ABSTRACT
Drug discrimination is a reliable, sensitive and specific behavioural procedure that provides a powerful tool in analyzing neuropharmacological mechanisms underlying the behavioural effects of diverse classes of compounds (e.g., Colpaert & Slangen, 1982; Colpaert & Balster, 1987). The specificity of drug discrimination is apparent from the fact that, in general, compounds from different pharmacological classes produce different discriminative stimulus effects, whereas compounds from the same class produce similar discriminative stimulus effects. Drug discrimination procedures may even differentiate between compounds within a single class. The opiates, for example, comprise a heterogenous group of compounds that can be partitioned into subgroups on the basis of their discriminative stimulus effects (e.g., Holtzman, 1985; Woods et al., 1987). Because of this high specificity, drug discrimination procedures are suitable not only to evaluate hypotheses about receptors at the behavioural level, but also to evaluate hypotheses about receptor subtypes.
