Effects of 5-HT in globus pallidus on haloperidol-induced catalepsy in rats

Histological, behavioral and electrophysiological studies have suggested that 5-HT may regulate motor function by affecting globus pallidus neurons activity. In this study, the effects of 5-HT in globus pallidus on haloperidol-induced catalepsy and its possible receptor mechanisms were examined in rats using bar tests. Bilateral microinjection of 5-HT (10 μM) into globus pallidus significantly attenuated haloperidol-induced catalepsy. This anticataleptic effect was completely counteracted by selective 5-HT1B receptors antagonist SB-224289 (10 μM), while partly reversed by selective 5-HT4 receptors antagonist GR-113808 (1 μM). In addition, the selective 5-HT7 receptors antagonist SB-269970 (1 μM) partly reversed the anticataleptic effect of 5-HT only at the incipient period after the intrapallidal injection. In conclusion, 5-HT in globus pallidus could attenuate haloperidol-induced catalepsy via multiple receptor mechanisms.