Figure 2.

Pan-NOS inhibition promotes functional recovery of aging WM only when applied before OGD. A, Representative CAP traces at baseline for control ACSF (Aa), 60 min OGD (Ab), and recovery (Ac) conditions are shown for control (blue), pan-NOS inhibitor l-NAME applied pre-OGD (green), and l-NAME applied post-OGD (red). Scale bars: 1 ms, 1 mV. B, CAP areas showed minimal recovery after OGD (Ba–Bc, blue; 10 ± 2%). l-NAME (200 μm) application before OGD (green) preserved CAP area during OGD and improved CAP area recovery during reperfusion. l-NAME post-OGD application (red) failed to promote aging axon function recovery during reperfusion. Green and red horizontal lines represent l-NAME pretreatment and post-treatment applications, respectively. C, Pan-NOS inhibition in aging WM preserved axon function only with pretreatment with l-NAME; post-treatment was ineffective. CAP area recovery after 60 min of OGD was robust when MONs were pretreated with l-NAME (56 ± 5%), whereas CAP area recovered to 9 ± 1% when MONs were post-treated with l-NAME. n = number of MONs. ***p < 0.001; one-way ANOVA followed by Bonferonni's post hoc test. Error bars indicate SEM.