Fig. 6. Thiol levels in Mytilus edulis gills as a function of Na2S concentration. Thiols pertaining to the left y-axis are thiosulfate (circles), glutathione (diamonds) and cysteine (upright triangles), connected with solid lines. Thiols pertaining to the right y-axis are sulfide (squares) and sulfite (inverted triangles), connected with broken lines. Lines serve only to connect data points. Values, except for glutathione, are means ± S.D. (N=3). Glutathione values are only the mean; standard deviations reach 71–99 % of the mean in gills exposed to any level of Na2S and are therefore not included. To eliminate overlap of error bars, some points have been offset by 2 µmol l-1. Asterisks designate a significant difference from the value at 0 µmol l-1 Na2S (Bonferroni test). (A) Gills exposed to 0.5 µmol l-1 5-HT. (B) Gills exposed to 10 µmol l-1 5-HT.
