Fig. 1.

Depolarization-activated K⁺currents in neostriatal cholinergic interneurons are dominated by an A current. A, Whole-cell K⁺ currents recorded from a cholinergic interneuron. Na⁺ and Ca²⁺ currents have been eliminated (see Materials and Methods). Inset, Photomicrograph of an acutely isolated cholinergic interneuron and a medium-sized neuron. Scale bar, 25 μm. B, Photomicrograph of an ethidium bromide-stained gel in which PCR amplicons from the cell recorded from in A were separated by electrophoresis. Note the presence of ChAT amplicon but not enkephalin (Enk) and substance P (SP) amplicons. C, Whole-cell recording from a medium spiny neuron showing currents that inactivate more slowly than in A. D, Photomicrograph of an ethidium bromide-stained gel in which PCR amplicons from the cell recorded from in C were separated by electrophoresis. Note the absence of ChAT amplicon and the presence of enkephalin but not substance P amplicons.