The long-term objectives of the present proposal is to study the physiology and plasticity of excitatory synapses in the rat visual cortex. It is proposed here to study glutamate receptor heterogeneity and processes regulating miniature EPSCs using new information and techniques resulting from research done under the current grant. Specifically, the aims of this proposal are: l. Characterization of the developmental regulation of NMDA receptor- channels in layers II-IV of rat visual cortex. 2. Regulation of miniature EPSC in layers II-IV of the rat visual cortex by calcium, protein phosphorylation and activation of metabotropic receptors. 3. Comparison among glutamate receptors in pyramidal and non-pyramidal neurons in layers II-IV of the rat visual cortex. Understanding how excitatory synapses operate in the visual cortex and how they are regulated is critical for understanding cortical function. Yet, the diversity of cortical neurons and synapses and their complex anatomical connections represents a major challenge. Using mEPSCs avoids problems associated with polysynaptic circuits and could distinguish between pre and post synaptic mechanisms. The experiments proposed here would examine the effects of manipulations, mimicking endogenous signals, on the properties of mEPSCs. Results obtained, under the current grant, using patch-clamp recording showed that NMDA receptors undergo developmental changes and that AMPA/Kainate receptors expressed in pyramidal neurons are different than those expressed in aspiny interneurons. It is proposed to characterize glutamate receptor properties (e.g., single-channel conductance; Mg2+ sensitivity, kinetics) during development in morphologically identified neurons.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Research Project (R01)
Project #
2R01EY009120-05
Application #
2162737
Study Section
Visual Sciences B Study Section (VISB)
Project Start
1993-08-01
Project End
1999-07-31
Budget Start
1994-08-01
Budget End
1995-07-31
Support Year
5
Fiscal Year
1994
Total Cost
Indirect Cost
Name
University of Tennessee Health Science Center
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
941884009
City
Memphis
State
TN
Country
United States
Zip Code
38163
Kim, Juhyun; Matney, Chanel J; Blankenship, Aaron et al. (2014) Layer 6 corticothalamic neurons activate a cortical output layer, layer 5a. J Neurosci 34:9656-64
Brown, Solange P; Hestrin, Shaul (2009) Cell-type identity: a key to unlocking the function of neocortical circuits. Curr Opin Neurobiol 19:415-21
Brown, Solange P; Hestrin, Shaul (2009) Intracortical circuits of pyramidal neurons reflect their long-range axonal targets. Nature 457:1133-6
Galarreta, Mario; Erdelyi, Ferenc; Szabo, Gabor et al. (2008) Cannabinoid sensitivity and synaptic properties of 2 GABAergic networks in the neocortex. Cereb Cortex 18:2296-305
Zsiros, Veronika; Hestrin, Shaul (2005) Background synaptic conductance and precision of EPSP-spike coupling at pyramidal cells. J Neurophysiol 93:3248-56
Hestrin, Shaul; Galarreta, Mario (2005) Electrical synapses define networks of neocortical GABAergic neurons. Trends Neurosci 28:304-9
Galarreta, Mario; Erdelyi, Ferenc; Szabo, Gabor et al. (2004) Electrical coupling among irregular-spiking GABAergic interneurons expressing cannabinoid receptors. J Neurosci 24:9770-8
Chu, Zhiguo; Galarreta, Mario; Hestrin, Shaul (2003) Synaptic interactions of late-spiking neocortical neurons in layer 1. J Neurosci 23:96-102
Galarreta, M; Hestrin, S (2001) Spike transmission and synchrony detection in networks of GABAergic interneurons. Science 292:2295-9
Galarreta, M; Hestrin, S (2000) Burst firing induces a rebound of synaptic strength at unitary neocortical synapses. J Neurophysiol 83:621-4

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