• Acrylamide as a Possible Factor Responsible for Inflammation in the Nervous System
  • Samaneh Feli,1,*
    1. Msc of Molecular Genetic Department of Genetics, Zanjan Branch, Islamic Azad University, Zanjan, Iran.


  • Introduction: Acrylamide (ACR) is a chemical compound that exhibits neurotoxic and genotoxic effects.It causes neurological symptoms such as tremors, general weakness, numbness, tingling in the limbs or ataxia. Numerous scientific studies show the effect of ACR on nerve endings and its close connection with the cholinergic system. The cholinergic system is part of the autonomic nervous system that regulates higher cortical functions related to memory, learning, concentration and attention. Within the cholinergic system, there are cholinergic neurons, anatomical cholinergic structures, the neurotransmitter acetylcholine (ACh) and cholinergic receptors. Acrylamide (ACR) is an organic chemical compound with the chemical formula C3H5NO. It is composed of carbon (50.69%), hydrogen (7.09%), nitrogen (19.71%) and oxygen (22.51%) atoms. At room temperature, it is an odorless, crystalline solid with a molecular weight of 71.08, a melting point of 84.5 _C and a density of 1.122 g/cm3 at 30 _C. Due to its relatively low volatility, its boiling point is 192.6 _C at a pressure of 1 atm (101.3 kPa). Due to the presence of functional groups, this compound is polar and very soluble both in water and in other polar solvents such as methanol or ethanol. However, it is insoluble in benzene and heptane. The aim of the study was to review the current state of knowledge of the influence of acrylamide on the cholinergic system and its possible effect on inflammatory processes.
  • Methods: This review study has been written from scientific databases such as Science Direct, Springer, Google Scholar, and PubMed.
  • Results: Some scientific reports suggest a negative effect of ACR on the cholinergic system and inflammatory reactions within the body. The cholinergic anti-inflammatory pathway (CAP) is a neuroimmunomodulatory pathway that is located in the blood and mucous membranes. The role of CAP is to stop the inflammatory response at the appropriate moment. It prevents the synthesis and release of pro-inflammatory cytokines and ultimately regulates the local and systemic immune response. The cellular molecular mechanism for inhibiting cytokine synthesis is attributed to acetylcholine (ACh), the major vagal neurotransmitter, and the 7 nicotinic receptors ( 7nAChR) subunit is a key receptor for the cholinergic anti-inflammatory pathway. The combination of ACh with 7nAChR results in inhibition of the synthesis and release of pro-inflammatory cytokines. The blood AChE is able to terminate the stimulation of the cholinergic anti-inflammatory pathway due to splitting ACh. Accordingly, cytokine production is essential for pathogen protection and tissue repair, but over-release of cytokines can lead to systemic inflammation, organ failure, and death. Inflammatory responses are precisely regulated to effectively protect against harmful stimuli. The central nervous system dynamically interacts with the immune system, modulating inflammation through the humoral and nervous pathways. The stress-induced rise in acetylcholine (ACh) levels acts to ease the inflammatory response and restore homeostasis. This signaling process ends when ACh is hydrolyzed by acetylcholinesterase (AChE). There are many scientific reports indicating the harmful effects of ACR on AChE. Most of them indicate that ACR reduces the concentration and activity of AChE. Due to the neurotoxic effect of acrylamide, which is related to the disturbance of the secretion of neurotransmitters, and its influence on the disturbance of acetylcholinesterase activity, it can be concluded that it disturbs the normal inflammatory response.
  • Conclusion: Studies on the harmful effects of acrylamide and its metabolites indicate three possible types of toxicity: neurotoxicity, genotoxicity, and carcinogenicity. So far, only the neurotoxic effect of acrylamide on the human body has been undoubtedly proven. The studies conducted so far indicate, first of all, the reduction of acetylcholinesterase activity. The genotoxic activity of acrylamide is mainly manifested after its metabolic conversion to the epoxide derivative glycidamide. The carcinogenic effect of acrylamide has been demonstrated in animal studies. For humans, exposure to acrylamide is assessed as evidence that acrylamide ingested with the diet can initiate the formation of cancer in humans and induce an inflammatory response.
  • Keywords: Acrylamide, Inflammation, Nervous System