Ca²⁺ responses to L-amino acids and IMP in MIX-responsive and non-MIX-responsive cells.

<p>Bars represent Mean±SEM Ca²⁺ responses. Average Ca²⁺ responses to the individual stimulus components of the MIX were compared for two groups of MIX-responsive cells: 1) non-synergistic and 2) synergistic cells. The increases in intracellular Ca²⁺ in response to IMP and the L-amino acids were significantly smaller for synergistic cells (gray bars) compared to non-synergistic (black bars) MIX-responsive cells. Cells that did not respond to the MIX but responded to an L-amino acid (non-MIX-responsive cells; white bars) presented alone also generated Ca²⁺ responses with a similar magnitude as those of MIX-responsive non-synergistic cells (gray bars). To eliminate bias by cells that may not have a receptor, only those cells with Ca²⁺ responses (ΔF≥5%) to L-amino acids were analyzed (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0130088#sec009" target="_blank">results</a>). For these cells, Ca²⁺ responses to individual L-amino acids were not significantly different from Ca²⁺ responses of MIX-responsive, non-synergistic cells (patterned bars). Unpaired t-test (for IMP), and One-way ANOVA followed by Bonferroni post hoc t-test (for L-amino acids) were used for statistical comparison. ***P<0.0001, **P<0.001, *P<0.05.