| 1. |
- Kruuse, Christina, et al.
(författare)
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Differential vasoactive effects of sildenafil and tadalafil on cerebral arteries
- 2012
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 1879-0712 .- 0014-2999. ; 674:2-3, s. 345-351
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Tidskriftsartikel (refereegranskat)abstract
- Phosphodiesterase 5 (PDE5) is associated with migraine pathophysiology, stroke recovery and vasospasm treatment The potential vascular interplay of PDE5 inhibitors sildenafil, tadalafil and UK-114,542 was studied by intra- versus extra-luminal administration in rat middle cerebral arteries in vitro and on middle meningeal arteries in vivo. By Western blot PDE5 was detected in both cerebral and meningeal arteries, though with minor variations in band intensity between vascular beds. Rat middle cerebral artery diameter was investigated using pressurised arteriography, applying UK-114,542, sildenafil, and tadalafil intra- or extraluminally. Effects on the dural middle meningeal artery were studied in the in vivo closed cranial window model. At high concentrations, abluminal sildenafil and UK-114,542, but not tadalafil, induced dilatation of the middle cerebral artery. Luminal application elicited a contraction of 4% (sildenafil, P = 0.03) and 10% (tadalafil, P = 0.02). In vivo, sildenafil, but not tadalafil, dose-dependently dilated middle meningeal artery concomitant to blood pressure reduction (1-3 mg/kg);1 mg/kg sildenafil inducing 60 +/- 14% (P = 0.04) and vehicle (DMSO) 13 +/- 6% dilatation. In conclusion, PDE5 inhibitors applied luminally had minor contractile effect, whereas abluminal sildenafil induced middle cerebral artery dilatation above therapeutic levels. In vivo, sildenafil dilated middle meningeal artery concomitant with a reduction in blood pressure. Tadalafil had no dilatory effects. PDE5 inhibitors show differential vascular activity in cerebral arteries from healthy animals; arterial dilatation is seen primarily above therapeutic levels. Such findings support clinical studies showing no vasodilator effects of sildenafil on cerebral arteries in healthy subjects. (C) 2011 Elsevier B.V. All rights reserved.
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| 2. |
- Ansar, Saema, et al.
(författare)
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MAPK signaling pathway regulates cerebrovascular receptor expression in human cerebral arteries
- 2013
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Ingår i: BMC Neuroscience. - : Springer Science and Business Media LLC. - 1471-2202. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Background: Cerebral ischemia results in enhanced expression of contractile cerebrovascular receptors, such as endothelin type B (ETB), 5-hydroxytryptamine type 1B (5-HT1B), angiotensin II type 1 (AT(1)) and thromboxane (TP) receptors in the cerebral arteries within the ischemic area. The receptor upregulation occurs via activation of the mitogen-activated protein kinases (MAPK) pathway. Previous studies have shown that inhibitors of the MAPK pathway diminished the ischemic area and contractile cerebrovascular receptors after experimental cerebral ischemia. The aim of this study was to examine if the upregulation of contractile cerebrovascular receptors after 48 h of organ culture of human cerebral arteries involves MAPK pathways and if it can be prevented by a MEK1/2 inhibitor. Human cerebral arteries were obtained from patients undergoing intracranial tumor surgery. The vessels were divided into ring segments and incubated for 48 h in the presence or absence of the specific MEK1/2 inhibitor U0126. The vessels were then examined by using in vitro pharmacological methods and protein immunohistochemistry. Results: After organ culture of the cerebral arteries the contractile responses to endothelin (ET)-1, angiotensin (Ang) II and thromboxane (TP) were enhanced in comparison with fresh human arteries. However, 5-carboxamidotryptamine (5-CT) induced decreased contractile responses after organ culture as compared to fresh arteries. Incubation with U0126 diminished the maximum contraction elicited by application of ET-1, Ang II and U46619 in human cerebral arteries. In addition, the MEK1/2 inhibitor decreased the contractile response to 5-CT. Immunohistochemistry revealed that organ culture resulted in increased expression of endothelin ETA, endothelin ETB angiotensin AT(2), 5-hydroxytryptamine 5-HT1B and thromboxane A2 receptors, and elevated levels of activated pERK1/2, all localized to the smooth muscle cells of the cerebral arteries. Co-incubation with U0126 normalized these proteins. Conclusion: The study demonstrated that there is a clear association between human cerebrovascular receptor upregulation via transcription involving activation of the MAPK pathway after organ culture. Inhibition of the MAPK pathways attenuated the vasoconstriction mediated by ET, AT and TP receptors in human cerebral arteries and the enhanced expression of their receptors. The results indicate that MAPK inhibition might be a novel target for treatment of cerebrovascular disorders.
