title: Effects of (-)-linalool in the acute hyperalgesia induced by carrageenan, L-glutamate and prostaglandin E2.
abstract: A series of studies performed in our laboratory have shown that (-)-linalool, the natural occurring enantiomer in essential oils, possesses anti-inflammatory and antinociceptive effects in different animal models. The antinociceptive effect of (-)-linalool has been ascribed to the stimulation of the cholinergic, opioidergic and dopaminergic systems, to its local anesthetic activity and to the blockade of N-methyl-D-aspartate (NMDA) receptors. In this study, we investigated the effect of systemic administration of (-)-linalool in the paw withdrawal test in rats, a model of thermal hyperalgesia induced by monolateral subplantar injection of carrageenan, L-glutamate or prostaglandin E(2). Carrageenan and L-glutamate induced a hyperalgesic effect on the injection side. In contrast, prostaglandin E(2) induced hyperalgesia in both the injection side and the contralateral side. Pretreatment with (-)-linalool (50-150 mg/kg) inhibited the development of acute hyperalgesia induced by carrageenan in the injected paw, with no effect on the contralateral paw. Furthermore, (-)-linalool at the highest dose used (200 mg/kg), reduced and reverted the decrease in paw withdrawal latencies induced by L-glutamate on the ipsilateral side, showing antihyperalgesic and antinociceptive effects. An antinociceptive effect was apparent also in the contralateral paw. Finally, (-)-linalool (200 mg/kg) increased paw withdrawal latency on the side contralateral to prostaglandin E(2) injection, but not on the side of the injection. The efficacy of (-)-linalool in decreasing the hyperalgesia induced by carrageenan, L-glutamate and prostaglandin E(2) suggests that this compound might be useful in pain conditions sustained by the development of neuronal sensitization.
authors.affiliation: Dipartimento di Scienze del Farmaco, Università degli, Studi di Sassari, via Muroni 23/a, Sassari 07100, Italy. apeana@uniss.it
authors.forename: Alessandra T
authors.initials: AT
authors.lastname: Peana
authors.forename: M Graziella
authors.initials: MG
authors.lastname: De Montis
authors.forename: Silvia
authors.initials: S
authors.lastname: Sechi
authors.forename: Gabriella
authors.initials: G
authors.lastname: Sircana
authors.forename: Paolo S
authors.initials: PS
authors.lastname: D'Aquila
authors.forename: Proto
authors.initials: P
authors.lastname: Pippia
mesh_terms: D000208:Acute Disease; D000080462:Acyclic Monoterpenes; D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D002351:Carrageenan; D015232:Dinoprostone; D004305:Dose-Response Relationship, Drug; D018698:Glutamic Acid; D006358:Hot Temperature; D006930:Hyperalgesia / Q000139:chemically induced / Q000188:drug therapy*; D008297:Male; D039821:Monoterpenes / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D014110:Touch
chemical_list: D000080462:Acyclic Monoterpenes; D000700:Analgesics; D039821:Monoterpenes; D018698:Glutamic Acid; D002351:Carrageenan; C018584:linalool; D015232:Dinoprostone