SECOBARBITAL IN HUMANS DISCRIMINATING TRIAZOLAM UNDER 2-RESPONSE AND NOVEL-RESPONSE PROCEDURES

Humans were trained to discriminate the benzodiazepine triazolam (0.32 mg/70kg) from placebo under a two-response (drug vs. placebo) drug di scrimination procedure. Dose-effect curves for several drugs were then determined in a crossover design using the two-response procedure and a 'novel-response procedure' that provided a never-appropriate respon se for drugs unlike triazolam or placebo. Three subjects were tested w ith triazolam (0.1-0.32 mg/70 kg), the barbiturate secobarbital (56-17 7 mg/70 kg), and caffeine (320 and 560 mg/70 kg). Triazolam dose depen dently increased triazolam-appropriate responding under both procedure s and generally did not occasion novel-appropriate responding under th e novel-response procedure. Secobarbital substituted for triazolam in the two-response procedure and dose-dependently increased novel-approp riate responding as well as occasioned some triazolam-appropriate resp onding in the novel-response procedure. Caffeine generally occasioned placebo-appropriate responding under the two-response procedure and a mix of novel-and placebo-appropriate responding under the novel-respon se procedure. Triazolam and secobarbital produced qualitatively simila r self-reported drug effects. These results suggest that the novel-res ponse procedure for human drug discrimination may enhance the pharmaco logical selectivity of triazolam- and placebo-appropriate responding. (C) 1997 Elsevier Science Inc.