scholarly journals ETB2 receptor subtype stimulation relaxes the iris sphincter muscle

2009 ◽  
pp. 835-842
Author(s):  
A Rocha-Sousa ◽  
J Saraiva ◽  
M Amaral ◽  
P Alves-Faria ◽  
F Falcão-Reis ◽  
...  
Keyword(s):  
Receptor Antagonist ◽  
Receptor Subtype ◽  
Sphincter Muscle ◽  
Receptor Stimulation ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Rabbit Iris Sphincter ◽  
Eta Receptor Antagonist ◽  
Rabbit Iris ◽  
Iris Sphincter

Effects of ETB receptor stimulation and its subcellular pathways were evaluated in carbachol pre-contracted rabbit iris sphincter muscles (n=51). ETB stimulation with sarafotoxin (SRTX-c; 10-10-10-6 M) was tested in the absence (n=7) or presence of 10-5 M of: BQ-788 (ETB2 receptor antagonist; n=6), L-NA (NOS inhibitor; n=7) or indomethacin (cyclooxygenase inhibitor; n=10). Effects of ETB stimulation by endothelin-1 (ET-1; 10-10– 10-7 M) in the presence of an ETA receptor antagonist (BQ-123; 10-5 M; n=7) and of ETB1 stimulation by IRL-1620 (10-10–10-7 M; n=7) were also tested. Finally, the effects of SRTX-c (10-9–10-7 M) in electric field stimulation (EFS) contraction were evaluated (n=7). ETB receptor stimulation by SRTX-c or ET-1 in presence of BQ-123 promoted a concentration-dependent relaxation of the rabbit iris sphincter muscle by 10.8±2.0 % and 9.4±1.8 %, respectively. This effect was blocked by BQ-788 (-2.3±2.0 %), L-NA (4.5±2.3 %) or indomethacin (2.3±2.9 %). Selective ETB1 stimulation by IRL-1620 did not relax the iris sphincter muscle (0.9±5.4 %). EFS elicited contraction was not altered by SRTX-c. In conclusion, ETB receptor stimulation relaxes the carbachol precontracted iris sphincter muscle, an effect that is mediated by the ETB2 receptor subtype, through NO and the release of prostaglandins.

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.

scholarly journals Effect of Endothelin-1 on Corticosteroid Secretion by the Frog Adrenal Gland Is Mediated by an EndothelinA Receptor*

Endocrinology ◽  
1997 ◽  
Vol 138 (10) ◽  
pp. 4358-4363 ◽  
Author(s):  
Franck Cartier ◽  
Isabelle Remy-Jouet ◽  
Alain Fournier ◽  
Hubert Vaudry ◽  
Catherine Delarue
Keyword(s):  
Adrenal Gland ◽  
Receptor Antagonist ◽  
Receptor Agonist ◽  
Receptor Subtype ◽  
Endothelin 1 ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Eta Receptor Antagonist ◽  
Corticosteroid Secretion

Abstract We have previously reported that endothelin-1 (ET-1) stimulates the in vitro secretion of corticosterone and aldosterone from the adrenal gland of the frog Rana ridibunda. The aim of the present study was to investigate the pharmacological profile of the endothelin receptor subtype involved in the corticotropic effect of ET-1. The mixed ETA/ETB receptor antagonist Ro 47–0203 (10−5m) totally blocked the stimulatory effect of ET-1 (5 × 10−9m) on corticosterone and aldosterone secretion. The action of ET-1 was also inhibited by the selective ETA receptor antagonist BQ-485 (10−7m). In contrast, the selective ETB receptor antagonist IRL 1038 (10−6m) did not affect the response of the frog adrenal gland to ET-1. In addition, the selective ETB receptor agonist IRL 1620 (10−6m) did not mimic the stimulatory effect of ET-1. The high affinity ETC receptor agonist endothelin-3 (ET-3) stimulated corticosteroid secretion, but was 400 times less potent than ET-1. Moreover, the action of ET-3 was also blocked by BQ-485 (10−7m). These data indicate that the stimulatory effects of ET-1 and ET-3 on corticosteroid secretion by the frog adrenal gland are mediated by an ETA receptor subtype.

scholarly journals Levels of IMeurokinin A, Neurokinin B and Substance P in Rabbit Iris Sphincter Muscle

1986 ◽  
Vol 42 (4) ◽  
pp. 590-593 ◽  
Author(s):  
Takashi TANIGUCHI ◽  
Motohatsu FUJIWARA ◽  
Yoshinori MASUO ◽  
Ichiro KANAZAWA
Keyword(s):  
Substance P ◽  
Sphincter Muscle ◽  
Neurokinin B ◽  
Rabbit Iris Sphincter Muscle ◽  
Rabbit Iris Sphincter ◽  
Rabbit Iris ◽  
Iris Sphincter

scholarly journals NONCHOLINERGIC, NONADRENERGIC CONTRACTION AND SUBSTANCE ऩ IN RABBIT IRIS SPHINCTER MUSCLE

1981 ◽  
Vol 31 (6) ◽  
pp. 1071-1080
Author(s):  
Naoko UEDA ◽  
Ikunobu MURAMATSU ◽  
Yoshihiko SAKAKIBARA ◽  
Motohatsu FUJIWARA
Keyword(s):  
Sphincter Muscle ◽  
Rabbit Iris Sphincter Muscle ◽  
Rabbit Iris Sphincter ◽  
Rabbit Iris ◽  
Iris Sphincter

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

Endothelin-1 and -3 cause endothelium-dependent hyperpolarization in the rat mesenteric artery

1993 ◽  
Vol 265 (6) ◽  
pp. H2137-H2141 ◽  
Author(s):  
M. Nakashima ◽  
P. M. Vanhoutte
Keyword(s):  
Mesenteric Artery ◽  
Mesenteric Arteries ◽  
Receptor Subtype ◽  
Spontaneously Hypertensive ◽  
Rat Mesenteric Artery ◽  
Significant Difference ◽  
Eta Receptor ◽  
Etb Receptor ◽  
Wistar Kyoto ◽  
Eta Receptor Antagonist

The present study was designed to determine whether endothelin (ET) induces endothelium-dependent hyperpolarization in the isolated rat mesenteric artery and, if so, to identify the receptor subtype involved. Main superior mesenteric arteries of Wistar-Kyoto and spontaneously hypertensive rats were used for the measurement of electrical responses of smooth muscle cells, using glass microelectrode. In tissues with endothelium of both strains, ET-1 (10(-8) M) caused an initial transient hyperpolarization followed by a sustained depolarization. In tissues without endothelium, only depolarization was observed. ET-3 (10(-8) M) produced transient hyperpolarizations only in preparations with endothelium. There was no significant difference in maximal amplitude of hyperpolarization between the two strains. BQ-123 (selective ETA-receptor antagonist) blocked the depolarization to ET-1 but did not inhibit hyperpolarizing responses to either isopeptide. IRL-1620 (specific ETB-receptor agonist) produced transient membrane hyperpolarizations in tissues with endothelium. The hyperpolarizations induced by ET were not affected by NG-nitro-L-arginine. These data suggest that both ET-1 and ET-3 can cause endothelium-dependent hyperpolarization in the rat mesenteric artery and that the endothelial receptor involved may belong to ETB subtype.

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.

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