[Abstract Title]. - Society for Neuroscience

chronic effects of nicotine in vivo. We thank Ron Lukas for hα4β2 SH-EP1 cells and Michael
Marks for mouse brain samples.
Disclosures: V. hosur, None; R.H. Loring, None.
Poster
234. A-Type Potassium Channels
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 234.1/C25
Topic: B.04.c. Potassium channels: Physiology
Title: Activity-dependent A-type K+-channel trafficking in CA1 pyramidal dendrites in
recordings from adult mouse hippocampal neurons
Authors: *E.-T. HAHM, D. HOFFMAN;
NICHD, NIH, Bethesda, MD
Abstract: A-type K+ currents (IA) are rapidly activating and inactivating and have been shown
to play an important role in regulating neuronal excitability. The A-type K+ channel subunit
Kv4.2 underlies the A-current in the dendrites of cultured hippocampal CA1 neurons and live
imaging showed that Kv4.2 internalization is induced rapidly upon glutamate receptor
stimulation (Kim et al., 2007). We report here the activity-dependent decrease of IA in the
dendrites of CA1 pyramidal neurons in acute hippocampal slices of adult mice. IA was measured
in cell-attached patch-clamp recordings from the soma and at various locations on the primary
apical dendrite (up to ~300 µm from soma). In somatic recordings, brief bath application of
AMPA (5 min, 50 µM) caused a reduction in peak A-current amplitude, similar to our previous
results reported in cultured hippocampal neurons (Kim et al., 2007). No change in the sustained,
or slowly inactivating K+ currents was found upon AMPA treatment. The transient current peak
amplitude in somatic recordings was 16.9 ± 2.0 pA pre-AMPA treatment and decreased to 8.3 ±
1.9 pA (n = 7, p = 0.002) afterward. The sustained current peak amplitude was unchanged upon
AMPA stimulation (pre: 10.4 ± 1.6 pA; AMPA: 8.4 ± 2.2 pA; n = 7; p = 0.84). In apical
dendrites, AMPA caused a selective decrease in peak A-current amplitude from 11.9 ± 2.2 pA to
6.9 ± 2.4 pA (n = 3; p = 0.046) with no change in sustained current amplitude (pre: 14.1 ± 4.0
pA; AMPA: 14.9 ± 8.6 pA; n = 3; p = 0.50).
Disclosures: E. Hahm , None; D. Hoffman, None.