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Published September 2012 | public
Journal Article

Electrophysiological characterization of Grueneberg ganglion olfactory neurons: spontaneous firing, sodium conductance, and hyperpolarization-activated currents

Abstract

Mammals rely on their acute olfactory sense for their survival. The most anterior olfactory subsystem in the nose, the Grueneberg ganglion (GG), plays a role in detecting alarm pheromone, cold, and urinary compounds. GG neurons respond homogeneously to these stimuli with increases in intracellular [Ca^(2+)] or transcription of immediate-early genes. In this electrophysiological study, we used patch clamp techniques to characterize the membrane properties of GG neurons. Our results offer evidence of functional heterogeneity in the GG. GG neurons fire spontaneously and independently in several stable patterns, including phasic and repetitive single-spike modes of discharge. Whole-cell recordings demonstrated two distinct voltage-gated fast-inactivating Na^+ currents with different steady-state voltage dependencies and different sensitivities to tetrodotoxin. Hodgkin-Huxley simulations showed that these Na^+ currents confer dual mechanisms of action potential generation and contribute to different firing patterns. Additionally, GG neurons exhibited hyperpolarization-activated inward currents that modulated spontaneous firing in vitro. Thus, in GG neurons the heterogeneity of firing patterns is linked to the unusual repertoire of ionic currents. The membrane properties described here will aid the interpretation of chemosensory function in the GG.

Additional Information

© 2012 American Physiological Society. Submitted 5 October 2011. Accepted in final form 29 May 2012. Published online before print May 30, 2012. This information is current as of September 7, 2012. We thank J. Gutierrez, A. R. Douglas, and S. M. M. Alaniz for animal care and husbandry. This project was supported by grants from the National Institutes of Health and the National Science Foundation. No conflicts of interest, financial or otherwise, are declared by the authors. Author contributions: C.Y.L., H.A.L., and D.S.K. conception and design of research; C.Y.L. and C.X. performed experiments; C.Y.L. and C.X. analyzed data; C.Y.L., C.X., and H.A.L. interpreted results of experiments; C.Y.L. prepared figures; C.Y.L. drafted manuscript; C.Y.L., C.X., S.E.F., H.A.L., and D.S.K. edited and revised manuscript; S.E.F. and D.S.K. approved final version of manuscript.

Additional details

Created:
August 19, 2023
Modified:
October 18, 2023