The long-term effects of 8-hydroxy-2-(di-n-propyl-amino)tetralin (8-OH-DPAT) on copulatory and exploratory behaviour in male rats.

The long-term effects of low doses of the 5-HT1A-agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), were studied to assess differences in the development of subsensitivity in 8-OH-DPAT-induced behavioural responses. Male rats received 33 or 100 micrograms/kg per day s.c. for 8 or 15 days. The chronic treatment did not alter the facilitatory effects of 8-OH-DPAT on male copulatory behaviour. In contrast, the effects on exploratory activity and the induction of flat body posture observed after the acute treatment were attenuated by prolonged administration of 8-OH-DPAT. The results presented indicate that gonadal hormones are involved in 5-HT receptor regulatory mechanisms.