Wirkung spezifischer Natriumkanalisoformen auf olfaktorisch-gesteuertes Verhalten
Final Report Abstract
To understand the molecular basis of neuronal excitation in the mammalian olfactory system, we analyzed the organization of voltage-gated sodium (Nav) channel α-subunits in the olfactory system of mouse using a combination of quantitative real time RT-PCR, immunohistochemistry, electrophysiology, and olfactory behavior in mice. We focussed on the main olfactory epithelium (MOE) and the vomeronasal organ (VNO), which represent the two main sensory substructures of the mouse olfactory system. qRT-PCR analyses showed that the mRNA encoding the Nav1.7 isoform is most abundant in both MOE and VNO. Immunohistochemistry for different sodium channel subtypes demonstrated that the channel subtypes Nav1.2 and Nav1.6 show expression particularly in the somata of vomeronasal sensory neurons, a subcellular localization that coincides with a function in action potential generation. On the other hand, Nav1.3 and Nav1.7 localize primarily but not exclusively to the axons of sensory neurons in the MOE and VNO. This suggests that these channels subtypes represent fundamental elements in the propagation of action potentials in both olfactory subsystems. Furthermore, we found several lines of functional evidence revealed that Nav1.7 may also contribute to signal transmission in the accessory olfactory system, which is an asset to our previous results in the MOE. In this study, we also investigated the function of Nav1.3. Analyses of a tissue-specific Nav1.3 knockout demonstrated that these mice exhibit an olfactory phenotype that is characterized by an elevated odor detection threshold and a reduced odor discrimination capability. Together our results show that the concerted action of different voltage-gated sodium channel subtypes regulate the neuronal excitation of sensory neurons of the mouse olfactory system.
Publications
- Organization and Plasticity of Sodium Channel Expression in the Mouse Olfactory and Vomeronasal Epithelia. Frontiers in Neuroanatomy,
VOLUME=11, YEAR=2017, April PAGES=28
Florian Bolz, Stephanie Kasper, Bernd Bufe, Frank Zufall, Martina Pyrski
(See online at https://doi.org/10.3389/fnana.2017.00028)
