Adrenaline induced disruption of endogenous melatoninergic system, antioxidant and inflammatory responses in the gastrointestinal tissues of male Wistar rat: an in vitro study

Abstract

The current study aimed to demonstrate the potentially adverse effects of adrenaline, an endogenous stressor, on the melatonergic system, oxidative status, antioxidative responses and inflammatory markers in different parts of gastrointestinal tract of Wistar rat. These included stomach, duodenum and colon and they were incubated with different concentrations (2.5, 5.0 and 10.0 µg/mL) of adrenaline for 1h, respectively. The levels of melatonin, gene expressions of arylalkylamine N-acetyltransferase (AANAT) and melatonin receptor 1 (MT1) as well as other stress-induced parameters including NF-kB expression, levels of cAMP, calcium, malondialdehyde, protein carbonyl content, reduced glutathione, nitrate, superoxide dismutase, catalase, glutathione peroxidase and glutathione S-transferase, tumour necrosis factor-α, IL-1β, IL6 and IL10 were systemically measured in these tissues. An adrenaline dose-dependent decrease in level of melatonin, AANAT, MT1 and NF-kB in these tissues were observed. In contrast, the profound increases in the levels of cAMP, calcium and all oxidative stress markers, inflammatory cytokines (except IL10), and activities of antioxidant enzymes (except superoxide dismutase) were observed after adrenaline treatment. A maximum effect was found in tissues treated with 5 µg/mL of adrenaline. The Correlation studies between melatonin level and other parameters (any two at a time) indicated a potentially physiological interplay between adrenaline stress and melatonin tissue levels. Collectively, the results provided the novel data on the adverse effects of adrenaline on the endogenous melatonergic system, antioxidant and inflammatory responses in the gastrointestinal tissues of rats.