| Abstract: | The effects of an Olea europaea L. dried leaf extract containing 3.2% of oleuropein were investigated on the rat isolated ileum and trachea. On basal tone rat isolated ileum, Olea europaea L. extract was shown to produce a dual effect characterized by a contraction at low doses (10?7-10?4g/mL) and a relaxation at high doses (3.10?4-10?3g/mL). The extract induced contractile effect was found to involve at least histamine, 5-hydroxytryptamine and thromboxane A2. On precontracted rat isolated ileum, the extract only induced a relaxation that was not modified by nifedipine, diltiazem, dipyridamone, verapamil or papaverine (10?6 M). The effects of the extract were also studied on the rat isolated trachea. On basal tone organs, Olea europaea L. extract did not produce any effect, whereas, when basal tone was raised by acetylcholine (ACh 10?3 M), the drug caused a relaxation (maximal effect 39.01% ± 5.40%) of the response to theophylline; (3.10 ± 10?3M n = 15). It is suggested that the induced relaxation is consecutive to an increase of intracellular 3′5′ cAMP. |
