title: The anaesthetic combination of ketamine/midazolam does not alter the acquisition of spatial and motor tasks in adult mice.
abstract: The ketamine/midazolam association of a dissociative with a sedative agent is used for the induction and maintenance of anaesthesia in laboratory animals. Anaesthesia may interfere with research results through side-effects on the nervous system, such as memory impairment. It is known that ketamine and midazolam affect cognition; however, their effects have not been clarified when used in a context of balanced anaesthesia. Thus, this study evaluated the effects of ketamine/midazolam on the acquisition of motor and of a spatial memory task in adult mice. Twenty-eight C57BL/6 adult male mice were divided into three groups: untreated control, treated with ketamine/midazolam (75 mg/kg / 10 mg/kg) and treated with midazolam (10 mg/kg) groups. Respiratory rate, heart rate and systolic pressure were measured every 5 min in the animals treated with ketamine/midazolam, as this was the only group that exhibited loss of the righting reflex. One day after treatment, animals were tested in the open field, rotarod and radial arm maze. There were no differences between treatments regarding open-field activity, rotarod performance or number of working and reference memory errors in the radial arm maze task. In conclusion, the learning process of spatial and motor tasks was not disrupted by the anaesthetic combination of ketamine/midazolam. These results suggest its safe use in adult mice in projects where acquisition of a spatial and motor task is necessary.
authors.affiliation: Laboratory Animal Science, Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal. amaria@ibmc.up.pt
authors.forename: A M
authors.initials: AM
authors.lastname: Valentim
authors.forename: I A S
authors.initials: IA
authors.lastname: Olsson
authors.forename: L M
authors.initials: LM
authors.lastname: Antunes
mesh_terms: D000758:Anesthesia / Q000379:methods / Q000662:veterinary; D000777:Anesthetics / Q000008:administration & dosage / Q000009:adverse effects*; D000818:Animals; D007649:Ketamine / Q000008:administration & dosage / Q000009:adverse effects*; D007756:Laboratory Animal Science / Q000379:methods; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D008568:Memory / Q000187:drug effects*; D051379:Mice; D008810:Mice, Inbred C57BL; D008874:Midazolam / Q000008:administration & dosage / Q000009:adverse effects*; D045442:Rotarod Performance Test
chemical_list: D000777:Anesthetics; D007649:Ketamine; D008874:Midazolam