Fig. 1.

Mean fluorescence intensity of coronal brain slices of rats indicating the appearance of the low molecular weight tracer Fluorescein-5-Isothiocyanate-Conjugated Dextran (FITC-d3; 3 kDa) at the level of bregma + 1.5 mm ∼ − 3.5 mm. The tracer was infused via the cisterna magna into the CSF and rats were killed 30, 180, and 360 min afterwards. Electroacupuncture (EAP) was delivered for 30 min at a frequency of 100 Hz (1 mA) to the left Zusanli (ST36) acupoint via insertion of a stainless steel needle. The sham acupuncture procedure meant that such a needle was inserted for 30 min to the Zusanli acupoint without electrical stimulation. The tail suspension test (TST) was applied for 5 min, immediately after EAP or sham EAP. Then, the mean fluorescence derived from these 6 slices and the mean fluorescence derived from the other 6 slices of additional rats under each treatment were averaged and plotted in A-C. Means±S.E.M. from 6 animals. *P < 0.05; statistically significant difference from the respective control values. ^#P < 0.05; statistically significant difference from the respective TST values. One-way ANOVA followed by the Holm-Sidak test was used in all cases. Two brain slices are shown out of the 6 slices prepared from each brain (D).