[Abstract Title]. - Society for Neuroscience

evoked excitatory and inhibitory currents occurred rhythmically with a period of approximately
70ms. During each oscillation cycle of the LFP, IPSCs occurred after EPSCs with an average
latency of 10ms. This time window may account for the tightly phase-locked spiking activity of
the cell. Furthermore, the amplitude of LFP beta oscillations was reduced greater than 80% in the
presence of the GABABR agonist baclofen, which spares excitatory synaptic transmission of the
lateral olfactory tract (LOT) while suppressing both associational and local inhibitory inputs
(Franks and Isaacson, 2006). In summary, we find that both odor-evoked excitatory and
inhibitory synaptic currents in vivo are coherent with LFP beta oscillations. Our results suggest
the participation of local inhibitory interneurons as well associational fibers in the generation of
these odor-evoked beta oscillations.
Disclosures: C. Poo , None; J.S. Isaacson, None.
Poster
237. Synaptic Integration II
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 237.3/D28
Topic: B.07.c. Synaptic integration
Support: Wellcome Trust Grant
Title: Hippocalcin signaling in spines of hippocampal neurons
Authors: V. CHERKAS 1 , A. DOVGAN 1 , D. FITZGERALD 2 , A. TEPIKIN 2 , R. D.
BURGOYNE 2 , *P. V. BELAN 1 ;
1 Dept Gen Physiol Nervous Syst, Bogomoletz Inst. Physiol, Kiev, Ukraine; 2 Physiol., Univ. of
Liverpool, Liverpool, United Kingdom
Abstract: Hippocalcin (HPCA) is a Ca 2+ -binding protein, and its Ca 2+ -dependent activation in
hippocampal neurons is one of the necessary steps involved in many signal transduction
mechanisms. We have earlier shown that HPCA can translocate to certain sites in a neuronal
dendritic tree of transiently transfected hippocampal cultured neurons as a result of ionotropic
glutamate receptor activation. In this work we have examined if synaptic glutamate receptor
activation can result in HPCA signaling in spines of hippocampal neurons.
Spontaneous and evoked synaptic activity induced excitatory postsynaptic potentials (EPSPs) in
the hippocampal neurons leading to AP bursts and HPCA-YFP translocation to many sites in a
neuronal dendritic tree including dendritic spines. At the same time miniature EPSPs and short
episodes of presynaptic activity did not result in HPCA-YFP translocation. Back propagating
APs induced by current stimulations increased [Ca 2+ ]i in spines but also did not result in