Fig. 4.

Functional astrocyte alteration in NMO-rat. a Rats were implanted (white arrow) with a microdialysis probe in the hippocampus (hip), where infused human IgG accumulated (lower figure) (D7). b Decreased glutamate uptake in NMO-rats detected using in vivo uptake of exogenous radioactive glutamate (³H-GLU) and mannitol (¹⁴C-MAN, used as the reference molecule not taken up by cells) in the brain of the vigil NMO-rats (IgG^AQP4+2, n = 4) and the Control-rats (IgG^Control2, n = 4) (10-min infusion and collection of microdialysis probe effluent every 2 min for dual-label counting). The relative glutamate uptake was determined by Eq. 3 (E_L-GLU = R_MAN − R_GLU/R_MAN) using the “recapture” curves for ³H-GLU and ¹⁴C-MAN and expressed as the mean ± SEM. c Change in the apparent molecular weight of the glutamate transporters GLT1 and GLAST detected by Western blot in the NMO-rats compared to the Control-rats (periventricular area, actin as control of protein deposition). d Cell fractioning of cultured astrocytes treated with IgG^AQP4+ (24 h): loss of GLT1 expression in the membrane fraction although the total cell lysate remained unchanged (Western blot). No similar effect with IgG^Control treatment