethidine, particularly in association with intracellular calcium.

METHODSAorta rings of Sprague-Dawley rats, with or without endothelium, were prepared in organ bath to measure the vascular tone. Pre-contractions by KCl (80 mmol/L) and phenylephrine (PhE) (10(-6)mol/L) were induced.

RESULTSPethidine did not alter the resting tension of aorta rings, but produced dose-dependent relaxation in KCl and PhE pre-treated aorta rings with or without endothelium. Pethidine did not change the caffeine-stimulated contraction, and still had similar inhibition in KCl pre-contracted aorta rings after pretreatment with ruthenium red. Pethidine decreased the contractile responses induced by PhE in Ca(2+)-free solution or by adding calcium into Ca(2+)-free solution.

CONCLUSIONPethidine could produce an endothelium-independent vasodilatation in KCl and PhE pre-contracted aorta rings, which is related to inhibition of Ca(2+)entry and IP3-sensitive Ca(2+) release in vascular smooth muscle.

Animals ; Caffeine ; pharmacology ; Calcium ; metabolism ; Male ; Meperidine ; pharmacology ; Potassium Chloride ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Vasodilator Agents ; pharmacology

OBJECTIVETo study the clinical causes of the erectile dysfunction (ED).

METHODSOne hundred and thirty cases of ED were examined by hemonamometry and cavernosography with vasodilating agent. The data about penile brachial index, intracavernous pressure, maintenance flow rate, and pressure loss change were obtained and the status of the penile veins was detected.

RESULTSAmong 130 patients with ED, 39 had venous leakage including penile arterial insufficiency simultaneous venous leakage in 15 patients. Various leakage sites were observed by using cavernosography. Twenty-eight patients showed deep dorsal veins only and the remaining crural veins.

CONCLUSIONHemodynamometry is effective to diagnose the cause of ED.

Adult ; Aged ; Erectile Dysfunction ; etiology ; physiopathology ; Hemodynamics ; Humans ; Male ; Middle Aged ; Vasodilator Agents ; pharmacology

OBJECTIVEIn our study, the function of the third-order branches of the mesentenc artery was measured by microvascular ring technique, which can be used to detect microvascular function in some disease related to microvascular dysfunction.

METHODSIsolated, fixed, standardized and then activated the third-order branches of rat mesenteric artery. Microvascular tone was measured by systolic and diastolic drags respectively, with the help of DMT tension apparatus and PowerLab data acquisition system.

RESULTSThe third-order branches of rat mesenteric artery showed excellent response to vasoactive drugs. The contraction effect of norepinephrine (NE) reached 19 in mN. When acetylcholine (Ach) or sodium nitroprusside (SNP) of 10(9)-10(5)mol/L was added, vascular tones showed gradient drop: 80% of maximal relaxation when adding ACh, while 95% of maximal relaxation when adding SNP.

CONCLUSIONThe third-order branches of the mesenteric artery function was successfully detected by using microvascular ring technique.

Acetylcholine ; pharmacology ; Animals ; In Vitro Techniques ; Male ; Mesenteric Arteries ; drug effects ; physiology ; Nitroprusside ; pharmacology ; Norepinephrine ; pharmacology ; Rats ; Vasoconstrictor Agents ; pharmacology ; Vasodilation ; physiology ; Vasodilator Agents ; pharmacology

Previous studies have shown that paeonol can antagonize acute myocardial ischemia and infarction in rat. This study further researched the effects of paeonol on blood pressure and blood flow in the artery of spontaneously hypertensive rats and its mechanisms related on vasomotion. Firstly, thirty spontaneously hypertensive rats were randomly divided into spontaneously hypertensive control group and paeonol-treating groups of high dose and low dose, and also, the other ten Wistar rats as healthy control group. Before and after the intraduodenal administration of the drug, arterial blood pressure was measured by carotid artery and blood flow through the renal artery and carotid artery in vivo were measured by animal flowmeter. The same volume of solvent was given to the spontaneously hypertensive control group and the healthy control group, and the other operations were same. In order to further study the effect of paeonol on vasomotor function, the superior mesenteric artery, renal artery and coronary artery of the spontaneously hypertensive rat were removed and separated, precontracted by a certain concentration of potassium chloride (KCl) and 5-serotonin (5-HT) respectively, and dilatory responses were assessed by cumulative addition of paeonol. Results showed that after duodenal one-time delivery of paeonol, the blood pressure significantly lowered, the renal arterial blood flow and the carotid arterial blood flow significantly increased in spontaneously hypertensive rat. And also, paeonol relaxed the mesenteric artery, renal artery and the coronary artery of spontaneously hypertensive rat in a concentration-dependent manner. These results indicated that the effect of paeonol on decreasing arterial blood pressure and increasing the arterial blood flow was related to its vasodilative effect.
Acetophenones ; pharmacology ; Animals ; Blood Pressure ; drug effects ; Male ; Rats ; Rats, Inbred SHR ; Regional Blood Flow ; drug effects ; Vasodilator Agents ; pharmacology

OBJECTIVETo investigate the effect of puerarin on the neural function and the histopathological changes after ischemic spinal cord injury in rabbits.

