title: S-(+)-Linalool from Lippia alba: sedative and anesthetic for silver catfish (Rhamdia quelen).
abstract: OBJECTIVE
  The present study describes the isolation of linalool from the essential oil of Lippia alba (Mill.) N. E. Brown, and its anesthetic effect in silver catfish (Rhamdia quelen) in comparison with essential oil. The potentiation of depressant effects of linalool with a benzodiazepine (BDZ) and the involvement of GABAergic system in its antagonism by flumazenil were also evaluated.
  
  
  METHODS
  Prospective experimental study.
  
  
  METHODS
  Juvenile silver catfish unknown sex weighing mean 9.24 ± 2.83 g (n = 6 for each experimental group per experiment).
  
  
  METHODS
  Column chromatography was used for the isolation of S-(+)-linalool. Fish (n = 6 for each concentration) were transferred to aquaria with linalool (30, 60, and 180 μL L(-1)) or EO of L. alba (50, 100, and 300 μL L(-1)) to determine the induction time for anesthesia. After induction, the animals were transferred to anesthetic-free aquaria to assess their recovery time. To observe the potentiation, fish were exposed to linalool (30, 60, and 180 μL L(-1)) in the presence or absence of BDZ (diazepam 150 μm). In another experiment, fish exposed to linalool (30 and 180 μL L(-1) or BDZ were transferred to an anesthetic-free aquaria containing flumazenil (5 μm) or water to assess recovery time.
  
  
  RESULTS
  Linalool had a similar sedation profile to the essential oil at a proportional concentration in silver catfish. However, the anesthesia profile was different. Potentiation of linalool effect occurred only when tested at low concentration. Fish exposed to BDZ showed faster anesthesia recovery in water with flumazenil, but the same did not occur with linalool.
  
  
  CONCLUSIONS
  The use of linalool as a sedative and anesthetic for silver catfish was effective at 30 and 180 μL L(-1), respectively. The mechanism of action seems not to involve the benzodiazepine site of the GABAergic system.
authors.affiliation: Department of Industrial Pharmacy, UFSM, Santa Maria, Brazil.
authors.forename: Clarissa G
authors.initials: CG
authors.lastname: Heldwein
authors.forename: Lenise de L
authors.initials: Lde L
authors.lastname: Silva
authors.forename: Eduarda Z
authors.initials: EZ
authors.lastname: Gai
authors.forename: Cassiela
authors.initials: C
authors.lastname: Roman
authors.forename: Thaylise V
authors.initials: TV
authors.lastname: Parodi
authors.forename: Marilise E
authors.initials: ME
authors.lastname: Bürger
authors.forename: Bernardo
authors.initials: B
authors.lastname: Baldisserotto
authors.forename: Érico M de M
authors.initials: ÉM
authors.lastname: Flores
authors.forename: Berta M
authors.initials: BM
authors.lastname: Heinzmann
mesh_terms: D000080462:Acyclic Monoterpenes; D000758:Anesthesia / Q000379:methods / Q000662:veterinary*; D000777:Anesthetics / Q000302:isolation & purification / Q000494:pharmacology; D000818:Animals; D002397:Catfishes; D002490:Central Nervous System / Q000187:drug effects; D003975:Diazepam / Q000494:pharmacology; D005442:Flumazenil / Q000494:pharmacology; D006993:Hypnotics and Sedatives / Q000302:isolation & purification / Q000494:pharmacology*; D032411:Lippia / Q000737:chemistry*; D039821:Monoterpenes / Q000302:isolation & purification / Q000494:pharmacology*; D010938:Plant Oils / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: D000080462:Acyclic Monoterpenes; D000777:Anesthetics; D006993:Hypnotics and Sedatives; D039821:Monoterpenes; D010938:Plant Oils; D005442:Flumazenil; C018584:linalool; D003975:Diazepam
keywords: GABA; Verbenaceae; anesthesia; benzodiazepine; sedation