Seasonal Reproduction in Vertebrates: Melatonin Synthesis, Binding, and Functionality Using Tinbergen’s Four Questions

viviD, Dax; Bentley, G.

doi:10.3390/molecules23030652

Cited by 34 publications

(29 citation statements)

References 368 publications

(540 reference statements)

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“…The photoperiod influences seasonal breeders through changes in melatonin secretion that affects the function of the hypothalamicpituitary-testicular axis (Bittman et al, 1983;Frungieri, Calandra, & Rossi, 2017;viviD & Bentley, 2018). Melatonin regulates androgen production in rodents via acting on Leydig cells.…”

Section: F I G U R Ementioning

confidence: 99%

Do seasonal variations in ambient temperature, humidity and daylight duration affect semen parameters? A retrospective analysis over eight years

et al. 2020

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Natural life depends on biological rhythms that enable living creatures to thrive and survive. Biological rhythms or clocks allow species to adapt their physiological functions to external environmental changes. The environmental changes, creating a complex circadian (day) and circannual (year) rhythmicity, affect the whole organism, particularly the endocrine glands and the gonads. The hypothalamic-pituitary-gonadal axis is extremely susceptible to circannual rhythmicity, regulating the hormone levels (Santi et al., 2020). One of the most critical functions of annual hormone changes in nature is the optimisation of reproduction timing, thereby ensuring the highest survival chances of the offspring (Henkel et al., 2006; Roenneberg & Aschoff, 1990). Unlike other animal species, humans do not necessitate to set a season of fertility and can reproduce throughout the entire year. Although the human is not normally considered a seasonal breeder, many reports demonstrated the seasonal changes in gonadotropins, gonadal hormones and melatonin

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Section: F I G U R Ementioning

confidence: 99%

Do seasonal variations in ambient temperature, humidity and daylight duration affect semen parameters? A retrospective analysis over eight years

et al. 2020

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“…Such a system is generally composed of (1) a pacemaker, circadian clock, or circadian oscillator that endogenously generates rhythms with a period close to 24 hours, (2) an entrainment pathway that entrains the clock daily by detecting 24-h light/dark cycles via photoreceptors, and (3) an output signal that is rhythmically produced and serves as a signal of environmental time to the rest of the organism. In vertebrates, a major output of circadian clocks is melatonin, which is produced during the dark period of the light/dark cycle and acts as a signal for "darkness" to regulate circadian rhythms and photoperiodic responses [5,11]. In vertebrates, melatonin is produced in the retina and pineal organs, which both play central roles in circadian regulation and seem to be ancient melatonin sources [12].…”

Section: Introductionmentioning

confidence: 99%

Light Pollution, Circadian Photoreception, and Melatonin in Vertebrates

et al. 2019

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Artificial light at night (ALAN) is increasing exponentially worldwide, accelerated by the transition to new efficient lighting technologies. However, ALAN and resulting light pollution can cause unintended physiological consequences. In vertebrates, production of melatonin—the “hormone of darkness” and a key player in circadian regulation—can be suppressed by ALAN. In this paper, we provide an overview of research on melatonin and ALAN in vertebrates. We discuss how ALAN disrupts natural photic environments, its effect on melatonin and circadian rhythms, and different photoreceptor systems across vertebrate taxa. We then present the results of a systematic review in which we identified studies on melatonin under typical light-polluted conditions in fishes, amphibians, reptiles, birds, and mammals, including humans. Melatonin is suppressed by extremely low light intensities in many vertebrates, ranging from 0.01–0.03 lx for fishes and rodents to 6 lx for sensitive humans. Even lower, wavelength-dependent intensities are implied by some studies and require rigorous testing in ecological contexts. In many studies, melatonin suppression occurs at the minimum light levels tested, and, in better-studied groups, melatonin suppression is reported to occur at lower light levels. We identify major research gaps and conclude that, for most groups, crucial information is lacking. No studies were identified for amphibians and reptiles and long-term impacts of low-level ALAN exposure are unknown. Given the high sensitivity of vertebrate melatonin production to ALAN and the paucity of available information, it is crucial to research impacts of ALAN further in order to inform effective mitigation strategies for human health and the wellbeing and fitness of vertebrates in natural ecosystems.

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“…The absence of changes in male BI vn , which value reflects the ACh content in the presynaptic vagus nerve terminals, may indicate either a lower melatonin mediation of the resynthesis and accumulation of a neurotransmitter in the presynaptic compartment, or its smaller amount in the body. It is known that in vertebrates, the hormone is mainly synthesized in darkness [18], therefore we rather tend to think that melatonin synthesis was less in males than in females as a result of 10-day complete darkness.…”

Section: Discussionmentioning

confidence: 92%

Sex differences in the cardiac cholinergic response to adrenalin-induced myocardial necrosis and light desynchronosis

et al. 2020

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The aim was to identify sex differences in the cardiac response to cholinergic stimuli in the development of myocardial necrosis and light desynchronosis. Materials and methods. Experiments were conducted in 144 albino rats (72 males, 72 females). Myocardial necrosis was induced by adrenaline (0.5 mg/kg, intramuscularly). The intensity of bradycardia that occurred as a response to intravenous acetylcholine injection and electrical stimulation of vagus nerve was measured. The animals were divided into 4 groups: 1-rats that were in a light balance (day/night); 2-rats exposed to light deprivation for 10 days; 3-rats exposed to permanent lighting for 10 days; 4-animals exposed to permanent lighting for 10 days and injected with melatonin (5 mg/kg) intraperitoneally 1 hour before the necrosis modeling. Results. The development of myocardial necrosis when occurring in light deprivation was characterized by an increased responsiveness of the rat heart to cholinergic stimulation due to an increase in both cholinoreceptors sensitivity and release of acetylcholine from the vagus nerve terminals in females, and due to only an increased cholinoreceptors sensitivity in males. The development of myocardial necrosis in rats exposed to permanent lighting was characterized by significantly higher sensitivity of cholinergic structures of the heart than that in light balance, especially in females. Melatonin injection in the development of myocardial necrosis contributed to the heart cholinergic structures response to the stimulation, which was close to that observed in conditions of light balance, though it remained somewhat higher: due to the facilitation of acetylcholine release from vagus nerve in females, and it was combined with a higher sensitivity of cholinoreceptors in males. Conclusions. The development of myocardial necrosis in light desynchronosis (light deprivation or permanent lighting) causes an increased heart response to cholinergic stimulation in rats. Such effects are stronger, especially in females in conditions of permanent lighting. The injection of melatonin in rats with myocardial necrosis and permanent lighting results in an approximation (but not restoration) of the heart sensitivity to cholinergic stimuli parameters to those that are observed in light balance. However, the heart response to cholinergic stimulation remains higher, especially in males.

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Seasonal Reproduction in Vertebrates: Melatonin Synthesis, Binding, and Functionality Using Tinbergen’s Four Questions

Cited by 34 publications

References 368 publications

Do seasonal variations in ambient temperature, humidity and daylight duration affect semen parameters? A retrospective analysis over eight years

Do seasonal variations in ambient temperature, humidity and daylight duration affect semen parameters? A retrospective analysis over eight years

Light Pollution, Circadian Photoreception, and Melatonin in Vertebrates

Sex differences in the cardiac cholinergic response to adrenalin-induced myocardial necrosis and light desynchronosis

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