[Abstract Title]. - Society for Neuroscience

apamin (20 nM) increased spike rate variance but did not appreciably change mean spike rate in
control conditions; however, apamin reversed the spike rate depression produced by propofol.
Thus, propofol activation of SKCa channels appeared to contribute to the increased spike rate
variance and depression of low frequency activity that we observed in human PD patients and in
rat brain slice recordings. The spike rate depression produced by riluzole and lack of effect of
varying calcium concentrations suggests that propofol may also target INaP, but not Ca channels,
to depress excitability. These effects would add to the enhanced GABA-mediated inhibition that
has been previously described.
Disclosures: M.B. MacIver, None; J.G. Brock-Utne, None; R.A. Jaffe, None.
Poster
237. Synaptic Integration II
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 237.16/D41
Topic: B.07.c. Synaptic integration
Support: NIH R01 MH065634
Title: Probing the synaptic response function of deep cerebellar nuclei neurons with artificial
small conductance Ca2+-mediated potassium (SK) conductance applied via dynamic clamping
Authors: *S. S. FENG 1,2 , T. SANGREY 2 , D. JAEGER 2 ;
1 Biomed. Engin., Georgia Inst. Tech., Atlanta, GA; 2 Biol., Emory Univ., Atlanta, GA
Abstract: Small conductance Ca 2+ -mediated potassium currents (SK) play an important role in
shaping the slow spike-afterhyperpolarization (sAHP) in multiple types of neurons, which
furthermore can affect intrinsic firing properties such as pacemaking and mode-switching,
synaptic plasticity, and synaptic integration through regulation of local dendritic Ca 2+ transients
(Bond, Maylie, et al., 2005, Curr. Opin. Biol. 15: 305-311). Neurons in the deep cerebellar nuclei
(DCN) show a pronounced SK dependent sAHP, but the significance of this current in
processing synaptic input from Purkinje cells and mossy fibers has not been established. We
used whole-cell patch clamp recordings from DCN neurons in acute rat brain slices to
characterize the influence of SK current on synaptic processing. In this study dynamic clamping
was used to apply simulated synaptic conductance patterns as previously described (Gauck and
Jaeger, 2000, J. Neurosci., 20: 3006-3016). New custom-made dynamic clamp software written
in RT-Labview (National Instruments, Inc) also allowed us to add or subtract simulated SK
conductance to recorded neurons. Since SK conductance is gated by intracellular Ca 2+ , we also
implemented the simulation of an intracellular Ca 2+ pool with inflow through a depolarization