POTASSIUM CHANNEL BLOCKADE DOES NOT ALTER THE MODULATORY EFFECTS OF DOPAMINE IN NEOSTRIATAL SLICES

This study assessed the contribution of Iii conductances to dopamine ( DA)-induced modulation of evoked depolarizing synaptic responses (DPSP s) in neostriatal slices obtained from mts. Intracellular recordings o f membrane properties and DPSPs evoked by local electrical stimulation were obtained from cells bathed in standard artificial cerebrospinal fluid (ACSF), 5 mM Cs- + in ACSF, 20 mM tetraethylammonium in ACSF, or 1 mM 4-aminopyridine in ACSF. DA altered response amplitude in approx imately equal proportions regardless of the presence or abscence of th ese K+-channel blockers. These findings suggest that K+ conductances d o not provide a major contribution ro DA-induced changes in DPSPs in t he neostriatum.