title: Effect of a short-term fast on ketamine-xylazine anesthesia in rats.
abstract: Although ketamine-xylazine (KX) anesthesia is commonly used in rats, it is often reported to have an inconsistent anesthetic effect, with a prolonged induction time, an inadequate anesthetic plane, or a very short sleep time. Blood flow to the liver is known to shift after a meal in rats, perhaps explaining anesthetic variability among rats with variable prandial status. The current study tested the hypothesis that a short period of fasting (3 h) prior to induction with intraperitoneal KX anesthesia would provide a shorter time to recumbency, a longer total sleep time, and a more consistent loss of toe pinch response than would fed rats. Two groups of male Sprague-Dawley rats were used in blinded, crossover experiments. KX anesthesia was administered at 2 different doses (50 mg/kg-5 mg/kg and 70 mg/kg-7 mg/kg) after ad libitum feeding or a 3-h fast. There were no significant differences between groups in induction time, total sleep time, or loss of toe pinch response. We conclude that fasting rats for 3 h prior to KX intraperitoneal anesthesia does not affect induction time, total sleep time, loss of toe pinch response or reduce KX anesthetic variability in male Sprague-Dawley rats.
authors.affiliation: Animal Care Services, University of Florida, Gainesville, Florida, USA. mbstruck@ufl.edu
authors.forename: Maggie B
authors.initials: MB
authors.lastname: Struck
authors.forename: Karl A
authors.initials: KA
authors.lastname: Andrutis
authors.forename: Harvey E
authors.initials: HE
authors.lastname: Ramirez
authors.forename: August H
authors.initials: AH
authors.lastname: Battles
mesh_terms: D000777:Anesthetics / Q000008:administration & dosage / Q000494:pharmacology*; D019162:Anesthetics, Combined / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D000830:Animals, Laboratory / Q000502:physiology; D018592:Cross-Over Studies; D005215:Fasting / Q000502:physiology*; D007274:Injections, Intraperitoneal; D007649:Ketamine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley / Q000502:physiology*; D012890:Sleep / Q000187:drug effects*; D013997:Time Factors; D016896:Treatment Outcome; D014991:Xylazine / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000777:Anesthetics; D019162:Anesthetics, Combined; D014991:Xylazine; D007649:Ketamine