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Ted Bartoletti

Ted Bartoletti - Postdoctoral Fellow    
BSc Benedictine College, Kansas
PhD University of Nebraska, 2011
PhD Dissertation:Synaptic Strength at the Photoreceptor Ribbon Synapse

Address - in progress.

Training
2010
PhD Experimental Neuroscience, Synaptic Physiology
University of Nebraska
Supervisor: W. B. Thoreson

2009
Novartis Pharma AG, Bone Metabolism Unit, Basel Switzerland


2011 -
Postdoctorate
University of Calgary
Calgary Alberta
Supervisor: Dr. R.W. Turner
 
Awards
PhD
Graduate Research Assistantship, 2006-2007
Graduate Research Fellowship, 2007-2010
Harris Award for Neurodegeneration Research, 2009


Postdoctorate
Alberta Innovation - Health Research Postdoctoral Fellowship
Canadian Institutes Health Postdoctoral Fellowship

Research Focus: Cav3-Kv4 interactions in cerebellum
Approach: Electrophysiology in vitro, optogenetics, pharmacology
Preparations: In vitro slice preparations
Below are short summaries of my publications.

PhD Thesis research:
My PhD work centered on the factors controlling transmitter release at the vertebrate photoreceptor ribbon synapse

Postdoctoral research:
My work is focused on the role of potassium channels in controlling neuronal excitability

Granule cells of teleost cerebellum

Model - Cerebellar granule cells
    Granule cells make up the input layer of cerebellum, receiving mossy fiber synaptic input that conveys sensory information, and project parallel fiber axons to the cerebellar cortex. Granule cells have long been known to express the A-type, Kv4 class of fast inactivating potassium channel. I study the role of Kv4 channels in controlling the excitability and spike output of granule cells using patch clamp recordings in an in vitro slice preparation.

Cav3 T-type channels form a unique interaction with BK potassium channels T type calcium channels form a unique interaction with BK potassium channels
   Big conductance (BK) potassium channels are known to complex with high voltage-activated calcium channels to interact at the nanodomain level. We now show that Cav3 T-type channels interact with the S0 segment of BK channels to evoke potassium current in the subthreshold range in tsA-201 cells and medial vestibular neurons. An unexpected ability to block the interaction with internal EGTA is traced to a relatively weak calcium domain supported by Cav3 calcium influx, requiring multiple Cav3 channels to effect BK channel activation at the level of a microdomain. See Rehak et al. (2013). PDF
A Cav3-Kv4 complex acts as a novel calcium sensor in stellate cells A novel calcium sensor dynamically adjusts inhibitory charge transfer to Purkinje cells
   Stellate cells were known to inhibit complex spikes of Purkinje cells but a mechanism that would allow them to respond to local repetitive climbing fiber input was unknown. This study shows that a Cav3-Kv4 complex expressed in stellate cells acts as a novel calcium sensor to dynamically adjust stellate cell frequency in relation to changes in [Ca]o during complex spike discharge. Inhibitory charge transfer to Purkinje cells is thus maintained in the face of a synaptically evoked decrease in [Ca]o that would otherwise alter network function. See Anderson et al. (2013).

Peer-Reviewed Publications

Cadetti, L., Bartoletti, T.M., and Thoreson, W. B (2008) Quantal mEPSCs and residual glutamate: how horizontal cell responses are shaped at the photoreceptor ribbon synapse. Eur J Neuroscience 27: 2575-2586.

Thoreson, W. B., Babai, N., and Bartoletti, T.M. (2008). Feedback from horizontal cells to rod photoreceptors in vertebrate retina. J. Neuroscience 28: 5691-5695.

Szikra, T., Cusato, K., Thoreson, W. B., Barabas P, Bartoletti, T.M., and Krizaj, D. (2008) Depletion of calcium stores regulates calcium influx and signal transmission in rod photoreceptors. J. Physiol. (Lond.) 586: 4859-4875.

Jackman S., Choi S.Y., Rabl R, Bartoletti T.M., Thoreson WB, and Kramer R.H. (2009) Depletion and resupply of vesicles on the synaptic ribbon govern transmission of the cone photoreceptor light response. Nature Neuroscience 12: 303-310.

Szikra, T., Barabas, P., Bartoletti, T.M., Huang, H., Cadetti, L., Thoreson, W. B. and Krizaj, D. (2009) Store-operated calcium channels modulate intracellular signaling and neurotransmission in salamander cones. PLoS One. 4(8): e672.

Bartoletti T.M., Babai N., Thoreson W.B. (2010) Vesicle pool size at the salamander cone ribbon synapse. J. Neurophysiology 103(1): 419-423.

Linton, J.D., Holzhausen, L.C., Babai, N., Song, H., Miyagishima, K.J., Stearns, G.W., Lindsay, K., Wei, J., Chertov, A.O., Peters, T.A., Caffe, R., Pluk, H., Seeliger, M.W., Tanimoto, N., Fong, K., Bolton, L., Kuok, D.L., Sweet, I.R., Bartoletti, T.M., Radu, R.A., Travis, G.H., Zagotta, W.N., Townes-Anderson, E., Parker, E., Van der Zee, C.E., Sampath, A.P., Sokolov, M., Thoreson, W.B., Hurley, J.B. (2010) Flow of energy in the outer retina in darkness and in light. Proc. Natl. Acad. Sci. 107(19): 8599-8604.

