Please use this identifier to cite or link to this item:
https://doi.org/10.1016/j.ejphar.2006.05.005
DC Field | Value | |
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dc.title | Mechanisms of direct relaxant effect of sildenafil, tadalafil and vardenafil on corpus cavernosum | |
dc.contributor.author | Lau, L.-C. | |
dc.contributor.author | Adaikan, P.G. | |
dc.date.accessioned | 2011-09-15T08:21:32Z | |
dc.date.available | 2011-09-15T08:21:32Z | |
dc.date.issued | 2006 | |
dc.identifier.citation | Lau, L.-C., Adaikan, P.G. (2006). Mechanisms of direct relaxant effect of sildenafil, tadalafil and vardenafil on corpus cavernosum. European Journal of Pharmacology 541 (3) : 184-190. ScholarBank@NUS Repository. https://doi.org/10.1016/j.ejphar.2006.05.005 | |
dc.identifier.issn | 00142999 | |
dc.identifier.uri | http://scholarbank.nus.edu.sg/handle/10635/25980 | |
dc.description.abstract | Sildenafil, tadalafil, vardenafil and verapamil induced concentration-dependent relaxation of the rabbit corpus cavernosum muscle precontracted with noradrenaline. The maximal relaxation (%) at 20 μM was 61.4 ± 6.9, 32.4 ± 5.4, 100.0 ± 5.5 and 86.6 ± 5.1 (n = 5 each) respectively. Pre-incubation of cavernosal muscle strips with Nω-nitro-l-arginine or guanylate cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) but not adenylate cyclase inhibitor, cis-N-[2-phenylcyclopentyl]-azacyclotridec-1-en-2-amine] (MDL12330A) culminated in only a 20-30% reduction in muscle relaxant action of the 3 phosphodiesterase inhibitors. This suggests that another mechanism of relaxation independent of nitric oxide-cGMP or cAMP pathway was involved. Higher concentrations of sildenafil (100 μM) and vardenafil (10 and 100 μM) produced non-competitive antagonism of noradrenaline-induced contraction characterized by reduced maximal effect. In contrast, tadalafil was devoid of significant effect on noradrenaline. On K+-depolarized tissues, sildenafil was as potent as vardenafil whereas tadalafil was the least effective in relaxing K+-induced tone. The maximal relaxation (% of K+-induced tone) at 20 μM sildenafil, tadalafil and vardenafil was respectively 84.1 ± 6.5, 9.0 ± 19.9, and 88.9 ± 6.2 (n = 5 each). In addition, verapamil, sildenafil and vardenafil were more efficacious than tadalafil in reversing tonic contractions by Ca2+ channel activator, 1,4,dihydro-2,6-dimethyl-5-nitro-4-[2(triflouromethyl)phenyl]pyridine-3-carboxylic acid methyl ester (BAY K-8644). These results indicate that vardenafil and sildenafil possess direct muscle relaxant potential possibly via inhibiting Ca2+ influx through both receptor-operated and voltage-dependent Ca2+ channels whereas tadalafil appears capable of inhibiting receptor-operated transmembrane Ca2+ entry only. © 2006 Elsevier B.V. All rights reserved. | |
dc.description.uri | http://libproxy1.nus.edu.sg/login?url=http://dx.doi.org/10.1016/j.ejphar.2006.05.005 | |
dc.source | Scopus | |
dc.subject | Corpus cavernosum | |
dc.subject | Signal transduction | |
dc.subject | Sildenafil | |
dc.subject | Tadalafil | |
dc.subject | Vardenafil | |
dc.type | Article | |
dc.contributor.department | OBSTETRICS & GYNAECOLOGY | |
dc.description.doi | 10.1016/j.ejphar.2006.05.005 | |
dc.description.sourcetitle | European Journal of Pharmacology | |
dc.description.volume | 541 | |
dc.description.issue | 3 | |
dc.description.page | 184-190 | |
dc.identifier.isiut | 000238875200009 | |
Appears in Collections: | Staff Publications |
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