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Targeting the Nervous System
Published in Nathan Keighley, Miraculous Medicines and the Chemistry of Drug Design, 2020
There are other avenues available to target the cholinergic receptor. Once acetylcholine has stimulated a neurone, it must be hydrolysed in order to prevent reactivation of the cholinergic receptor, which would increase cholinergic effects. This destruction of acetylcholine is done by an enzyme called acetylcholinesterase. Inhibitors of this enzyme, referred to as anticholinesterases will have the same biological effect as a cholinergic agonist.
Heterocyclic Drug Design and Development
Published in Rohit Dutt, Anil K. Sharma, Raj K. Keservani, Vandana Garg, Promising Drug Molecules of Natural Origin, 2020
Garima Verma, Mohammad Shaquiquzzaman, Mohammad Mumtaz Alam
Acetylcholinesterase agents are those which prevent the breakdown of acetylcholine, a neurotransmitter. These inhibitors inhibit the enzyme cholinesterase which is actually responsible for the lysis of acetylcholine. They are used for the treatment of dementia encountered in the patients suffering from Alzheimer’s disease (Ogbru, 2017). Some frequently used cholinesterase inhibitors are tacrine, donepezil, galantamine, rivastigmine, and memantine. Inhibitors obtained from plants are given in Table 9.14.
Aedes-aegypti organophosphate resistance detection in the Rawasari subdistrict of Central Jakarta, Indonesia, as an effort for dengue hemorrhagic fever vector control
Published in Ade Gafar Abdullah, Isma Widiaty, Cep Ubad Abdullah, Medical Technology and Environmental Health, 2020
A. Hardjanti, I. Indrawati, E. Donanti, H. Wibowo, Z. Zulhasril
Organophosphate is an acetylcholinesterase inhibitor. Acetylcholinesterase is an enzyme that hydrolyzes acetylcholine to become acetic and choline. Organophosphate reacts with the active part of this enzyme and blocks its functions. The level of acetylcholine in nerve synapses will increase, causing a persistent postsynaptic stimulus. Acetylcholine is present in all nervous systems, including the autonomic nervous system, and acts as a neurotransmitter in sympathetic and parasympathetic nerve ganglion.
Mixed and non-competitive enzyme inhibition: underlying mechanisms and mechanistic irrelevance of the formal two-site model
Published in Journal of Enzyme Inhibition and Medicinal Chemistry, 2023
The acetylcholinesterase inhibitors developed as potential anti-Alzheimer’s drugs perhaps constitute the most prominent example of mixed dead-end inhibition of an iso-mechanism enzyme55. However, there are no reliable data on the prevalence of iso-mechanisms, so it is difficult to estimate their contribution to the overall occurrence of mixed inhibition. It is worth noting that the product form of the free enzyme is a short-lived molecular species generated along with the catalysis rather than a stable enzyme isoform. This implies that isomerisation in the forward direction (F→E) is necessarily faster than in the reverse direction (F←E) 52, which is consistent with the finding that the chemical segment is always the rate-limiting step50. Consequently, even though the Kius generated by iso-mechanisms cannot be algebraically shown to be necessarily greater than the Kics, mechanistic considerations explain why Fiso is practically always less than 1 and, consequently, why, in this case too, the mixed inhibition is dominated by the competitive component.
Effect of diet supplemented with African Star Apple Fruit Pulp on purinergic, cholinergic and monoaminergic enzymes, TNF-α expression and redox imbalance in the brain of hypertensive rats
Published in Nutritional Neuroscience, 2023
Tosin A. Olasehinde, Seun F. AKomolafe, Iyabo F. Oladapo, Sunday I. Oyeleye
High acetylcholinesterase activity was observed in the brain of hypertensive rats, and this suggests rapid hydrolysis of acetylcholine which may reduce its level in the synaptic cleft, hence disrupting cholinergic metabolism and neurotransmission. Low levels of acetylcholine have been linked with cognitive dysfunction [60]. Acetylcholine is an important neurotransmitter involved in transmitting nerve impulses from one neuron to another [61]. The observed increase in AChE activity also correlates with the significant increase in AChE mRNA expression in the brain of hypertensive rats. These results established that high blood pressure may contribute to cholinergic deficit and impaired cholinergic transmission. After supplementation with FP, acetylcholinesterase activity and AChE mRNA expression was significantly reduced in the brain of hypertensive rats, which suggest inhibition of rapid hydrolysis and depletion of acetylcholine. FP may contain some compounds that may inhibit AChE, hence the observed reduction of the enzyme activity. Compounds such as catechins, epigallocatechin, beta-amyrin acetate and myricetin rhamnoside, previously identified in FP, may induce inhibition of AChE. Previous reports have also indicated that these compounds are potent AChE inhibitors [62–65].
Neurotoxic responses of rainbow trout (Oncorhynchus mykiss) exposed to fipronil: multi-biomarker approach to illuminate the mechanism in brain
Published in Drug and Chemical Toxicology, 2022
Arzu Uçar, Fatma Betül Özgeriş, Veysel Parlak, Aslı Çilingir Yeltekin, Esat Mahmut Kocaman, Gonca Alak, Muhammed Atamanalp
Acetylcholinesterase is a hydrolase enzyme, predominantly found in muscle tissue and the nervous system of organisms. It acts an important role in the neurotransmission and widely used enzyme in the determination of the neurotoxic effects of xenobiotics in the aquatic ecosystem (Kim and Lee 2018). The research have shown that Acetylcholinesterase (AChE) activity is blockaged by metals, pesticides, pharmaceuticals and other pollutants in aquatic medium (Rhee et al.2013, Ezeoyili et al.2019), and at pesticides exposed organisms AChE activity acts as a neurotoxicity indicator (Amiard-Triquet 2009). Pesticides have a very specific mode of action that inhibits cholinesterase enzyme (ChE) activity in the nervous system. This makes it important to determine AChE activity in toxicity tests (Sandoval-Herrera et al.2019).