scholarly journals Evidence for altered vascular responses to exogenous endothelin-1 in patients with advanced cirrhosis with restoration of the normal vasoconstrictor response following successful liver transplantation

Gut ◽  
2003 ◽  
Vol 52 (10) ◽  
pp. 1505-1510 ◽  
Author(s):  
R B Vaughan
Keyword(s):  
Liver Transplantation ◽  
Vascular Responses ◽  
Endothelin 1 ◽  
Advanced Cirrhosis ◽  
Vasoconstrictor Response

scholarly journals Effects of Endothelin-1 on Hepatic Blood Flow

HPB Surgery ◽  
1996 ◽  
Vol 9 (3) ◽  
pp. 153-159 ◽  
Author(s):  
Kjetil Unneberg ◽  
Marianne Mjaaland ◽  
Elin Helseth ◽  
Arthur Revhaug
Keyword(s):  
Liver Transplantation ◽  
Blood Flow ◽  
Portal Vein ◽  
Plasma Concentrations ◽  
Hepatic Clearance ◽  
Elevated Plasma ◽  
Central Venous ◽  
Portal Vein Pressure ◽  
Portal Vein Flow ◽  
Endothelin 1

Endothelin-1 belongs to a family of potent vasoconstrictors, recently isolated from endothelial cells. Endothelin-1 has a variety of hepatic effects and hepatic clearance from the circulation is important. Elevated plasma concentrations of Endothelin-1 are found after orthotopic liver transplantation and in cirrhosis with ascites.This study in piglets on hepatic bloodflow was designed to compare differences in effects between central venous and intraportal injection of endothelin-1, and to evaluate effects of repeated injections. Central venous injection of endothelin-1 caused a larger reduction in portal vein flow, while intraportal injection caused a larger increase in portal vein pressure. Repeated injections resulted in a reduction in portal vein flow and an increase in portal vein vascular resistance.

Enhanced endothelin-1 response and receptor expression in small mesenteric arteries of insulin-resistant rats

2001 ◽  
Vol 280 (2) ◽  
pp. H522-H527 ◽  
Author(s):  
Prasad V. G. Katakam ◽  
Jennifer S. Pollock ◽  
David M. Pollock ◽  
Michael R. Ujhelyi ◽  
Allison W. Miller
Keyword(s):  
Receptor Expression ◽  
Mesenteric Arteries ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Binding Characteristics ◽  
Endothelin 1 ◽  
Insulin Resistant ◽  
Vasoconstrictor Response ◽  
Enhanced Expression

Hyperinsulinemia, a primary feature of insulin resistance, is associated with increased endothelin-1 (ET-1) activity. This study determined the vascular response to ET-1 and receptor binding characteristics in small mesenteric arteries of insulin-resistant (IR) rats. Rats were randomized to control (C) ( n = 32) or IR ( n = 32) groups. The response to ET-1 was assessed (in vitro) in arteries with (Endo+) and without (Endo−) endothelium. In addition, arteries (Endo+) were pretreated with the ETBantagonist A-192621 or the ETA antagonist A-127722. Finally, binding characteristics of [125I]ET-1 were determined. Results showed that in Endo+ arteries the maximal relaxation ( E max) to ET-1 was similar between C and IR groups; however, the concentration at 50% of maximum relaxation (EC50) was decreased in IR arteries. In Endo− arteries, the E max to ET-1 was enhanced in both groups. Pretreatment with A-192621 enhanced the E max and EC50 to ET-1 in both groups. In contrast, A-127722 inhibited the ET-1 response in all arteries in a concentration-dependent manner; however, a greater ET-1 response was seen at each concentration in IR arteries. Maximal binding of [125I]ET-1 was increased in IR versus C arteries although the dissociation constant values were similar. In conclusion, we found the vasoconstrictor response to ET-1 is enhanced in IR arteries due to an enhanced expression of ET receptors and underlying endothelial dysfunction.

