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.

Immune-induced flavor aversion in mice: modification by neonatal capsaicin treatment.

OBJECTIVE: This study was designed to evaluate the role of c-sensitive fibers in the establishment of immune-induced flavor aversion in mice. METHODS: Mice were treated neonatally with capsaicin in order to destroy c-sensitive fibers; after such treatment, adult animals, immunized or not with ovalbumin, were submitted to a two-bottle preference test, with a choice between water and a sweetened egg white solution. RESULTS: Neonatal capsaicin treatment was unsuccessful in preventing the development of immune-induced aversion to the sweetened solution containing the antigen. Nonetheless, amongst immunized mice, those which had been previously treated with capsaicin showed a significant increment in the preference for the sweetened egg white solution. Furthermore, our data showed that neonatal capsaicin treatment did not interfere with either IgG1 or IgE production. CONCLUSION: The present results suggest that c-sensitive fibers have a role in the transmission of the signals generated by this immune response to the central nervous system, thus contributing to the development of a flavor aversion in mice.