title: Involvement of opioidergic and serotonergic systems in the analgesic activity of Cissus quadrangularis L. stem extract in mice.
abstract: BACKGROUND
  Cissus quadrangularis L. (Vitaceae) is used as a bonesetter and as an analgesic. However, the bioactive fractions and the pharmacological mechanism of analgesic activity are not clearly known. Hence, this study aimed to characterize the analgesic activity profile of successively extracted fractions of C. quadrangularis and the pharmacological mechanism of analgesic activity in mice.
  
  
  METHODS
  Dried C. quadrangularis stem was extracted successively with chloroform and methanol. The dried extracts were separately administered to mice intraperitoneally at the doses of 75, 150 and 300 mg/kg. The mice were tested separately in hot plate and tail flick tests. The mechanism of analgesic activity of chloroform extract was explored in the hot plate test at the dose of 300 mg/kg after pretreatment with naloxone, p-chlorophenylalanine methyl ester (pCPA) and phentolamine. The data were analyzed by one-way analysis of variance followed by Dunnett's test.
  
  
  RESULTS
  Chloroform extract showed significant (p<0.05) analgesic effect at the doses of 75, 150 and 300 mg/kg in hot plate and tail flick tests. Methanol extract showed significant (p<0.05) analgesic effect at the dose of 300 mg/kg in hot plate and tail flick tests. Analgesic activity was not blocked (p<0.05) in the group pretreated with phentolamine but blocked in the groups pretreated with naloxone and pCPA.
  
  
  CONCLUSIONS
  The chloroform extract was found to be more potent than methanol extract in inducing analgesic effect in mice, and the analgesic activity may be mediated through opioidergic and serotonergic pathways.
authors.forename: Tan Wee
authors.initials: TW
authors.lastname: Nie
authors.forename: Mohamed Saleem Abdul
authors.initials: MS
authors.lastname: Shukkoor
authors.forename: Rajesh Sreedharan
authors.initials: RS
authors.lastname: Nair
authors.forename: Fatimah Khursiah Binti
authors.initials: FK
authors.lastname: Amiruddin
authors.forename: Shamala
authors.initials: S
authors.lastname: Ramasamy
mesh_terms: D000700:Analgesics / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D000818:Animals; D032422:Cissus / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D010134:Fenclonine / Q000031:analogs & derivatives / Q000494:pharmacology; D051379:Mice; D009270:Naloxone / Q000494:pharmacology; D010146:Pain / Q000188:drug therapy*; D010646:Phentolamine; D010936:Plant Extracts / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D018547:Plant Stems; D012997:Solvents / Q000737:chemistry
chemical_list: D000700:Analgesics; D010936:Plant Extracts; D012997:Solvents; C020261:4-chlorophenylalanine methyl ester; D009270:Naloxone; D010134:Fenclonine; D010646:Phentolamine