Differential effects of bromopride and domperidone on cholinesterase activity in rat tissues

Bromopride (BRO) and domperidone (DOMP) are dopamine D2 blocking agents used in gastroenterology clinics because of their anti emetic effect as well as their central and peripheral actions of increasing gastrointestinal motor activity. The rationale for these experiments was to compare BRO- and DOMP-effects on plasma, brain, and intestinal cholinesterase activity in vitro. BRO and DOMP effects on cholinesterase activity in plasma, striatum, duodenum and ileum of adult male rats were measured for drug concentrations ranging from 0.006 to 3.134 microM for BRO and from 0.006 to 125 microM for DOMP. The results demonstrate that both BRO and DOMP can inhibit cholinesterase activity in all tissues studied, with DOMP being more potent than BRO in plasma and intestinal tissues. These data suggest the existence of a cholinergic mechanism of action for these dopamine blocking agents.