A new link between D2R and 5-HT1AR in regulating the E-I balance and the plasticity. Functional 5-HT1ARs are needed to allow the “classic” effect of D2R on plasticity. Loss of GSK3β signaling recruitment by D2Rs when 5-HT1ARs are absent. Dopamine action could be impaired in human pathologies linked to 5-HT1ARs depletion.