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Characterization of an unusual collection of olfactory neurons in the nose

Citation

Liu, Cambrian Yangshao (2012) Characterization of an unusual collection of olfactory neurons in the nose. Dissertation (Ph.D.), California Institute of Technology. http://resolver.caltech.edu/CaltechTHESIS:05062012-022516031

Abstract

We have used a combination of histochemical, electrophysiological, and behavioral approaches to study signal transduction, membrane biophysics, and chemosensory function in the neurons of the mouse Grueneberg ganglion (GG) olfactory subsystem. The GG is a recently appreciated collection of ~1,000 clustered primary olfactory neurons located at the anterior tip of the mammalian nasal cavity. Despite their far-forward position, GG neurons are fully trapped beneath a keratinized epithelium and are wrapped by glial cells. This raises the question of how they contribute to the sense of smell. We found that GG neurons have key components of cGMP signal transduction pathway and are molecularly similar to GC-D neurons, which project to the enigmatic necklace glomeruli in the olfactory bulb. In electrophysiological analyses, individual GG neurons spontaneously discharged action potentials in one of three distinct temporal patterns that were stable for >20 min. An auxiliary fast-inactivating Na+ current accounted for the various discharge patterns in computer simulations of the neuronal ionic currents. Despite differences in baseline activity, the majority of GG neurons responded to specific mammalian pheromones. In behavioral experiments, we found that the weaning of adolescent mice induced GG activity; however, the effects did not depend on ambient temperature or the presence of other animals. Because GG neurons reside on a dense vascular bed, have specialized access to serum contents, and directly responded to pressure ejections of serum, their activity can likely be modulated by internally circulating hormones or proteins associated with specific physiological states such as stress. Taken together, our results demonstrate unusual molecular and functional aspects of a morphologically and anatomically atypical olfactory nerve.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:olfaction; mouse; Grueneberg; ganglion; cGMP; patch; clamp; electrophysiology; pheromones; Fos
Degree Grantor:California Institute of Technology
Division:Biology
Major Option:Biochemistry and Molecular Biophysics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Fraser, Scott E.
Thesis Committee:
  • Lester, Henry A. (chair)
  • Patterson, Paul H.
  • Allman, John Morgan
  • Fraser, Scott E.
Defense Date:17 February 2012
Author Email:Cambrian.Liu (AT) gmail.com
Record Number:CaltechTHESIS:05062012-022516031
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:05062012-022516031
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1002/cne.22096DOIArticle adapted for ch. 1
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7007
Collection:CaltechTHESIS
Deposited By: Cambrian Liu
Deposited On:14 May 2012 19:04
Last Modified:14 Jan 2014 23:54

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PDF (Acknowledgments, Abstract, Table of Contents) - Final Version
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PDF (Chapter 1: Introduction) - Final Version
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PDF (Chapter 2: cGMP pathway stainings) - Final Version
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PDF (Chapter 3: Ionic conductances in GG) - Final Version
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PDF (Chapter 4: GG responses to odors and pheromones) - Final Version
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PDF (Chapter 5: cFos stainings) - Final Version
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PDF (Chapter 6: Future directions) - Final Version
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