Our previous work demonstrated that functional voltage-dependent and ligand-activated channels mature during early differentiation of amphibian spinal neurons, with a similar time course both in vivo and dissociated cell culture. These findings suggest that ion channel activity participates in signal transduction that influences subsequent steps of development. Our recent work indicates that spontaneous transient elevations of intracellular calcium affect later aspects of differentiation in vitro, in both neurons and myocytes. The proposed studies address the role and mechanisms by which ion channel activity controls long-lasting molecular events required for proper differentiation, both in vitro and in vivo. The proposed research has three specific aims. The first two address different aspect of calcium-dependent regulation of neurite extension and navigation.
The third aim analyzes calcium-dependent expression of neurotransmitter.
Our first aim i s to determine the function of spontaneous calcium transients in neurite extension and navigation in vivo.
Our second aim i s to analyze the roles of glutamate receptors in elevating intracellular calcium and regulating neurite outgrowth in vivo.
Our third aim i s to analyze the basis of calcium-dependent regulation of expression of GABA by spontaneous transient neuronal calcium spikes in culture. The immediate goal is to test hypotheses about specific mechanisms underlying differentiation of vertebrate spinal neurons in order to define the roles of early ion channel activity in driving differentiation. The long term goal is to provide information about the cellular and molecular machinery that governs processes of development. It is expected that this work will contribute to understanding developmental disorders of the nervous system.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS015918-18
Application #
2431122
Study Section
Neurology B Subcommittee 2 (NEUB)
Program Officer
Small, Judy A
Project Start
1980-01-01
Project End
1999-05-31
Budget Start
1997-06-01
Budget End
1998-05-31
Support Year
18
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of California San Diego
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
077758407
City
La Jolla
State
CA
Country
United States
Zip Code
92093
Dulcis, Davide; Lippi, Giordano; Stark, Christiana J et al. (2017) Neurotransmitter Switching Regulated by miRNAs Controls Changes in Social Preference. Neuron 95:1319-1333.e5
Spitzer, Nicholas C (2015) Neurotransmitter Switching? No Surprise. Neuron 86:1131-44
Guemez-Gamboa, Alicia; Xu, Lin; Meng, Da et al. (2014) Non-cell-autonomous mechanism of activity-dependent neurotransmitter switching. Neuron 82:1004-16
Spitzer, Nicholas C; Borodinsky, Laura N; Root, Cory M (2013) Imaging and manipulating calcium transients in developing Xenopus spinal neurons. Cold Spring Harb Protoc 2013:653-64
Demarque, Michael; Spitzer, Nicholas C (2012) Neurotransmitter phenotype plasticity: an unexpected mechanism in the toolbox of network activity homeostasis. Dev Neurobiol 72:22-32
Dulcis, Davide; Spitzer, Nicholas C (2012) Reserve pool neuron transmitter respecification: Novel neuroplasticity. Dev Neurobiol 72:465-74
Spitzer, Nicholas C (2012) Activity-dependent neurotransmitter respecification. Nat Rev Neurosci 13:94-106
Rosenberg, Sheila S; Spitzer, Nicholas C (2011) Calcium signaling in neuronal development. Cold Spring Harb Perspect Biol 3:a004259
Nicol, Xavier; Hong, Kwan Pyo; Spitzer, Nicholas C (2011) Spatial and temporal second messenger codes for growth cone turning. Proc Natl Acad Sci U S A 108:13776-81
Velazquez-Ulloa, Norma A; Spitzer, Nicholas C; Dulcis, Davide (2011) Contexts for dopamine specification by calcium spike activity in the CNS. J Neurosci 31:78-88

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