Relaxant and Antispasmodic Actions of Methyleugenol on Guinea-Pig Isolated Ileum

Abstract

The effects of methyleugenol (ME) on guinea-pig isolated ileum were studied. ME reversibly relaxed basal tonus (EC₅₀ of 52.2 ± 18.3 μM), an action unaltered by 0.5 μM tetrodotoxin or 0.5 mM hexamethonium, and relaxed the ileum pre-contracted with 60 mM KCl. ME slightly hyperpolarised the ileum from - 57.3 to - 62.8 mV but had no effect in depolarised tissues. ME inhibited contractions induced by ACh, histamine and KCl with IC₅₀ values of approximately 82, 124, and 65 μM, respectively. Our results suggest that ME induces relaxation of guinea-pig ileum by a direct action on smooth muscle via a mechanism largely independent of alterations of membrane potential (E_m).

Key words

Essential oil - methyleugenol - ileum - smooth muscle - antispasmodic - myorelaxant

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