The influence of lighting conditions upon the level and course of increase in specific activity of serotonin N-acetyltransferase in the developing chick pineal gland

1976 ◽  
Vol 54 (2) ◽  
pp. 103-109 ◽  
Author(s):  
I. H. Fraser ◽  
S. D. Wainwright
Keyword(s):  
Pineal Gland ◽  
Specific Activity ◽  
Major Product ◽  
Constant Darkness ◽  
Dark Phase ◽  
Light Phase ◽  
Normal Cycle ◽  
Lighting Conditions ◽  
Hydroxyindoleacetic Acid ◽  
Unidentified Metabolite

A diurnal cycle in level of serotonin acetyltransferase (acetyl-CoA: arylamine N-acetyltransferase (EC 2.3.1.5)) activity was found in the pineal gland of chicks aged 16 to 20 days maintained under diurnal lighting conditions. Diurnal variation in levels of activity was markedly reduced in the pineal gland of birds kept in constant darkness, and suppressed in the gland of chicks under constant illumination. High levels of activity attained during the dark phase of the normal cycle rapidly declined when the birds were transferred to the light. The light phase level of serotonin acetyltransferase of the pineal increased progressively from the 11th day of incubation to about 1 week post-hatch. This course of increase in enzyme activity was largely unaffected by lighting conditions. Under conditions for assay of serotonin acetyltransferase activity in the chick pineal gland and brain, radioactive serotonin gave rise to N-acetylserotonin, 5-hydroxyindoleacetic acid and a further unidentified metabolite, which was quantitatively the major product.

Melatonin Formation in Pineal Gland from Rats with Hexachlorobenzene Experimental Porphyria

2007 ◽  
Vol 26 (6) ◽  
pp. 545-551
Author(s):  
Elena B. C. Llambías ◽  
Marta B. Mazzetti ◽  
Sandra M. Lelli ◽  
Carmen Aldonatti ◽  
Leonor C. San Martín de Viale
Keyword(s):  
Pineal Gland ◽  
Porphyria Cutanea Tarda ◽  
Dark Phase ◽  
Methyltransferase Activity ◽  
Dark Cycle ◽  
Hydroxyindoleacetic Acid ◽  
Tryptophan Content ◽  
Tryptophan Metabolite ◽  
Characteristic Features ◽  
And Oxidative Stress

Hexachlorobenzene produces an experimental hepatic por-phyria in rats, which is similar to human porphyria cutanea tarda, with hyperpigmentation as one of its characteristic features. Alterations in tryptophan metabolism have been previously observed in this chronic porphyria. Melatonin formation from tryptophan via serotonin shows diurnal rhythmicity in the pineal gland, and higher values are observed during the dark phase of an imposed light-dark cycle. The purpose of this study was to determine the contents of tryptophan and its metabolites in pineal gland of normal and hexachlorobenzene-treated rats in order to find alterations potentially related to porphyria cutanea tarda. Results show that in animals with this experimental porphyria some tryptophan metabolite levels (serotonin and 5-hydroxyindoleacetic acid) increase only during the light period, whereas tryptophan content remained equal to the controls. Hydroxyindole- O-methyltransferase activity also increases by light in pineal gland from hexachlorobenzene-treated rats. On the other hand, tryptophan is converted to melatonin in the dark period, but this route is not exacerbated in hexachloroben-zene porphyria. The relevance of these alterations is discussed in relation to hyperpigmentation, neoplastic and oxidative stress processes associated with this porphyria.

Lighting conditions alter Candida albicans-induced sleep responses in rabbits

1995 ◽  
Vol 269 (6) ◽  
pp. R1441-R1447 ◽  
Author(s):  
L. A. Toth ◽  
J. M. Krueger
Keyword(s):  
Candida Albicans ◽  
Slow Wave ◽  
Slow Wave Sleep ◽  
Constant Darkness ◽  
Dark Phase ◽  
Circadian Period ◽  
Delta Wave ◽  
Lighting Conditions ◽  
Before And After ◽  
Sleep Alterations

To evaluate the influence of light on sleep patterns after microbial challenge, we studied rabbits housed in 12:12-h light-dark (LD), constant light (LL), or constant darkness (DD) before and after intravenous Candida albicans inoculation. Compared with the LD group, uninoculated LL rabbits sporadically increased slow-wave sleep and delta-wave amplitudes during the circadian period previously associated with the dark phase. In contrast, uninfected DD rabbits showed reduced sleep during the circadian period previously associated with the light phase. Inoculation of LD rabbits with Candida approximately 2 h after light onset increased slow-wave sleep and delta-wave amplitudes during hours 4-8 postinoculation and reduced these parameters during hours 20-46. In contrast, Candida-inoculated LL rabbits demonstrated increased slow-wave sleep for up to 28 h after inoculation, with little subsequent reduction; delta-wave amplitudes were similar to those of LD rabbits. Candida-inoculated DD rabbits demonstrated attenuated increases in slow-wave sleep and delta-wave amplitudes, but the suppression phase was not altered. We conclude that lighting conditions modulate microbially induced sleep alterations.

scholarly journals Circadian regulation of hydroxyindole-O-methyltransferase mRNA in the chicken pineal gland in vivo and in vitro

