title: Yohimbine ameliorates the effects of endotoxin on gastric emptying of the liquid marker acetaminophen in horses.
abstract: The effect of yohimbine pretreatment on gastric emptying of a liquid marker in horses was evaluated by measuring serum concentrations of acetaminophen. Gastric emptying was determined in normal, fasted horses, in horses given endotoxin (E. coli 055 B5; 0.2 microg/kg) intravenously, and in horses given yohimbine (0.25 mg/kg, IV, over 30 minutes) plus endotoxin. Acetaminophen (20 mg/kg) was given by stomach tube 15 minutes after the endotoxin infusion. Blood samples for acetaminophen analysis were collected, and time to reach the peak serum concentration (Tmax), the maximum serum concentration (Cmax) and the area under the acetaminophen serum concentration versus time curve (AUC) were determined for each treatment group. Endotoxin significantly increased Tmax, indicating a profound delay in gastric emptying and yohimbine pretreatment significantly (P < or = 0.05) prevented this effect.
authors.affiliation: Department of Large Animal Clinical Sciences, The University of Tennessee, College of Veterinary Medicine, Knoxville, 37901-1071, USA.
authors.forename: S D
authors.initials: SD
authors.lastname: Meisler
authors.forename: T J
authors.initials: TJ
authors.lastname: Doherty
authors.forename: F M
authors.initials: FM
authors.lastname: Andrews
authors.forename: D
authors.initials: D
authors.lastname: Osborne
authors.forename: D L
authors.initials: DL
authors.lastname: Frazier
mesh_terms: D000082:Acetaminophen / Q000493:pharmacokinetics; D000317:Adrenergic alpha-Antagonists / Q000493:pharmacokinetics / Q000494:pharmacology*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000493:pharmacokinetics; D019540:Area Under Curve; D004347:Drug Interactions; D004731:Endotoxins / Q000494:pharmacology*; D005260:Female; D005746:Gastric Emptying / Q000187:drug effects*; D006736:Horses / Q000502:physiology*; D015016:Yohimbine / Q000493:pharmacokinetics / Q000494:pharmacology*
chemical_list: D000317:Adrenergic alpha-Antagonists; D000894:Anti-Inflammatory Agents, Non-Steroidal; D004731:Endotoxins; D015016:Yohimbine; D000082:Acetaminophen