Figure 6. Patterns of H₂O₂ regulation in striatal MSNs mirror those predicted from modulation of evoked striatal DA release.

A) Inhibition of GSH peroxidase by MCS (1 mM) amplifies stimulus-evoked increases in DCF FI (30 pulses, 10 Hz) (upper panel), with no effect on action potential generation in recorded MSNs (lower panel). In MCS, 7 of 7 MSNs showed a significant increase in DCF FI (p < 0.001). B) The usual stimulus-induced increase in DCF FI in MSNs (Fig. 2B) was prevented by an AMPAR antagonist, GYKI-52466 (50-100 μM) (upper panel), an AMPAR antagonist, as were stimulus-evoked action potentials monitored during simultaneous current-clamp recording (lower panel) (n = 7; p > 0.05 vs. basal) (in (A) and (B), scale bar = 20 μm). C. Average stimulus-induced changes in DCF FI in H₂O₂ source MSNs under control conditions (Con; n = 7), in the presence of MCS (n = 7), or in the presence of GYKI (n = 7) (**p < 0.01 vs. basal; ***p < 0.001 vs. basal). The increase in DCF FI in MCS was nearly 2-fold greater than under control conditions, whereas AMPAR blockade with GYKI markedly attenuated the usual control response (###p < 0.001 vs. control) (modified from Avshalumov and others 2008; copyright American Physiological Society, used with permission).