Figure 4.

Ambient glutamate is unaffected by the lack of Ca²⁺ increases in astrocytes. A, Bath application of 50 μm d-AP-5 blocked a tonic NMDAR current in CA1 pyramidal neurons held at +40 mV in ACSF from both littermate control and IP₃R2 KOs. B, The amplitude of the d-AP-5-sensitive NMDAR current was not significantly different (p = 0.8) in IP₃R2 KO neurons (n = 5) versus littermate controls (n = 6). C, Representative traces showing that bath application of 100 μm TBOA induced a large fold increase of the tonic current in CA1 pyramidal neurons held at +40mV from both littermate control and IP₃R2 KOs. D, The fold increase over baseline induced by TBOA is not significantly different (p = 0.4) between IP₃R2 (n = 5 cells) and littermate controls (n = 6 cells). Error bars indicate SEM.