“…Although a 5-HT immunolabeling alone does not allow conclusive determination of whether 5-HT release was affected, the previously described decrease in 5-HT release in 12N under CIH reinforces this hypothesis (Wu et al, 2017 ). Such a decrease is compatible with observations from clinical and animal studies, leading to the proposition of 5-HT drugs as a potential therapy for OSA (Veasey et al, 1996 , 1999 , 2001 ; Carley and Radulovacki, 1999 ; Nakano et al, 2001 ; Ogasa et al, 2004 ; Saunamäki and Jehkonen, 2007 ; Prasad et al, 2010 ; Zhong et al, 2010 ; Hein et al, 2017 ). This may thus contribute to the lower upper airway muscle tone described in male subjects and male mice than that of females (O'Donnell et al, 2000 ; Jordan et al, 2004 ; Chin et al, 2012 ; O'Halloran et al, 2017 ), because of a decrease in the excitatory influence of 5-HT on hypoglossal motoneurons (Fenik et al, 1997 , 2005 ; Prasad et al, 2010 ).…”