This study investigated the role of calcium-activated Cl⁻ channels (CaCCs) in mediating vasomotor activity of cerebral basilar artery (BA) of Wistar rat. Pressure myograph was used to examine the changes in diameter of isolated BA to vasoactive reagents. The results showed that (1) The rate of pressure-induced vasomotor activity was 78.6% (n = 28) in BA from 0 to 100 mmHg working pressure. The contractile phase of the response was faster than the relaxation phase; (2) The amplitude of contraction was (62.6 ± 6.4) µm (n = 22), the frequency of contraction was variable and the highest value was 8.0 ± 2.3 per 5 min at 60 mmHg working pressure (n = 22); (3) The pressure-induced vasomotor activity of BA was markedly attenuated when Ca²⁺ was removed from medium; (4) The pressure-induced vasomotor activity was blocked by voltage dependent Ca²⁺ channel blocker nimodipine; (5) The pressure-induced vasomotor was inhibited by CaCC antagonists NFA and NPPB. These results suggest that the pressure-induced vasomotor activity of isolated BA is associated with Ca²⁺ influx that activates CaCCs.
Animals ; Basilar Artery ; physiology ; Calcium ; physiology ; Chloride Channels ; physiology ; Rats ; Rats, Wistar ; Vasoconstriction ; Vasodilation

AIM AND METHODSTo study the roles of carbon monoxide on hypoxic pulmonary vasoconstriction (HPV) by investigating the effects of exogenous carbon monoxide and heme oxygenase inhibitor ZnPPIX on hypoxic vasoconstriction reaction of isolated rat pulmonary arterial rings (PAR).

RESULTSHypoxia caused constriction in PAR preconstricted by PE. Both ZnPPIX and carbon monoxide inhibited hypoxic pulmonary constriction significantly by increasing the cGMP level after hypoxia.

CONCLUSIONZnPPIX and exogenous carbon monoxide can inhibit HPV. The reduction of cGMP induced by the decreased of CO may be one of reasons of HPV.

Animals ; Carbon Monoxide ; physiology ; Hypoxia ; In Vitro Techniques ; Male ; Pulmonary Artery ; physiology ; Rats ; Rats, Wistar ; Vasoconstriction ; physiology

The aim of the present study was to investigate the effect of removal of the adventitia on vascular remodeling and vasoconstriction of the carotid artery in New Zealand rabbit. Adventitia of carotid artery was removed mechanically. The histology, morphology and reactivity of the carotid artery was observed by immunohistochemistry and measurement of carotid ring tension immediately, 1 week and 2 weeks after removal of the adventitia. No damage of intima and media was observed after removing the adventitia. Removal of the adventitia caused a remarkable proliferation of the vascular media and formed the neointima. Compared with the control ring, norepinephrine (NE)-induced vasocontraction in adventitia-denuded carotid artery was significantly reduced immediately and 1 week after the operation (P<0.05). Adventitia removal promoted the neointima formation and decreased vasoconstriction of the carotid artery, indicating that the adventitia is involved in the regulation of vascular remodeling and vasoconstriction.
Animals ; Carotid Arteries ; pathology ; physiology ; surgery ; Connective Tissue ; physiology ; surgery ; Muscle, Smooth, Vascular ; pathology ; Rabbits ; Tunica Intima ; pathology ; Vasoconstriction ; physiology

Animals ; Aorta, Thoracic ; physiology ; Dopamine ; pharmacology ; Hydrogen-Ion Concentration ; In Vitro Techniques ; Rats ; Vasoconstriction ; drug effects

Adenosine was identified as a regulator of skeletal muscle blood flow almost 50 years ago. It was first proposed that increased use of ATP during muscle contractions led to net ATP breakdown, and its breakdown product, adenosine, diffused through the interstitial space to the blood stream to be washed away. En-route to its removal, adenosine was suggested to relax the vascular smooth muscle, thereby increasing the blood flow and oxygen supply to the contracting muscle. This mechanism has been researched quite intensively over the years, yet there are still many aspects that remain unclear. It has been confirmed that adenosine does, indeed, relax vascular smooth muscle and contribute to exercise hyperaemia, but the discovery that adenosine was formed extracellularly has shifted the research focus onto its precursor, ATP. ATP is released from many tissues, and produces many effects, including both vasodilation and vasoconstriction, as well as modulation of the neural mechanisms for skeletal muscle blood flow control. This review summarizes the current state of knowledge on the contributions of adenosine and ATP to the skeletal muscle vasodilation that accompanies contractile activity.
Adenosine ; physiology ; Adenosine Triphosphate ; physiology ; Exercise ; physiology ; Hemodynamics ; Humans ; Muscle Contraction ; Muscle, Skeletal ; blood supply ; Muscle, Smooth, Vascular ; physiology ; Regional Blood Flow ; physiology ; Vasoconstriction ; Vasodilation

