کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2537550 | 1559192 | 2006 | 7 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: In vitro and in vivo vasodilator activity of racemic tramadol and its enantiomers in Wistar rats In vitro and in vivo vasodilator activity of racemic tramadol and its enantiomers in Wistar rats](/preview/png/2537550.png)
Tramadol ((±)-tramadol) is an analgesic agent formulated as a racemic mixture (1 : 1) of (−)- and (+)-tramadol, which differ in their potency to bind to μ-opioid receptors and to inhibit monoamine-reuptake. We investigated the stereoselectivity of in vitro tramadol-induced vasodilatation of aortic rings and its effect on the arterial blood pressure measured in conscious Wistar rats. (+)-Tramadol, but not (−)-tramadol, produced a concentration-dependent relaxation of aorta precontracted with phenylephrine. The concentration–response curve was significantly altered by the removal of endothelium. Vascular relaxation was also inhibited by pre-incubation of endothelium-intact aorta with naloxone, suggesting the involvement of opioid receptors. The vasodilatation produced by tramadol was stereoselective, and the (+)-tramadol-induced vasodilatation was mediated by μ-opioid receptors and partially dependent on endothelium integrity. The hypotensive response induced by (+)-tramadol was also observed after bolus injection of 5.0 and 10.0 mg/kg. The results indicate that only high doses of tramadol cause cardiac depression and hypotension, indicating that it can be used safely.
Journal: European Journal of Pharmacology - Volume 530, Issues 1–2, 13 January 2006, Pages 117–123