Fig. 5

ARBs affect the crosstalk between astrocytes and cortical neurons. *p < 0.05, **p < 0.01, and ***p < 0.001 compared different experimental groups as marked by horizontal bar; graphs depict mean values ± standard error of the mean (SEM). A Experimental timeline. Three to five days after subculturing, astrocytes were left unstimulated (control), treated with 10 µM PD123319 or 10 µM telmisartan for 48 h. Next, fresh culture medium was added, and the cells were allowed to recover in regular culture medium over 24 h. This so-called conditioned medium (CM) of astrocytes was consecutively collected for further experiments. For the experiments, half of the neurobasal media was removed and replaced with CM of unstimulated astrocytes (CM Co), 10 µM telmisartan- (CM Telmisartan) and 10 µM PD123319- (CM PD123319) stimulated astrocytes. A naïve control group (Ctrl) received the same volume of neurobasal media. B Representative brightfield image of cortical neurons after 15 days of culture on a 60MEA200/30iR-T (MCS, Reutlingen, Germany) with additional focus on six representative electrodes; scale bars = 200 µM. C The ratio of alive cells to total cells did not change significantly for neurons exposed to CM Co, CM Telmisartan, or CM PD123319 compared to untreated control cells. D Changes in spike rate (Hz) were studied in relation to baseline measurements between the different treatment groups at different time points: Measurements were performed before addition of CM (baseline), immediately (acute), and at 1 h, 4 h, and 24 h after application of CM of unstimulated astrocytes (CM Co), 10 µM telmisartan- (CM Telmisartan), and 10 µM PD123319- (CM PD123319) stimulated astrocytes for 5 min, respectively. A naïve control group (Ctrl) received the same volume of neurobasal media. E Changes in burst rate per min were studied in relation to baseline measurements between the different treatment groups at different time points. Data are shown as mean ± SEM. For the MEA data, n = 40 networks were used. F Glutamate concentration of untreated resting, telmisartan-stimulated, and PD123319-stimulated astrocytes after 48 h of incubation. G Expression of the excitatory amino acid transporter 2 (EAAT2) in untreated resting, telmisartan-stimulated, and PD123319-stimulated astrocytes after 48 h of incubation. H Expression of EAAT2 in CM Control, CM Telmisartan, and CM PD123319-stimulated neurons after 48 h of incubation