Effect of toluene and cresols on Na+,K+-ATPase, and serotonin in rat brain.

The objective of the present trial was to evaluate the effect of toluene and o-cresol, m-cresol, and p-cresol on serotonin (5-HT), its precursor 5-hydroxytryptophane (5-HTP), Na(+),K(+)-ATPase, total ATPase, and lipid peroxidation (TBARS) in rat brain. Evaluation of lipid peroxidation was realized by means of TBARS, determination of biogenic amines and enzymes assay was carried out in brain homogenate samples using HPLC and spectrophotometry, respectively. Five groups of male Wistar rats (200 g) were treated as follow: control, toluene, o-cresol, m-cresol, and p-cresol groups, which were administered 35 mg/kgi.p. of each compound, the control group was given only glycerine as vehicle. 5-HT and 5-HTP levels increased significantly (p < 0.001) in toluene and o-cresol groups. Lipid peroxidation increased significantly (p < 0.002) in all groups. A significant increase (p < 0.001) of Na(+),K(+)-ATPase was noted in the toluene and o-cresol groups, while this enzyme was reduced in the p-cresol group compared to the control group. Total ATPase showed significant differences in the p-cresol group, compared to the control group. Based in our results, it can be concluded that toluene and all cresols groups may increase lipid peroxidation and consequently induce changes in membrane fluidity.