Association Between Mobile Phone Radiation Exposure and the Secretion of Melatonin and Cortisol,Two Markers of the Circadian System: A Review

The extremely important use of mobile phones in the world, at all ages of life, including children and adolescents, leads to significant exposure of these populations to electromagnetic waves of radiofrequency. The question, therefore, arises as to whether exposure to these radiofrequencies (RFs) could lead to deleterious effects on the body's biological systems and health. In the current article, we review the effects, in laboratory animals and humans, of exposure to RF on two hormones considered as endocrine markers: melatonin, a neurohormone produced by the pineal gland and cortisol, a glucocorticosteroid synthesized by the adrenal glands. These two hormones are also considered as markers of the circadian system. The literature search was performed using PubMed, Medline, Web of Sciences (ISI Web of Knowledge), Google Scholar, and EMF Portal. From this review on RF effects on cortisol and melatonin, it appears that scientific papers in the literature are conflicting, showing effects, no effects, or inconclusive data. This implies the need for additional research on higher numbers of subjects and with protocols perfectly controlled with follow‐up studies to better determine whether the chronic effect of RF on the biological functioning and health of users exists (or not). Bioelectromagnetics. 2021;42:5–17. © 2020 Bioelectromagnetics Society     

Effects of 5-HT7 receptors on circadian rhythm of mice anesthetized with isoflurane

ABSTRACT

The role of the serotonin 7 receptor (5-HT₇ receptor) subtype in a number of domains has been widely recognized, but its role in the regulation of changes of the circadian rhythm after anesthesia is still unclear. We used intraperitoneal injection of 5-HT₇ receptor agonist LP-211 or antagonist SB-269970 in mice to influence the level of 5-HT₇ receptor protein in the SCN and to observe the role of this receptor on circadian rhythm changes after isoflurane anesthesia. Our results show the appropriate dose of SB-269970 significantly alleviated the circadian rhythm disorder induced by isoflurane anesthesia, while LP-211 significantly aggravated it after anesthesia, which is different from the phase shift that can be caused by the administration of LP-211 before anesthesia. These findings may indicate the 5-HT₇ receptor plays a complex role in the regulation of circadian rhythm after anesthesia. Our findings may provide some positive significance for alleviating circadian rhythm disorder in patients after anesthesia and ultimately promoting rapid postoperative recovery.     

中国西北沙漠夜间活动的东鳖甲属昆虫二新种(鞘翅目:拟步甲科:漠甲亚科)

记述中国西北地区东鳖甲属2新种:巴丹东鳖甲A.badainica Ba,Ren&Liu sp.nov.和古尔班东鳖甲A.gurbantunggutica Ba&Ren sp.nov.,提供了主要鉴别特征和形态图,并简要讨论了其昼夜活动规律.     

Visual shape discrimination in the fiddler crab,Uca pugilator

1. Research into the visual shape discrimination abilities of compound‐eyed animals has almost exclusively been limited to insects, the crustaceans having been virtually ignored. The two groups have many dissimilarities, having primarily adapted in different habitats to different lifestyles. Differences may exist in visual systems and visually mediated behavior.

2. Fiddler crabs (Uca pugilator), without training, differentially approached dissimilar silhouettes presented simultaneously, demonstrating visual discrimination between stationary, geometric shapes of equal‐area. The strength of response was ordered hierarchically: vertical rectangle, horizontal rectangle, triangle, square, circle.

3. Basic geometric shapes were used to facilitate replication and comparison with research findings from other species.

     

Circadian rhythm does not affect responses to chemical cues in the red swamp crayfish,Procambarus clarkii

Studies of crayfish chemical ecology have been conducted in both day and night conditions. This variation may hinder the comparison of data among studies, if the responses by crayfish to chemical cues are dependent upon the time at which the cues are encountered. We tested the hypothesis that responses to chemical cues are dependent on observation time using the red swamp crayfish, Procambarus clarkii. Procambarus clarkii is known to exhibit a light-regulated circadian rhythm, with nocturnal activity peaks. Habitat use differed significantly between non-stimulated periods and periods of exposure to a food stimulus, but no effects of photoperiod (normal vs. reversed) or laboratory conditions (dark vs. light) were observed. The results suggest that, all else being equal, (1) studies of crayfish chemical ecology can be successfully conducted in a variety of experimental conditions, and (2) previous studies conducted at various times of the day should have comparable results.     