AIMTo investigate the role of calcium-activated chloride channels and the Cl- channel blockers niflumic acid (NFA) and indanyloxyacetic acid (IAA-94) in the regulation of vascular contraction induced by phenylephrine (PE).

METHODSThe PE-induced contraction in rat pulmonary artery was observed by using routine blood vascular perfusion in vitro. The fluorescence Ca2+ indicator Fura-2/AM was used to observe intracellular free Ca2+ concentration ([Ca2+]i) of rat pulmonary artery smooth muscle cells (PASMCs) which were obtained by the acute enzyme separation method (collagenase I plus papain) on NFA and IAA-94 effects on PE-induced contraction. Changes of [Ca2+]i in PASMCs were measured by spectrofluorometry.

RESULTSThe anion channel blockers NFA and IAA-94 produced inhibitory effects on PE-induced contractions in the pulmonary artery. NFA and IAA-94 negligibly affected the KCl-induced pulmonary artery contractions. PE could increase [Ca2+]i but NFA and IAA-94 negligibly affected it.

CONCLUSIONCalcium-activated chloride channels contribute to the agonist-induced pulmonary artery contractions under physiological conditions, which may be a new clue to investigate the hypoxic pulmonary vasoconstriction.

Animals ; Calcium ; physiology ; Chloride Channels ; physiology ; Glycolates ; pharmacology ; Male ; Muscle, Smooth, Vascular ; physiology ; Niflumic Acid ; pharmacology ; Phenylephrine ; pharmacology ; Pulmonary Artery ; physiology ; Rats ; Rats, Sprague-Dawley ; Vasoconstriction

To investigate the effect of ethanol on the zero-stress state of rabbit artery, a rabbit animal model of blood ethanol concentration gradient was established by intragastric administration of ethanol (IGAE). The blood ethanol concentration of each group was measured. The zero-stress state characterized by opening angle was observed by an image processing system. The results revealed that the blood ethanol concentration of each group increased after IGAE. The magnitude of the blood ethanol concentration came to the peak at 1.5-2 h after IGAE. The opening angle decreased with the increase of the magnitude of blood ethanol concentration and the opening angle in each group. These findings suggest that the zero-stress state of the rabbit artery has close relationship with ethanol concentration.
Animals ; Aorta ; physiology ; Arteries ; physiology ; Dose-Response Relationship, Drug ; Ethanol ; blood ; pharmacology ; Female ; Male ; Rabbits ; Random Allocation ; Stress, Mechanical ; Vasoconstriction ; physiology ; Vasodilation ; physiology

Kidney is one of the important organs of the body.With both excretory and endocrine functions,it plays a vital role in regulating the normal physiological state.As a precursor of the nitric oxide(NO)synthesis
Animals ; Arginine/physiology* ; Kidney/physiology* ; Muscle, Smooth, Vascular ; Nitric Oxide/physiology* ; Rats ; Receptors, Adrenergic, alpha-1/physiology* ; Renal Insufficiency/physiopathology* ; Signal Transduction ; Vasoconstriction

OBJECTIVETo investigate the role of voltage-gated potassium channels in the acute hypoxic pulmonary vasoconstriction.

METHODSThirty Wistar rats were divided into two groups, namely the normoxic group and hypoxic group. The single smooth muscle cell was obtained from the pulmonary artery of Wistar rats with acute enzymatic digestion method. The conventional whole-cell patch clamp technique was used to record the resting membrane potential(Em) and the potassium currents of voltage-gated potassium channel (IKv) in rat pulmonary arterial smooth muscle cells(PASMC). Intracellular application of Kv1.2, Kv1.3, Kv1.5, and Kv2.1 antibodiesè1:125éwas conducted through the whole-cell patch clamp system.

