Evidence for a role of 5-HT(1A) receptor on antinociceptive action from Geissospermum vellosii.
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.
Werner
Juliana A T
JA
Programa de Pós-graduação em Farmacologia, Centro de Ciências da Saúde, Universidade Federal de Santa Maria, Santa Maria, Brazil.
Oliveira
Sara M
SM
Martins
Daniel F
DF
Mazzardo
Leidiane
L
Dias
Josiane de F G
Jde F
Lordello
Ana L L
AL
Miguel
Obdúlio G
OG
Royes
Luiz Fernando
LF
Ferreira
Juliano
J
Santos
Adair R S
AR
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*
D000700:Analgesics; D010936:Plant Extracts; D044282:Receptor, Serotonin, 5-HT1A; D005557:Formaldehyde; D019342:Acetic Acid