title: Effect of ketamine on the limb withdrawal reflex evoked by transcutaneous electrical stimulation in ponies anaesthetised with isoflurane.
abstract: The purpose of this study was to evaluate the anti-nociceptive activity of ketamine and isoflurane in horses using a limb withdrawal reflex (WR) model. Single and repeated stimulations were applied to the digital nerve of the left forelimb in ponies anaesthetised with isoflurane before, during and after intravenous administration of racemic ketamine. Surface electromyographic activity was recorded from the deltoid muscle. Higher stimulation intensity was required to evoke a reflex during ketamine administration. Furthermore, the amplitudes of response to stimulations were significantly and dose-dependently depressed and a flattening of the stimulus-response curves was observed. The reflex activity recovered partially once the ketamine infusion finished. The results demonstrated that the limb WR can be used to quantify the temporal effect of ketamine on the sensory-motor processing in ponies anaesthetised with isoflurane.
authors.affiliation: Division of Veterinary Anaesthesiology, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland. Olivier.levionnois@kkh.unibe.ch
authors.forename: Olivier L
authors.initials: OL
authors.lastname: Levionnois
authors.forename: Monika
authors.initials: M
authors.lastname: Menge
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Thormann
authors.forename: Meike
authors.initials: M
authors.lastname: Mevissen
authors.forename: Claudia
authors.initials: C
authors.lastname: Spadavecchia
mesh_terms: D000778:Anesthetics, Dissociative / Q000008:administration & dosage / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D004576:Electromyography / Q000662:veterinary; D005552:Forelimb; D006736:Horses / Q000502:physiology*; D007530:Isoflurane / Q000008:administration & dosage / Q000494:pharmacology; D007649:Ketamine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D012018:Reflex / Q000187:drug effects* / Q000502:physiology
chemical_list: D000778:Anesthetics, Dissociative; D018685:Anesthetics, Inhalation; D007649:Ketamine; D007530:Isoflurane