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| 3. |
- Edvinsson, Lars, et al.
(författare)
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Effect of the calcitonin gene-related peptide (CGRP) receptor antagonist telcagepant in human cranial arteries.
- 2010
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Ingår i: Cephalalgia. - : SAGE Publications. - 0333-1024 .- 1468-2982. ; 30:10, s. 1233-1240
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: Calcitonin gene-related peptide (CGRP) is a neuronal messenger in intracranial sensory nerves and is considered to play a significant role in migraine pathophysiology. MATERIALS AND METHODS: We investigated the effect of the CGRP receptor antagonist, telcagepant, on CGRP-induced cranial vasodilatation in human isolated cerebral and middle meningeal arteries. We also studied the expression of the CGRP receptor components in cranial arteries with immunocytochemistry. Concentration response curves to αCGRP were performed in human isolated cerebral and middle meningeal arteries in the absence or presence of telcagepant. Arterial slices were stained for RAMP1, CLR and actin in a double immunofluorescence staining. RESULTS: In both arteries, we found that: (i) telcagepant was devoid of any contractile or relaxant effects per se; (ii) pretreatment with telcagepant antagonised the αCGRP-induced relaxation in a competitive manner; and (iii) immunohistochemistry revealed expression and co-localisation of CLR and RAMP1 in the smooth muscle cells in the media layer of both arteries. CONCLUSIONS: Our findings provide morphological and functional data on the presence of CGRP receptors in cerebral and meningeal arteries, which illustrates a possible site of action of telcagepant in the treatment of migraine.
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| 4. |
- Edvinsson, Lars, et al.
(författare)
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Inhibitory effect of BIBN4096BS, CGRP(8-37), a CGRP antibody and an RNA-Spiegelmer on CGRP induced vasodilatation in the perfused and non-perfused rat middle cerebral artery.
- 2007
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Ingår i: British Journal of Pharmacology. - : Wiley. - 1476-5381 .- 0007-1188. ; 150:5, s. 633-640
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Tidskriftsartikel (refereegranskat)abstract
- Background and purpose: A new concept for the inhibition of CGRP signalling has been developed by interaction with the CGRP molecule per se by using a CGRP antibody or a CGRP binding RNA-Spiegelmer (NOX-C89). We have compared these CGRP scavengers with two known receptor antagonists (CGRP8-37 and BIBN4096BS) on CGRP-induced relaxations in the rat middle cerebral artery (MCA). Furthermore, the role of the endothelial barrier has been studied. Experimental approach: We used the luminally perfused MCA in an arteriograph, pressurized to 85mm Hg and myograph studies of isolated ring segments of the MCA. Key results: In myograph studies and in the perfusion system during abluminal application, alpha CGRP and beta CGRP induced concentration-dependent dilatation of the MCA. Given luminally neither peptide was significantly vasodilator. Adrenomedullin and amylin induced weak dilatations. In myograph experiments, relaxation induced by a alpha CGRP was prevented by the four CGRP blockers (CGRP8-37, BIBN4096BS, the CGRP antibody and NOX-C89.). In abluminal perfusion experiments, the relaxant response to alpha CGRP was prevented by these agents to a varying degree. Dilatation induced by abluminal application of alpha CGRP was inhibited by luminal CGRP8-37 but not by luminal BIBN4096BS, CGRP antibody or NOX-C89. Conclusions and Implications: alpha or beta CGRP acted on smooth muscle cell CGRP receptors in rat MCA and were effectively prevented from reaching these receptors by the endothelial barrier. The CGRP blockers significantly inhibited alpha CGRP induced relaxation but were also prevented from reaching the CGRP receptors by the arterial endothelium.
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| 5. |
- Granström, Bengt, et al.
