The lowest dose of clonidine to suppress alcohol drinking (40 µg/kg) had previously been reported to produce no motor impairment in the rotarod test (De Luca, Nunes de Souza, Yada, & Meyer, 1999) and not to compromise operant responding for food (Shaham et al., 2000), suggesting that the decrease in alcohol intake after treatment with this dose of clonidine was not due to sedation or motor impairment. To test this further, we assessed the effect of this dose of clonidine on intake of a palatable saccharin solution and found that saccharin intake was reduced as well as alcohol intake. This suppression of saccharin intake may in part reflect motor or hypnotic effects, or may be due to a more generalized suppression in intake of reinforcing substances. At the highest clonidine dose used in the current study (80 µg/kg BW), it is likely that acute hypotensive/sedating effects, which are known to be associated with high doses of clonidine, contributed to the profound clonidine-induced suppression of alcohol consumption. It has been reported that when a bolus intravenous (IV) injection of clonidine was
