Similarity and dissimilarity of thiols as anti-nitrosative agents in the nitric oxide–superoxide system

l-Cysteine ethyl ester reverses the deleterious effects of morphine on, arterial blood–gas chemistry in tracheotomized rats

“…Cysteine (Deneke, 2000; Métayer et al, 2008; Winterbourn et al, 2008), glutathione (Hill and Bhatnagar, 2007) and hydrogen sulfide (Peng et al, 2010) exert redox-dependent effects in cells and hydrogen sulfide promotes minute ventilation via actions in the carotid bodies (Peng et al, 2010). Finally, the generation of intracellular S-nitrosothiols such as L-S-nitrosoglutathione and an increase overall S-nitrosylation status of proteins in cells (Gow et al, 1991; Kharitonov et al, 1995; Keszler et al, 2010; Hu and Ho, 2011) may contribute to the ventilatory excitant effects of L-CYSee in morphine-treated rats. This especially is because (1) microinjections of S-nitrosothiols into the nucleus tractus solitarii of conscious rats cause pronounced increases minute ventilation (Lipton et al, 2001), (2) S-nitrosothiols promote skeletal muscle activity via activation of ryanodine receptors (Stoyanovsky et al, 1997), and (3) S-nitrosothiols exert positive effects on ventilatory function and pulmonary gas-exchange mechanisms (Gaston et al, 1994, 2006; Lipton et al, 2001).…”

“…The increased availability of cysteine directly alters the redox status of cells (Métayer et al, 2008; Winterbourn et al, 2008) and enhances glutathione production (Kimura and Kimura, 2004; Kimura, 2010), which exerts redox-dependent (reductive) effects and S-glutathiolation of proteins (Hill and Bhatnagar, 2007), and hydrogen sulfide (Kimura, 2010), which also activates redox processes and increases minute ventilation via actions in the carotid bodies (Peng et al, 2010). The enhanced biovailability of L-cysteine and L-glutathione would also promote the direct formation of the S-nitrosothiols, L-S-nitrosocysteine and L-S-nitrosoglutathione and the overall S-nitrosylation status of functional proteins in cells (Gow et al, 1991; Kharitonov et al, 1995; Keszler et al, 2010; Hu and Ho, 2011). S-nitrosothiols have diverse activities via S-nitrosylation of functional proteins (Lipton et al, 1993; Foster et al, 2003) and it is known that S-nitrosothiols within the brainstem (Lipton et al, 2001) and peripheral structures (Gaston et al, 1994, 2006; Stoyanovsky et al, 1997) exert positive effects on ventilatory function and pulmonary gas-exchange mechanisms.…”

A novel chemoprotective effect of tiopronin against diethylnitrosamine‐induced hepatocellular carcinoma in rats: Role of ASK1/P38 MAPK‐P53 signalling cascade

“…Tiopronin was reported as a free radical scavenger similar to glutathione since they both undergo the same thiol-disulfide exchange. 48 Interestingly, the current study found that the ASK1-p38-p53 signalling pathway was upregulated in DENA-treated rats as compared to the control group. In addition, we found that the expression of caspase 3 increased in DENA-treated rats as compared to the control group.…”

“…Remarkably, the hepatoprotective activity of tiopronin can be partly explained by its antioxidant activity that was evidenced by a significant decrease in MDA and NO levels as well as a significant increase in CAT and GPx activities. Tiopronin was reported as a free radical scavenger similar to glutathione since they both undergo the same thiol‐disulfide exchange . Therefore, tiopronin can act as a thiol donor to enhance GPx activity, however, other studies have reported that tiopronin inhibited GPx activity via formation of thioselenate adduct in the active site of the enzyme without inhibiting other ROS related antioxidant enzymes such as catalase …”

Evidence of Oxidative Injury of the Spinal Cord in 2 Horses With Equine Degenerative Myeloencephalopathy

“…Reactive oxygen and nitrogen species are generated through physiologic processes but, when produced in excess, overwhelm endogenous antioxidant and antinitrosative agents, resulting in oxidative and nitrosative stress. 12 Some oxygen metabolites, such as superoxide radical, hydrogen peroxide, and hydroxyl radical, serve as potent oxidants capable of causing cellular injury and lipid peroxidation. 7 These reactive oxygen species are associated with local cellular injury; however, breakdown products produced during lipid peroxidation create lipid peroxides, such as 4-HNE, malonaldehyde, acrolein, and hexanal; diffuse from their site of origin; and may have toxic and reactive properties.…”