Endotoxaemia in dairy cattle: mechanism of reticulorumen stasis.
The objective of this study was to determine whether blockade of alpha(-2) adrenergic receptors would restore reticulorumen motility during toxaemia in cows. Reticulorumen contractions were measured via a water-filled balloon connected to a pressure transducer. Intravenous infusion of endotoxin (100 ng kg-1 over 30 min) significantly decreased the number of reticulorumen contractions. Intravenous infusion of yohimbine (125 micrograms kg-1 over 30 min) alone did not affect reticulorumen contractions. However, when yohimbine (125 micrograms kg-1 over 30 min) was infused concurrently with endotoxin (100 ng kg-1 over 30 min), the effects of endotoxin on reticulorumen contraction frequency decreased, suggesting that endotoxaemia causes reticulorumen stasis via a mechanism that involves alpha(-2) adrenergic receptors.
Eades
S C
SC
Department of Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens 30602, USA.
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D002417:Cattle; D002418:Cattle Diseases / Q000139:chemically induced / Q000503:physiopathology*; D019446:Endotoxemia / Q000139:chemically induced / Q000503:physiopathology / Q000662:veterinary*; D004731:Endotoxins; D004926:Escherichia coli; D005260:Female; D005769:Gastrointestinal Motility / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000502:physiology; D018341:Receptors, Adrenergic, alpha-2 / Q000502:physiology; D012119:Respiration / Q000187:drug effects; D012159:Reticulum / Q000187:drug effects / Q000502:physiology*; D012417:Rumen / Q000187:drug effects / Q000502:physiology*; D015016:Yohimbine / Q000494:pharmacology
D000317:Adrenergic alpha-Antagonists; D004731:Endotoxins; D018341:Receptors, Adrenergic, alpha-2; D015016:Yohimbine