RT Journal Article
SR Electronic
T1 Constitutively Active G-Protein-Gated Inwardly Rectifying K<sup>+</sup> Channels in Dendrites of Hippocampal CA1 Pyramidal Neurons
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 3787
OP 3792
DO 10.1523/JNEUROSCI.5312-04.2005
VO 25
IS 15
A1 Xixi Chen
A1 Daniel Johnston
YR 2005
UL http://www.jneurosci.org/content/25/15/3787.abstract
AB A diversity of ion channels contributes to the active properties of neuronal dendrites. From the apical dendrites of hippocampal CA1 pyramidal neurons, we recorded inwardly rectifying K+ channels with a single-channel conductance of 33 pS. The inwardly rectifying K+ channels were constitutively active at the resting membrane potential. The amount of constitutive channel activity was significantly larger in the apical dendrites than in the soma. Activities of these inwardly rectifying K+ channels were inhibited by Ba2+ (200 μm) and tertiapin (10 nm), both of which are believed to block G-protein-coupled inwardly rectifying K+ (GIRK) channels. Intracellularly applied GTPγS (20 μm) during dual dendritic recordings significantly increased constitutive channel activity. Baclofen (20 μm), an agonist for the G-protein-coupled GABAB receptor, also significantly increased the level of channel activity. Therefore, these channels are GIRK channels, which are constitutively active at rest in the apical dendrites of CA1 pyramidal neurons and can be further activated via G-protein-coupled neurotransmitter receptors.