scholarly journals Pharmacological Modulation of Mucosa-Related Impairment of β-Adrenoceptor-Mediated Relaxation in Human Detrusor

2015 ◽  
Vol 95 (3) ◽  
pp. 300-308 ◽  
Author(s):  
Stefan Propping ◽  
Melanie Roedel ◽  
Manfred P. Wirth ◽  
Ursula Ravens
Keyword(s):  
Receptor Antagonist ◽  
Force Measurement ◽  
P2x Receptor ◽  
Nitric Oxide Synthase Inhibitor ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Set Up ◽  
Eta Receptor Antagonist ◽  
Synthase Inhibitor ◽  
Human Detrusor

Objectives: The mucosa of human detrusor strips impairs catecholamine-induced relaxation. In order to elucidate which signal transduction pathways are involved in this cross talk between the mucosa and detrusor, we have studied the effects of several pharmacological agonists and antagonists on noradrenaline-mediated relaxation in intact and mucosa-denuded detrusor strips. Patients and Methods: Strips of detrusor tissue were obtained from patients who had undergone cystectomy for bladder cancer and were set up for force measurement. KCl- or carbachol-precontracted strips were relaxed with increasing concentrations of noradrenaline in the absence and in the presence of nitric oxide synthase inhibitor, L-NAME; P2X-receptor antagonist, PPADS; ETA-receptor antagonist, BQ-123; ETB-receptor antagonist, BQ-788; cyclooxygenase inhibitor, diclofenac; AT1-receptor antagonist, candesartan; and NK1-receptor antagonist, L-703,606. Results: In intact strips, KCl-stimulated force was enhanced by all blockers; carbachol-stimulated force increased with L-703,606. In denuded strips, only L-NAME augmented the KCl-stimulated contraction. Noradrenaline relaxed the precontracted detrusor strips to a significantly larger extent and at lower concentrations in denuded than in intact strips. L-NAME, PPADS and BQ-123/BQ-788 had little effect on noradrenaline-induced relaxation, whereas diclofenac, candesartan and L-703,606 sensitized intact carbachol-stimulated detrusor strips to noradrenaline-induced relaxation. Conclusion: Inhibition of the noradrenaline-induced relaxation of precontracted human detrusor strips by the mucosa is attenuated by diclofenac, candesartan and L-703,606 suggesting the involvement of prostanoids, angiotensin and neurokinin pathways. Further experiments are required to unravel the exact mechanisms.

Analysis of vasocontractile responses to endothelin-1 in rabbit retinal vessels using an ETA receptor antagonist and an ETB receptor agonist

Life Sciences ◽  
1993 ◽  
Vol 53 (6) ◽  
pp. PL111-PL115 ◽  
Author(s):  
Kazuo Takei ◽  
Tsuyoshi Sato ◽  
Tomohito Nonoyama ◽  
Takashi Miyauchi ◽  
Katsutoshi Goto
Keyword(s):  
Receptor Antagonist ◽  
Receptor Agonist ◽  
Retinal Vessels ◽  
Endothelin 1 ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Eta Receptor Antagonist

Differential regulation of renal regional blood flow by endothelin-1

1996 ◽  
Vol 271 (6) ◽  
pp. F1166-F1172 ◽  
Author(s):  
K. Gurbanov ◽  
I. Rubinstein ◽  
A. Hoffman ◽  
Z. Abassi ◽  
O. S. Better ◽  
...  
Keyword(s):  
Blood Flow ◽  
Receptor Antagonist ◽  
Bolus Injection ◽  
Regional Blood Flow ◽  
Doppler Flowmetry ◽  
Endothelin 1 ◽  
Male Wistar Rats ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Eta Receptor Antagonist

The present study evaluated the effects and mechanisms of action of endothelin-1 (ET-1) on medullary and cortical blood flow (MBF and CBF, respectively). CBF and MBF were measured simultaneously by laser-Doppler flowmetry in anesthetized male Wistar rats. Bolus injection of ET-1 (1.0 nmol/kg iv) produced a sustained decrease in CBF (delta = -30%) and a transient increase in MBF (delta = +35%). The medullary vasodilation induced by ET-1 was observed with doses lower than that required to produce cortical vasoconstriction; was completely blocked by bosentan, a mixed ETA/B-receptor antagonist; and was mimicked by IRL-1620, a specific ETB-receptor agonist. In contrast, BQ-123, an ETA-receptor antagonist, failed to inhibit the ET-1-dependent medullary vasodilation but effectively blocked the cortical vasoconstriction induced by the peptide. Finally, inhibition of nitric oxide (NO) synthase completely abolished, whereas cylooxygenase inhibition attenuated, the effect of ET-1 on MBF. The data demonstrate that ET-1 exerts opposite effects on renal cortical and medullary circulation, i.e., ETA-receptor-mediated cortical vasoconstriction and ETB-mediated medullary vasodilation. Furthermore, the medullary vasodilation induced by ET-1 is dependent on the NO system and, to a lesser extent, on prostaglandin generation.