Nitric oxide attenuates endothelin-1-induced vasoconstriction in canine stomach

1996 ◽  
Vol 271 (1) ◽  
pp. G27-G35
Author(s):  
J. G. Wood ◽  
Q. Zhang ◽  
Z. Y. Yan ◽  
L. Y. Cheung
Keyword(s):  
Nitric Oxide ◽  
Methyl Ester ◽  
Ischemia Reperfusion ◽  
Nitric Oxide Donor ◽  
Question Mark ◽  
Endothelin 1 ◽  
Vasoconstrictor Response ◽  
Anesthetized Dogs ◽  
Spermine Nonoate

We previously observed that endothelin-1 (ET-1)-induced gastric vasoconstriction is enhanced after ischemia-reperfusion. The purpose of our present study was to examine the role of nitric oxide in regulating ET-1-induced vasoconstriction under normal conditions and after ischemia-reperfusion. Using a mechanically perfused stomach segment from chloralose-anesthetized dogs, we examined 1) responses to NG-nitro-L-arginine methyl ester (L-NAME) alone and in combination with L-arginine, 2) whether L-NAME affects ET-1-induced vasoconstriction under normal conditions and after ischemia-reperfusion, and 3) if spermine NONOate inverted question mark1,3-propanediamine-N-[4-1-(3-aminopropyl)-2-hydroxy-2-nitrosohydrazi no] butyl; a nitric oxide donor inverted question mark attenuates the augmented response to ET-1 after ischemia-reperfusion. Our results show that 1) L-NAME significantly increased baseline vascular resistance and this response was reduced by L-arginine, 2) ET-1-induced vasoconstriction was enhanced by L-NAME, and 3) administration of spermine NONOate during reperfusion largely attenuated the vasoconstrictor response to ET-1 after ischemia-reperfusion. Our findings are consistent with the hypothesis that nitric oxide modulates responses to ET-1 under normal conditions, and loss of this vasodilator after ischemia-reperfusion results in an augmented response to ET-1.

Changes in vascular responses of the basilar artery to acetylcholine and endothelin-1 in an experimental rabbit vasospasm model

2003 ◽  
Vol 145 (7) ◽  
pp. 571-577 ◽  
Author(s):  
C.-Y. Kim ◽  
S. H. Paek ◽  
B. G. Seo ◽  
J. H. Kim ◽  
D. H. Han
Keyword(s):  
Basilar Artery ◽  
Vascular Responses ◽  
Endothelin 1

Cutaneous and skeletal muscle vascular responses to hypothermia

1981 ◽  
Vol 240 (6) ◽  
pp. H868-H873 ◽  
Author(s):  
T. C. Major ◽  
J. M. Schwinghamer ◽  
S. Winston
Keyword(s):  
Skeletal Muscle ◽  
Vascular Resistance ◽  
Sympathetic Nerves ◽  
Local Cooling ◽  
Right Heart ◽  
Vascular Responses ◽  
External Cooling ◽  
Vasoconstrictor Response ◽  
The Right ◽  
Cutaneous Vasoconstriction

Vascular resistance and capacitance were studied in innervated or denervated canine forelimbs. Hypothermia (38-28 degrees C) was induced systemically, by external cooling of blood which returned to the right heart, or locally, by cooling blood perfusing the forelimb. Systemic cooling to 33 and then to 28 degrees C elicited significant decreases in limb weight with substantial increases in both skin and skeletal muscle vascular resistances. Acute denervation of the forelimbs attenuated both the fall in limb weight and increase in skin vascular resistance associated with cooling. These data support the contention that cutaneous vasoconstriction during systemic cooling is mediated primarily by sympathetic nerves, whereas skeletal muscle vasoconstriction is mediated primarily by circulating hormones. Local cooling elicited skin and skeletal muscle vascular dilation at 33 degrees C in both innervated and denervated forelimbs whereas either no change or a slight increase in skin and skeletal muscle vascular resistance resulted upon local cooling to 28 degrees C, perhaps due to the inhibition of Na+ - K+ - ATPase activity and/or a rise in blood viscosity. The locally induced vasodilation was found to override the powerful vasoconstrictor response caused by systemic cooling. The vasodilation is considered active rather than passive, because the increase in forelimb weight and decreases in forelimb vascular resistances occurred in the denervated as well as innervated limbs.

