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Toxic Responses of the Nervous System
Published in Stephen K. Hall, Joana Chakraborty, Randall J. Ruch, Chemical Exposure and Toxic Responses, 2020
The neurotransmitter system of the neuron represents yet another target for certain neurotoxic substances. A classic example of neurotoxicity due to disruption of the neurotransmitter system involves inhibition of acetylcholinesterase by various organophosphorus insecticides. During normal impulse conduction, the neurotransmitter, acetylcholine, is released from synaptic end bulbs of an axon into the synapse. The neurotransmitter molecules then interact with receptors on the dendrite of an opposing neuron to continue impulse conduction. An endogenous enzyme, acetylcholinesterase, then inactivates the acetylcholine molecules. However, when present in the synaptic region, organophosphorus compounds bind with the endogenous acetylcholinesterase molecules rendering the enzyme ineffective. Consequently, the acetylcholine transmitter accumulates in the synapse and inappropriately continues impulse conduction. The signs and symptoms of organophosphate poisoning are predictable based on this mechanism of action and include increased salivation, lacrimation, and sweating; ataxia, tremors, muscle fasciculations, and convulsions; constriction of the pupils; bronchial constriction; and increased peristalsis with consequent development of nausea, vomiting, abdominal cramps, and diarrhea. In fatal organophosphorus poisoning, death is due to asphyxiation resulting from respiratory failure. However, in most acute exposures, full recovery occurs following cessation of the exposure.
Biomarkers in Occupational Neurotoxicology
Published in Lucio G. Costa, Luigi Manzo, Occupatinal Neurotoxicology, 2020
Organophosphorus compounds are among the most widely used insecticides; their mechanism of action involves inhibition of acetylcholinesterase (AChE), which leads to accumulation of acetylcholine at cholinergic synapses with an ensuing cholinergic crisis.104 AChE is widely distributed throughout the body and is also present in blood cells, such as erythrocytes and lymphocytes, though its physiological role in these cells, which are devoid of synaptic contacts, has not been elucidated. Inhibition of AChE, as well as of pseudocholinesterase in plasma, has been extensively used as a biomarker of exposure to, and effect of, organophosphates.105,106 When used as a marker of exposure in populations studies, one should consider the issue of interpersonal variability in the activity of these enzymes. In the best circumstances, baseline values should be obtained for each individual, and variations below these activity levels, rather than absolute levels, should be utilized to assess exposure. In the absence of pre-exposure measurements, repeated post-exposure measurements at different intervals should be obtained, rather than comparison with population ranges. If acute exposure to an organophosphate has occurred, AChE activity would increase over time to reach a level considered normal for that individual.107
Microwave-Assisted Hirao and Kabachnik–Fields Phosphorus–Carbon Bond Forming Reactions
Published in Banik Bimal Krishna, Bandyopadhyay Debasish, Advances in Microwave Chemistry, 2018
Organophosphorus compounds find numerous potential applications in the areas of industrial, agricultural, and medicinal chemistry, owing to their biological and physical properties. Phosphorus-carbon (P-C) bond formation, thus, remains a valid and active exercise in chemical research. It has been well-demonstrated that a P-C bond may offer different kinds of biological activities, and, accordingly, there has been a growing interest in these classes of organophosphorous compounds in medicinal and nucleic acid chemistry. Substituted phosphonates, phosphine oxides, and α-aminophosphonates are a notable class of phosphorus-functionalized compounds which have invoked tremendous interest among researchers, including synthetic chemists, medicinal chemists, pharmacologists, biologists, and others working in various interdisciplinary areas.
Association of occupational exposure to pesticides with overweight and abdominal obesity in family farmers in southern Brazil
Published in International Journal of Environmental Health Research, 2022
Roberta Andressa Line Araújo, Cleber Cremonese, Ramison Santos, Camila Piccoli, Gabriela Carvalho, Carmen Freire, Raquel Canuto
The physiological mechanisms involved in this association are not totally clear yet, but it seems that organophosphorus compounds impair the enzymatic pathways participating in the metabolism of carbohydrates, fats, and proteins in the cytoplasm, mitochondria, and proxisomes. Organophosphorus compounds are believed to have this effect by inhibiting the enzyme acetylcholinesterase (AChE) or by directly affecting target organs (Martini et al. 2012). Martini et al. (2012) investigated the influence of a commercial formulation of glyphosate on the proliferation, survival, and differentiation of 3T3-L1 fibroblasts. They demonstrated that the glyphosate formulation inhibited cell proliferation in a time- and dose-dependent manner. It also inhibited mitotic clonal expansion and differentiation of 3T3-L1 fibroblasts into adipocytes. Years later, the same group showed the influence of glyphosate-based herbicides on genes associated with adipogenesis and oxidative stress induction. They demonstrated that the glyphosate formulation inhibited the induction of peroxisome proliferator-activated receptor (PPAR) gamma, the master gene of adipogenesis, and had no influence on CCAAT-enhancer-binding protein (C-EBP) beta, which upregulates PPAR gamma in 3T3-L1 cells and mouse embryonic fibroblasts (Martini et al. 2016).
Toxicity, monitoring and biodegradation of organophosphate pesticides: A review
Published in Critical Reviews in Environmental Science and Technology, 2019
Gurpreet Kaur Sidhu, Simranjeet Singh, Vijay Kumar, Daljeet Singh Dhanjal, Shivika Datta, Joginder Singh
Organophosphate pesticides (OPs) are organic ester derivatives of phosphorous, generally thiol or amide derivatives of thiophosphoric, phosphinic, phosphonic, phosphoric acids with additional side chains of phenoxy, cyanide and thiocyanate group (Kumar, Kaushik, & Villarreal-Chiu, 2016; O'Brien, 2016). Organophosphate compounds are the main components of herbicides, pesticides, and insecticides. Organophosphate compounds are also the main components of nerve gas (Adeyinka & Pierre, 2018). OPs constitute a group of biogenic and synthetic compounds which contains C-P linkage which is thermally and chemically inert and are resistant to thermal hydrolysis, photolytic degradation and chemical decomposition as compared to similar OPs containing more reactive S-P, O-P or N-P linkages (Greaves & Letcher, 2017; O'Brien, 2016; Kumar, Upadhay, Wasit, Singh, & Kaur, 2013). The basic structure of OPs consists of terminal oxygen connected to phosphorus by a double bond, i.e. a phosphoryl group, two lipophilic groups bonded to the phosphorus, and a leaving group bonded to the phosphorous which is often a halide (Kumar et al., 2013). Organophosphorus compounds are widely used for agriculture, horticulture, pest control, industrial, vector control, plastic making, warfare agents and domestic purposes (Adeyinka & Pierre, 2018; Singh & Prasad, 2018; Ballantyne & Marrs, 2017; Yadav et al., 2017; Eskenazi et al., 2014).
Removal and recovery of phosphonates from wastewater via adsorption
Published in Critical Reviews in Environmental Science and Technology, 2023
Rubina Altaf, Bo Sun, Huijie Lu, Heping Zhao, Dezhao Liu
Phosphorus (P) is a finite resource and essential element for agriculture and food production but so far, it is only considered to be recovered in a few countries in the world. Among the various types of phosphorus, organophosphonates represent an important kind of molecules because of their effectiveness as pesticides and nerve agents (Jang et al., 2015). Phosphonates are organophosphorus compounds that comprised with carbon-phosphorus (C-P) bonds. The bond of C-P is hydrolytically stable and chemically inert (Kamat & Raushel, 2013).