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Magnetic Resonance Spectroscopy
Published in Ioannis Tsougos, Advanced MR Neuroimaging, 2018
Glu is the major excitatory neurotransmitter in the mammalian brain and the direct precursor for the major inhibitory neurotransmitter, γ-aminobutyric acid (GABA). Besides these roles, Glu is also an important component in the synthesis of other small metabolites (e.g., Glutathione) as well as larger peptides and proteins. The amino acid Gln, which is primarily located in astroglia, is involved in intermediary metabolism and is synthesized from Glu (De Graaf, 2007). The Glx complex plays a role in detoxification and regulation of neurotransmitters. Increased levels of Glx complex are markers of epileptogenic processes (Hammen et al., 2003; Simister et al., 2009) and decreased levels of Glx have been observed in Alzheimer, dementia and patients with chronic schizophrenia (Kantarci et al., 2003; Théberge et al., 2003). Glx complex increments have also been observed in the peritumoral brain edema correlated with neuronal loss and demyelination (Ricci et al., 2007). As reported by Srinivasan et al. (2005), Glx might be used as an in vivo index of inflammation since they observed elevated Glx levels in acute MS plaques but not in chronic ones.
Synapses
Published in Nassir H. Sabah, Neuromuscular Fundamentals, 2020
GABA (γ-aminobutyric acid), derived from the nonessential amino acid glutamine, is a major neurotransmitter of inhibitory neurons, such as cerebellar Purkinje cells, and inhibitory interneurons in the brain, as well as some inhibitory interneurons in the spinal cord. Glycine, a nonessential amino acid that is derived from the nonessential amino acid serine, is the major neurotransmitter of inhibitory interneurons in the spinal cord. The amino acids glutamine, glycine, and serine are abundant in living cells and partake in many important cellular functions and structures. The phospholipid phosphatidylserine is a major constituent of cell membranes and the myelin sheath.
Properties, toxicity and current applications of the biolarvicide spinosad
Published in Journal of Toxicology and Environmental Health, Part B, 2020
Vanessa Santana Vieira Santos, Boscolli Barbosa Pereira
As a neurotoxic compound, the mode of action (MOA) of spinosad affects the nicotinic acetylcholine receptors (nAChRs) directly in the nervous system, precisely acting as allosteric modulator (Biondi et al. 2012). Through stimulation of nAChR and γ-aminobutyric acid (GABA) receptors, spinosad induces rapid excitation of the organism nervous system, producing paralysis and death. Several investigators showed that spinosad binds at a different site in comparison to the neonicotinoid pesticides that act through an allosteric mechanism (Orr et al. 2009; Puinean et al. 2013). Specifically, Salgado (1998) reported that spinosad directly affects the insect central nervous system, inducing involuntary neuronal rapid excitation that consequently initiating tremors, prolonged muscle contractions, paralysis, and death.
Cholinergic alterations by exposure to pesticides used in control vector: Guppies fish (Poecilia reticulta) as biological model
Published in International Journal of Environmental Health Research, 2018
G. A. Toledo-Ibarra, E. J. Rodríguez-Sánchez, H. G. Ventura-Ramón, K. J. G. Díaz-Resendiz, M. I. Girón-Pérez
Moreover, it has been reported that different species of mosquitoes have developed resistance to temephos, making it less effective over time (WHO 1992; Ricardo-Leyva et al. 2010). Thus, the use of natural pesticides or bio-pesticides derived from animals, plants, and micro-organisms has been implemented as an alternative. In general, these are highly specific against their target organism and are believed to pose little or no risk to human health or the environment (Leahy et al. 2014). Bio-pesticides are divided into microbial and biochemical (Nava-Pérez et al. 2012). The first are pesticides derived from bacteria, one example of this type is spinosad, a substance composed of spinosyn A (2-[(6-deoxy-2,3,4-tri-O-methyl-αL-mannopyranosyl)oxy]-13-{[5-(dimethylamino) tetrahydro-6-methyl-2H-pyran-2-yl]oxy}-9-ethyl-2,3, 3a,5a,5b,6,9,10,11,12,13,14,16a,16b-tetra-decahydro-14-methyl-1H-as-indaceno(3,2-d)oxacyclododecin-7,15-dione), and spynosin D (2-[(6-deoxy-2,3,4-tri-O-methyl-αL-mannopyranosyl)oxy]-13-{(5-dimethylamino)tetrahydro-6-methyl-2H-pyran-2-yl]oxy}-9-ethyl-2,3,3a,5a,5b,6,9,10,11,12,13,14,16a,16b-tetradecahydro- 4,14-dimethyl-1H-as-indaceno(3,2-d)oxacyclododecin-7,15-dione), which originate as the fermentation product of an actinobacteria called Saccharopolyspora spinosa used for the control of pests and vectors (Piner and Üner 2012). Spinosad can linger in aquatic ecosystems for different periods of time depending on external conditions. In water, it has a half-life of 9–21 days while in aquatic sediment, its half-life increases up to 120 days (Lewis et al. 2016). Spinosad acts by stimulating the nervous system through the activation of nicotinic acetylcholine receptors (nAChR) and γ-aminobutyric acid receptors (GABA), leading to involuntary muscle contractions, which may cause tremors, paralysis, and death (Fulton and Key 2001).