Effects of serotonergic 5-HTIA and 5-HTIB ligands on ventral pallidal neuronal activity

To clarify the role of the 5-HT system in limbic outputs, the present study compared the effects of the 5-HTIA agonist 8-OH-DPAT and the 5-HTIB agonis t CP-94253 with the nonselective 5-HT agonist TFMPP on the firing rate of v entral pallidal (VP) neurons recorded in chloral hydrate-anesthetized rats. 8-OH-DPAT (0.25-256 mu g/kg i.v.) dose-dependently enhanced (9/26 neurons) or suppressed (8/26) activity, and the 5-HTIA antagonist (+)WAY-100135 oft en attenuated these responses. TFMPP (0.011-1.453 mg/kg i.v.) dose-dependen tly reduced the firing rate of 7/8 VP neurons tested. In contrast, CP-94253 (0.0 13-12.8 mg/kg i.v.) had little or no effect. In sum, these data sugge st that the 5-HTIA receptor appears to be particularly important in influen cing limbic outputs mediated via the VP. NeuroReport 11:2849-2853 (C) 2000 Lippincott Williams & Wilkins.