Neuropeptides influence mood, sensation, learning and memory, and the function of peripheral organs. Their release typically begins slowly only after bursts of electrical activity and is limited so that distal terminals are not easily emptied. Our goal is to understand how these unique properties are generated. Initially, we used live cell imaging of calcium and a GFP-tagged neuropeptide/hormone along with patch clamping to study peptide release by cultured cells. These experiments demonstrated great diversity in the handling of peptidergic dense core vesicles (DCVs). We then generated transgenic animals to study DCV dynamics in synaptic boutons. In vivo experiments with Drosophila synapses suggest that calcium influx, triggered by depolarization or electrical activity, increases DCV motion within boutons to facilitate recruitment for neuropeptide release. Furthermore, we generated a new fluorescent protein construct to measure the delay in release following fusion pore formation, and have produced transgenic flies that express this protein. Also, we generated animals for inducible expression of fluorescent DCVs. Finally, we began to study the basis of regulated DCV motion. We are now poised to study processes that could govern the time and activity dependence of neuropeptide release.
Aim 1 will determine the activity and calcium dependence of DCV motion within synaptic boutons and neuropeptide release.
Aim 2 examines the mechanistic basis for regulated DCV movement within boutons.
Aim 3 will determine whether the releasable DCVs in synapses are replenished first by refractory DCVs that were already present in boutons, or by new DCVs transported into the bouton from the axon.
Aim 4 will detect the initial fusion with the plasma membrane to learn about the location and speed of neuropeptide exocytosis. Understanding DCV dynamics is essential for determining how neuropeptide release is uniquely controlled. This could provide a basis for controlling secretion of neuropeptides that are involved in pain, mood, hunger, and sleep

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS032385-11
Application #
7234699
Study Section
Neurotransporters, Receptors, and Calcium Signaling Study Section (NTRC)
Program Officer
Stewart, Randall R
Project Start
1995-08-04
Project End
2008-05-31
Budget Start
2007-06-01
Budget End
2008-05-31
Support Year
11
Fiscal Year
2007
Total Cost
$350,387
Indirect Cost
Name
University of Pittsburgh
Department
Pharmacology
Type
Schools of Medicine
DUNS #
004514360
City
Pittsburgh
State
PA
Country
United States
Zip Code
15213
Bulgari, Dinara; Jha, Anupma; Deitcher, David L et al. (2018) Myopic (HD-PTP, PTPN23) selectively regulates synaptic neuropeptide release. Proc Natl Acad Sci U S A 115:1617-1622
Bulgari, Dinara; Deitcher, David L; Levitan, Edwin S (2017) Loss of Huntingtin stimulates capture of retrograde dense-core vesicles to increase synaptic neuropeptide stores. Eur J Cell Biol 96:402-406
Tao, Juan; Bulgari, Dinara; Deitcher, David L et al. (2017) Limited distal organelles and synaptic function in extensive monoaminergic innervation. J Cell Sci 130:2520-2529
Rao, Kavitha; Stone, Michelle C; Weiner, Alexis T et al. (2016) Spastin, atlastin, and ER relocalization are involved in axon but not dendrite regeneration. Mol Biol Cell 27:3245-3256
Cavolo, Samantha L; Bulgari, Dinara; Deitcher, David L et al. (2016) Activity Induces Fmr1-Sensitive Synaptic Capture of Anterograde Circulating Neuropeptide Vesicles. J Neurosci 36:11781-11787
Roland, Bartholomew P; Zeccola, Alison M; Larsen, Samantha B et al. (2016) Structural and Genetic Studies Demonstrate Neurologic Dysfunction in Triosephosphate Isomerase Deficiency Is Associated with Impaired Synaptic Vesicle Dynamics. PLoS Genet 12:e1005941
Cavolo, Samantha L; Zhou, Chaoming; Ketcham, Stephanie A et al. (2015) Mycalolide B dissociates dynactin and abolishes retrograde axonal transport of dense-core vesicles. Mol Biol Cell 26:2664-72
Wong, Man Yan; Cavolo, Samantha L; Levitan, Edwin S (2015) Synaptic neuropeptide release by dynamin-dependent partial release from circulating vesicles. Mol Biol Cell 26:2466-74
Li, Long; Tian, Xiaolin; Zhu, Mingwei et al. (2014) Drosophila Syd-1, liprin-?, and protein phosphatase 2A B' subunit Wrd function in a linear pathway to prevent ectopic accumulation of synaptic materials in distal axons. J Neurosci 34:8474-87
James, Rebecca E; Hoover, Kendall M; Bulgari, Dinara et al. (2014) Crimpy enables discrimination of presynaptic and postsynaptic pools of a BMP at the Drosophila neuromuscular junction. Dev Cell 31:586-98

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