Arteriolar responses to extracellular ATP in striated muscle

1997 ◽  
Vol 272 (4) ◽  
pp. H1886-H1891 ◽  
Author(s):  
W. T. McCullough ◽  
D. M. Collins ◽  
M. L. Ellsworth
Keyword(s):  
Striated Muscle ◽  
Atp Release ◽  
Cheek Pouch ◽  
Retractor Muscle ◽  
Vascular Responses ◽  
Local Tissue ◽  
Dilatory Response ◽  
Vasoconstrictor Response

Blood flow and its distribution must be appropriately regulated to ensure that perfusion is matched to local tissue demands. We investigated the role of ATP in triggering a conducted alteration in arteriolar diameter in the Saran-covered cheek pouch retractor muscle of anesthetized hamsters (n = 60). Vascular responses were observed using in vivo video microscopy upstream from the site of micropressure application of ATP (10(-8)-10(-4) M) either into the lumen or just outside the wall of first- and second-order arterioles. The role of nitric oxide (NO) in the vascular responses to ATP was determined by inhibiting NO synthase activity with N(omega)-nitro-L-arginine methyl ester (L-NAME) with and without coadministration of an excess of L-arginine. Intraluminal application of ATP led to a concentration-dependent vasodilation, which was conducted upstream along the arteriole. The dilatory response was blocked by systemic pretreatment with L-NAME and was maintained in the presence of an excess of L-arginine. In contrast, ATP introduced extraluminally resulted in a conducted vasoconstrictor response that was enhanced by pretreatment with L-NAME. The dilator response to intraluminal ATP, in the context of ATP release from erythrocytes under conditions associated with decreased supply relative to demand, supports a role for the erythrocyte in communicating local tissue needs to the vasculature, enabling the appropriate matching of oxygen supply to demand.

Tone-dependent responses to acetylcholine in the feline pulmonary vascular bed

1988 ◽  
Vol 64 (5) ◽  
pp. 2002-2009 ◽  
Author(s):  
A. L. Hyman ◽  
P. J. Kadowitz
Keyword(s):  
Arterial Pressure ◽  
Base Line ◽  
High Tone ◽  
Vascular Responses ◽  
Vascular Bed ◽  
Vasoconstrictor Response ◽  
Steady Level ◽  
Low Tone ◽  
Type Receptor ◽  
Pulmonary Vascular Bed

The effects of an increase in base-line tone on pulmonary vascular responses to acetylcholine were investigated in the pulmonary vascular bed of the intact-chest cat. Under conditions of controlled blood flow and constant left atrial pressure, intralobar injections of acetylcholine under low-tone base-line conditions increased lobar arterial pressure in a dose-related manner. When tone was increased moderately by alveolar hypoxia, acetylcholine elicited dose-dependent decreases in lobar arterial pressure, and at the highest dose studied, acetylcholine produced a biphasic response. When tone was raised to a high steady level with the prostaglandin analogue, U46619, acetylcholine elicited marked dose-related decreases in lobar arterial pressure. Atropine blocked both vasoconstrictor responses at low tone and vasodilator responses at high tone, whereas meclofenamate and BW 755C had no effect on responses to acetylcholine at low or high tone. The vasoconstrictor response at low tone was blocked by pirenzepine (20 and 50 micrograms/kg iv) but not gallamine (10 mg/kg iv). The vasodilator response at high tone was not blocked by pirenzepine (50 micrograms/kg iv) or gallamine or pancuronium (10 mg/kg iv). The present data support the concept that pulmonary vascular responses to acetylcholine are tone dependent and suggest that the vasoconstrictor response under low-tone conditions is mediated by a high-affinity muscarinic (M1)-type receptor. These data also suggest that vasodilator responses under high-tone conditions are mediated by muscarinic receptors that are neither M1 nor M2 low-affinity muscarinic-type receptor and that responses to acetylcholine are not dependent on the release of cyclooxygenase or lipoxygenase products.

