Figure 5.

Homosynaptic and heterosynaptic plasticity are expressed partially via presynaptic mechanisms. A, B, Correlation of changes in the PPR with changes in EPSP amplitude at paired inputs (A) and heterosynaptic inputs (B; unpaired inputs and after intracellular tetanization). Data for three drug groups: control ACSF (blue triangles); 30 nm A₁R antagonist DPCPX (green circles); 20 μm adenosine (red squares). Changes in the PPR were negatively correlated with EPSP amplitude changes. This relationship was generally strengthened as a function of adenosine receptor activation. Compared with control, r values were higher in adenosine, but lower in DPCPX groups.