SELECTIVE SEROTONIN REUPTAKE INHIBITORS POTENTIATE 8-OH-DPAT-INDUCED STIMULUS-CONTROL IN THE PIGEON

The effects of two selective serotonin reuptake inhibitors, fluoxetine and citalopram, and a nonselective monoamine reuptake inhibitor, imip ramine, were characterized in pigeons that had been trained to discrim inate 0.64 mg/kg of 8-hydroxy-(2-di-n-propylamino)tetralin hydrobromid e (8-OH-DPAT), a 5-HT1A receptor agonist, from saline. Neither fluoxet ine, citalopram, nor imipramine generalized to the 8-OH-DPAT-induced s timulus cue. However, when administered in addition to 8-OH-DPAT, both fluoxetine (10 mg/kg) and citalopram (10 mg/kg) lowered the ED50 for generalization of 8-OH-DPAT from 0.16 mg/kg (8-OH-DPAT by itself) to 0 .05 mg/kg (fluoxetine + 8-OH-DPAT) and 0.06 mg/kg (citalopram + 8-OH-D PAT). Under similar conditions, imipramine (1 mg/kg) had no effect on the generalization curve for 8-OH-DPAT. The data support the hypothesi s that activation of the 5-HT1A receptor may be relevant to the mechan ism of action of serotonin reuptake inhibitors. (C) 1998 Elsevier Scie nce B.V.