Human Endothelin Subtype A Receptor Enhancement during Tissue Culture via de Novo Transcription

Neurosurgery ◽  
2002 ◽  
Vol 50 (1) ◽  
pp. 127-136 ◽  
Author(s):  
Jacob Hansen-Schwartz ◽  
Carl-Henrik Nordström ◽  
Lars Edvinsson
Keyword(s):  
Organ Culture ◽  
Receptor Antagonist ◽  
De Novo ◽  
Cerebral Arteries ◽  
Maximal Response ◽  
Messenger Ribonucleic Acid ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Eta Receptor Antagonist

ABSTRACT OBJECTIVE Endothelin (ET) has, since its discovery, increasingly been considered a key player in the pathophysiological processes of cerebral vasospasm in the course of subarachnoid hemorrhage, although it remains unclear how ET is involved. We present data that indicate an inherent capacity of human cerebral arteries to change their sensitivity to ET. METHODS Human cerebral arteries were obtained from patients undergoing intracranial tumor surgery. The vessels were divided into segments and subjected to organ culture for 48 hours. The vessels were then examined by using in vitro pharmacological methods and molecular biological techniques. RESULTS After organ culture of the cerebral arteries, both the sensitivity to and potency of ET were enhanced (maximal response, 152 ± 9%; −log (50% effective concentration), 10.3 ± 0.3), in comparison with data for fresh cerebral arteries. Contractions were inhibited by both FR139317 (a specific ETA receptor antagonist) and bosentan (a mixed ETA and ETB receptor antagonist), in a manner indicating the sole presence of contractile ETA receptors. An inconsistent dilative response to the selective ETB receptor agonist sarafotoxin 6c was observed; the response was preserved in some segments and abolished in others, and potentiation of the precontraction was observed in yet other segments. No isolated contractile response to sarafotoxin 6c was observed, however. In reverse transcription-polymerase chain reaction assays, both ETA and ETB receptor messenger ribonucleic acid was detected. CONCLUSION These results demonstrate that human cerebral arteries are capable of enhancing the function of ETA receptors.

scholarly journals Autocrine effects of endothelin-1 on leukocyte-endothelial interaction: stimulation of endothelin B receptor subtype reduces endothelial adhesiveness via a nitric oxide-dependent mechanism

Blood ◽  
1996 ◽  
Vol 88 (10) ◽  
pp. 3894-3900 ◽  
Author(s):  
T Murohara ◽  
AM Lefer
Keyword(s):  
Nitric Oxide ◽  
Receptor Antagonist ◽  
Receptor Subtype ◽  
Endothelin 1 ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Endothelin B ◽  
Eta Receptor Antagonist ◽  
Inhibition Of Thrombin

The effects of endothelin-1 (ET-1) on P-selectin-mediated leukocyte endothelial interaction were examined in vitro. Adherence of autologous polymorphonuclear leukocytes (PMNs) to the endothelium was markedly enhanced by endothelial stimulation with either (2 U/mL) thrombin, (1 mumol/L) histamine, or (100 nmol/L) phorbol myristate acetate (PMA). In contrast, ET-1 alone (10 and 100 nmol/L) only slightly increased the number of adhering PMNs. The increased PMN adherence to thrombin- or histamine-stimulated endothelium, which was blocked by an anti-P-selectin monoclonal antibody, was also significantly attenuated by preincubation of coronary segments with (100 nmol/L) ET-1. We further investigated the mechanism of this anti-adherence action of ET-1 on thrombin-stimulated endothelial adhesiveness. Preincubation of coronary segments with a selective ETA receptor antagonist, BQ485 (1 mumol/L), had no effect on ET-1 inhibition of thrombin-induced PMN adherence. In contrast, preincubation with a selective ETB receptor antagonist, BQ788 (1 mumol/L) significantly reversed ET-1 inhibition of thrombin-induced PMN adherence, whereas the selective ETB receptor agonist BQ-3020 mimicked the inhibitory action of ET-1 on thrombin-induced PMN adherence. Furthermore, (100 mumol/L) N omega-nitro-L-arginine methyl ester (L-NAME), a nitric oxide synthase (NOS) inhibitor, significantly attenuated ET-1 inhibition of thrombin-stimulated PMN adherence. These results suggest that ET-1 may inhibit P-selectin-mediated leukocyte-endothelial interaction via ETB receptor stimulation and subsequent endothelial NO formation. This autocrine effect of ET-1 may be involved in pathophysiologic states such as early atherogenesis by preventing leukocyte-endothelial interaction in constricted blood vessels.

