Endothelial modulation of porcine coronary microcirculation perfused via immature collaterals

1992 ◽  
Vol 262 (6) ◽  
pp. H1669-H1675 ◽  
Author(s):  
F. W. Sellke ◽  
Y. Kagaya ◽  
R. G. Johnson ◽  
T. Shafique ◽  
F. J. Schoen ◽  
...  
Keyword(s):  
Sodium Nitroprusside ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Flow State ◽  
Vascular Studies ◽  
Collateral Vessels ◽  
Endothelium Dependent Relaxation ◽  
Minimal Evidence ◽  
Dependent Agents

Porcine hearts have relatively few native collateral vessels and lack the propensity to develop normal perfusion to the collateral-dependent myocardium. To examine microvascular responses in the collateral-dependent region, collateral vessels were stimulated in pigs by the Ameroid constrictor technique. After 4–7 wk, isolated microarterial vessels (90–170 microns ID) were studied in a pressurized (40 mmHg), no-flow state. Microvessels from noninstrumented pigs were used as controls for vascular studies. Although myocardium in the collateral-dependent region showed minimal evidence of infarction, percent systolic shortening was reduced at rest and after pacing compared with myocardium in the normally perfused region. Relaxations to the receptor-mediated endothelium-dependent agents ADP and bradykinin were impaired in collateral-dependent coronary microvessels. Relaxations to the calcium ionophore A23187, which acts through a non-receptor-mediated mechanism, were similar in control and Ameroid microvessels. Relaxations to the endothelium-independent agent sodium nitroprusside were markedly enhanced in microvessels from the collateral-dependent region compared with microvessels from control hearts. In conclusion, receptor-mediated endothelium-dependent relaxation is impaired and endothelium-independent relaxation to sodium nitroprusside is enhanced in microvessels from myocardium perfused by immature collateral vessels.

scholarly journals Endothelial Dysfunction in Cerebral Vessels following Carotid Artery Infusion of Phorbol Ester in Rabbits: The Role of Polymorphonuclear Leukocytes

1994 ◽  
Vol 14 (6) ◽  
pp. 1078-1087 ◽  
Author(s):  
S. E. Akopov ◽  
R. Sercombe ◽  
J. Seylaz
Keyword(s):  
Endothelial Dysfunction ◽  
Carotid Artery ◽  
Sodium Nitroprusside ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Significant Difference ◽  
Left And Right ◽  
Endothelium Dependent Relaxation

The effect of 4β-phorbol-12β-myristate-13α-acetate (PMA) on endothelium-dependent and endothelium-independent vasoconstriction and vasodilation was studied in isolated segments of rabbit middle cerebral artery (MCA). Concentration-dependent responses of the left and right MCA to the constrictors KCl, noradrenaline, uridine 5′-triphosphate, serotonin, and histamine, as well as to the dilators acetylcholine, bradykinin, sodium nitroprusside, and calcium ionophore (A23187), were compared in control animals and after PMA injection into the left common carotid artery. In the control animals there was no significant difference in the responses of the left and right MCA to either the constrictors or the dilators studied. After PMA injection the endothelium-dependent relaxation in response to acetylcholine, bradykinin, and A23187 was reduced in the left MCA (PMA-injected side), whereas the effect of the endothelium-independent dilator sodium nitroprusside remained unchanged. Simultaneously greater contractile responses of the left MCA to serotonin and histamine were obtained. Neither infusion of l-arginine in vivo before the PMA injection nor incubation of the isolated MCA segments with l-arginine affected this difference in MCA reactivity. Platelet depletion did not change the PMA-induced reduction in the endothelium-dependent relaxation, whereas after leukocyte depletion this reduction practically disappeared. These results suggest that the PMA-induced brain microembolia causes acute endothelial dysfunction, which is possibly mediated by intravascular activation of leukocytes and is independent of nitric oxide synthesis from l-arginine. This phenomenon might play an important role in cerebral angiospastic disorders after intravascular activation of leukocytes in cerebral ischemia and reperfusion.

