Figure 3.

LTP produced by systemic 3-NP is NMDA receptor dependent. A, Plots of tetanus-induced long-term synaptic plasticity in rats injected 24 h earlier with 3-NP. The 3-NP group is the same as that shown in Figure 1, where brain slices were perfused with normal aCSF. Perfusion of brain slices taken from rats injected 24 h earlier with 3-NP with the NMDA receptor antagonist APV blocked the induction of LTP seen in normal aCSF. B, The NMDA/AMPA-kainate synaptic current ratio does not change at corticostriatal synapses from rats injected 24 h earlier with 3-NP. B1, Bar graph of NMDA/AMPA-kainate current synaptic ratio from saline and 3-NP-injected rats. B2, Examples of corticostriatal synaptic currents evoked at the indicated holding potentials using single electrode switch clamp methods. C, MK-801 binding to NMDA receptors from the dorsomedial striatum does not change 24 h after systemic injection with 3-NP. Bar graphs illustrate MK-801 binding in saline-injected and 3-NP-injected rats (24 and 48 h after 3-NP).