Endothelin stimulates an endogenous nitric oxide synthase inhibitor, asymmetric dimethylarginine, in experimental heart failure

2002 ◽  
Vol 103 (s2002) ◽  
pp. 241S-244S ◽  
Author(s):  
Masato OHNISHI ◽  
Atsuyuki WADA ◽  
Takayoshi TSUTAMOTO ◽  
Masanori FUJII ◽  
Takehiro MATSUMOTO ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Vascular Resistance ◽  
Vascular Tone ◽  
Asymmetric Dimethylarginine ◽  
No Production ◽  
Plasma Adma ◽  
Eta Receptor ◽  
Eta Receptor Antagonist ◽  
Synthase Inhibitor ◽  
Regulation Of Vascular Tone

Congestive heart failure (CHF) is characterized by increased peripheral vascular resistance. Endothelin-1 (ET-1), a potent endothelium-derived vasoconstrictor, is present at increased concentrations in the plasma and contributes to the regulation of vascular tone in CHF. An endothelium-derived relaxing factor, nitric oxide (NO), also regulates vascular tone, but endothelium-dependent NO-mediated vasodilation is blunted in CHF. An endogenous NO synthase inhibitor, asymmetric dimethylarginine (ADMA), which inhibits NO production and endothelium-dependent relaxation, is present at increased levels in the plasma and plays a role in impaired endothelial function in CHF. However, at present, the relationship between ET-1 and impaired vascular relaxation in CHF is not well known. We hypothesized that ET-1 inhibits NO-mediated vasodilation via increased ADMA production in CHF, and that an endothelin receptor antagonist can prevent this increase in plasma ADMA levels. In the present study, we first examined whether circulating ADMA levels were increased in a dog model of CHF induced by 3 weeks of rapid ventricular pacing (n = 5; 270beats/min) compared with normal dogs (n = 5). After 3 weeks of pacing, cardiac output had decreased significantly (1.56±0.16 compared with 2.93±0.25litres/min; P<0.01) and systemic vascular resistance had increased (4653±374 compared with 3227±396dyn·s·cm-5; P<0.01) in dogs with CHF compared with normal dogs. Plasma levels of both ET-1 (4.95±0.83 compared with 2.12±0.39pg/ml; P<0.05) and ADMA (3.27±0.49 compared with 1.91±0.25nmol/ml; P<0.05) were significantly increased in CHF dogs. A significant positive correlation was observed between plasma ET-1 and ADMA levels (r = 0.72, P<0.05). Secondly, we chronically administered an ETA receptor antagonist, TA-0201 (0.3mg/kg; n = 5), to paced CHF dogs. Drug administration started on day 8 of pacing and continued throughout the experiment. TA-0201 significantly increased cardiac output (2.58±0.24litres/min; P<0.01) and suppressed the increases in plasma ADMA levels and systemic vascular resistance (2.36±0.30nmol/ml and 2423±188dyn·s·cm-5 respectively; P<0.05 for each) compared with CHF dogs without TA-0201 treatment. In conclusion, ET-1 contributes to the regulation of vascular tone due, in part, to increased levels of an endogenous NO synthase inhibitor in CHF, and an ETA receptor antagonist can prevent the inhibition of NO production and the increased peripheral vascular resistance observed in CHF.