Segmental heterogeneity of NO-mediated pulmonary vasodilation in rats

1994 ◽  
Vol 267 (2) ◽  
pp. H494-H499 ◽  
Author(s):  
M. R. Eichinger ◽  
B. R. Walker
Keyword(s):  
Sodium Nitroprusside ◽  
Arginine Vasopressin ◽  
Calcium Ionophore ◽  
Vascular Occlusion ◽  
Physiological Saline ◽  
Calcium Ionophore A23187 ◽  
Pulmonary Vasculature ◽  
Ionophore A23187 ◽  
Sprague Dawley ◽  
No Donor

Nitric oxide (NO) is known to elicit vasodilation in the preconstricted rat lung. However, the sites of dilation within the pulmonary vasculature remain unknown. We hypothesized that donated NO would dilate all areas of constriction within the pulmonary vasculature, whereas receptor-mediated, NO-induced dilations would correspond to regional binding of agents. Isolated lungs from male Sprague-Dawley rats were perfused at constant flow with physiological saline solution. Pulmonary arterial and pulmonary venous pressures were monitored, while pulmonary microvascular pressures were estimated by vascular occlusion. Lungs were constricted with U-46619, and upon development of a stable degree of vasoconstriction, the NO donor sodium nitroprusside or the endothelium-dependent dilators A23187, arginine vasopressin, or ATP were administered. U-46619 caused constriction of both arterial and venous segments. Administration of sodium nitroprusside and the calcium ionophore A23187 elicited similar dilation of preconstricted arterial and venous segments. Arginine vasopressin significantly dilated both arterial and venous segments, with a greater reversal of venous resistance. In contrast, ATP significantly reduced arterial resistance more than venous. These results demonstrate that donated NO uniformly dilates all constricted regions of the pulmonary vasculature. However, receptor-mediated, endothelium-dependent dilators display characteristic heterogeneities in the sites of decreased pulmonary vascular resistance.

Alterations in endothelium-dependent responsiveness of the canine basilar artery after subarachnoid hemorrhage

1988 ◽  
Vol 69 (2) ◽  
pp. 239-246 ◽  
Author(s):  
Phyo Kim ◽  
Thoralf M. Sundt ◽  
Paul M. Vanhoutte
Keyword(s):  
Subarachnoid Hemorrhage ◽  
Basilar Artery ◽  
Calcium Ionophore ◽  
Adenosine Diphosphate ◽  
Canine Model ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Content Type ◽  
Endothelium Dependent Relaxation

✓ To investigate the alteration of endothelium-dependent responses in chronic vasospasm after subarachnoid hemorrhage (SAH), experiments were carried out in the double-hemorrhage canine model. After the presence of vasospasm was confirmed by cerebral angiography on Days 0 and 7, pharmacological studies on the basilar artery were conducted in vitro on Day 8. In the SAH group, endothelium-dependent relaxation was abolished in response to arginine vasopressin and was significantly reduced in response to thrombin. Endothelium-independent relaxation in the SAH group was preserved in response to papaverine and was minimally reduced in response to sodium nitroprusside. Endothelium-dependent contraction in response to arachidonic acid, acetylcholine, the calcium ionophore A23187, adenosine diphosphate, mechanical stretching, and hypoxia persisted in the SAH group. The maximal contraction to KCl and uridine triphosphate, which is endothelium-independent, was diminished in the SAH group, but no changes in sensitivity were noted in the concentration-response relationships. A significant correlation was observed between the degree of vasospasm determined angiographically and the loss of endothelium-dependent relaxation. The loss of endothelium-dependent relaxation and the persistence of endothelium-dependent contraction suggest that the deterioration in the endothelium-dependent responses may be an important component in the pathogenesis of cerebral vasospasm.

