Thesis
The putative role of Katpchannels in nodose ganglion for glucose sensing: investigations with glibenclamide and extracellular glucose
Washington State University
Master of Science (MS), Washington State University
2011
Handle:
https://hdl.handle.net/2376/100365
Abstract
In this work we report presence of neurons that respond to glibenclamide (a KATP channel blocker) in cultures of nodose neurons. We used the fluorescent calcium-sensitive indicator Fura-2 to identify cells that were activated by various challenges. We studied the effect of in vitro hypoglycemic and hyperglycemic conditions on responses in the cultured neurons. Acute challenges to changes in glucose (from 2 mM or 6 mM to 15 mM or from 15 mM to 2 mM) did not produce any detectable changes in cytosolic calcium. However, a subpopulation of neurons (19%) did respond to challenges with glibenclamide, an inhibitor of KATP channels. Responsiveness to glibenclamide occurred almost exclusively in neurons that responded to capsaicin, indicating that glibenclamide responses occur primarily in C-type vagal afferents. We further investigated if changes in glucose in the culture medium (2 mM, 6 mM, or 15 mM) for short term (1-2 h) or long term (20 - 28 h) had any effect on the responsiveness of cultured nodose neurons to glibenclamide. Short term exposure to different glucose concentrations had no effect on the relative percentage cells responding to glibenclamide, or the magnitude of the calcium response induced by glibenclamide. However, long term exposure to low glucose concentrations (2.5 mM) resulted in a significant decrease in the percentage of cells that were responsive to glibenclamide. Since KATP channels are thought to act as the transducer between metabolic changes and changes in neuronal activity, the presence of glibenclamide sensitive neurons indicate that a subpopulation of nodose neurons may be sensitive to changes in metabolic status.
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Details
- Title
- The putative role of Katpchannels in nodose ganglion for glucose sensing
- Creators
- Swami Prakash
- Contributors
- Steven M. Simasko (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Integrative Physiology and Neuroscience, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525197001842
- Language
- English
- Resource Type
- Thesis