The Zebrafish, an Outstanding Model for Biomedical Research in the Field of Melatonin and Human Diseases

Abstract

The zebrafish has become an excellent model for the study of human diseases because it offers many advantages over other vertebrate animal models. The pineal gland, as well as the biological clock and circadian rhythms, are highly conserved in zebrafish, and melatonin is produced in the pineal gland and in most organs and tissues of the body. Zebrafish have several copies of the clock genes and of aanat and asmt genes, the latter involved in melatonin synthesis. As in mammals, melatonin can act through its membrane receptors, as with zebrafish, and through mechanisms that are independent of receptors. Pineal melatonin regulates peripheral clocks and the circadian rhythms of the body, such as the sleep/wake rhythm, among others. Extrapineal melatonin functions include antioxidant activity, inducing the endogenous antioxidants enzymes, scavenging activity, removing free radicals, anti-inflammatory activity through the regulation of the NF-κB/NLRP3 inflammasome pathway, and a homeostatic role in mitochondria. In this review, we introduce the utility of zebrafish to analyze the mechanisms of action of melatonin. The data here presented showed that the zebrafish is a useful model to study human diseases and that melatonin exerts beneficial effects on many pathophysiological processes involved in these diseases.

Chronodisruption and Loss of Melatonin Rhythm, Associated with Alterations in Daily Motor Activity and Mitochondrial Dynamics in Parkinsonian Zebrafish, Are Corrected by Melatonin Treatment

“…This rhythm was affected by MPTP treatment, inducing a phase advance of 3–4 h, starting the activity at 5 am instead of 8 am. Probably, the advance occurs because of the alteration in melatonin production, since it controls the rhythm of activity in zebrafish [ 12 ]. Consequently, the embryos are more active during the night instead of the day.…”

“…In mammals, the biological clock is in the suprachiasmatic nuclei of the hypothalamus, and it is controlled by the photoperiod via the information provided by the optic nerve through the suprachiasmatic nucleus, giving a period of oscillation of 24 h [ 10 ]. In zebrafish, the clock is contained in the pineal gland, which acts as a direct photoreceptor to control the 24 h oscillatory activity of the clock genes [ 11 , 12 ]. Moreover, and in line with other vertebrates, the clock controls melatonin production, which increases at night and decreases during the day [ 11 ].…”

From Chronodisruption to Sarcopenia: The Therapeutic Potential of Melatonin

“…Two types of G-protein-coupled membrane receptors for melatonin have been described in vertebrate animals, MT1 (Mel1 a ) and MT2 (Mel1 b ). Both have seven transmembrane domains, and, upon melatonin binding, they can modulate the activity of adenylate cyclase, phospholipases C and A2, potassium and calcium channels, and guanylate cyclase through different mechanisms [129,130]. At one point, the existence of a third melatonin binding site on the cell membrane (MT3 receptor) was theorized [131].…”

Photoprotective Effects of Epigallocatechin Gallate on Ultraviolet-Induced Zebrafish and Human Skin Fibroblasts Cells

“…Moreover, the zebrafish ( Danio rerio ) is an emerging model organism that serves as vertebrate development, biomedical research, drug development, and clinical therapy. This is main due to the high level of genome structure shared between zebrafish and humans, easy maintenance, year-round spawning, high fecundity (300–600 by single female at one time), undergo rapid external development, optical transparency of early stages, and common molecular pathways can be studied [ 13 , 14 ]. Therefore, our study investigated the protective effects and mechanisms of EGCG in the development of oxidative stress and inflammation caused by UVR-induced photoaging in zebrafish and HSF cells.…”