Inhibitory Effects of Etomidate and Ketamine on Endothelium-dependent Relaxation in Canine Pulmonary Artery

2001 ◽  
Vol 94 (4) ◽  
pp. 668-677 ◽  
Author(s):  
Koji Ogawa ◽  
Satoru Tanaka ◽  
Paul A. Murray
Keyword(s):  
Pulmonary Artery ◽  
Calcium Ionophore ◽  
Receptor Activation ◽  
Isometric Tension ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Inhibitory Effects ◽  
Pulmonary Arterial ◽  
Synthase Inhibitor ◽  
Endothelium Dependent Relaxation

Background The authors recently demonstrated that acetylcholine-induced pulmonary vasorelaxation had two primary components, nitric oxide (NO) and endothelium-derived hyperpolarizing factor (EDHF). The goal was to investigate the effects of etomidate and ketamine on the NO- and EDHF-mediated components of pulmonary vasorelaxation in response to acetylcholine, bradykinin, and the calcium ionophore, A23187. Methods Canine pulmonary arterial rings with an intact endothelium were suspended in organ chambers for isometric tension recording. The effects of etomidate and ketamine (10(-5) M and 10(-4) M) on vasorelaxation responses to acetylcholine, bradykinin, and A23187 were assessed in phenylephrine-contracted rings. The NO- and EDHF-mediated components of relaxation were assessed using a NO synthase inhibitor (N-nitro-L-arginine methylester [L-NAME]: 10(-4) M) and a Ca2+-activated potassium channel inhibitor (tetrabutylammonium hydrogen sulfate [TBA]: 10(-3) M) in rings pretreated with a cyclooxygenase inhibitor (ibuprofen: 10(-5) M). Intracellular calcium concentration ([Ca2+]i) was measured in cultured bovine pulmonary artery endothelial cells loaded with acetoxylmethyl ester of fura-2. Results Etomidate and ketamine attenuated pulmonary vasorelaxation in response to acetylcholine and bradykinin, whereas they had no effect on the response to A23187. The relaxant responses to acetylcholine and bradykinin were attenuated by L-NAME or TBA alone and were abolished by combined inhibition in rings pretreated with ibuprofen. Etomidate and ketamine further attenuated both L-NAME-resistant and TBA-resistant relaxation. These anesthetics also inhibited increases in endothelial [Ca2+]i in response to bradykinin, but not A23187. Conclusion These results indicate that etomidate and ketamine attenuated vasorelaxant responses to acetylcholine and bradykinin by inhibiting both NO- and EDHF-mediated components. Moreover, our results suggest that these anesthetics do not directly suppress NO or EDHF activity, but rather inhibit the endothelial [Ca2+]i transient in response to receptor activation.

L-arginine restores endothelium-dependent relaxation in pulmonary circulation of chronically hypoxic rats

1992 ◽  
Vol 263 (2) ◽  
pp. L194-L200 ◽  
Author(s):  
S. Eddahibi ◽  
S. Adnot ◽  
C. Carville ◽  
Y. Blouquit ◽  
B. Raffestin
Keyword(s):  
Vascular Tone ◽  
Pressor Response ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Relaxing Factor ◽  
Isolated Lungs ◽  
Endothelium Dependent Relaxation

We investigated whether loss of endothelial-derived relaxing factor (EDRF) activity in the pulmonary vessels of chronically hypoxic rats could be restored by pretreatment with L-arginine. We measured vasodilation to acetylcholine (ACh), calcium ionophore A23187, or linsidomine (Sin-1) under conditions of increased vascular tone induced by U-46619 (50 pmol/min), as well as vasoconstriction to endothelin-1 (ET) in isolated lungs pretreated with meclofenamate (3 microM). In lungs from normoxic (N) rats, in vitro L- or D-arginine (10(-3) M) did not alter vasodilation to the endothelium-dependent agents ACh (10(-9)-10(-6) M) and A23187 (10(-9)-10(-7) M), but NG-monomethyl-L-arginine (10(-3) M) completely abolished it. In lungs from rats exposed to 3 wk of hypoxia (H), vasodilation to ACh or A23187 was fully restored after in vitro L-arginine (10(-3) M) or N alpha-benzoyl-L-arginine (5 x 10(-5) M) but remained abolished after D-arginine, L-citrulline, L-ornithine, or L-argininosuccinic acid. In vivo pretreatment of H rats with L-arginine (300 mg/kg iv) 30 min before isolating the lung also restored vasodilation to A23187. Vasodilation to the endothelium-independent agent Sin-1 was similar in both groups of lungs and was not altered by in vitro L-arginine. L-arginine attenuated the increased pressor response to ET (300 pmol) of H rat lungs but had no effect in N rats. Our results demonstrate that loss of EDRF activity associated with hypoxic pulmonary hypertension may be reversed by supplying L-arginine.

