Kinzo Matsumoto (1), Shin-ichi Kohno (1), Yasuhiro Tezuka (2), Shigetoshi Kadota (2) and Hiroshi Watanabe (1)
(1) Department of Pharmacology, (2) Department of Natural Products Chemistry, Research Institute for Wakan-Yaku, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama 930-01, Japan
Abstract: We investigated the effect of the aqueous extract of Japanese angelica root (JAR) on pentobarbital (PB) sleep in group-housed and socially isolated mice. The JAR extract (1.25 - 2.5 g/kg, p.o.) dose-dependently reversed the decrease in PB sleep caused by isolation stress without affecting PB sleep in group-housed mice. The JAR extract (2.5 g/kg, p.o.) also antagonized the decrease in PB sleep caused by the alpha2-adrenoceptor antagonists yohimbine and idazoxan (1 mg/kg, i.p.) and the alpha1-adrenoceptor agonist methoxamine (200 nmol, i.c.v.) in group-housed mice. These results suggest that the JAR extract reverses changes in the arousal level caused by isolation stress and the activation of central noradrenergic systems.
Keywords: Angelicae radix, Social isolation stress, Pentobarbital sleep