Intracellular but not extracellular conversion of nitroxyl anion into nitric oxide leads to stimulation of human neutrophil migration

Abstract

Considerable controversy exists in the literature with regard to the nature of the agent mediating the biological effects of nitroxyl (NO-) donors. Here it is demonstrated that Angeli's salt (AS), a generator of NO-, enhanced human neutrophil migration. Under aerobic conditions, AS was converted to peroxynitrite to a small extent. However, using methionine, a scavenger of peroxynitrite, it was shown that peroxynitrite was not involved in AS-induced migration. AS equally enhanced human neutrophil migration under aerobic and anaerobic conditions, which strongly suggests that extracellular conversion of NO- to .NO by oxygen was not required. Furthermore, metHb and L-cysteine, which react more readily with NO- than with .NO, inhibited AS-induced migration, whereas the response towards gaseous .NO remained unaffected. AS induced an increase in the intracellular level of cGMP, although the curves for migration and cGMP level appeared to be slightly different in their concentration dependence. An inhibitor of soluble guanylate cyclase and antagonists of cGMP-dependent protein kinase had a more pronounced inhibitory effect on .NO-induced migration than on AS-induced migration. This suggests that the cGMP signalling cascade is partially, but not solely, responsible for AS-induced migration. As it has been demonstrated that soluble guanylate cyclase can only be activated by .NO, and not by NO-, these data indicate that NO- is at least partly converted intracellularly to .NO.

The Specificity of Nitroxyl Chemistry Is Unique Among Nitrogen Oxides in Biological Systems

“…Although it is logical to assume that ONOO -or peroxynitrous acid is the species generated from the reaction of HNO with O 2 , there are several important lines of evidence that show distinct differences between synthetic ONOO -and HNO donors in aerobic solution (32,42,91,109,113,122,136,145,165,166,172 (109). Despite experimental and computational efforts (92,107,109,113,145), the structure of the HNO autoxidation product is currently unknown.…”

Oxidative Stress: Role of Eruca sativa Extract on Male Reproduction in Rats

“…Fasting blood samples were collected at 0, 30, 60 days of the experiment by cardiac puncture technique (cardiocentesis) by using vacuum tube with gel colt activator. Serum was collected and kept at -18°C until analysis for measurement of serum testosterone (T), follicular stimulating hormone (FSH), luteal hormones (LH) using Kits-Monobind Inc, USA and peroxynitrite radical concentrations (Vanuffelen et al, 1998), as well as, catalase activity was determined according to Goth (1991). At the end of experiment left testis was excised and covered with physiological normal saline, cleaned from attached fat and connective tissue, tail of the epididymis was taken for preparation of epididymal sperm suspension as described by Sakamoto and Hashimoto (1986) to perform routine sperm evaluation.…”

Effect of Alcoholic Extract of Salvia officinalis Leaves on some Physiological Parameters Aspects in Acrylamide-Treated Rats

“…Then serum samples were separated and frozen at -20°C until analysis of the following parameters: Serum total protein and albumin concentrations was measured using total protein and albumin kits (Biomaghreb-Germany) immunoglobulin G (IgG) concentration was measured using IgG kit ELISA (Hcusabio-China) serum peroxynitrite radical concentration was determined according to (Vanuffelen et al, 1998) reduced glutathione (GSH) concentration was measured according to (Burtis and Ashwood, 1999). Furthermore, determination of bone marrow cellularity (Mitotic index %) has been determined as described by Savage (1975) and determination of Phagocytic Index % according to Weber and Osborn (1982).…”