Lopes, Luana TenorioCanto-de-Souza, Lucas [UNESP]Baptista-de-Souza, Daniela [UNESP]de Souza, Rimenez RodriguesNunes-de-Souza, Ricardo L. [UNESP]Canto-de-Souza, Azair [UNESP]2022-04-282022-04-282022-01-24Behavioural Brain Research, v. 417.1872-75490166-4328http://hdl.handle.net/11449/222478The monoamine neurotransmitter serotonin (5-HT) modulates anxiety by its activity on 5-HT2C receptors (5-HT2CR) expressed in the dorsal periaqueductal gray (dPAG). Here, we investigated the presence of 5-HT3A receptors (5-HT3AR) in the dPAG, and the interplay between 5-HT2CR and 5-HT3AR in the dPAG in mediating anxiety-like behavior in mice. We found that 5-HT3AR is expressed in the dPAG and the blockade of these receptors using intra-dPAG infusion of ondansetron (5-HT3AR antagonist; 3.0 nmol) induced an anxiogenic-like effect. The activation of 5-HT3ABR by the infusion of mCPBG [1-(m-Chlorophenyl)-biguanide; 5-HT3R agonist] did not alter anxiety-like behaviors. In addition, blockade of 5-HT3AR (1.0 nmol) prevented the anxiolytic-like effect induced by the infusion of the 5-HT2CR agonist mCPP (1-(3-chlorophenyl) piperazine; 0.03 nmol). None of the treatment effects on anxiety-like behaviors altered the locomotor activity levels. The present results suggest that the anxiolytic-like effect exerted by serotonin activity on 5-HT2CR in the dPAG is modulated by 5-HT3AR expressed in same region.eng5-HT3A and 5-HT2C receptorsElevated Plus-Maze (EPM)MCPBGMCPPMiceOndansetronArtigo10.1016/j.bbr.2021.1135882-s2.0-85115660845