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The effect of xylazine on the isolated sheep trachea
Author(s) -
PAPAZOGLOU L.,
RAPTOPOULOS D.,
KOUNENIS G.
Publication year - 1995
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1111/j.1365-2885.1995.tb00581.x
Subject(s) - xylazine , anesthesia , medicine , veterinary medicine , ketamine
The effect of xylazine on the isolated sheep trachea and its possible interactions with the α 2 ‐adrenergic antagonist, atipamezole, and the anticholinergic agent, atropine, was studied. The mechanical responses of the tracheal preparations were recorded after exposing each one to cumulatively increasing concentrations of xylazine alone or in the presence of atipamezole or atropine. Xylazine exerted a concentration‐dependent contractile effect, with a threshold concentration of 10 ‐ ‐ 7 M while the maximum activity was produced at a concentration of 10 ‐ ‐ 5 M (EC 50 = 2.3 × 10 ‐ ‐ 7 ). This xylazine‐induced contractile effect was inhibited by atipamezole, but not significantly modified by atropine. Thus, it is concluded that α 2 ‐adrenoceptors exist in the sheep trachea and it is suggested that α 2 ‐adrenoceptor agonists may act on airways in sheep directly through stimulation of peripheral α 2 ‐adrenergic receptors and indirectly via central α 2 ‐adrenergic receptor activation of parasympathetic tone.