Abstract
Nicotine is commonly understood to be an appetite suppressant, but perceptual mechanisms that might underlie this anecdotal effect have received little study. It is possible that nicotine might simply reduce thirst (and hunger), thereby altering consumption behavior in a fairly stimulus- general manner. Alternatively, nicotine might alter taste perception, perhaps making particular tastes less palatable. We decided to test these hypotheses in rodents by looking at changes in consumption in a brief-access task (BAT), which allowed us to rapidly assess preferences for tastants varying in quality and hedonics, in rats recently given doses of nicotine or saline via subcutaneous injection. Acute nicotine administration reduced consumption of all presented solutions, but not monolithically—the reduction in consumption increased as palatability of the solution decreased. We further investigated this phenomenon, testing whether the effect of acute exposure to nicotine was a product of the novelty of the experience or of the nicotinic state itself. We repeated Experiment 1 but added one group of which rats were exposed to 4 injections of nicotine prior to the collection of BAT data; for these rats, nicotine was no longer novel, but they had not received enough exposure to develop dependency. The results of this experiment replicated the effect found in experiment 1—the more aversive a taste, the greater the reduction in consumption—and therefore suggested that taste-specific reduction of consumption is a product of nicotine itself, not just the novel state.