The effect of a new selective alpha 2-adrenoreceptor antagonist, idazoxan, and the agonist, clonidine, on fasting antroduodenal motility in healthy volunteers.

Studies were carried out on 16 healthy male volunteers to investigate whether intravenous administration of the alpha 2-adrenoreceptor antagonist, idazoxan, could affect fasting antroduodenal motility with and without administration of the agonist, clonidine. Contractile activity was recorded using an oral tube with perfused side holes positioned in the stomach and duodenum. Clonidine decreased antral contractile activity, an effect that idazoxan did not restore. Idazoxan alone did not affect antral motility. In the duodenum, clonidine decreased the number of contractions significantly and idazoxan restored them. Idazoxan alone did not increase duodenal motility but clonidine induced phase-III activity within the first 15 min after administration. The observations indicate that regulation of antroduodenal motility is influenced by alpha 2-adrenoreceptor drugs. Idazoxan may have potential as a motility restoring drug, for example, in postoperative ileus.