Calcium Antagonistic Properties of the Sesquiterpene T‐Cadinol : A Comparison with Nimodipine in the Isolated Rat Aorta

• Abstract: (+)‐T‐Cadinol is a sesquiterpene with smooth muscle relaxing properties. In the isolated rat aorta, T‐cadinol relaxed contractions induced by 60 mM K+ in a concentration‐dependent fashion. The dihydropyridine calcium antagonist nimodipine was approximately 4,000 times more potent than T‐cadinol. While both drugs nearly abolished the K+‐induced contractions, they only partially relaxed contractions induced by phenylephrine. The relaxation induced by T‐cadinol and nimodipine in K+‐contracted aortic rings, was completely reversed by the calcium channel activator Bay K8644. In aortic preparations partially depolarized by 20 mM K+, Bay K8644 induced a concentration‐dependent contraction. Nimodipine shifted the Bay K8644 concentration‐response curve to the right in a parallel manner, consistent with a competitive mode of inhibition. T‐cadinol at concentrations less than 10−3.5 M also produced a right‐ward shift of the Bay K8644 concentration‐response curve with a maintained maximum response. However, the highest T‐cadinol concentration used (10−3.5 M) significantly reduced the maximum response. In conclusion, although T‐cadinol and nimodipine display marked structural differences, their pharmacological profiles of action have several features in common, suggesting that T‐cadinol is a calcium antagonist, possibly interacting with the dihydropyridine binding sites on the calcium channels. 1991 Nordic Pharmacological Society

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MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Farmakologi och toxikologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Pharmacology and Toxicology (hsv//eng)

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