Abstract
Pigeons were trained to discriminate an IM injection of racemic pentobarbital sodium (5.0 mg/kg) from saline under a second-order color-tracking schedule of mixed grain presentation. In a time-course study, maximal pentobarbital-appropriate responding occurred 15 min after administration of 5.0 mg/kg racemic pentobarbital sodium, the pretreatment time used for subsequent experiments. Racemic pentobarbital sodium, the R(+) and S(-) isomers of pentobarbital, racemic secobarbital sodium, and the R(+) and S(-) isomers of secobarbital all produced dose-dependent increases in pentobarbital-appropriate responding. Racemic secobarbital sodium, the secobarbital isomers, and the R(+) isomer of pentobarbital were equipotent to each other and slightly less potent than racemic pentobarbital and the S(-)-pentobarbital isomer in this regard. Except for R(+)-pentobarbital, all barbiturates caused dose-dependent decreases in response rate over the dose range tested.
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Wessinger, W.D., Wenger, G.R. The discriminative stimulus properties of barbiturate stereoisomers. Psychopharmacology 92, 334–339 (1987). https://doi.org/10.1007/BF00210840
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DOI: https://doi.org/10.1007/BF00210840