The Intercalated Cells of the Rodent Amygdala

Cornelia Strobel (2011). The Intercalated Cells of the Rodent Amygdala PhD Thesis, Queensland Brain Institute, The University of Queensland.

       
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Author Cornelia Strobel
Thesis Title The Intercalated Cells of the Rodent Amygdala
School, Centre or Institute Queensland Brain Institute
Institution The University of Queensland
Publication date 2011-11
Thesis type PhD Thesis
Supervisor Prof. P. Sah
Dr R. Sullivan
Total pages 168
Total colour pages 22
Total black and white pages 146
Language eng
Subjects 110903 Central Nervous System
110902 Cellular Nervous System
060110 Receptors and Membrane Biology
Abstract/Summary The medial intercalated cell masses (mITCs) of the amygdala are a cluster of GABAergic neurons located between the basolateral complex (BLA) and central nucleus (CeA), the main input and output stations of the amygdala. The mITCs play an important role during fear conditioning and extinction by processing excitatory inputs from the BLA and infralimbic cortex and generate feedforward inhibition of intercalated cells themselves as well as the central amygdala. Despite their important functional roles, intrinsic and synaptic properties of these cells are not well understood. In this study, using immunohistochemistry, electrophysiology and calcium imaging, I have characterized the properties of mITCs from GAD67-GFP transgenic mice. Electrophysiologically, I observed a variety of passive and active membrane properties in the mITCs, however, these differences could not clearly separate mITCs into different subgroups. A single action potential propagated not more than ~ 70 μm into the dendritic. In this area, back-propagating action potentials also led to rapid [Ca2+] increases in spines. However, when characterizing the properties of synaptic inputs of these cells from the surrounding BLA, I found two different mITCs populations, either expressing calcium-permeable or calcium-impermeable AMPA receptors. Besides excitatory inputs, mITCs are also under tight inhibitory control and receive GABAergic inputs from local mITCs. Despite being GABAergic neurons, immunohistochemistry revealed, that mITCs do not express any of the classical calcium-binding proteins and neuropeptides. Furthermore and even though LTP (long-term potentiation) has been previously reported in mITCs, in my study, the induction of LTP in mITCs had a low success rate. In this study, chemical and physiological properties of mITCs were investigated. My findings suggest, that even though intrinsic and histochemical properties seemed to be similar between mITCs, different mITC subpopulations exist, based on the presence of calcium-permeable and impermeable AMPA receptors. The functional significance of this segregation is unknown, but paves the way for further studies of these very interesting cells.
Keyword intercalated cells
amygdala
electrophysiological and morphological characterization
receptors
calcium imaging
Additional Notes 19, 21, 25, 28, 57, 59, 63, 66, 68, 69, 87, 89, 92, 94, 96, 98, 119, 121, 122, 125, 126, 127

 
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Created: Wed, 23 May 2012, 12:57:16 EST by Cornelia Strobel on behalf of Library - Information Access Service