The overall aim of this project is to investigate the roles of nitric oxide (NO), cGMP, and cGMP dependent protein kinase (PKG) in long-term potentiation (LTP) at the Schaffer collateral synapse in the hippocampus. While there is general agreement that LTP at this synapse is initiated by a rise in postsynaptic Ca entering through either NMDA receptors or, under some conditions, voltage-gated Ca channels, the mechanisms for expression of the LTP are highly controversial. There is evidence to suggest that expression involves changes in postsynaptic glutamate receptors, while other data suggest that LTP involves increases in presynaptic transmitter release. Expression mechanisms therefore are argued to be either postsynaptic or presynaptic with few people arguing both. The PI and his collaborators in this center are clearly in the presynaptic camp. The implication for a presynaptic expression mechanism is that there must be some form of communication between the postsynaptic sensing of a rise in Ca and the presynaptic change in transmitter release. A number of so-called retrograde messengers have been implicated in this process. These include NO, CO, AA, platelet activating factor, and neurotrophins. The PI and collaborators have amassed a considerable body of evidence to suggest that NO plays a role as a retrograde messenger, and this grant is intended to further explore this role and to identify the downstream targets of NO such as cGMP and PKG in mediating the presynaptic changes in transmitter release. This group has also identified various phases to the expression of LTP. The late phase (L-LTP), which begins about 90 min after induction and requires 3 or 4 trains of 100 Hz, 1 sec stimulation, is protein and RNA synthesis dependent while the early phase (E-LTP), which occurs during approximately the first 60 min after induction and is induced with 1 train of stimulation, is not. There is also a recently described intermediate phase, which is dependent on PKA but not protein synthesis, although this project does not specifically address this intermediate phase. The two specific aims for this project are to explore further the role of NO, cGMP, and PKG in early and late phase LTP at the Schaffer collateral synapse in hippocampus. For early LTP, the PI and his colleagues propose: 1) to examine LTP in mice with targeted deletions or overexpression of NO synthase or soluble guanylyl cyclase; 2) to test the site of action of these molecules during LTP using intracellular injection methods in hippocampal slices; 3) to examine the cellular localization of these molecules using immunocytochemistry; 4) to examine the roles of these molecules in the induction and expression of LTP using electrophysiological and imaging techniques in cultured hippocampal neurons where the pre- and postsynaptic neurons are accessible for study. For late LTP they propose: 1) to investigate whether NO has different sites of action for late vs. early LTP; 2) to determine some of the downstream targets of NO for late LTP, focusing on two candidate for which they have preliminary evidence, ryanodine receptors and CREB.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Specialized Center (P50)
Project #
5P50MH050733-09
Application #
6654619
Study Section
Project Start
2002-09-01
Project End
2003-08-31
Budget Start
Budget End
Support Year
9
Fiscal Year
2002
Total Cost
Indirect Cost
Name
Columbia University (N.Y.)
Department
Type
DUNS #
167204994
City
New York
State
NY
Country
United States
Zip Code
10032
Caron, Sophie J C; Ruta, Vanessa; Abbott, L F et al. (2013) Random convergence of olfactory inputs in the Drosophila mushroom body. Nature 497:113-7
Chi, Xuan; Hadjantonakis, Anna-Katerina; Wu, Zaiqi et al. (2009) A transgenic mouse that reveals cell shape and arrangement during ureteric bud branching. Genesis 47:61-6
Huang, Yan-You; Kandel, Eric R (2007) Low-frequency stimulation induces a pathway-specific late phase of LTP in the amygdala that is mediated by PKA and dependent on protein synthesis. Learn Mem 14:497-503
Huang, Yan-You; Kandel, Eric R (2007) 5-Hydroxytryptamine induces a protein kinase A/mitogen-activated protein kinase-mediated and macromolecular synthesis-dependent late phase of long-term potentiation in the amygdala. J Neurosci 27:3111-9
Yoshida, Yutaka; Han, Barbara; Mendelsohn, Monica et al. (2006) PlexinA1 signaling directs the segregation of proprioceptive sensory axons in the developing spinal cord. Neuron 52:775-88
Lu, Fang-Min; Hawkins, Robert D (2006) Presynaptic and postsynaptic Ca(2+) and CamKII contribute to long-term potentiation at synapses between individual CA3 neurons. Proc Natl Acad Sci U S A 103:4264-9
Shumyatsky, Gleb P; Malleret, Gael; Shin, Ryong-Moon et al. (2005) stathmin, a gene enriched in the amygdala, controls both learned and innate fear. Cell 123:697-709
Huang, Yan-You; Kandel, Eric R (2005) Theta frequency stimulation induces a local form of late phase LTP in the CA1 region of the hippocampus. Learn Mem 12:587-93
Wang, Hong-Gang; Lu, Fang-Min; Jin, Iksung et al. (2005) Presynaptic and postsynaptic roles of NO, cGK, and RhoA in long-lasting potentiation and aggregation of synaptic proteins. Neuron 45:389-403
Huang, Yan-You; Kandel, Eric R (2005) Theta frequency stimulation up-regulates the synaptic strength of the pathway from CA1 to subiculum region of hippocampus. Proc Natl Acad Sci U S A 102:232-7

Showing the most recent 10 out of 50 publications