INCREASED AIRWAY PRESSURE IN RESPONSE TO XYLAZINE IS INHIBITED BY BOTH ATIPAMEZOLE AND ATROPINE IN SHEEP

The effect on airway pressure of xylazine alone or following the admin istration of atipamezole or atropine was studied in 31 halothane-anaes thetized sheep. Xylazine produced a significant increase in airway pre ssure which lasted for at least 30 min. This effect was inhibited by b oth atipamezole and atropine. The results suggest that the xylazine-in duced increase in airway pressure in sheep is alpha2-adrenergically me diated. Moreover, activation of central alpha2-adrenoceptors leading t o vagal stimulation may be involved.