Figure 5. Bicuculline (Bicu), a [small gamma, Greek]-amino-butyric acid A receptor antagonist, does not affect the inhibition of thiopental (Thio) on the high K^+-mediatedincrease in [Ca²⁺]ⁱin a hippocampal slice. The vertical bar indicates real change in the ratio of fluorescence intensities at 340 nm and 380 nm.