J Neurophysiol (January 1, 2003). 10.1152/jn.00545.2002
Submitted on Submitted 11 July 2002; accepted in final form 19 September 2002

Ion Conductances in Supporting Cells Isolated From the Mouse Vomeronasal Organ

 ¹Dipartimento di Scienze Biomediche, Università di Modena e Reggio Emilia, 41100 Modena; and  ²Istituto di Fisiologia Umana, Università di Parma, 43100 Parma, Italy

Ghiaroni, Valeria, Francesca Fieni, Roberto Tirindelli, Pierangelo Pietra, and Albertino Bigiani. Ion Conductances in Supporting Cells Isolated From the Mouse Vomeronasal Organ. J. Neurophysiol. 89: 118-127, 2003. The vomeronasal organ (VNO) is a chemosensory structure involved in the detection of pheromones in most mammals. The VNO sensory epithelium contains both neurons and supporting cells. Data suggest that vomeronasal neurons represent the pheromonal transduction sites, whereas scarce information is available on the functional properties of supporting cells. To begin to understand their role in VNO physiology, we have characterized with patch-clamp recording techniques the electrophysiological properties of supporting cells isolated from the neuroepithelium of the mouse VNO. Supporting cells were distinguished from neurons by their typical morphology and by the lack of immunoreactivity for G8 and OMP, two specific markers for vomeronasal neurons. Unlike glial cells in other tissues, VNO supporting cells exhibited a depolarized resting potential (about 29 mV). A Goldman-Hodgkin-Katz analysis for resting ion permeabilities revealed indeed an unique ratio of P_K:P_Na:P_Cl = 1:0.23:1.4. Supporting cells also possessed voltage-dependent K⁺ and Na⁺ conductances that differed significantly in their biophysical and pharmacological properties from those expressed by VNO neurons. Thus glial membranes in the VNO can sustain significant fluxes of K⁺ and Na⁺, as well as Cl. This functional property might allow supporting cells to mop-up and redistribute the excess of KCl and NaCl that often occurs in certain pheromone-delivering fluids, like urine, and that could blunt the sensitivity of VNO neurons to pheromones. Therefore vomeronasal supporting cells could affect chemosensory transduction in the VNO by regulating the ionic strength of the pheromone-containing medium.