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Effects Of Melatonin On Heartbeat And Possible Identification Of A Melatonin Receptor In Drosophila Melanogaster, Tricia L. Vankirk

Electronic Theses and Dissertations

Chapter 1 of this manuscript is a literature review that serves as an introduction to the entire dissertation. Chapter 2 examines the effects of the melatonin injection on heart rate and rhythmicity in Drosophila melanogaster Canton-S (wild-type) pupae and pupae bearing a variety of heart mutations. Chapter 3 investigates further the possible mechanisms of melatonin’s ability to increase heart rhythmicity without significantly affecting heart rate. A melatonin antagonist, luzindole; a high-affinity melatonin agonist, 2-iodomelatonin and RNAi techniques are used to identify a possible melatonin receptor in Drosophila melanogaster.

An appendix contains a previously published manuscript detailing experiments performed at the …

Melatonin, Mitochondria, And Ca2+ Homeostasis In The Exocrine Pancreas: An Overview, Antonio Gonzalez, Patricia Santofimia-Castaño, Gines Maria Salido

Turkish Journal of Biology

Melatonin, a derivative of the amino acid tryptophan, was initially thought to be mainly produced and secreted by the pineal gland; with time, it was also found in other tissues and organs, and even in plants. Since its discovery, the study of the role of the indole in cellular homeostasis has generated impressive data, which have led researchers to a common idea regarding the positive actions of melatonin in health. The uncontrolled production of free radicals in cellular systems leads to the situation termed oxidative stress, which has been signaled as the basis of disease and aging. In the exocrine …

Expression Profiles Of Genes Related To Melatonin And Oxidative Stress In Human Renal Proximal Tubule Cells Treated With Antibiotic Amphotericin B And Its Modified Forms, Joanna Gola, Aleksandra Skubis, Bartosz Sikora, Celina Kruszniewska-Rajs, Jolanta Adamska, Urszula Mazurek, Barbara Strzalka-Mrozik, Grzegorz Czernel, Mariusz Gagos

Turkish Journal of Biology

Melatonin protects cells from oxidative stress caused by antibiotics. Through the generation of reactive oxygen species (ROS), amphotericin B (AmB) causes oxidative injuries of the kidneys and liver. Generation of oxidized forms of AmB (AmB-ox) in a patient's circulation may also generate ROS, causing side effects. Studies aimed at elimination of toxic properties of AmB are focused on forming complexes of AmB with copper(II) ions (AmB-Cu2+). However, the influence of such modified forms on renal cells and their transcriptome has not been studied so far. Therefore, the aim of this study was to answer the question of whether AmB-Cu2+ complexes …

Melatonin Induces Antiproliferative Activity Through Modulation Of Apoptoticpathway In H-Ras Oncogene Transformed 5rp7 Cells, Ayşe Kaplan, Gülşen Akalin Çi̇ftçi̇, Hati̇ce Mehtap Kutlu

Turkish Journal of Biology

In the present study, cytotoxic and apoptotic effects of melatonin were investigated on H-ras oncogene transformed rat embryo fibroblast 5RP7 cells. Melatonin inhibited cell growth and induced apoptosis in 5RP7 cells. We showed inhibition of cell proliferation that was time- and dose-dependent in 5RP7 cells for 24 and 48 h. Melatonin was not toxic in NIH/3T3 primary mouse embryonic fibroblast cells at low doses for 24 and 48 h. The IC50 (380 μM) value of melatonin for 48 h was chosen for advanced assays. The percentages of early/late apoptotic cells to which melatonin (IC50: 380 μM) was administered were increased …

Melatonin Attenuates Apoptosis And Mitochondrial Depolarization Levels In Hypoxic Conditions Of Sh-Sy5y Neuronal Cells Induced By Cobalt Chloride (Cocl2), Abdülhadi̇ Ci̇hangi̇r Uğuz, Ahmi̇ Öz, Büşra Yilmaz, Seda Altunbaş, Ömer Çeli̇k

