Melatonin controls superoxide anion level: Modulation of superoxide dismutase activity in ring dove heterophils

Abstract

The pineal gland and the immune system in mammals and birds are functionally connected, with some recent findings showing that melatonin, the major secretory product of the pineal gland in vertebrates, is a free-radical scavenger and general antioxidant. In birds, heterophils, with their ability to ingest and kill different antigens, play a central role in the host defense mechanism. This in vitro study investigated the possible antioxidant action of melatonin in heterophils isolated from adult male and female ring dove (Streptopelia risoria). The superoxide anion levels (O2-.) and the superoxide dismutase (SOD) activity were evaluated as indicators of the metabolic burst of heterophils after ingestion of inert particles (latex beads) at the basal time (0 min) and 15, 30, 45, and 60 min of incubation with 100 microM melatonin. The heterophil O2-. levels, measured by the nitroblue tetrazolium reduction test, were lower after incubation in the presence of melatonin at all the times studied, a time-dependent effect. Latex beads produced a significant increase in SOD activity, whereas there was a significant decrease in the presence of melatonin. In addition, when heterophils were incubated in the presence of both latex beads and melatonin, the indole appeared to annul the enhancement of SOD activity (U-525nm) produced by latex beads. In conclusion, our findings show that the neurohormone melatonin could be a useful antioxidant.

Melatonin protects hippocampal neurons in vivo against kainic acid-induced damage in mice

“…Another means by which melatonin could have prolonged beneficial effects is via its enhancement of other protective agents. In this context, melatonin has been reported to increase the activities of certain antioxidative enzymes, including glutathione peroxidase and glutathione reductase (BarlowWalden et al, 1995;Pablos et al, 1998), glucose-6-phosphate dehydrogenase (Pierrefiche et al, 1995), and superoxide dismutase (Antolin et al, 1996;Rodriquez et al, 1998). Also, melatonin has been shown to inhibit a prooxidative enzyme, nitric oxide synthase (NOS) (Pozo et al, 1997;Bettahi et al, 1998).…”

The Effect of Melatonin on Liver Superoxide Dismutase Activity, Serum Nitrate and Thyroid Hormone Levels.

“…Melatonin, with its hepatic metabolite, 6-hydroxymelatonin sulfate, is a free radical scavenger. Rodriguez and co-workers have shown that SOD activity in ring dove leucocytes decreased in the presence of melatonin [3]. On the other hand, Antolin and co-workers reported that both Mn-SOD and Cu,Zn-SOD increased after treatment with melatonin in the harderian gland, and they suggested that melatonin may induce mRNA increments for SOD [24].…”

“…It is important in the antioxidative defense mechanism [3]. NOS is also included in free radical generation in the absence of Larginine [23].…”

Effect of melaxen on free radical processes intensity and some antioxidant enzymes activity in rats liver and blood serum under type 2 diabetes mellitus

“…По-видимому, это может являться результатом проявления мелатонин-корригирующей способности мелаксена. Обладая антиоксидантной активностью, мелатонин нейтрализует большое число реактивных молекул, в том числе О 2 ·-и Н 2 О 2 [24,25]. В результате сокращения уровня активных кислородных метаболитов, вероятно, происходила нормализация окислительных процессов в тканях и, как следствие, снижение активности СОД и каталазы.…”