Physiological characterization of formyl peptide receptor expressing cells in the mouse vomeronasal organ

Abstract

The mouse vomeronasal organ (VNO) is a chemosensory structure that detects both hetero- and conspecific social cues. Based on largely monogenic expression of either type 1 or 2 vomeronasal receptors (V1Rs/V2Rs) or members of the formyl peptide receptor (FPR) family, the vomeronasal sensory epithelium harbors at least three neuronal subpopulations. While various neurophysiological properties of both V1R- and V2R-expressing neurons have been described using genetically engineered mouse models, the basic biophysical characteristics of the more recently identified FPR-expressing vomeronasal neurons have not been studied. Here, we employ a transgenic mouse strain that coexpresses an enhanced variant of yellow fluorescent protein together with FPR-rs3 allowing to identify and analyze FPR-rs3-expressing neurons in acute VNO tissue slices. Single neuron electrophysiological recordings allow comparative characterization of the biophysical properties inherent to a prototypical member of the FPR-expressing subpopulation of VNO neurons. In this study, we provide an in-depth analysis of both passive and active membrane properties, including detailed characterization of several types of voltage-activated conductances and action potential discharge patterns, in fluorescently labeled vs. unmarked vomeronasal neurons. Our results reveal striking similarities in the basic (electro) physiological architecture of both transgene-expressing and non-expressing neurons, confirming the suitability of this genetically engineered mouse model for future studies addressing more specialized issues in vomeronasal FPR neurobiology.

Organization and Plasticity of Sodium Channel Expression in the Mouse Olfactory and Vomeronasal Epithelia

“…Most intriguingly, Na v 1.2 was limited to VSN somata of the basal layer, suggesting that this channel may play a special role in these VSNs. This is in agreement with earlier reports demonstrating that the electrophysiological characteristics of sodium currents differ in apical vs. basal VSNs (Liman and Corey, 1996; Fieni et al, 2003; Ukhanov et al, 2007; Ackels et al, 2014). Na v currents of basal VSNs were shown to be smaller using a dissociated VNO preparation (Fieni et al, 2003).…”

The Effects of Essential Oils and Terpenes in Relation to Their Routes of Intake and Application

“…In addition, there are separate sensory receptors expressed in other sensory neurons that reside in the main olfactory epithelium or vomeronasal organ, but carry different receptor types. These are the receptor guanylyl cyclase (GC-D) [16] and trace amine-associated receptors (TAAR) [17,18] in the main olfactory epithelium and formyl peptide receptors in the vomeronasal organ [18,19]. The sensory neurons project their axons to the olfactory bulb.…”

Immuno-moodulin: a new anxiogenic factor produced by autoimmune-prone T cells

“…Of interest, studies have shown that these receptors have more than one way to help the host sensing the danger. Their expression in the olfactory system allow mice to 'sense' the presence of infectionassociated olfactory cues thus allowing animals to move away from the source of infection [76][77][78] . Other lines of evidence support a role for FPR in regulating behaviour.…”