Effect of (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin hydrobromide on spinal motor systems in anesthetized intact and spinalized rats.

In the present study, we examined the effect of the 5-HT1A receptor agonist (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin hydrobromide (8-OH-DPAT), on the mono- and polysynaptic reflexes in intact and spinalized rats. 8-OH-DPAT (10 micrograms/kg i.v.) significantly potentiated the amplitude of the monosynaptic reflex in intact rats. In contrast, 8-OH-DPAT (30 and 100 micrograms/kg i.v.) produced a significant dose-related inhibition of the amplitude of the monosynaptic reflex in spinalized rats. These results suggest that 8-OH-DPAT predominantly excites spinal motor systems at the supraspinal site, and inhibits such systems at a spinal cord site.