The inhibition of the reticular groove reflex in sheep by clonidine.

Intravenous clonidine, an alpha-2 adrenoreceptor agonist, at 2 micrograms.kg-1 and 4 micrograms.kg-1, inhibited the activation by oral copper sulphate of the reticular groove reflex in adult sheep. The plasma concentration of xylose after oral dosing was used as an indicator of groove activation. The inhibition was prevented by prior injection of an alpha-2 antagonist, idazoxan. Indirect evidence of prolongation of intestinal transit time was found with the lower dose of clonidine. Idazoxan injected alone appeared to increase the absorption of xylose.