Turkish Journal of Biology

Melatonin (MEL) and its metabolites serve as endogenous reactive oxygen species (ROS) scavengers and have a wide spectrum of antioxidant activity. Cobalt chloride is one of the commonly used hypoxia-mimetic agents, due to blocking the degradation of and triggering the accumulation of hypoxia-inducible factor-1 alpha (HIF-1α ) protein, which is very well known as a critical regulator of the cellular response against hypoxia. In the current study we aimed to determine the possible protective effects of melatonin on a cobalt chloride-induced hypoxia model of SH-SY5Y neuronal cells. Group I was the control group and SH-SY5Y cells were incubated in normal …

Dna Protective And Antioxidative Effects Of Melatonin In Streptozotocin-Induced Diabetic Rats, Seli̇m Sekki̇n, Eda Duygu İpek, Murat Boyacioğlu, Cavi̇t Kum, Ümi̇t Karademi̇r, Hande Sultan Yalinkilinç, Mehmet Onur Ak, Hulki̇ Başaloğlu

Turkish Journal of Biology

Diabetes mellitus is a chronic disease characterized by elevated blood sugar levels. In diabetic patients, oxidative stress induced by the presence of excessive free radicals is closely associated with chronic in?ammation, leading to potential tissue damage. Melatonin (MEL) is a compound synthesized by the pineal gland and a scavenger of free radicals. The aim of this study was to research the effects of MEL on oxidative stress and its DNA protective effects in streptozotocin-induced diabetic rats. In total, 32 rats were equally divided into four experimental groups: control, melatonin, diabetic, and diabetic + melatonin. A single dose of streptozotocin (60 …

Effects Of Photoperiod Variations And Alpha-Lipoic Acid Treatment On Melatonin,Cortisol, And Oxidative Stress Levels In The Blood Of Rats, Cahi̇de Çevi̇k, Recep Aslan

Turkish Journal of Biology

This study aimed to investigate the effects of frequently changing photoperiods and alpha-lipoic acid treatment on melatonin, cortisol, oxidative markers, and some blood parameters. Eighty-four rats were randomly and equally divided into 7 groups: a control group, 3 prolonged light groups, and 3 prolonged dark groups. The study was completed in 2 stages, with 1- and 4-week periods, respectively. Blood samples were obtained at the end of the first and fourth weeks, and at the end of the dark period for the first and second stages. Serum aspartate aminotransferase and creatinine levels were significantly elevated in the prolonged dark olive …

Melatonin Increased Vitamin C And Antioxidant Enzyme Values In The Plasma,Heart, Liver, And Kidney Of Adriamycin-Treated Rats, Ali̇ Zi̇ya Karakilçik, Muharrem Bi̇ti̇ren, Mustafa Zeri̇n, Haki̇m Çeli̇k, Nurten Aksoy

Turkish Journal of Biology

Adriamycin, an anticarcinogenic agent, causes excessive production of reactive oxygen species (ROS). These radicals may affect antioxidant defense systems. The present study was designed to investigate the effects of melatonin on antioxidant enzyme activities and vitamin C in Adriamycin-treated rats. In the current study, rats were divided into three groups: control, Adriamycin, and melatonin+Adriamycin groups. The control group was intraperitoneally injected physiological saline (0.9%) as a placebo. The Adriamycin and melatonin+Adriamycin groups were administered Adriamycin (25 mg/kg body weight). The melatonin+Adriamycin group was pretreated with melatonin (0.5 mg/kg body weight). Vitamin C concentration and catalase (CAT), superoxide dismutase (SOD), glutathione …

Role Of Melatonin On Calcium Signaling And Mitochondrial Oxidativestress In Epilepsy: Focus On Trp Channels, Mustafa Naziroğlu

