title: Effects of piperitenone oxide on the intestinal smooth muscle of the guinea pig.
abstract: 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.
authors.affiliation: Departamento de Fisiologia e Farmacologia, Universidade Federal do Ceará, Fortaleza, Brasil.
authors.forename: P J
authors.initials: PJ
authors.lastname: Sousa
authors.forename: P J
authors.initials: PJ
authors.lastname: Magalhães
authors.forename: C C
authors.initials: CC
authors.lastname: Lima
authors.forename: V S
authors.initials: VS
authors.lastname: Oliveira
authors.forename: J H
authors.initials: JH
authors.lastname: Leal-Cardoso
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D005765:Gastrointestinal Agents / Q000494:pharmacology; D006168:Guinea Pigs; D007082:Ileum / Q000187:drug effects*; D007659:Ketones / Q000494:pharmacology; D008297:Male; D039821:Monoterpenes; D009119:Muscle Contraction / Q000502:physiology; D009126:Muscle Relaxation / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects*; D009543:Nifedipine / Q000494:pharmacology; D010938:Plant Oils / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D013729:Terpenes / Q000494:pharmacology*; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
chemical_list: D014151:Anti-Anxiety Agents; D002121:Calcium Channel Blockers; D005765:Gastrointestinal Agents; D007659:Ketones; D039821:Monoterpenes; D010938:Plant Oils; D013729:Terpenes; D013757:Tetraethylammonium Compounds; D011189:Potassium Chloride; D009543:Nifedipine; C044956:piperitenone; D000109:Acetylcholine