Melatonin is an indoleamine produced from the amino acid l-tryptophan, whereas metabolites of melatonin are known as kynuramines. One of the best-known kynuramines is N1-acetyl-N1-formyl-5-methoxykynuramine (AFMK). Melatonin has attracted scientific attention as a potent antioxidant and protector of tissue against oxidative stress. l-Tryptophan and kynuramines share common beneficial features with melatonin. Melatonin was originally discovered as a pineal product, has been detected in the gastrointestinal tract, and its receptors have been identified in the pancreas. The role of melatonin in the pancreatic gland is not explained, however several arguments support the opinion that melatonin is probably implicated in the physiology and pathophysiology of the pancreas. (1) Melatonin stimulates pancreatic enzyme secretion through the activation of entero-pancreatic reflex and cholecystokinin (CCK) release. l-Tryptophan and AFMK are less effective than melatonin in the stimulation of pancreatic exocrine function; (2) Melatonin is a successful pancreatic protector, which prevents the pancreas from developing of acute pancreatitis and reduces pancreatic damage. This effect is related to its direct and indirect antioxidant action, to the strengthening of immune defense, and to the modulation of apoptosis. Like melatonin, its precursor and AFMK are able to mimic its protective effect, and it is commonly accepted that all these substances create an antioxidant cascade to intensify the pancreatic protection and acinar cells viability; (3) In pancreatic cancer cells, melatonin and AFMK activated a signal transduction pathway for apoptosis and stimulated heat shock proteins. The role of melatonin and AFMK in pancreatic tumorigenesis remains to be elucidated.

Abstract:Background: Ulcerative colitis (UC) is a chronic inflammatory autoimmune disease with limited treatment modalities. The animal model of colitis induced by treatment with trinitrobenzene sulfonic acid (TNBS-colitis) is commonly used to test new therapies of this disease. In our previous work we found that epicutaneous (EC) immunization with protein antigen induced a state of profound immunosuppression that inhibited inflammatory response in contact sensitivity, in experimental autoimmune encephalomyelitis (EAE) and in allogeneic skin graft rejection. Methods: TNBS-induced colitis was used as an experimental model. Results: In our current work, we showed that EC immunization with TNP-conjugated mouse immunoglobulin (TNP-Ig) prior to induction of TNBS-colitis alleviates disease severity what was determined by the body weight, the length and the weight of the colon, the histological activity index (HAI) and myeloperoxidase activity (MPO). Observed amelioration of the disease in TNP-Ig patched mice was accompanied with decreased production of IFN-g and IL-17A by splenocytes. Additionally, spleen cells isolated from mice EC immunized with TNP-Ig prior to colitis induction showed increased production of IL-10 suggesting that this cytokine might be involved in inhibiting inflammatory response in the colon. Conclusion: This work shows that EC immunization with protein antigen prior to TNBS-colitis induction ameliorates disease and observed suppression of inflammatory response in the colon might be mediated by IL-10.

Hydrogen sulfide (H2S) is a crucial co-modulator of cardiovascular, nervous, digestive and excretory systems function. The pleiotropic action of atorvastatin exceeds simple 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibition and involves multiple biological mechanisms. This study assesses the influence of atorvastatin on the H2S tissue concentration in mouse brain, liver, heart and kidney. Twenty-four female CBA strain mice received an intraperitoneal injection. The mice were given one of the following solutions: 0.1 mg atorvastatin (5 mg/kg of body weight (b.w.)/day--group D1, n=8), 0.4 mg atorvastatin (20 mg/kg b.w./day--group D2, n=8) or a saline physiological control (0.2 ml--group C, n=8). A modified Siegel spectrophotometric method was used for the H2S tissue concentration measurements. There was a remarkable rise in the H2S concentration [μg/g] in the kidney (C: 5.26±0.09, D1: 5.77±0.11, p=0.0003; D2: 7.48±0.09, p<0.0001). There were also slight H2S tissue level changes in the brain (C: 1.61±0.01, D1: 1.75±0.03, p=0.0001; D2: 1.78±0.03, p<0.0001), the heart (C: 4.54±0.08, D1: 4.86±0.10, p=0.0027; D2: 4.56±0.07, p=0.6997) and the liver (C: 3.45±0.03, D1: 3.27±0.02, p=0.0001; D2: 3.31±0.02, p=0.0003). Our study supports the influence of atorvastatin on H2S tissue concentration in kidneys and other mouse organs.

