Interoceptive stimulus effects

Abstract Behavioral discrimination procedures clearly demonstrate that nicotine elicits interoceptive stimulus effects in humans that are malleable by various pharmacological manipulations as well as by some behavioral manipulations. The parameters of nicotine discrimination and both chronic and acute factors that may alter discrimination behavior are addressed in this chapter, which emphasizes research by the author involving nicotine delivered by nasal spray. Human discrimination of nicotine is centrally mediated, as the central and peripheral nicotine antagonist mecamylamine blocks discrimination but the peripheral antagonist trimethaphan does not. The threshold dose for discrimination of nicotine via spray appears to be very low in smokers as well as nonsmokers. Because smoked tobacco delivers nicotine more rapidly than spray, the threshold dose of nicotine via smoking is probably even lower. In terms of individual differences, smokers may become tolerant to the discriminative stimulus effects of higher nicotine doses but not of low doses. 

Nicotine discrimination behavior, which is mediated by nicotine actions in the CNS, is strongly related to dose, as indicated in tests of generalization across doses (e.g.. Fig. 1), and may be sensitive to very small doses of nicotine (i.e., threshold), below those commonly administered via cigarette smoking. However, it would be a mistake to view any drug discrimination behavior as based solely on the intensity of the interoceptive stimulus effects of that drug. The observed discrimination behavior is... 

An alternative method of assessing interoceptive drug effects is the behavioral drug discrimination procedure, which relies on observable behavioral responses to determine whether a drug s stimulus effects have been perceived by the subject (Preston 1991 Overton 1991). Behavioral drug discrimination is widely used in animal studies (Holtzman 1990 see chapter by Stolerman, this volume) because it... 

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