Effect of 5-HT-1A receptor agonists on paw licking reaction on hot plate and unpunished drinking in rat

5-HT-1A receptor agonists suppress the rat hind paw licking reaction on a hot-plate and unpunished drinking in thirsty rats with the order of potency: 8-OH-DPAT > Ru 24.969 > buspirone > gepirone > ipsapirone. The behavioral activity of these drugs is in agreement with their affinity for [3H] 8-OH-DPAT binding sites with the exception of ipsapirone, which is a partial agonist at the 5-HT-1A receptor. Our data and data reported previously indicate that the effects of 5-HT-1A agonists in both behavioral tests can not be attributed to the reduction of pain sensitivity or to the inhibition of locomotor activity. It is suggested that the observed effects may reflect the suppression of an emotional-motivational component of animal behavior.