title: Evidence for a role of 5-HT(1A) receptor on antinociceptive action from Geissospermum vellosii.
abstract: BACKGROUND
  Geissospermum vellosii is a tree widely found throughout the Amazonic forest and frequently used by the native population for painful disorders.
  
  
  OBJECTIVE
  The present study examined the antinociceptive effects of Geissospermum vellosii in behavioral models of nociception.
  
  
  RESULTS
  Oral administration of crude extract of Geissospermum vellosii or its dichloromethane fraction (1-100 mg/kg) inhibited formalin-induced inflammatory nociception and acetic acid-induced visceral nociception. The antinociceptive effect of Geissospermum vellosii was unrelated with motor dysfunctions. Furthermore, the alkaloid 12-metoxy-1-methyl-aspidospermidine (0.001-1 mg/kg), isolated from the dichloromethane fraction, also produced antinociception. The antinociception caused by the dichloromethane fraction was significantly attenuated by pre-treatment of mice with p-chlorophenylalanine methyl ester (PCPA, an inhibitor of serotonin synthesis, 100 mg/kg once a day for 4 consecutive days) and WAY-100635 (a 5-HT(1A) receptor antagonist, 0.3 mg/kg). In contrast, dichloromethane fraction antinociception was not affected by pre-treatment of animals with ketanserin (a 5-HT(2) receptor antagonist, 0.3 mg/kg) or ondansetron (a 5-HT(3) receptor antagonist, 0.5 mg/kg).
  
  
  CONCLUSIONS
  Together, these results indicate that Geissospermum vellosii produces antinociception through an interaction with 5-HT(1A) receptors. Furthermore, the alkaloid 12-metoxy-1-methyl-aspidospermidine contributes to the antinociceptive properties reported for Geissospermum vellosii.
authors.affiliation: Programa de Pós-graduação em Farmacologia, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, Brazil.
authors.forename: Juliana A T
authors.initials: JA
authors.lastname: Werner
authors.forename: Sara M
authors.initials: SM
authors.lastname: Oliveira
authors.forename: Daniel F
authors.initials: DF
authors.lastname: Martins
authors.forename: Leidiane
authors.initials: L
authors.lastname: Mazzardo
authors.forename: Josiane de F G
authors.initials: Jde F
authors.lastname: Dias
authors.forename: Ana L L
authors.initials: AL
authors.lastname: Lordello
authors.forename: Obdúlio G
authors.initials: OG
authors.lastname: Miguel
authors.forename: Luiz Fernando
authors.initials: LF
authors.lastname: Royes
authors.forename: Juliano
authors.initials: J
authors.lastname: Ferreira
authors.forename: Adair R S
authors.initials: AR
authors.lastname: Santos
mesh_terms: D019342:Acetic Acid / Q000008:administration & dosage; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D029062:Apocynaceae / Q000737:chemistry*; D005557:Formaldehyde / Q000008:administration & dosage; D008124:Locomotion / Q000187:drug effects; D008297:Male; D051379:Mice; D010936:Plant Extracts / Q000494:pharmacology*; D044282:Receptor, Serotonin, 5-HT1A / Q000502:physiology*
chemical_list: D000700:Analgesics; D010936:Plant Extracts; D044282:Receptor, Serotonin, 5-HT1A; D005557:Formaldehyde; D019342:Acetic Acid