Comparative neurotoxicity of cadmium in growing and adult rats after repeated administration.

The effect of cadmium administration (Cd 0.4 mg/kg, ip, intraperitoneally, daily for 30 days) on its accumulation, contents of 5-hydroxytryptamine (5-HT) and 5-hydroxyindole acetic acid (5-HIAA) in different brain regions in growing and adult rats was investigated. Cadmium was found to significantly increase the levels of 5-HT and 5-HIAA in all the brain regions of adult rats while the levels of 5-HT and 5-HIAA were significantly decreased in most of the brain regions of growing rats. The accumulation of cadmium in all the brain regions was significantly more marked in growing rats compared to adults after identical exposure. In conclusion, there was an age difference in both the accumulation of cadmium and 5-HT turnover in the brain regions. However, the regional neurochemical changes were not correlated with the magnitude of cadmium accumulation in both the groups.