(författare)
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Smoking particles enhance endothelin A and endothelin B receptor-mediated contractions by enhancing translation in rat bronchi.
- 2006
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Ingår i: BMC Pulmonary Medicine. - : Springer Science and Business Media LLC. - 1471-2466. ; 6:6
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Tidskriftsartikel (refereegranskat)abstract
- Background Smoking is known to cause chronic inflammatory changes in the bronchi and to contribute to airway hyper-reactivity, such as in bronchial asthma. To study the effect of smoking on the endothelin system in rat airways, bronchial segments were exposed to DMSO-soluble smoking particles (DSP) from cigarette smoke, to nicotine and to DMSO, respectively. Methods Isolated rat bronchial segments were cultured for 24 hours in the presence or absence of DSP, nicotine or DMSO alone. Contractile responses to sarafotoxin 6c (a selective agonist for ETB receptors) and endothelin-1 (an ETA and ETB receptor agonist) were studied by use of a sensitive myograph. Before ET-1 was introduced, the ETB receptors were desensitized by use of S6c. The remaining contractility observed was considered to be the result of selective activation of the ETA receptors. ETA and ETB receptor mRNA expression was analyzed using real-time quantitative PCR. The location and concentration of ETA and ETB receptors were studied by means of immunohistochemistry together with confocal microscopy after overnight incubation with selective antibodies. Results After being cultured together with DSP for 24 hours the bronchial segments showed an increased contractility mediated by ETA and ETB receptors, whereas culturing them together with nicotine did not affect their contractility. The up-regulation of their contractility was blunted by cycloheximide treatment, a translational inhibitor. No significant change in the expression of ETA and ETB receptor mRNA through exposure to DMSO or to nicotine exposure alone occurred, although immunohistochemistry revealed a clear increase in ETA and ETB receptors in the smooth muscle after incubation in the presence of DSP. Taken as a whole, this is seen as the presence of a translation mechanism. Conclusion The increased contractility of rat bronchi when exposed to DSP appears to be due to a translation mechanism.
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| 6. |
- Granström, Bengt, et al.
(författare)
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Up-regulation of endothelin receptor function and mRNA expression in airway smooth muscle cells following sephadex-induced airway inflammation.
- 2004
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Ingår i: Basic & Clinical Pharmacology & Toxicology. - : Wiley. - 1742-7843 .- 1742-7835. ; 95:1, s. 43-48
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Tidskriftsartikel (refereegranskat)abstract
- The hypothesis that up-regulation of bronchial constrictor endothelin receptors in airway smooth muscle cells may contribute to hyperreactivity during airway inflammation was tested in the present study by quantitative endothelin receptor mRNA analysis and functional responses in ring segments of rat trachea and bronchi. Real time reverse transcription polymerase chain reaction was used to quantify endothelin receptor expression in rat airway smooth muscle cells following Sephadex-induced inflammation. Compared with controls, Sephadex-induced airway inflammation caused a significant increase (3.9 times P<0.05) of endothelin receptor type B mRNA expression in bronchial smooth muscle cells, but not in tracheal smooth muscle cells. Functional myograph studies of bronchial and tracheal ring segments without epithelium (mechanically denuded) revealed an increase of the maximum contractile effects of endothelin-1 (a dual agonist for both endothelin type A and B receptors) and sarafotoxin 6c (a selective agonist for endothelin B receptors) in bronchial smooth muscle cells in Sephadex-induced inflammation, but not in tracheal smooth muscle cells. The enhanced maximal responses of bronchial smooth muscle cells to endothelin-1 and sarafotoxin 6c in Sephadex-induced inflammation support our molecular findings and hence imply a role for endothelin B receptors in airway hyperreactivity during airway inflammation.
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| 7. |
- Grände, Gustaf, et al.
(författare)
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Comparison of responses to vasoactive drugs in human and rat cerebral arteries using myography and pressurized cerebral artery method.
- 2012
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Ingår i: Cephalalgia. - : SAGE Publications. - 0333-1024 .- 1468-2982.