scholarly journals Linolenic Acid Attenuates the Vasodilation Induced by Acetylcholine in Isolated Rat Aortae

Dose-Response ◽  
2019 ◽  
Vol 17 (4) ◽  
pp. 155932581989414 ◽  
Author(s):  
Soo Hee Lee ◽  
Seong-Ho Ok ◽  
Ji-Yoon Kim ◽  
Raghavendra Baregundi Subbarao ◽  
Sung Il Bae ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Sodium Nitroprusside ◽  
Linolenic Acid ◽  
Calcium Ionophore ◽  
Underlying Mechanism ◽  
Cyclic Guanosine Monophosphate ◽  
Calcium Ionophore A23187 ◽  
Guanosine Monophosphate ◽  
Ionophore A23187 ◽  
Isolated Rat

This study aims to examine the effect of linolenic acid on the vasodilation or vasoconstriction induced by acetylcholine and bupivacaine in isolated rat aortae and its underlying mechanism. The effect of linolenic acid on the vasodilation induced by acetylcholine, the calcium ionophore A23187, sodium nitroprusside, and 8-bromoguanosine 3′,5′-cyclic monophosphate sodium salt (bromo-cyclic guanosine monophosphate [bromo-cGMP]) in endothelium-intact and endothelium-denuded aortae was examined. Linolenic acid inhibited vasodilation induced by acetylcholine, calcium ionophore A23187, and sodium nitroprusside. However, this fatty acid increased bromo-cGMP-induced vasodilation in endothelium-denuded aortae. Linolenic acid increased bupivacaine-induced contraction in endothelium-intact aortae, whereas it decreased bupivacaine-induced contraction in endothelium-intact aortae with Nω-nitro-l-arginine methyl ester and endothelium-denuded aortae. Linolenic acid inhibited acetylcholine- and bupivacaine-induced phosphorylation of endothelial nitric oxide synthase. Sodium nitroprusside increased cGMP in endothelium-denuded aortic strips, whereas bupivacaine decreased cGMP in endothelium-intact aortic strips. Linolenic acid decreased cGMP levels produced by bupivacaine and sodium nitroprusside. Together, these results suggest that linolenic acid inhibits acetylcholine-induced relaxation by inhibiting a step just prior to nitric oxide-induced cGMP formation. In addition, linolenic acid-mediated inhibition of vasodilation induced by a toxic concentration (3 × 10−4 M) of bupivacaine seems to be partially associated with inhibition of the nitric oxide–cGMP pathway.

Complement-induced endothelial dysfunction in rabbits: mechanisms, recovery, and gender differences

1996 ◽  
Vol 270 (6) ◽  
pp. H1924-H1932 ◽  
Author(s):  
P. F. Lennon ◽  
C. D. Collard ◽  
M. A. Morrissey ◽  
G. L. Stahl
Keyword(s):  
Complement Activation ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Acute Effects ◽  
Anion Formation ◽  
Alternative Pathways ◽  
And Gender ◽  
Endothelium Dependent Relaxation ◽  
Endothelial Tissue

Activation of complement and attenuation of endothelium-dependent relaxation occur in a number of pathophysiological conditions. The aim of this study was to investigate the mechanisms of human complement activation and loss of endothelium-dependent relaxation in rabbit tissue, the duration of this loss, and the effects of gender and serum concentration. In rabbit thoracic aortic rings precontracted with phenylephrine, human serum (HS) concentration dependently induced a loss of endothelium-dependent relaxation to the receptor-dependent vasodilator acetylcholine (ACh) and receptor-independent vasodilator calcium ionophore A23187. Serum-induced loss of ACh-dependent relaxation was decreased when rings were bathed in 1) HS depleted of factor B, C2, or C8, 2) heat-inactivated HS, or 3) HS with complement inhibitor sCR1 or sCR1[desLHR-A]. Superoxide dismutase had no effect on serum-induced loss of ACh-dependent relaxation. Serum-induced loss of ACh-dependent relaxation returned to control values after removal of HS. Serum-induced loss of ACh-dependent relaxation was greater in male than in female aortic rings. These results suggest that 1) complement activation directly attenuates endothelium-dependent relaxation via the classical and alternative pathways independent of superoxide anion formation, 2) this attenuation is concentration dependent, reversible, and dependent on formation of C5b-9, and 3) endothelial tissue from males is more susceptible than that from females to the acute effects of complement activation.

