Figure 1.

Arachidonic acid (AA) induces an increase in intracellular Ca²⁺ concentration ([Ca²⁺]_i) in hCMEC/D3 cells. (A) Intracellular Ca²⁺ signals evoked by increasing doses of AA in the hCMEC/D3 cell line. In this and the following figures, agonists and drugs were administered as indicated by the horizontal bars above the traces. (B) Dose–response relationship of the amplitude of AA-evoked Ca²⁺ signals in hCMEC/D3 cells. The continuous line was obtained from a fit to a sigmoidal concentration-response curve by using Equation (1). (C) 30 μM AA evoked a rapid increase in [Ca²⁺]_i that decayed to the baseline upon agonist removal from the perfusate. When AA was re-added at the same dose, it induced a second elevation in [Ca²⁺]_i that achieved the same peak amplitude as the first one.