It cannot interconvert between they have distinct signaling properties and effects on neuronal function

In the mice of lacked mGluR5, hippocampal long-term potentiation was abnormal, and the mice exhibited deficits in both spatial learning and fear conditioning. Our results showed that mGluR5 mRNA and protein expressions in the hippocampus and cortex in arsenic-exposed rats markedly decreased. However, no association was found between fluoride exposure and mGluR5 mRNA or protein expression in the hippocampus or cortex. These findings indicate that individual arsenic exposure and combined fluoride and arsenic exposure have more significant effects on mGluR5 expression than fluoride exposure alone. Interestingly, compared with fluoride or arsenic exposure alone, rats in the F+As group exhibited a downregulation of mGluR5 mRNA expression in the cortex and mGluR5 protein expression in the hippocampus. These results suggest that a synergistic interaction exists between these two trace elements. Altogether, mGluR5s may be involved in spatial learning and memory impairment caused by arsenic exposure and combined fluoride and arsenic exposure. In our study, there were no differences among four groups for mGluR1 mRNA expression. Although mGluR1 and mGluR5 are both G-protein-coupled mGluRs that stimulate intracellular Ca2+ release. Choi et al. reported that calmodulin is a strong regulator of mGluR5 trafficking and mGluR5-induced calcium signaling. Although it has been accepted that both mGluR1 and mGluR5 interact with CaM, they showed that CaM specifically binds mGluR5 and not mGluR1. Our study supported that fluoride and/or arsenic only changed the expression of mGluR5, not for mGluR1. The reductions of glutamate levels and mGluR5 mRNA and protein expressions in the hippocampus and cortex may be involved in impairments in learning and memory ability. Most Western diets are deficient in omega-3 polyunsaturated fatty acids and abundant in omega-6 PUFAs. Current nutritional research shows that a diet enriched in omega-3s offers health benefits and anti-inflammatory properties and that an excess of omega-6s might contribute to the pathogenesis of many chronic diseases, including cardiovascular, autoimmune and Alzheimer’s diseases. The imbalance between omega-6s and omega-3s is largely the result of the traditional reliance of Western diets on vegetables oils such as corn, soybean, safflower, and sunflower. These oils are enriched in omega-6 PUFAs, such as linoleic acid, which can be metabolized in animals and humans to form longer chain fatty acids such as di-homo-gammalinolenic acid, docosapentaenoic acid, and arachidonic acid are. At the same time, Western diets are lacking in leafy green vegetables, which are enriched in the omega-3 fatty acid, alpha-linolenic acid, and in oily fish, which contain the longer-chain omega-3 PUFAs such as eicosapentaenoic acid, omega-3 DPA, and docosahexaenoic acid. The human body cannot synthesize PUFAs de novo and must rely entirely on dietary intake for these essential nutrients.

Leave a Reply