[Effect of chronic exposure by mercury contaminated rice on neurotransmitter level changes in rat brain]

In order to survey the potential health risk of environmental exposure by mercury, Sprague-Dawley rats were reared by mercury contaminated rice from mercury mining area. The changes of neurotransmitter acetylcholine (ACh) and acetylcholinesterase (AChE) in rat brain were examined at different times. The results show that the mercury-contaminated rice significantly increase the content of ACh in rat brain after exposure for 7 days. ACh maintained at a high level even after exposure for 30 days, but decreased significantly after exposure for 90 days. The changes of AChE represented an inverse trend compared with that of ACh. The coexisting selenium in rice exhibited antagonistic effects on both mercury accumulation and toxicity. The findings suggested that neurotoxic effects of environmental mercury contamination had been significantly represented after chronically dietary exposure. Further studies are needed to examine the relationship between the neurotransmitter level changes and the Alzheimer's Disease (AD).