Geraniol Induces Antinociceptive Effect in Mice Evaluated in Behavioural and Electrophysiological Models.
Geraniol (GER) is a monoterpene alcohol with various biochemical and pharmacological properties present in the essential oil of more than 160 species of herbs (especially the Cymbopogon genus). In this study, we evaluated the antinociceptive activity of GER in behavioural and electrophysiological in vitro experimental models of nociception using male Swiss mice. GER (12.5, 25 or 50 mg/kg i.p. and 50 or 200 mg/kg p.o.) reduced the number of writhes induced by acetic acid. The opioid antagonist naloxone (5 mg/kg s.c.) administered in mice subsequently treated with GER (25 mg/kg i.p.) did not reverse such antinociceptive activity, suggesting a non-opioid pathway for the mechanism of action. GER (12.5, 25 and 50 mg/kg i.p.) reduced paw licking time in the second phase of the formalin test. Also, in the glutamate test, GER when administered 50 mg/kg i.p. reduced paw licking time, probably modulating glutamatergic neurotransmission. GER blocked reversibly components of the compound action potential (CAP) recorded in isolated sciatic nerve in a concentration- and drug exposure time-dependent manner: 1 mM to 120 min. for the first component and 0.6 mM to 90 min. for the second component. The IC50was calculated for the peak-to-peak amplitude (PPA) at 0.48 ± 0.04 mM. The conduction velocity was also reduced by exposure to GER starting from the concentration of 0.3 mM for both components of the CAP. In conclusion, it is suggested that GER has antinociceptive activity, especially in pain related to inflammation, and in part related to reduced peripheral nerve excitability.
Postgraduate Program in Biotechnology (Renorbio), Federal University of Paraíba, João Pessoa, Brazil.
Viviana
V
La Rocca
Postgraduate Program in Natural and Bioactive Synthetics Products (PgPNSB), Federal University of Paraíba, João Pessoa, Brazil.
Diogo Vilar
DV
da Fonsêca
Laboratory of Electrophysiology, Institute of Biomedical Sciences, State University of Ceará, Fortaleza, Brazil.
Kerly Shamyra
KS
Silva-Alves
Laboratory of Electrophysiology, Institute of Biomedical Sciences, State University of Ceará, Fortaleza, Brazil.
Francisco Walber
FW
Ferreira-da-Silva
Department of Pharmaceutical Sciences, Health Science Center, Federal University of Paraíba, João Pessoa, Brazil.
Damião Pergentino
DP
de Sousa
Department of Physiology, Federal University of Sergipe, São Cristovão, Brazil.
Priscila Laise
PL
Santos
Department of Physiology, Federal University of Sergipe, São Cristovão, Brazil.
Lucindo José
LJ
Quintans-Júnior
Laboratory of Electrophysiology, Institute of Biomedical Sciences, State University of Ceará, Fortaleza, Brazil.
José Henrique
JH
Leal-Cardoso
Department of Physiology and Pathology, Health Science Center, Federal University of Paraíba, João Pessoa, Brazil.
Reinaldo Nóbrega
RN
de Almeida
D000200:Action Potentials / Q000187:drug effects; D000080462:Acyclic Monoterpenes; D000284:Administration, Oral; D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D055724:Electrophysiological Phenomena / Q000187:drug effects; D066298:In Vitro Techniques; D007274:Injections, Intraperitoneal; D007700:Kinetics; D008297:Male; D051379:Mice; D008959:Models, Neurological; D009431:Neural Conduction / Q000187:drug effects; D009443:Neuritis / Q000188:drug therapy* / Q000276:immunology; D009474:Neurons / Q000187:drug effects* / Q000276:immunology; D012584:Sciatic Nerve / Q000187:drug effects* / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects; D013729:Terpenes / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*
D000080462:Acyclic Monoterpenes; D000700:Analgesics; D013729:Terpenes; C007836:geraniol