[Abstract Title]. - Society for Neuroscience

from live imaging experiments of hippocampal neurons expressing mGFP-CaMKII as well as
evidence from antibody labeling of the endogenous protein which demonstrate that CaMKII
undergoes a redistribution following NMDAR activation. Preliminary data suggest that
excitatory LTP-inducing NMDAR activation drives CaMKII preferentially to excitatory
synapses, while inhibitory LTP-inducing NMDAR stimulation results in accumulation of
CaMKII at inhibitory synapses. We are currently analyzing several mutant mGFP-CaMKII
constructs to determine whether this redistribution requires CaMKII activation,
autophosphorylation, or calmodulin binding. Biochemical analysis of protein derived from
hippocampal slices will also allow us to determine whether CaMKII interacts with components
of the inhibitory synapse following NMDAR activation. Our data suggest that redistribution of
CaMKII may underlie the potentiation of inhibitory synapses, and future experiments will
examine the mechanism and functional consequences of this process.
Disclosures: K.C. Marsden , None; K.U. Bayer, None; R.C. Carroll, None.
Poster
238. LTD: Hippocampus and Cortex
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 238.23/D68
Topic: B.08.f. Long-term depression ( LTD )
Support: NIH GM 60655
Alfred P. Sloan Foundation
Title: Low-frequency potentiation of perforant path-dentate gyrus synapses in vivo
Authors: *D. M. VILLARREAL, F. L. JONES, K. E. ANGUIANO, B. E. DERRICK;
Dept Biol Sci., Univ. Texas San Antonio, San Antonio, TX
Abstract: Low-frequency potentiation (LFP) is a sustained form of synaptic plasticity seen in a
number of synapses, including afferents to the amygdala (Huang and Kandel, Learn. & Mem.,
2007). In an attempt to determine optimal stimulation parameters for the induction of LTD at
perforant path-dentate gyrus synapses in behaving animals, we used paradigms previously found
effective in inducing LTD at other hippocampal synapses. However, stimulation of either medial
or lateral perforant path projections to the dentate (900 pulses, 1 Hz) produced a robust LTP.
This was observed in both the medial and lateral perforant pathways, although the lateral
perforant pathway appears particularly amenable to LFP. In this pathway, LFP was seen with as
few as 25 pulses at 0.3 Hz. Although LTP induced in both pathways by LFS was robust (100%