Carvedilol induces endogenous hydrogen sulfide tissue concentration changes in various mouse organs. Folia biologica (Kraków) 59: 151-155. Carvedilol, a third generation non-selective adrenoreceptor blocker, is widely used in cardiology. Its action has been proven to reach beyond adrenergic antagonism and involves multiple biological mechanisms. The interaction between carvedilol and endogenous gasotransmitter hydrogen sulfide (H S) is unknown. The aim of the study is to assess the influence of carvedilol on the H S tissue level in mouse brain, liver, heart and kidney. Twenty eight SJL strain female mice were administered intraperitoneal injections of 2.5 mg/kg b.w./d (group D1, n = 7), 5 mg/kg b.w./d (group D2, n = 7) or 10 mg/kg b.w./d of carvedilol (group D3, n = 7). The control group (n = 7) received physiological saline in portions of the same volume (0.2 ml). Measurements of the free tissue H S concentrations were performed according to the modified method of Siegel. A progressive decline in H S tissue concentration along with an increase in carvedilol dose was observed in the brain (12.5%, 13.7% and 19.6%, respectively). Only the highest carvedilol dose induced a change in H S tissue level in the heart an increase by 75.5%. In the liver medium and high doses of carvedilol increased the H S level by 48.1% and 11.8%, respectively. In the kidney, group D2 showed a significant decrease of H S tissue level (22.5%), while in the D3 group the H S concentration increased by 12.9%. Our study has proven that carvedilol affects H S tissue concentration in different mouse organs.

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The results of the present study suggest that ASA affects sulfur metabolism, in particular, renal and hepatic production of sulfane sulfur and NPSH in mice.

WILIÑSKI B., WILIÑSKI J., SOMOGYI E., GÓRALSKA M., PIOTROWSKA J. 2010. Ramipril affects hydrogen sulfide generation in mouse liver and kidney. Folia biol. (Kraków) 58: 177-180. Hydrogen sulfide (H S) is a modulator of various physiological and pathological processes in the cardiovascular and nervous system and plays an important role in the regulation of gastrointestinal tract, liver and kidney function. The effect of the pleiotropic action of the tissue specific angiotensin-converting enzyme inhibitor (ACEI), ramipril, exceeds renin-angiotensin aldosterone system (RAAS) blockade and involves different biological mechanisms. The aim of the study is to assess the influence of ramipril on H S production in mouse liver and kidneys. Thirty mice (CBA) of both sexes were given intraperitoneal injections of ramipril solutions 0.125 mg (5 mg/ kg group D1) and 0.25 mg (10 mg/ kg group D2) for 5 consecutive days at the same time of the day (10:30 am). The control group received physiological saline in portions of the same volume 0.2 ml. The measurements of the tissue concentration of H S were performed using the modified spectrophotometric method of Siegel. There was a significant rise in the tissue concentration of H S [Fg/g] in livers of group D1 (2.70 ± 0.02 vs 2.81 ± 0.06; P = 0.03) and group D2 (2.70 ± 0.02 vs 2.98 ± 0.03; P <0.001) and a significant decrease of H S kidney tissue concentration in group D1 (3.35 ±0.06 vs 3.15 ± 0.07; P = 0.02) and in group D2 (3.35 ± 0.06 vs 2.89 ± 0.03; P< 0.001).Our results show that ACEI ramipril affects hydrogen sulfide generation in mouse liver and kidneys.

This study was designed to investigate the effect of aspirin (ASA) on anaerobic cysteine metabolism, which yields sulfane sulfur-containing compounds and hydrogen sulfide (H(2)S), in mouse liver and brain. In order to solve this problem, we determined the levels of sulfane sulfur and H(2)S, and the activities of cystathionase, the enzyme directly engaged in H(2)S synthesis, and rhodanese, the enzyme that catalyzes sulfane sulfur transfer to different acceptors. Moreover, we examined the effect of ASA on glial Gomori-positive cells (GGPC) in the brain that contain sulfur-rich glial Gomori-positive material (GGPM). The studies indicated an ASA-induced decrease in H(2)S levels in the brain and an increase in the liver. ASA-treated animals had lower cerebral levels of GGPM-containing GGPCs but the sulfane sulfur level was not affected. Conversely, the sulfane sulfur content in the liver dropped. ASA did not change cystathionase and rhodanese activity in either organ. The obtained results revealed that ASA was able to influence anaerobic cysteine metabolism, leading to the formation of sulfane sulfur and H(2)S in the mouse liver and brain, and to affect the numbers of GGPM-containing GGPCs.