Removal of the superior cervical ganglia fails to block Fos induction in the accessory olfactory system of male mice after exposure to female odors.

When exposed to female odors, testosterone-primed male mice show a robust expression of immediate early genes in the vomeronasal organ (VNO) and associated accessory olfactory structures. We asked whether the superior cervical ganglia (SCG), which provide autonomic inputs to the VNO, are required for odor induction of Fos. Gonadally intact male mice received sham, unilateral, or bilateral SCG lesions and were exposed to odors from estrous females. In comparison to clean bedding, female odors significantly increased neuronal Fos immunoreactivity in sites throughout the VNO projection pathway, but these responses were not reliably modified by SCG removal. Thus, noradrenergic inputs to the VNO, which regulate a pumping mechanism thought to facilitate entrance of chemosignals into the VNO lumen, are not required for odors to induce Fos in the mouse accessory olfactory system.