[Abstract Title]. - Society for Neuroscience

Topic: A.04.i. Dendritic growth and branching
Support: NSF SOMAS Grant DUE-0426266
Lycoming College Professional Development Grant
Title: Purkinje neuron survival and dendrite structure: MAP and PI-3 kinase pathway
contributions
Authors: *M. E. MORRISON, A. C. CAMPBELL;
Biol., Lycoming Col., Williamsport, PA
Abstract: Purkinje neurons are the major information processing neurons in the cerebellum; they
are responsible for coordination of locomotion, balance, and smooth eye movements. Granule
neurons, the presynaptic afferents of Purkinje cells, are potent regulators of Purkinje cell
differentiation. Purified cultures of Purkinje cells survive poorly, never developing mature
dendrites, while Purkinje cells cocultured with granule neurons survive better and develop
dendrites studded with synapse-bearing spines. The molecular conversation between the granule
and Purkinje neurons is the main focus of our lab.
BDNF/TrkB signaling regulates Purkinje cell spine number and morphology. We present
experiments designed to elucidate the signal transduction steps that link BDNF/TrkB signaling to
changes in neuronal morphology and function, using the MAP kinase pathway inhibitor
PD98059 and the PI3-kinase pathway inhibitor LY294002. Preliminary data indicate that
inhibiting either pathway decreases the total cell area (soma + dendrites), without altering the
cell soma size. Inhibiting MAP kinase signaling decreases the length of the longest dendrite,
while inhibiting PI3-kinase signaling does not. These data, taken together, reveal that MAP
kinase pathway inhibition produces shorter and/or less branched dendrites, while PI3-kinase
inhibition affects total dendrite outgrowth. We will further assess the relative contributions of
these pathways to the survival and development of Purkinje cell dendrites in cultures of mixed
cerebellar cells and cocultures of purified granule and Purkinje neurons.
Disclosures: M.E. Morrison , None; A.C. Campbell, None.
Poster
231. Dendrite Growth and Branching: Signaling
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 231.18/B31
Topic: A.04.i. Dendritic growth and branching