RU-24969-INDUCED LOCOMOTION IN RATS IS MEDIATED BY 5HT(1A) RECEPTORS

The locomotor response to RU 24969 (5-methoxy-3-(1,2,3,6-tetrahydropyr idin-4-yl) 1H-indole; 10 mg/kg, s.c.), a preferential 5-HT1B receptor agonist, was investigated in the rat, using two novel 5-HT1A receptor antagonists, WAY-100635 (0.3 mg/kg and 1 mg/kg, s.c.) and SDZ 216-525 (0.3 mg/kg, s.c.), and the novel 5-HT1B/5-HT1D receptor antagonist, GR 127935 (1 mg/kg, s.c.). The antagonists per se did not alter spontane ous locomotion. Both selective 5-HT1A receptor antagonists blocked RU 24969-induced hyperlocomotion, whilst the 5-HT1B receptor antagonist w as without effect. These results suggest that RU 24969-induced hyperlo comotion in the rat is mediated by 5-HT1A receptors.