Antinociceptive mechanisms of orally administered decursinol in the mouse Seong-Soo Choi a , Ki-Jung Han a , Jin-Koo Lee a , Han-Kyu Lee a , Eun-Jung Han a , Do-Hoon Kim b , Hong-Won Suh a, * a Department of Pharmacology, College of Medicine, and Institute of Natural Medicine, Hallym University, 1 Okchun-dong, Chunchon, Kangwon Do, 200 – 702, South Korea b Department of Psychiatry, College of Medicine, Hallym University, Chunchon, Kangwon Do, 200– 702, South Korea Received 20 March 2002; accepted 10 February 2003 Abstract Antinociceptive profiles of decursinol were examined in ICR mice. Decursinol administered orally (from 5 to 200 mg/kg) showed an antinociceptive effect in a dose-dependent manner as measured by the tail-flick and hot- plate tests. In addition, decursinol attenuated dose-dependently the writhing numbers in the acetic acid-induced writhing test. Moreover, the cumulative response time of nociceptive behaviors induced by an intraplantar formalin injection was reduced by decursinol treatment during the both 1st and 2nd phases in a dose-dependent manner. Furthermore, the cumulative nociceptive response time for intrathecal (i.t.) injection of TNF-a (100 pg), IL-1h (100 pg), IFN-g (100 pg), substance P (0.7 Ag) or glutamate (20 Ag) was dose-dependently diminished by decursinol. Intraperitoneal (i.p.) pretreatment with yohimbine, methysergide, cyproheptadine, ranitidine, or 3,7- dimethyl-1-propargylxanthine (DMPX) attenuated inhibition of the tail-flick response induced by decursinol. However, naloxone, thioperamide, or 1,3-dipropyl-8-(2-amino-4-chloro-phenyl)-xanthine (PACPX) did not affect inhibition of the tail-flick response induced by decursinol. Our results suggests that decursinol shows an antinociceptive property in various pain models. Furthermore, antinociception of decursinol may be mediated by noradrenergic, serotonergic, adenosine A 2 , histamine H 1 and H 2 receptors. D 2003 Elsevier Science Inc. All rights reserved. Keywords: Decursinol; Antinociception; Inflammatory pain; Serotonin receptor; a 2 adrenoceptor; Histamine receptor; Adenosine receptor 0024-3205/03/$ - see front matter D 2003 Elsevier Science Inc. All rights reserved. doi:10.1016/S0024-3205(03)00311-4 * Corresponding author. Tel.: +82-33-240-1654; fax: +82-33-240-1652. E-mail address: hwsuh@hallym.ac.kr (H.-W. Suh). www.elsevier.com/locate/lifescie Life Sciences 73 (2003) 471 – 485