Negative chronotropic and inotropic effects of endothelin isopeptides in mammalian cardiac muscle

1997 ◽  
Vol 273 (1) ◽  
pp. H119-H127 ◽  
Author(s):  
Y. Zhu ◽  
H. T. Yang ◽  
M. Endoh
Keyword(s):  
Receptor Antagonist ◽  
Positive Inotropic Effect ◽  
Dominant Role ◽  
Negative Inotropic Effect ◽  
Camp Level ◽  
Inotropic Effect ◽  
Inotropic Effects ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Eta Receptor Antagonist

In isolated rabbit right atria, endothelin (ET) isopeptides ET-1 and ET-3 elicited a concentration-dependent negative chronotropic effect (NCE) in the presence of isoproterenol (Iso): ET-1 was approximately 10 times more potent than ET-3. The NCE of ET-1 was abolished by the ETA- and ETB-receptor antagonist TAK-044 (1 microM) or the ETA-receptor antagonist BQ-123 (10 microM), but it was not affected by the ETB-receptor antagonist RES-701-1 or BQ-788. ET-1 decreased the adenosine 3',5'-cyclic monophosphate (cAMP) level in the presence of Iso in rabbit atria. Pretreatment with pertussis toxin (PTX) markedly attenuated the NCE of ET-1 and abolished the decrease in the cAMP level induced by ET-1. In isolated dog ventricular trabeculae, ET-1 elicited a pronounced negative inotropic effect (NIE), whereas ET-3 induced a small but significant positive inotropic effect in the presence of Iso. The NIE was abolished by the ETA-receptor antagonist BQ-123 (1 microM) and partially attenuated by the ETB-receptor antagonist RES-701-1. The positive inotropic effect of ET-3 was abolished by RES-701-1. Although pretreatment with PTX markedly attenuated the NIE of ET-1, cAMP levels in dog ventricular muscle were not decreased by ET-1. These results indicate that activation of an ETA receptor that is coupled to the PTX-sensitive G protein plays a dominant role in the NCE and NIE of ET-1. The NCE of ET-1 may, in part, be due to a decrease in cAMP level. By contrast, the NIE of ET-1 does not involve an alteration of cAMP accumulation. The present findings imply that ET isopeptides might antagonize the cardiostimulatory action of catecholamines mediated by beta-adrenoceptors when the blood level of both endogenous regulators are increased under cardiovascular pathophysiological situations.

Positive inotropic responses mediated by endothelin ETA and ETB receptors in human myocardial trabeculae

2000 ◽  
Vol 99 (3) ◽  
pp. 161-168 ◽  
Author(s):  
Ole SAETRUM OPGAARD ◽  
Sebastian MÖLLER ◽  
René DE VRIES ◽  
Lars EDVINSSON ◽  
Pramod R. SAXENA
Keyword(s):  
Receptor Antagonist ◽  
Positive Inotropic Effect ◽  
Inotropic Effect ◽  
Maximum Effect ◽  
Inotropic Effects ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Eta Receptor Antagonist ◽  
The Right ◽  
Inotropic Responses

The aim of the present study was to determine possible inotropic effects mediated by endothelin ETA and ETB receptors in human myocardial trabeculae from the right atrium and the left ventricle. Isolated trabeculae from human hearts were paced at 1.0 Hz in tissue baths, and changes in isometric contractile force upon exposure to agonist were studied. Endothelin-1 (ET-1) and ET-3 had a strong positive inotropic effect in all trabeculae. ET-1 was significantly more potent than ET-3 in both atrial (P < 0.001) and ventricular (P < 0.05) trabeculae. Preincubation with the ETA receptor antagonist FR139317 (1 μM) decreased significantly (P < 0.005) the potency of ET-1 in both atrial and ventricular trabeculae, without any significant changes in Emax (maximum effect obtained with an agonist). The ETB receptor agonist IRL 1620 had a positive inotropic effect only in some trabeculae, and the ETB receptor antagonist BQ 788 (1 μM) almost completely blocked this effect. These results suggest that both ETA and ETB receptors mediate positive inotropic responses at both the atrial and ventricular level in the human heart.

Endothelin receptor subtypes in human versus rabbit pulmonary arteries

1994 ◽  
Vol 76 (5) ◽  
pp. 1976-1982 ◽  
Author(s):  
T. Fukuroda ◽  
M. Kobayashi ◽  
S. Ozaki ◽  
M. Yano ◽  
T. Miyauchi ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Pulmonary Arteries ◽  
Receptor Subtypes ◽  
Binding Assays ◽  
High Concentration ◽  
Pulmonary Vasodilator ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Human Pulmonary Artery ◽  
Eta Receptor Antagonist

