Abstract
Long Evans rats were trained to discriminate 0.2 mg/kg IP (±)-rolipram from vehicle injection in a food-motivated two-lever operant task. Eight out of nine rats acquired the discrimination after an average of 91 sessions (min 65, max 137). The ED50 of (±)-rolipram was 0.06 mg/kg IP. Generalization tests with (−)- and (+)-rolipram showed that the (−)-isomer was 8 times more active than (+)-rolipram with an ED50 of 0.06 and 0.4 mg/kg IP respectively. The phosphodiesterase inhibitor RO 20-1724 partially (83%) generalized to (±)-rolipram in doses of 0.6 and 1.0 mg/kg IP. IBMX 5 mg/kg IP showed 63% generalization. Tests with imipramine and the (+)- and (−)-isomer of the noradrenaline uptake inhibitor oxaprotiline suggest that NA-uptake inhibiting drugs do not form an interoceptive cue which is (±)-rolipram-like. dbcAMP 12.5 mg/kg SC and 100 mg/kg SC dbcGMP did not generalize to the training drug. The nature of the discriminative stimulus produced by this dose of (±)-rolipram in rats remains to be elucidated.
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Ortmann, R., Meisburger, J.G. Rolipram forms a potent discriminative stimulus in drug discrimination experiments in rats. Psychopharmacology 89, 273–277 (1986). https://doi.org/10.1007/BF00174358
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DOI: https://doi.org/10.1007/BF00174358