Figure 6. The effects of manipulating Ca²⁺ and GABA signaling in the culture medium.

Bar graphs comparing the proportion of cells firing sAPs (A) and mean V_m (B) following 3 weeks of differentiation in ACM alone, or ACM with 10µM bicuculline (a GABA_A antagonist), with 2 µM nifedipine (an L-type Ca²⁺ channel antagonist), with 100 nM conotoxin (a N-type Ca²⁺ channel toxin) or with 100 nM SNX482 (an R- type Ca²⁺ channel toxin). Chi² tests were performed comparing the ACM with each toxin against ACM alone. ^±P < 0.05, ***P < 0.001, ^nsnot significant, n = 57.

Bar graphs comparing the proportion of cells firing sAPs (C) and mean V_m (D) following 1 and 2 weeks of differentiation in control medium (0.6 mM Ca²⁺), high Ca²⁺ medium (1.8mM Ca²⁺), control medium with 300µM GABA and, high Ca²⁺ medium with 10µM bicuculline). T-tests were performed comparing the GABA and high Ca²⁺ media with control medium and the bicuculline medium with high Ca²⁺ medium for each week. ^±P < 0.05, ***P < 0.0001, ^nsnot significant, n = 133.