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Tidskriftsartikel (refereegranskat)abstract
- Background:Dilatation of cranial vessels has been proposed as a part of the cascade that initiates an episode of migraine. This is based on the observation that intravenous administration of several substances with vasodilator properties can trigger migraine-like symptoms in migraineurs.Methods:We used in vitro myography of human cerebral arteries and in vitro pressurized arteriography of rat middle cerebral artery (MCA) to evaluate the vasomotor responses of cerebral arteries to increasing concentrations of vasoactive substances used to elicit migraine-like attacks.Results:All substances except carbachol induced a strong vasodilatory response when applied to the abluminal side of a rat MCA but negligible response when applied to the luminal side. Luminal carbachol gave a strong dilatory response but a weak response at the abluminal side. The prostaglandins PGE(2) and epoprostenol constricted the rat MCA while human cerebral arteries relaxed. The pEC(50) of carbachol, histamine, epoprostenol, VIP and sildenafil differed significantly between cerebral arteries from man and rat. The differences in pEC(50) for SNP, αCGRP, PACAP-27 and PACAP-38 were not significant between the species. PGE(2) had no noticeable effect on human arteries in vitro.Conclusion:All tested substances with the exception of VIP and carbachol have been found to elicit migraine-like attacks in migraineurs. Since these two agents have vasodilatory effects in humans, it suggests that vasodilatation is not the only reason for eliciting a migraine-like attack in migraineurs. In addition, there are significant species differences that show the importance of performing experiments in human vessels.
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| 8. |
- Hansen-Schwartz, Jacob, et al.
(författare)
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Endothelium-Dependent Relaxant Responses to Selective 5-HT(1B/1D) Receptor Agonists in the Isolated Middle Cerebral Artery of the Rat.
- 2003
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Ingår i: Journal of Vascular Research. - : S. Karger AG. - 1423-0135 .- 1018-1172. ; 40:6, s. 561-566
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Tidskriftsartikel (refereegranskat)abstract
- The vasomotor effects of triptans in the middle cerebral artery (MCA) of rats were studied using the pressurised arteriography method and in vitro vessel baths. Using the arteriograph, MCAs from Sprague-Dawley rats were mounted on two glass micropipettes, pressurised to 85 mm Hg and luminally perfused. Luminally added 5- hydroxytryptamine (5-HT), sumatriptan and rizatriptan induced maximal dilatations of 22 ± 4, 10 ± 2 and 13 ± 5%, respectively, compared to the resting diameter. The relaxant effect of sumatriptan was blocked by the 5- HT<sub>1B/1D</sub> receptor selective antagonist GR 55562 (10<sup>–6</sup><i>M</i>). The use of N<sup>ω</sup>-nitro-<i>L</i>-arginine and charybdotoxin revealed that the dilatation involved both nitric oxide and endothelially derived hyperpolarising factor. Thus, the earlier demonstrated expression of 5-HT<sub>1B/1D</sub> immunoreactivity in the endothelium may well translate into a relaxant response to 5-HT and triptans. Using the vessel bath technique, MCA segments were mounted on two metal wires. The relaxant responses to sumatriptan could not be reproduced using this model; instead, weak contractile responses (6 ± 3% of submaximal contractile capacity) were observed. The difference in observations between the experimental models may be related to the maintenance of shear stress in the arteriograph.
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| 9. |
- Wackenfors, Angelica, et al.
(författare)
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Angiotensin II-induced vasodilatation in cerebral arteries is mediated by endothelium-derived hyperpolarising factor.
- 2006
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 1879-0712 .- 0014-2999. ; 531:1-3, s. 259-263
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Tidskriftsartikel (refereegranskat)abstract
- The angiotensin II-induced vasodilatation was evaluated in rat middle cerebral artery, especially regarding endothelium-derived hyperpolarising factor (EDHF), by use of a pressurised arteriograph. The angiotensin II dilatation was partly antagonised by inhibitors of nitric oxide synthase and cyclo-oxygenase. The remaining dilatation was inhibited by the potassium channel blockers, charybdotoxin and apamin, providing direct evidence that angiotensin II induces EDHF-mediated dilatation in cerebral arteries. The angiotensin II dilatation was blocked by the angiotensin AT(1) and AT(2) receptor blockers candesartan and PD 123319. Both angiotensin AT(1) and AT(2) receptors were detected on the endothelium by imnitmohistochemistry. (c) 2005 Elsevier B.V. All rights reserved.
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