Babai, N., Bartoletti, T.M., and Thoreson, W.B. (2010) Calcium regulates vesicle replenishment at the cone ribbon synapse. J. Neuroscience 30(47): 15866-15877

Snellman, J., Mehta, B., Babai, N., Bartoletti, T.M., Akmentin, W., Francis, A., Matthews, G., Thoreson, W., Zenisek, D.  (2011)  Acute destruction of the synaptic ribbon reveals a role for the ribbon in vesicle priming. Nature Neuroscience 14(9): 1135-1141.

Bartoletti, T.M., Jackman, S.L., Babai, N., Mercer, A.J., Kramer, R.H., Thoreson, W.B. (2011)  Release from the cone ribbon synapse under bright light conditions can be controlled by the opening of only a few calcium channels. J. Neurophysiology, Aug, eprint.

Rehak, R., Bartoletti, T.M., Engbers, J.D.T., Berecki, G., Turner, R.W. and Zamponi, G.W. (2013)  Low voltage activation of KCa1.1 current by Cav3-KCa1.1 complexes. PLoS One 8 (4): e61844. PDF

Anderson, D.*, Engbers, J.D.T.*, Heath, N.C., Bartoletti, T.M., Mehaffey, W.H., Zamponi, G.W., and Turner, R.W. (2013). The Cav3-Kv4 complex acts as a calcium sensor to maintain inhibitory charge transfer during extracellular calcium fluctuations. J. Neuroscience 33: 7811-7824. * Shared first authors. PDF


Key Abstracts

Bartoletti, T.M.  and Thoreson, W. B. Counting calcium channels and vesicles at the cone ribbon synapse: two to three calcium channel openings are associated with exocytosis of a single vesicle. FASEB, Saxtons River, VT, 2010.

Bartoletti, T.M., Thoreson, W. B. Increasing the presynaptic cytosolic glutamate concentration enhaces post-synaptic currents at the cone synapse. Midwest Students in Biomedical Research Forum, Omaha, NE, 2010.

Bartoletti, T.M., Babai N., Thoreson, W. B Counting released vesicles and Ca2+ channels at the cone ribbon synapse reveals that few channel openings regulate exocytosis of each synaptic vesicle. Assoc. Research in Vision and Ophthalmology, Ft. Lauderdale, FL, 2009.

Bartoletti, T.M., Babai N., Thoreson, W. B Counting released vesicles and Ca2+ channels at the cone ribbon synapse reveals that few channel openings regulate exocytosis of each synaptic vesicle. Midwest Students in Biomedical Research Forum, Omaha, NE, 2009.

Bartoletti, T.M., Babai N., Thoreson, W. B. Counting calcium channels and vesicles at the cone ribbon synapse: two to three calcium channel openings are associated with exocytosis of a single vesicle. FASEB, Snowmass, CO 2008.

Thoreson, W. B., Babai, N., and Bartoletti, T.M. Feedback from horizontal cells to rod photoreceptors. Assoc. Research in Vision and Ophthalmology, Ft. Lauderdale, FL, 2008.

Anderson, D.*, Engbers*, J.D.T., Heath, N.C., Bartoletti, T.M., Mehaffey, W.H., Zamponi, G.W. and Turner, R.W. The Cav3-Kv4 complex acts as a calcium sensor to adaptively modulate inhibitory network function during repetitive excitatory input. Can. Assoc. Neurosci., 2013.

Dykstra, S.N., Engbers, J.D.T., Bartoletti, T.M., Bosman, L.W.J, Owens, C.B., deZeeuw, C.I., and Turner, R.W. Deep cerebellar neurons differentially encode inhibitory inputs of Purkinje cells. Can. Assoc. Neurosci., 2013.

Asmara, H., Bartoletti, T.M., Rehak, R., Micu, I., Hameed, S., Stys, P., Zamponi, G.W. and Turner, R.W. A novel complex between T-type calcium channels and calmodulin. Can. Assoc. Neurosci., 2013.

Bartoletti, T.M, Rehak, R., Zamponi, G.W. and Turner R.W. Low voltage activation of BK calcium-activated potassium channels by a novel complex with T-type calcium channels. Can. Assoc. Neurosci., 2013.

Bartoletti, T.M., Rehak, R., Engbers, J.D.T., Zamponi, G.W. and Turner, R.W. A T-type-BK complex identified in medial vestibular neurons. Gordon Conference, Cerebellum, 2013.

Asmara, H., Heath N.C., Simms, B., Bartoletti, T.M., Rehak, R., Micu, I., Zhang, F.X., Stys, P., Zamponi, G.W. and Turner, R.W. T-type calcium channels form a calcium-dependent complex with calmodulin. Proc. Soc. Neurosci., 2014.

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