Turkish Journal of Biology

Calcium ion (Ca2+) accumulation and excessive oxidative stress in the hippocampus and brain cortex have long been known as major contributors to the etiology of epilepsy. I have reviewed the role of Ca2+ signaling through cation channels and mitochondria-mediated oxidative stress on epilepsy in human and animals. A review of the relevant papers and results from recent studies were obtained from PubMed and the Science Citation Index. Current literature findings indicate that melatonin and agomelatine reduce activation of hippocampal transient receptor potential (TRP), glutamate receptors, and voltage-gated calcium channels that are critical for the development of abnormal Ca2+ homeostasis and …

Melatonin As A Stabilizer Of Mitochondrial Function: Role In Diseases And Aging, Cristina Carrasco, Ana B. Rodriguez, Jose A. Pariente

Turkish Journal of Biology

It is now almost 60 years since the discovery of melatonin and new physiological functions of the indole continuously appear in the most recent studies worldwide. Experimental evidence emphasizes its importance as a stabilizer of the mitochondrial bioenergetics, which could be related to the prevention of development of aging and several diseases. In the next years, conscientious investigation about this topic should be undertaken by scientists of different research areas to achieve a better understanding of the molecular mechanisms implied. This will ultimately allow the development and clinical application of efficacious treatments.

Prooxidant Effects Of Melatonin: A Brief Review, Malwina S. Munik, Cem Ekmekçi̇oğlu

Turkish Journal of Biology

Melatonin acts classically through the widely expressed G protein-coupled membrane receptors MT1 and MT2, respectively. The functional role of the MT receptors is not fully clear with multiple effects, such as effects on the circadian, reproductive, immune, cardiovascular, and intestinal systems, being suggested. In addition to receptor-mediated effects, melatonin also acts as a potent antioxidant and it is quite evident that melatonin and its metabolites efficiently reduce oxidative damage to proteins, lipids, and DNA and also exert protective effects on mitochondria. The potent antioxidant activity of melatonin stems from various complex mechanisms, including direct scavenging of radicals, stimulation of antioxidant …

The Effects Of Agomelatine And Melatonin On Ecog Activity Of Absenceepilepsy Model In Wag/Rij Rats, Hati̇ce Aygün, Duygu Aydin, Sema İnanir, Fati̇h Eki̇ci̇, Mustafa Ayyildiz, Erdal Ağar

Turkish Journal of Biology

The aim of this study was to evaluate the effect of the melatonergic M1 and M2 receptor agonist and serotonergic 5-HT2C receptor antagonist agomelatine on the spike wave discharges (SWDs) seen in electrocorticographic (ECoG) recordings of WAG/Rij rats with absence epilepsy. Twenty-one WAG/Rij male rats were used in this study. Tripolar electrodes were placed on skulls and control ECoG activities were recorded. Experimental groups received normal saline (Group I: 1 mL, intraperitoneally (i.p)), agomelatine (Group II: 40 mg/kg, i.p), and melatonin (Group III: 40 mg/kg, i.p) injections for 7 days. Following this period, 2-h ECoG recordings were repeated. The number …

Melatonin Is A Potent Modulator Of Antioxidative Defense And Cellular Proliferation Against Aluminum Toxicity In Rats, Ni̇hal Ömür Bulan, Guner Sarikaya-Unal, Sevim Tunali, Pelin Arda Pi̇ri̇nççi̇, Refiye Yanardag

Turkish Journal of Biology

Aluminum is the most abundant metal on earth, known for its toxicity to humans and laboratory animals. Melatonin, produced by the pineal gland, has been shown to be an effective antioxidant. In this study, we investigated the possible protective role of melatonin in modulating toxicity and oxidative stress induced by chronic exposure to aluminum in the small intestine of rats. Wistar albino rats were divided into five groups. Group I served as the control and received only physiological saline, Group II served as the control for the melatonin group and received ethanol and physiological saline, Group III received melatonin, Group …