Fig. 6.

Characterization of different ionotropic glutamate receptors in MCCs. MCCs were differentiated for 24 days and subsequently used for Ca²⁺ signalling or MEA analysis. Agonists of different ionotropic glutamate receptors were applied. a The changes of Ca²⁺ indicator fluorescence (= delta signal intensity) of each individual cell treated with the negative control HBSS, nicotine [50 µM], the glutamate receptor agonists glutamate [10 µM], NMDA [50 µM], S-AMPA [10 µM], kainate [10 µM] or KCl [30 mM] is shown as a dot. The mean and SD is shown in purple. The threshold of Δ signal intensity ≥ 9 (= defined as reactive cell) is shown as dotted line. On DoD24 MCCs on MEAs were treated with b S-AMPA [10 µM], c kainate [10 µM] (blue, addition is indicated by the black arrow; baseline in red). The generation of spikes was recorded directly before and after administration and the number of spikes was binned (bin size 0.1 s). A respective example of the acute response is shown. d The data from (a) are shown as the percentage of reactive cells from the whole population. ***p value < 0.001, ns  not significant (color figure online)