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- Adner, Mikael, et al.
(författare)
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Contractile endothelin-B (ETB) receptors in human small bronchi
- 1996
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Ingår i: European Respiratory Journal. - : European Respiratory Society (ERS). - 1399-3003 .- 0903-1936. ; 9:2, s. 351-355
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Tidskriftsartikel (refereegranskat)abstract
- Endothelins (ETs) are a family of novel regulatory peptides and various lines of evidence suggest an important role for ETs in regulating pulmonary function. Two receptors for endothelin, ETA and ETB, have been found in the human lung, and according to recent studies a non-ETA receptor seems to mediate the contraction of large sized human bronchi. Several studies have emphasized the importance of small bronchi in the pathogenesis of airway disease. In the present paper, improved methodology was used which enables in vitro studies of small human bronchi down to a diameter of 0.5-1.0 mm. Using the new methodology we have tried to further characterize this receptor. Small bronchi from the distal parts of the bronchial tree were obtained from pulmonary tissue removed from 15 patients with lung cancer. They were dissected and cut into ring segments, in which isometric tension was recorded. ET-1, ET-2 and ET-3 elicited strong concentration-dependent contractions of the human small bronchus. Basically, the three peptides were equipotent with about the same maximal response. Upon reapplication, they all showed the same tachyphylaxis pattern, reaching half the initial contraction. Comparative analysis of IRL 1620, a selective ETB receptor agonist, revealed that the effect of the ETB agonist was, in all respects, similar to the responses induced by the ETs. PD 145065, a combined ETA/ETB receptor antagonist competitively inhibited the contractions induced by IRL 1620, whereas FR139317, a selective ETA receptor antagonist, was without effect. In conclusion, the present study shows that accurate measurements can be made in vitro on small human bronchi and all present data are in favour of an ETB receptor mediating endothelin-induced contraction of human bronchi smaller than 1.0 mm.
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| 2. |
- Adner, Mikael, et al.
(författare)
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Regional variation in appearance of vascular contractile endothelin-B receptors following organ culture
- 1998
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Ingår i: Cardiovascular Research. - 1755-3245. ; 37:1, s. 254-262
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The aim of this study was to investigate the appearance of contractile endothelin (ET)-B receptors following organ culture in different vascular regions. METHOD: The contractile responses of vascular smooth muscle induced by ET-1 and the selective ETB receptor agonist sarafotoxin 6c (S6c) were investigated in circular segments representing eight vascular regions in the rat (aorta, femoral artery, mesenteric artery, branch of the mesenteric artery, proximal and distal parts of the caudal artery, femoral and mesenteric veins). To allow the ETB receptor to be expressed, the segments were placed in organ culture for 1 to 5 days. Pharmacological characterisation of the ET receptors was performed in mesenteric arterial segments. All contractile responses were measured in percentage of K(+)-induced contraction. RESULTS: ET-1 induced strong concentration-dependent contractions of all fresh (not cultured) segments. S6c had negligible effects on all fresh vessels with the exception of the mesenteric vein, where a small contraction was seen. After 1 day of organ culture all tested segments, with the exception of aorta and the proximal part of the caudal artery, showed concentration-dependent contractile responses to S6c which were further augmented after 5 days of culture. The ET-1-induced responses were only slightly affected by organ culture. Contractions induced by S6c were more enhanced in small arteries and veins than in larger arteries. Furthermore, the S6c-induced response was more pronounced in the mesenteric region as compared to the hindlimb. In fresh mesenteric arterial segments FR139317 (ETA receptor antagonist) and bosentan (ETA/ETB receptor antagonist) but not IRL 2500 (ETB receptor antagonist) shifted the ET-1-induced concentration-response curve in parallel to the right. In contrast, after organ culture the S6c-induced concentration-response curves were shifted parallel to the right in the following potency order: IRL 2500 > bosentan > FR139317. CONCLUSION: During normal conditions, the ETA receptor is the dominating mediator of endothelin-induced contraction in eight different vascular regions. Furthermore, this study indicates that most of the vessels have the ability to develop contractile ETB receptors and that this plasticity differs in vascular regions.
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| 3. |
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| 4. |
- Zhang, Yaping, et al.
(författare)
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MAPK/NF-kappa B-dependent upregulation of kinin receptors mediates airway hyperreactivity: A new perspective for the treatment
- 2013
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Ingår i: Pharmacological Research. - : Elsevier BV. - 1096-1186 .- 1043-6618. ; 71, s. 9-18
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Forskningsöversikt (refereegranskat)abstract
- Airway hyperreactivity (AHR) is a major feature of asthmatic and inflammatory airways. Cigarette smoke exposure, and bacterial and viral infections are well-known environmental risk factors for AHR, but knowledge about the underlying molecular mechanisms on how these risk factors lead to the development of AHR is limited. Activation of intracellular mitogen-activated protein kinase (MAPK)/nuclear factor-kappa B (NF-kappa B) and their related signal pathways including protein kinase C (PKC), phosphoinositide 3-kinase (PI3K) and protein kinase A (PKA) signaling pathways may result in airway kinin receptor upregulation, which is suggested to play an important role in the development of AHR. Environmental risk factors trigger the production of pro-inflammatory mediators such as tumor necrosis factor-alpha (TNF-alpha) and interleukins (ILs) that activate intracellular MAPK- and NF-kappa B-dependent inflammatory pathways, which subsequently lead to AHR via kinin receptor upregulation. Blockage of intracellular MAPK/NF-kappa B signaling prevents kinin B-1 and B-2 receptor expression in the airways, resulting in a decrease in the response to bradykinin (kinin B-2 receptor agonist) and des-Arg(9)-bradykinin (kinin B-1 receptor agonist). This suggests that MAPK- and NF-kappa B-dependent kinin receptor upregulation can provide a novel option for treatment of AHR in asthmatic as well as in other inflammatory airway diseases. (C) 2013 Elsevier Ltd. All rights reserved.
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