RESULTSEm of PASMC was depolarized in hypoxia compared with that of control cells. The mixture of Kv1.2, Kv1.3, Kv1.5, and Kv2.1 antibodiesè1:125é depolarized Em and inhibited Ikv in PASMC from normoxic rat,whereas the mixture of Kv1.2, Kv1.3, Kv1.5, Kv2.1 antibodiesè1:125éhad no effects on Ikv and Em in hypoxic rats.

CONCLUSIONKv1.2, Kv1.3, Kv1.5, Kv2.1 might be oxygen sensitive potassium channels which mediated acute hypoxic pulmonary vasoconstriction.

Animals ; Hypoxia ; physiopathology ; Membrane Potentials ; drug effects ; Muscle, Smooth, Vascular ; physiopathology ; Patch-Clamp Techniques ; Potassium Channels, Voltage-Gated ; physiology ; Pulmonary Artery ; pathology ; physiology ; Rats ; Rats, Wistar ; Vasoconstriction ; physiology

The present study was designed to investigate the effects of high-saturated and high-unsaturated fatty acid diets on relaxation and contraction of the renal arteries in insulin resistance (IR) rats. Wistar rats were fed normal chow diet (control), high-saturated fatty acid diet or high-unsaturated fatty acid diet for 6 months (n=14 in each group). IR was evaluated by glucose infusion rate (GIR) of hyperinsulinemic euglycemic clamp. Blood pressure was measured via the tail-cuff method. Body weight (BW), plasma total triglyceride (TG), free fatty acid (FFA), insulin, fasting blood glucose (FBG) and nitric oxide metabolite (NO2(-)/NO3(-)) were compared among the three groups. The rats were sacrificed and the renal arterial rings were placed in the physiological tissue baths for measurement of vascular response to various agents. After the arterial rings were constricted with 3 mmol/L noradrenaline (NA), endothelium-dependent vasorelaxation to acetylcholine (ACh) and endothelium-independent vasorelaxation to sodium nitroprusside (NTP) were measured. Endothelium-dependent vasorelaxation to ACh was also observed in renal arterial rings incubated with L-arginine (L-Arg), N(omega)-nitro-L-arginine (L-NNA) and methylene blue (MB), respectively. Arterial contractility was evaluated from concentration-response curves to 10 nmol/L-100 micromol/L NA. Saturated or unsaturated fatty acids led to moderate rises in blood pressure (P<0.05). It was associated with higher levels of plasma lipids and lower whole body insulin sensitivity (P<0.01). There were no significant differences in BW, FBG, TG, insulin and FFA between saturated and unsaturated fatty acid-fed rats. A decrease in endothelium-dependent vasorelaxation of the renal arteries in saturated and unsaturated fatty acid-fed rats was observed (P<0.01), but there was no marked difference between the two high-fatty acid diet groups. Endothelium-dependent vasorelaxation was increased when the arteries were incubated with L-Arg and decreased when incubated with L-NNA and MB in both high-fatty acid diet groups (P<0.05, P<0.01). But no difference was found before and after incubation with L-Arg, L-NNA and MB in the control rats. In the mean time, endothelium-independent maximal vasorelaxation response of renal arteries to NTP and renal arterial contractile responses to cumulative dose of NA were assayed, and there was no difference among the three groups (P>0.05). Endothelium-dependent vasorelaxation was negatively correlated with systolic blood pressure and TG, and positively correlated with NO2(-)/NO3(-) and GIR. There was a significantly negative correlation between FFA and NO2(-)/NO3(-). The present study suggests that both high-saturated and unsaturated fatty acid diets result in hypertension associated with significantly decreased endothelium-dependent vasorelaxation, dyslipidemia and IR, and that decreased endothelium-dependent vasorelaxation induced by high fatty acid diets is associated with impaired L-Arg-NO-cGMP pathways.
Animals ; Dietary Fats, Unsaturated ; administration & dosage ; Endothelium, Vascular ; physiology ; Fatty Acids ; administration & dosage ; Insulin Resistance ; Male ; Nitric Oxide ; physiology ; Rats ; Rats, Wistar ; Renal Artery ; physiology ; Systole ; Vasoconstriction ; Vasodilation