Figure 3.

Increase in the intracellular concentrations of cysteine by sulfite compared with that by H₂S, H₂S₂ and H₂S₃, and a time course of the conversion of cystine to cysteine in the culture medium induced by sulfur containing molecules. Intracellular concentrations of cysteine in primary neuronal cultures were measured by HPLC 4 h after the addition of Na₂SO₃ (A), Na₂S (B), Na₂S₂ (C), and Na₂S₃ (D), with or without glutamate (Glu). All data shown are means ± SEM (n = 5). *P < 0.05, significantly different as indicated, for values without glutamate; Tukey−Kramer test. ^# P < 0.05, significantly different as indicated, for values with glutamate. Furthermore, 10 μM (E) and 100 μM (F) sulfur‐containing molecules indicated in (E) were applied to MEM and incubated in an atmosphere with 10% CO₂, and the concentrations of cysteine in the medium were measured. All data shown are means ± SEM (n = 9).