METHODSThirty male New Zealand white rabbits were randomly divided into three groups as follows: puerarin group (n=10) receiving intravenous infusion of 30 mg/kg puerarin for 10 minutes, control group (n=10) receiving intravenous infusion of the same volume of normal saline as puerarin for 10 minutes, and sham operation group (n=10) undergoing only the surgical exposure of the abdominal aorta. Temporary spinal cord ischemia was induced by infrarenal aortic occlusion for 20 minutes and followed by reperfusion. The neural status was scored with the Tarlov criteria at 8, 12, 24 and 48 hours after reperfusion. All the animals were killed at 48 hours after reperfusion and the spinal cords (L5) were removed immediately for histopathological study.

RESULTSThe neural function scores at 8, 12, 24 and 48 hours after reperfusion were higher in the puerarin group and sham operation group than those in the control group (P<0.05). More normal motor neurons in the anterior horn of spinal cord were present in the puerarin group and sham operation group than those in the control group (P<0.01). There was a strong correlation between the final neural function scores and the number of normal motor neurons in the anterior horn of spinal cord (r=0.839, P<0.01).

CONCLUSIONSPuerarin can significantly ameliorate the neural function and the histopathological damages after transient spinal cord ischemia in rabbits.

Animals ; Isoflavones ; pharmacology ; Male ; Motor Neurons ; pathology ; Rabbits ; Spinal Cord Ischemia ; drug therapy ; pathology ; physiopathology ; Vasodilator Agents ; pharmacology

OBJECTIVETo study the selective dilatation effects of iptakalim (Ipt) on basilar and pulmonary arterioles, and endothelial cell function of these arterioles in hypoxic rats.

METHODSSD male rats were divided into 2 groups:control and hypoxic group fed in normobaric hypoxic environment (O2 7.8%, 8 h). Arteriole rings about (204 + 5) pm were isolated and the tension of hypoxic arterioles pre-contracted by 6 nmol/L endothelin-1 (ET-1) was observed with wire myograph system model (DMT 610 m). The relaxing response of hypoxic arterioles induced by different concentration of Ipt were detected and endothelial activity was also tested by acetylcholine.

RESULTS10(5) mol/L acetylcholine (ACh)-mediated vasodilatation of basilar and pulmonary arterioles was greatly reduced in the hypoxic group than those in control group (P < 0.05). Compared with normal group, a novel ATP-sensitive potassium channel opener Ipt at the concentration ranging from 10(-11) mol/L to 10(3) mol/L, caused stronger dose dependent vasodilatation on hypoxic pulmonary arterioles, and there was no significant difference between control and hypoxic basilar arterioles.

CONCLUSIONThe endothelial function of basilar and pulmonary arterioles was damaged under hypoxic state, and Ipt selectively increased dilatation effects on hypoxic pulmonary arterioles, but not on hypoxic basilar arterioles which could improve high altitude pulmonary edema pathological state and be the novel drug in the treatment of pulmonary hypertension.

Acetylcholine ; pharmacology ; Altitude ; Altitude Sickness ; physiopathology ; Animals ; Arterioles ; drug effects ; Dilatation ; Endothelin-1 ; pharmacology ; Hypoxia ; KATP Channels ; drug effects ; Male ; Propylamines ; pharmacology ; Rats ; Vasodilation ; Vasodilator Agents ; pharmacology

AIMIn order to evaluate the regulatory effects of nucleotides and adenosine on ATP-sensitive potassium channel (K(ATP)) in artery smooth muscles, the effects of them on vascular relaxation induced by K(ATP) opener pinacidil(Pin) were investigated.

METHODSThe isolated endothelium- denuded aorta rings were preincubated with nucleotides or nucleotides and glibenclamide (Gli) for 10 min, the vascular relaxation induced by Pin in aorta precontracted with 20 mmol x L(-1) KCl was observed.

RESULTSAfter the isolated endothelium-denuded aorta rings were preincubated with ATP, ADP, UDP, GTP and adenosine (Ade) 100 micromol x L(-1) respectively, the vascular relaxation induced by Pin was changed as following: (1) ATP could inhibit the K(ATP) activation by Pin and enhance the blockade of K(ATP) by Gli. (2) ADP could inhibit the K(ATP) activation by Pin and attenuate the blockade of K(ATP) by Gli. (3) The regulatory effect of Ade on K(ATP) was similar with that of ADP. (4) UDP could enhance the K(ATP) activation by Pin and attenuate the blockade of K(ATP) by Gli. (5) GTP could enhance the K(ATP) activation by Pin, but had no effects on the blockade of K(ATP) by Gli.

CONCLUSIONNucleotides and adenosine, related to energy metabolism, could modulate the functions of K(ATP) in vascular smooth muscle. But their pharmacological characteristics were different.

Animals ; Aorta ; cytology ; drug effects ; Glyburide ; pharmacology ; In Vitro Techniques ; KATP Channels ; metabolism ; Male ; Muscle, Smooth, Vascular ; drug effects ; Nucleotides ; pharmacology ; Pinacidil ; pharmacology ; Rats ; Rats, Wistar ; Vasodilator Agents ; pharmacology