RESUMEN
We investigated the effects of piperitenone oxide (PO), a major constituent of the essential oil of Mentha x villosa, on the guinea pig ileum. PO (30 to 740 micrograms/ml) relaxed basal tonus without significantly altering the resting membrane potential. In addition, PO relaxed preparations precontracted with either 60 mM K+ or 5 mM tetraethylammonium in a concentration-dependent manner. At concentrations from 0.1 to 10 micrograms/ml PO potentiated acetylcholine-induced contractions, while higher concentrations (> 30 micrograms/ml) blocked this response. These higher PO concentrations also inhibited contractions induced by 60 mM K+. PO also blocked the components of acetylcholine contraction which are not sensitive to nifedipine or to solutions with nominal zero Ca2+ and EGTA. These results show that PO is a relaxant of intestinal smooth muscle and suggest that this activity may be mediated at least in part by an intracellular effect.
Asunto(s)
Bloqueadores de los Canales de Calcio/farmacología , Íleon/efectos de los fármacos , Monoterpenos , Relajación Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Terpenos/farmacología , Acetilcolina/farmacología , Animales , Ansiolíticos/farmacología , Fármacos Gastrointestinales/farmacología , Cobayas , Cetonas/farmacología , Masculino , Contracción Muscular/fisiología , Nifedipino/farmacología , Aceites de Plantas/farmacología , Cloruro de Potasio/farmacología , Compuestos de Tetraetilamonio/farmacologíaRESUMEN
We investigated the effects of piperitenone oxide (PO), a major constituent of the essential oil of Mentha x villosa, on the guinea pig ileum. PO (30 to 740 mug/ml) relaxed basal tonus without significantly alterating the resting membrane potential. In addition, PO relaxed preparations precontracted with either 60 mM K+ or 5 mM tetraethyl-ammonium in a concentration-dependent manner. At concentrations from 0.1 to 10 mug/ml PO potentiated acetylcholine-induced contractions, while higher concentrations (>30 mug/ml) blocked this response. These higher PO concentrations also inhibited contractions induced by 60 mM K+. PO also blocked the components of acetylcholine contraction which are not sensitive to nifedipine or to solutions with nominal zero Ca2+ and EGTA. These results show that PO is a relaxant of intestinal smooth muscle and suggest that this activity may be mediated at least in part by an intracellular effect.