Figure 2: Accumulation of ASP+, the fluorescent substrate for high-affinity monoamine transporters and organic cation transporters in astrocytes in hippocampal brain slices. (a) Astrocytes current response to voltage step protocol application reveals a linear IV-relationship. (b) Puff-application of ASP+ elicited transporter current in astrocytes, maintained previously at zero current. Arrow indicates the moment of application. (c) and (d) The same astrocyte with attached patch-pipette before (in (c), infrared DIC) and after (in (d), fluorescence) the application of 50 μM ASP+. Scale on (c) and (d) 20 μm.