Endothelium-dependent relaxation in isolated human arteries and veins

1987 ◽  
Vol 73 (5) ◽  
pp. 547-552 ◽  
Author(s):  
S. Thom ◽  
A. Hughes ◽  
G. Martin ◽  
P. S. Sever
Keyword(s):  
Vasoactive Intestinal Peptide ◽  
Soluble Guanylate Cyclase ◽  
Pulmonary Arteries ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Lipoxygenase Inhibitor ◽  
Human Arteries ◽  
Endothelium Dependent Relaxation

1. The role of the endothelium in mediating relaxation to acetylcholine, the calcium ionophore A23187, vasoactive intestinal peptide and peptide histidine methionine was studied using isolated human blood vessels. 2. Segments of renal, colic, pulmonary, uterine, transverse cervical, brachial, coronary and coeliac branch arteries, and saphenous veins, were obtained from surgical resection material for use in tissue bath studies. 3. Acetylcholine or A23187 produced endothelium-dependent relaxation in isolated vessels from all vascular beds studied. Coronary arteries, however, differed in their response to acetylcholine which produced predominantly a contractile response, either alone or after initial relaxation. 4. Vasoactive intestinal peptide and peptide histidine methionine produced endothelium-dependent relaxation in coeliac branch arteries. However, these peptides relaxed isolated pulmonary arteries independently of endothelium. 5. Endothelium-dependent relaxation in response to acetylcholine and A23187 was antagonized by nordihydroguaretic acid, a lipoxygenase inhibitor, and methylene blue and haemoglobin, inhibitors of soluble guanylate cyclase. In these respects the endothelium-dependent responses of human arteries to acetylcholine and A23187 resemble those described in other species.

Antenatal betamethasone therapy potentiates nitric oxide-mediated relaxation of preterm ovine coronary arteries

1996 ◽  
Vol 270 (2) ◽  
pp. H538-H544 ◽  
Author(s):  
Y. Gao ◽  
H. Zhou ◽  
J. U. Raj
Keyword(s):  
Nitric Oxide ◽  
Coronary Arteries ◽  
Soluble Guanylate Cyclase ◽  
Calcium Ionophore ◽  
Ringer Solution ◽  
Isometric Tension ◽  
Calcium Ionophore A23187 ◽  
Ionophore A23187 ◽  
Cyclic Monophosphate ◽  
Endothelium Dependent Relaxation

The present study was designed to test the hypothesis that betamethasone may potentiate nitric oxide-mediated relaxation of coronary arteries of preterm lambs. Isolated coronary arteries were obtained from lambs delivered at 128 days gestation. The lambs were treated intramuscularly with a single dose of betamethasone or saline 48 h before delivery and were killed after 3 h of ventilation after delivery. Vessel rings were suspended in organ chambers filled with modified Krebs-Ringer solution (95% O2-5% CO2, 37 degrees C), and their isometric tension was recorded. The endothelium-dependent relaxation induced by bradykinin and calcium ionophore A23187 was greater in arteries from antenatal betamethasone-treated lambs than in arteries from control lambs. The relaxation was abolished by N omega-nitro-L-arginine. Nitric oxide induced a greater relaxation in vessels from antenatal betamethasone-treated lambs and in vessels preincubated with betamethasone than in vessels from controls. Coronary arteries from control and antenatal betamethasone-treated lambs relaxed similarly to 8-bromoguanosine 3',5'-cyclic monophosphate. Nitric oxide induced a greater increase in guanosine 3',5'-cyclic monophosphate content in coronary arteries from antenatal betamethasone-treated lambs than in arteries from control lambs. Our data suggest that antenatal betamethasone therapy potentiates nitric oxide-mediated relaxation in coronary arteries from preterm lambs, probably by affecting the activity of soluble guanylate cyclase of vascular smooth muscle cells.

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