Seasonal changes in entrainment cues for the circadian rhythm of the supratidal amphipod Talorchestia longicornis

The supratidal amphipod Talorchestia longicornis Say has a circadian rhythm in activity, in which it is active on the substrate surface at night and inactive in burrows during the day. The present study determined: (1) the circadian rhythms in individual versus groups of amphipods; (2) the range of temperature cycles that entrain the circadian rhythm; (3) entrainment by high-temperature cycles versus light?:?dark cycles, and (4) seasonal substrate temperature cycles. The circadian rhythm was determined by monitoring temporal changes in surface activity using a video system. Individual and groups of amphipods have similar circadian rhythms. Entrainment occurred only to temperature cycles that included temperatures below 20°C (10–20, 15–20, 17–19, 15–25°C) but not to temperatures above 20°C (20–25, 20–30°C), and required only a 2°C temperature cycle (17–19°C). Diel substrate temperatures were above 20°C in the summer and below 20°C during the winter. Upon simultaneous exposure to a diel high-temperature cycle (20–30°C) and a light?:?dark cycle phased differently, amphipods entrained to the light?:?dark cycle. Past studies found that a temperature cycle below 20°C overrode the light?:?dark cycle for entrainment. The functional significance of this change in entrainment cues may be that while buried during the winter, the activity rhythm remains in phase with the day?:?night cycle by the substrate temperature cycles. During the summer, T. longicornis switches to the light?:?dark cycle for entrainment, perhaps as a mechanism to phase activity precisely to the short summer nights.     

Diurnal and circadian regulations by three melatonin receptors in the brain and retina of olive flounder Paralichthys olivaceus: profiles following exogenous melatonin

To establish the molecular basis of circadian rhythm control by melatonin receptors (MTs), we investigated the mitochondrial ribonucleic acid (mRNA) expressions of three types of MTs in different tissues of the olive flounder (Paralichthys olivaceus). All three types of MT mRNAs were expressed in the neural tissues, while MT1 mRNA was expressed in the peripheral tissues and MT2 and MT3 mRNAs were weakly expressed or undetected in these tissues. We observed increased MT mRNA expression in the neural tissues at night under both light–dark (LD) and constant dark (DD) conditions. Although the melatonin-treated cultured pineal gland samples showed similar diurnal variations with high-MT mRNA expression levels at night compared to those of untreated cultured pineal gland samples, the expression levels were considerably higher in the melatonin-treated samples. The plasma melatonin level also significantly increased at night. Under DD conditions, the expression patterns of MT mRNAs were similar to those under the LD photocycle, but the peak was lower and the circadian change patterns were less clear. These findings reinforce the hypothesis that MTs are active in processing light information, and that these genes are regulated by the circadian clock and light, thus suggesting that MTs play an important role in daily and circadian variations in the brain and retina of olive flounders.     

Cell signaling,receptors, electrical effects and therapy in circadian rhythm

Abstract

Circadian rhythm has been the object of much attention. This review addresses the aspects of cell signaling, receptors, therapy and electrical effects in a multifaceted fashion. The pineal gland, which produces the important hormones melatonin and serotonin, exerts a prominent influence, in addition to the supraschiasmatic nucleus. Many aspects involve free radicals which have played a widespread role in biochemistry.     

卧龙保护区三种中型食肉动物的生态位差异

2014至2019年,利用红外相机对卧龙保护区的赤狐（Vulpes vulpes）、黄喉貂（Martes flavigula）和豹猫（Prionailurus bengalensis）进行了监测,并分析比较了三者的栖息地分布和日活动节律。结果显示,赤狐栖息地主要分布于保护区西部高海拔地区,与黄喉貂和豹猫栖息地重叠较少;豹猫和黄喉貂的栖息地均集中分布于皮条河以南,且相互重叠部分达56.7%;在日活动节律方面,赤狐和豹猫表现出夜行性,黄喉貂表现出昼行性。本研究表明,三种食肉动物均通过栖息地或日活动节律的差异产生了生态位分离,从而实现了在卧龙保护区内的相互共存。