Influence of route of administration on potency of the selective 5HT-1A agonist, 8-hydroxy-2-(di-n-propylamino)tetralin, in rats.

8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) decreased the concentration of 5-hydroxyindoleacetic acid (5HIAA), the deaminated metabolite of serotonin, in rat brain. 8-OH-DPAT was much more potent when injected subcutaneously than when injected intraperitoneally, the potency difference being approximately 17-fold. The important influence of route of administration on the potency of 8-OH-DPAT must be considered in interpreting the various functional effects that have been reported with it.