Forearm vascular responses to baroreceptor unloading at the onset of dynamic exercise

1993 ◽  
Vol 75 (2) ◽  
pp. 979-985 ◽  
Author(s):  
T. Nishiyasu ◽  
X. Shi ◽  
G. W. Mack ◽  
E. R. Nadel
Keyword(s):  
Lower Body Negative Pressure ◽  
Dynamic Exercise ◽  
Central Command ◽  
Lower Body ◽  
Physically Active ◽  
Vascular Responses ◽  
Vasoconstrictor Response ◽  
The Relationship ◽  
Forearm Vascular Resistance ◽  
Cardiac Stroke Volume

To determine the extent to which reflexes accompanying muscular exercise (associated with central command) interact with cardiopulmonary (CP) baroreceptor-mediated reflexes controlling forearm vascular resistance (FVR), we examined the forearm vasoconstrictor response at the onset of dynamic exercise, with and without CP baroreflex unloading, in 10 physically active men. CP baroreceptors were unloaded by application of lower body negative pressure (LBNP) at rest and during five 4-min bouts of supine exercise at 25 and 32 degrees C. Exercise intensities were 10 (essentially no load) and 100 W, and LBNP was applied at -10, -20, -30, and -40 mmHg during rest and at -20 and -40 mmHg during exercise. Resting FVR was 33.0 +/- 3.2 and 14.0 +/- 2.7 resistance units, and cardiac stroke volume (SV) was 117 +/- 7 and 126 +/- 9 ml/beat at 25 and 32 degrees C, respectively. We found a linear relationship between the increase in FVR and decrease in SV during LBNP; the slope of the relationship was significantly lower at 32 degrees C (FVR = 51.7–0.29SV) than at 25 degrees C (FVR = 123–0.79SV). At the onset of 100-W exercise without LBNP, FVR increased significantly to 50.2 +/- 9.0 and 21.2 +/- 3.2 units at 25 and 32 degrees C, respectively, whereas SV was unchanged. Application of -40-mmHg LBNP reduced SV significantly to 68 +/- 5 and 71 +/- 6 ml/beat and increased FVR significantly to 89.0 +/- 11.3 and 36.3 +/- 7.6 units at 25 and 32 degrees C, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Sympathetic, sensory, and nonneuronal contributions to the cutaneous vasoconstrictor response to local cooling

2005 ◽  
Vol 288 (4) ◽  
pp. H1573-H1579 ◽  
Author(s):  
John M. Johnson ◽  
Tony C. Yen ◽  
Kun Zhao ◽  
Wojciech A. Kosiba
Keyword(s):  
Sensory Nerve ◽  
Sympathetic Nerves ◽  
Local Cooling ◽  
Vascular Responses ◽  
Y1 Receptor ◽  
Vasoconstrictor Response ◽  
Forearm Skin ◽  
Cold Sensitive ◽  
Cutaneous Vascular Conductance ◽  
Cutaneous Vasoconstriction

Previous work indicates that sympathetic nerves participate in the vascular responses to direct cooling of the skin in humans. We evaluated this hypothesis further in a four-part series by measuring changes in cutaneous vascular conductance (CVC) from forearm skin locally cooled from 34 to 29°C for 30 min. In part 1, bretylium tosylate reversed the initial vasoconstriction (−14 ± 6.6% control CVC, first 5 min) to one of vasodilation (+19.7 ± 7.7%) but did not affect the response at 30 min (−30.6 ± 9% control, −38.9 ± 6.9% bretylium; both P < 0.05, P > 0.05 between treatments). In part 2, yohimbine and propranolol (YP) also reversed the initial vasoconstriction (−14.3 ± 4.2% control) to vasodilation (+26.3 ± 12.1% YP), without a significant effect on the 30-min response (−26.7 ± 6.1% YP, −43.2 ± 6.5% control; both P < 0.05, P > 0.05 between sites). In part 3, the NPY Y1 receptor antagonist BIBP 3226 had no significant effect on either phase of vasoconstriction ( P > 0.05 between sites both times). In part 4, sensory nerve blockade by anesthetic cream (Emla) also reversed the initial vasoconstriction (−20.1 ± 6.4% control) to one of vasodilation (+213.4 ± 87.0% Emla), whereas the final levels did not differ significantly (−37.7 ± 10.1% control, −37.2 ± 8.7% Emla; both P < 0.05, P > 0.05 between treatments). These results indicate that local cooling causes cold-sensitive afferents to activate sympathetic nerves to release norepinephrine, leading to a local cutaneous vasoconstriction that masks a nonneurogenic vasodilation. Later, a vasoconstriction develops with or without functional sensory or sympathetic nerves.

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