Existence of Gα_i2-Expressing Axon Terminals in the Goat Main Olfactory Bulb

Abstract

In rodents, Gα_i2-expressing sensory neurons (SNs) that co-express vomeronasal receptor type 1 (V1R) are specifically found in the vomeronasal organ (VNO) and project their axons to the accessory olfactory bulb (AOB). In goats, however, Gα_i2/V1R-expressing SNs exist in both the VNO and the olfactory epithelium. Thus, we examined whether the Gα_i2-expressing axons functionally project to the main olfactory bulb (MOB). We analyzed the expression of Gα_i2 in the olfactory bulb and found small Gα_i2-immunoreactive clusters in the MOB. The Gα_i2-immunoreactive axons in these clusters made synaptic contacts with second-order neurons in the MOB. These results suggest that some Gα_i2-expressing SNs functionally project their axons to the MOB in goats.