We studied which endothelin (ET) receptor subtypes mediate ET-1-induced vasocontraction in the human pulmonary artery (PA) compared with the rabbit PA. ET-1 produced potent contraction in both human and rabbit isolated PAs. In human PA, ET-1-induced contraction was competitively antagonized by BQ-123 (an ETA receptor antagonist) with a pA2 value of 7.68. In rabbit PA, however, even a high concentration of BQ-123 (1 microM) did not affect the contraction. BQ-3020 (an ETB receptor agonist) produced potent contraction in rabbit PA but not in human PA. Binding assays of the membrane preparations showed that human and rabbit PAs contained ETA and ETB receptors in ratios of 93:7 and 23:77, respectively. These results suggest interspecies differences in the ET receptor subtypes that mediate ET-1-induced vasocontraction; ETA receptors are dominant in the human PA, whereas ETB receptors are dominant in the rabbit PA. Furthermore, the predominance of ETA receptors in human PA was supported by autoradiographical studies. If ET-1 acts as a physiological and/or pathophysiological vasocontractor in the human pulmonary circulation, an ETA receptor antagonist would function as a pulmonary vasodilator in humans.

scholarly journals Role of Endothelin-1 in the Migration of Human Olfactory Gonadotropin-Releasing Hormone-Secreting Neuroblasts

Endocrinology ◽  
2005 ◽  
Vol 146 (10) ◽  
pp. 4321-4330 ◽  
Author(s):  
Roberto G. Romanelli ◽  
Tullio Barni ◽  
Mario Maggi ◽  
Michaela Luconi ◽  
Paola Failli ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Receptor Activation ◽  
Dependent Manner ◽  
Endothelin 1 ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Migratory Pattern ◽  
Biochemical Analyses ◽  
Eta Receptor Antagonist ◽  
Dose Dependent

FNC-B4 neuroblasts that express both neuronal and olfactory markers have been established and cloned. These cells express GnRH and both the endothelin-1 (ET-1) gene and protein and respond in a migratory manner to GnRH in a dose-dependent manner. Previous research has shown that FNC-B4 cells produce and respond to ET-1 by regulating the secretion of GnRH through endothelin type A receptors and by stimulating their proliferation through endothelin type B (ETB) receptors. In this study, we found that FNC-B4 cells are able to migrate in response to ET-1 through the involvement of ETB receptors. Combined immunohistochemical and biochemical analyses showed that ET-1 triggered actin cytoskeletal remodeling and a dose-dependent increase in migration (up to 6-fold). Whereas the ETB receptor antagonist (B-BQ788) blunted the ET-1-induced effects, the ETA receptor antagonist (A-BQ123) did not. Moreover, we observed that FNC-B4 cells were independently and selectively stimulated by ET-1 and GnRH. We suggest that ET-1, through ETB receptor activation, may be required to maintain an adequate proliferative stem cell pool in the developing olfactory epithelium and the subsequent commitment to GnRH neuronal migratory pattern. The coordinate interaction between ET receptors and GnRH receptor participates in the fully expressed GnRH-secreting neuron phenotype.

ETA receptors mediate vasoconstriction, whereas ETB receptors clear endothelin-1 in the splanchnic and renal circulation of healthy men

2003 ◽  
Vol 104 (2) ◽  
pp. 143-151 ◽  
Author(s):  
Felix BÖHM ◽  
John PERNOW ◽  
Jonas LINDSTRÖM ◽  
Gunvor AHLBORG
Keyword(s):  
Receptor Antagonist ◽  
Vascular Resistance ◽  
Vascular Tone ◽  
Renal Vasoconstriction ◽  
Healthy Humans ◽  
Arterial Blood ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Eta Receptor Antagonist ◽  
Renal Vascular

The contribution of the endothelin (ET) receptors ETA and ETB to basal vascular tone and ET-1-induced vasoconstriction in the renal and splanchnic vasculature was investigated in six healthy humans. ET-1 was infused alone and in combination with the selective ETA receptor antagonist BQ123 or the selective ETB receptor antagonist BQ788 on three different occasions. BQ123 did not affect basal arterial blood pressure, splanchnic vascular resistance (SplVR) or renal vascular resistance (RVR), but inhibited the increase in vascular resistance induced by ET-1 [64±18 versus -1±7% in SplVR (P<0.05); 36±6 versus 12±3% in RVR (P<0.0001)]. BQ788 increased basal SplVR and RVR [38±16% (P = 0.01) and 21±5% (P<0.0001) respectively], and potentiated the ET-1-induced vasoconstriction. Plasma ET-1 increased more after ETB blockade than under control conditions or after ETA blockade. These findings suggest that the ETA receptor mediates the splanchnic and renal vasoconstriction induced by ET-1 in healthy humans. The ETB receptor seems to function as a clearance receptor and may modulate vascular tone by altering the plasma concentration of ET-1.

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