dogs pretreated with phosphodiesterase inhibitors ( theophylline , 3-isobutyl-1-methylxanthine , or ro 1724 ) showed a shift in the threshold concentration of the above substances that triggered emesis , such that emesis was evoked by lower concentrations than in the control .
C0039771
theophylline
C0000096
3-isobutyl-1-methylxanthine