FIGURE 1.

The up‐down superfusion of a thin layer of synaptosomes as first proposed by Maurizio Raiteri and colleagues in 1974. (a) The continuous flowing of the superfusion medium assures the quick removal of any endogenous substance released by the superfused particles, then minimizing the shortcomings due to the presence of the biophase (which has major effects on electrophysiological recordings in slices). (b) In this dynamic condition, presynaptic release‐regulating receptors are activated by receptor ligands exogenously added to the superfusion medium. By acting at the respective binding sites (e.g., on the respective GluN subunits), the orthosteric agonists added to the superfusion medium (e.g., glutamate and glycine for the NMDA receptors) influence the molecular events controlling vesicular exocytosis, then causing significant changes to transmitter overflow that could be quantified and correlated with the activation of the presynaptic receptors. Notably, the technique also permits distinguishing between the spontaneous and the depolarization‐evoked release of a selected transmitter, a discrimination that cannot be easily achieved in electrophysiological studies (see for technical information Raiteri & Raiteri, 2000)