The selective dopamine uptake inhibitor GBR 12909: its effects on the microstructure of feeding in rats.

Previous experiments have investigated the anorectic effects of mazindol and cocaine, both of which can inhibit dopamine (DA) uptake into presynaptic terminals but do not do so selectively. GBR 12909, however, is an example of a potent and selective inhibitor of DA uptake and, therefore, the present study was concerned with investigating its possible effects on feeding behavior in nondeprived rats given access to a sweetened palatable diet. GBR 12909 (5-20 mg/kg, IP) was injected 2 h before a 60 min observation test. It produced a significant reduction in food intake, as a consequence of a reduction in the duration of feeding, without reducing the rate of eating. This anorectic profile is consistent with earlier findings for mazindol and cocaine. The other main behavioral effect of GBR 12909, observed in the present study, was to induce intense sniffing activity, but, unlike cocaine, it did not suppress grooming or induce hyperlocomotion. This selective behavioral effect of GBR 12909 indicates that sniffing can be isolated as one component of a broader array of components typically associated with DA-related stereotyped behavior.