Effects of piperitenone oxide on the intestinal smooth muscle of the guinea pig

• Published in: Brazilian journal of medical and biological research Vol. 30; no. 6; pp. 787 - 791
• Main Authors: Sousa, P J, Magalhães, P J, Lima, C C, Oliveira, V S, Leal-Cardoso, J H
• Format: Journal Article
• Language: English
• Published: Brazil Associação Brasileira de Divulgação Científica 01-06-1997
• Subjects: acetylcholine; Acetylcholine - pharmacology; Animals; Anti-Anxiety Agents - pharmacology; BIOLOGY; Calcium Channel Blockers - pharmacology; essential oil; Gastrointestinal Agents - pharmacology; Guinea Pigs; ileum; Ileum - drug effects; K+-induced contraction; Ketones - pharmacology; Male; MEDICINE, RESEARCH & EXPERIMENTAL; Mentha x villosa; Monoterpenes; Muscle Contraction - physiology; muscle relaxation; Muscle Relaxation - drug effects; Muscle, Smooth - drug effects; Nifedipine - pharmacology; piperitenone oxide; Plant Oils - pharmacology; Potassium Chloride - pharmacology; Terpenes - pharmacology; Tetraethylammonium Compounds - pharmacology; ileum; K+-induced contraction; piperitenone oxide; essential oil; acetylcholine; muscle relaxation; Mentha x villosa
• ISSN: 0100-879X; 1414-431X; 0100-879X; 1414-431X
• DOI: 10.1590/S0100-879X1997000600014

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.