“…Although HA is classically known for its involvement with allergic and inflammatory reactions, its role as neurotransmitter in the CNS in the regulation of feeding, sleep, hormonal homeostasis, and cognitive function has been focus of several researchers worldwide (Hu & Chen, 2017). HA acts through the activation of four different receptor subtypes (H 1 , H 2 , H 3, and H 4 receptors, H 1 R‐H 4 R) (Corrêa & Fernandes, 2015; Correa & Fernandes, 2018), which are part of the G‐protein coupled receptors (GPCRs) family, although G‐protein independent signaling pathways such as β‐arrestin (Pietraszewska‐Bogiel & Goedhart, 2019; Rosethorne & Charlton, 2011) and MAPK (Beermann et al., 2015; Rapanelli et al., 2016) pathways are frequently reported. All these receptors are expressed in the CNS, in neuronal and/or glial cells, playing roles in the neurotransmission of several neuronal pathways and brain processes.…”