Dopamine-modulated potassium channels on rat striatal neurons: specific activation and cellular expression

摘要: We have used cell-attached patch-clamp electrophysiology to characterize the activation and distribution of an 85 pS K+ channel on freshly dissociated rat striatal (caudate-putamen) neurons. In recordings from 643 cells, openings this showed absolute dependence presence dopamine or D2-like receptor agonist quinpirole in patch pipette, but were never seen when D2 antagonist domperidone was applied along with quinpirole, absence drug. This displayed inward rectification at depolarized membrane potentials, its otherwise voltage insensitive. It largely restricted a subset cells diameters > = 10 microns, about 25% patches. When present, there typically multiple channels per patch. Cells size immunocytochemically stained for neuron-specific enolase not glial fibrillary acidic protein; 40% also labeled gamma-amino butyric acid (GABA) 60% NADPH diaphorase, GABAergic displaying shape most similar that expressing channel. A large number distinct types other comprising inwardly rectifying 5–35 conductance voltage-activated 100–250 pS, frequencies occurrence fractional open times these independent dopaminergic agonists. Thus, uniquely requires by neurons, is selectively expressed which are likely be