Eye and heart morphogenesis are dependent on the melatonin signaling in chick embryos

Abstract

Calmodulin is vital for chick embryos morphogenesis in the incubation time 48-66 h when the rudimentary C-shaped heart attains an S-shaped pattern and the optic vesicles develop into optic cups. Melatonin is in the extraembryonic yolk sac of the avian egg; melatonin binds calmodulin. The aim of this study was to investigate the function of melatonin in the formation of the chick embryo optic cups and S-shaped heart, by pharmacological methods and immunoassays. Mel1a melatonin receptor immunofluorescence was distributed in the optic cups and rudimentary hearts. We separated embryonated chicken eggs at 48 h of incubation into basal, control and drug-treated groups, with treatment applied in the egg air sac. At 66 h of incubation, embryos were excised from the eggs and analyzed. Embryos from the basal, control (distilled water), melatonin and 6-chloromelatonin (melatonin receptor agonist) groups had regular optic cups and an S-shaped heart, while those from the calmidazolium (calmodulin inhibitor) group did not. Embryos from the luzindole (melatonin receptor antagonist) and prazosin (Mel1c melatonin receptor antagonist) groups did not have regular optic cups. Embryos from the 4-P-PDOT (Mel1b melatonin receptor antagonist) group did not have an S-shaped heart. Previous application of the melatonin, 6-chloromelatonin or forskolin (adenylate cyclase enhancer) prevented the abnormal appearance of chick embryos from the calmidazolium, luzindole, prazosin and 4-P-PDOT groups. However, 6-chloromelatonin and forskolin only partially prevented the development of defective eye cups in embryos from the calmidazolium group. The results suggested that melatonin modulates chick embryo morphogenesis via calmodulin and membrane receptors.

Exploring associations of maternal sleep during periconceptional period with congenital heart disease in offspring

“…Except for this, previous studies have put forward another explanation that disturbed sleep during early pregnancy could contribute to an increased inflammatory response, and then as a result, impaired uterine/placenta blood blow and functioning (Okun et al, ; Okun & Coussons‐Read, ). Furthermore, the research progress in melatonin, a circadian rhythm messenger between mother and fetal, revealed that it played an important role in cardiac differentiation and the maturation of embryonic stem cells, and the formation of the embryo S‐shaped heart as well (Ansari, Agathagelidis, Lee, Korf, & von Gall, ; Bian et al, ; Kudova et al, ; Nogueira & Sampaio, ).…”

“…Studies within the last decade suggested that melatonin, a sleep–wake and other circadian rhythm messenger linking mother and fetus, has essential functions in fetal maturation and placenta/uterine homeostasis (Reiter, Tan, Korkmaz, & Rosales‐Corral, ; Voiculescu, Zygouropoulos, Zahiu, & Zagrean, ). Besides, two recent studies jointly revealed that melatonin is involved in embryonic cardiac development (Kudova, Vasicek, Ciz, & Kubala, ; Nogueira & Sampaio, ). Since it has been confirmed that sleep disturbance during pregnancy could interfere the rhythm and amplitude of melatonin secretion (Shimada, Seki, Samejima, Hayase, & Shirai, ; Suzuki et al, ), it is now an opportune time to explore the relationship of maternal sleep with heart development and disease.…”

Rumen-Protected 5-Hydroxytryptophan Improves Sheep Melatonin Synthesis in the Pineal Gland and Intestinal Tract

“…These results showed that the increased plasma MLT level might be derived from the gut. The majority of studies have reported MLT levels in the plasma as measured by radioimmunoassay and gas chromatography–mass spectrometry in pinealectomized chicks [45], rats [46], sheep [47], and Syrian hamsters [48]. Daytime MLT levels were found to be almost unaffected by the removal of the pineal gland [49–51]; only the nighttime rise of plasma MLT was prevented.…”

Melatonin supplementation protects against the benzo(e)pyrene cytotoxicity and optic cup formation disruption in chicken embryos

“…The melatonin synthetic machinery and the mRNA transcripts of melatonin receptors were identified in the fertilized avian egg, which also content substantial amounts of the melatonin (11)(12)(13). Regarding to melatonin membrane receptors, Mel1a was localized in mammalian blastocysts (14), in the embryos of the reptiles (15), and in the avian embryos (16).…”

“…In chicken embryos, the rudimentary retina begins to develop at 48 h of incubation and forms the optic cups with the calcium-calmodulin-dependent invagination of the optic vesicles (40). Remarkably, melatonin in the eggs activates calmodulin pathway and melatonin receptors to regulate the formation of the optic cup (16). In the present study, the cytotoxicity of benzo(e)pyrene on formation of the optic cup in chicken embryos and the potential protective effects of melatonin were investigated by visually yes/no observation method, using a simple microscope.…”