Striatal cholinergic interneurons express a receptor-insensitive homomeric TASK-3-like background K+ current.
J Neurophysiol
; 97(2): 1546-52, 2007 Feb.
Article
em En
| MEDLINE
| ID: mdl-17167057
ABSTRACT
Large aspiny cholinergic interneurons provide the sole source of striatal acetylcholine, a neurotransmitter essential for normal basal ganglia function. Cholinergic interneurons engage in multiple firing patterns that depend on interactions among various voltage-dependent ion channels active at different membrane potentials. Leak conductances, particularly leak K(+) channels, are of primary importance in establishing the prevailing membrane potential. We have combined molecular neuroanatomy with whole cell electrophysiology to demonstrate that TASK-3 (K(2P)9.1, Kcnk9) subunits contribute to leak K(+) currents in striatal cholinergic interneurons. Immunostaining for choline acetyltransferase was combined with TASK-3 labeling, using nonradioactive cRNA probes or antisera selective for TASK-3, to demonstrate that striatal cholinergic neurons universally express TASK-3. Consistent with this, we isolated a pH-, anesthetic-, and Zn(2+)-sensitive current with properties expected of TASK-3 homodimeric channels. Surprisingly, activation of Galphaq-linked receptors (metabotropic glutamate mGluR1/5 or histamine H1) did not appear to modulate native interneuron TASK-3-like currents. Together, our data indicate that homomeric TASK-3-like background K(+) currents contribute to establishing membrane potential in striatal cholinergic interneurons and they suggest that receptor modulation of TASK channels is dependent on cell context.
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Base de dados:
MEDLINE
Assunto principal:
Sistema Nervoso Parassimpático
/
Canais de Potássio
/
Neostriado
/
Canais de Potássio de Domínios Poros em Tandem
/
Interneurônios
Limite:
Animals
Idioma:
En
Revista:
J Neurophysiol
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Estados Unidos