Poster session

[P2-3-08] Stress contagion affects masseter muscle nociception with changes in serotonergic immunoreactivities in the rostral ventromedial medulla in mice

〇Kajita Piriyaprasath¹, Mana Hasegawa^1,2, Yoshito Kakihara³, Noritaka Fujii², Kensuke Yamamura¹, Keiichiro Okamoto¹ (1. Div Oral Physiol, Niigata Univ Grad Sch Med Dent Sci , 2. Gen Dent Clin Educ Unit, Niigata Univ Grad Sch Med Dent Sci , 3. Div Dent Pharmacol, Niigata Univ Grad Sch Med Dent Sci )

Keywords:stress contagion、orofacial pain、RVM

Recently, we showed that STRESS CONTAGION (SCO) increased masseter muscle (MM) nocifensive behaviors and neural activities in the cervical spinal cord region (C1/C2) in mice. This study assessed the effects of SCO on neural responses indicated by c-Fos and serotonergic (5HT) immunoreactivities in the rostral ventromedial medulla (RVM), including the nucleus raphe magnus (NRM) and lateral paragigantocellular nuclei (LPGi). ELISA methods were conducted to quantify the level of 5HT in the RVM. SCO increased c-Fos (+) cells in both areas. The number of 5HT (+) cells in the LPGi, but not NRM, was increased in SCO mice, while the level of 5HT was increased in the RVM in SCO mice. The density of 5HT in the C1/C2 region was greater after SCO. These findings conclude that STRESS CONTAGION could cause functional changes in the RVM, resulting in increased MM nociception.