1996 ◽  
Vol 319 (3) ◽  
pp. 761-766 ◽  
Author(s):  
Pierre GRÈVE ◽  
Pierre VOISIN ◽  
Aline GRECHEZ-CASSIAU ◽  
Marianne BERNARD ◽  
Jean-Pierre COLLIN ◽  
...  
Keyword(s):  
Pineal Gland ◽  
Constant Darkness ◽  
Dark Phase ◽  
Mrna Levels ◽  
Circadian Oscillators ◽  
The Stability ◽  
Daily Changes ◽  
Effect Of Light

The production of the pineal hormone melatonin displays circadian variations with high levels at night. The last enzyme involved in melatonin biosynthesis is hydroxyindole-O-methyltransferase (HIOMT, EC 2.1.1.4). The expression of the mRNA encoding chicken HIOMT was investigated in vivo and in vitro throughout the light/dark cycle, in constant darkness and with light interruption of the dark phase. The stability of HIOMT mRNA was also examined. A day/night rhythm of HIOMT mRNA levels, with a peak at the midlight phase, was observed in vivo as well as in vitro. Constant darkness did not abolish this rhythm in vivo. One cycle of the HIOMT mRNA rhythm could be observed in constant darkness in vitro. In addition, a stimulatory effect of light on HIOMT mRNA levels during the dark phase could be observed in vivo as well as in vitro. HIOMT mRNA stability was not affected by light or dark conditions, as demonstrated by chase experiments with actinomycin D. The results indicate that the daily changes in HIOMT mRNA concentration reflect transcriptional regulation by circadian oscillators and photosensory mechanisms that are endogenous to the pineal gland.

CIRCADIAN RHYTHM OF PINEAL UPTAKE OF 32P IN DOMESTIC FOWL

1977 ◽  
Vol 73 (1) ◽  
pp. 99-103 ◽  
Author(s):  
J. W. SACKMAN
Keyword(s):  
Circadian Rhythm ◽  
Pineal Gland ◽  
Domestic Fowl ◽  
Gallus Domesticus ◽  
Dark Phase ◽  
White Leghorn ◽  
Light Phase ◽  
Radioactive Phosphorus ◽  
Light:Dark Cycle ◽  
Constant Dark

SUMMARY The uptake of radioactive phosphorus by the pineal gland in White Leghorn cockerels (Gallus domesticus) showed a diurnal variation with maxima in the light phase and minima in the dark phase of the light:dark cycle. Constant light caused the rhythm to disappear while constant dark had no effect other than lowering the amplitude of the variations. These data indicate that the rhythm in pineal uptake of 32P is circadian.

Effects of Changes in Environmental Lighting Upon Levels of Hydroxyindole O-Methyltransferase Activity in the Developing-Chick Pineal Gland

1975 ◽  
Vol 53 (4) ◽  
pp. 438-443 ◽  
Author(s):  
S. D. Wainwright
Keyword(s):  
Enzyme Activity ◽  
Pineal Gland ◽  
Diurnal Cycle ◽  
Enzymic Activity ◽  
Constant Light ◽  
Constant Darkness ◽  
Methyltransferase Activity ◽  
Constant Illumination ◽  
Lighting Conditions ◽  
Environmental Lighting

The level of hydroxyindole O-methyltransferase (HIOMT) activity in the pineal gland of developing chicks raised under constant illumination rose more rapidly and to higher values than in the gland of birds maintained in constant darkness. Rates of net increase in activity, and levels of activity attained, for birds raised under a diurnal cycle of illumination were intermediate between those maintained in constant light or darkness. Under each of the lighting conditions, the course of increase in enzymic activity was markedly affected by variations in an unidentified factor, the source of which appeared to be the hatching eggs.Birds transferred from constant light to the dark showed either an arrest of increase in enzyme activity or a loss of activity until the level equalled that observed for chicks of the same age raised in constant darkness. Chicks transferred from constant darkness to constant illumination showed marked increases in levels of enzyme activity at rates comparable with the maximal values observed with birds maintained under constant illumination, regardless of age and without delay. No diurnal cycle in level of HIOMT activity was observed in the pineals of 15-day birds.

scholarly journals Melatonin MT1 and MT2 Receptors Exhibit Distinct Effects in the Modulation of Body Temperature across the Light/Dark Cycle

2019 ◽  
Vol 20 (10) ◽  
pp. 2452 ◽  
Author(s):  
Martha López-Canul ◽  
Seung Hyun Min ◽  
Luca Posa ◽  
Danilo De Gregorio ◽  
Annalida Bedini ◽  
...  
Keyword(s):  
Body Temperature ◽  
Receptor Antagonist ◽  
Partial Agonist ◽  
Receptor Subtypes ◽  
Dark Phase ◽  
Light Phase ◽  
Dark Cycle ◽  
Simultaneous Activation ◽  
Type 3 ◽  
G Protein Coupled

Melatonin (MLT) is a neurohormone that regulates many physiological functions including sleep, pain, thermoregulation, and circadian rhythms. MLT acts mainly through two G-protein-coupled receptors named MT1 and MT2, but also through an MLT type-3 receptor (MT3). However, the role of MLT receptor subtypes in thermoregulation is still unknown. We have thus investigated the effects of selective and non-selective MLT receptor agonists/antagonists on body temperature (Tb) in rats across the 12/12-h light–dark cycle. Rectal temperature was measured every 15 min from 4:00 a.m. to 9:30 a.m. and from 4:00 p.m. to 9:30 p.m., following subcutaneous injection of each compound at either 5:00 a.m. or 5:00 p.m. MLT (40 mg/kg) had no effect when injected at 5 a.m., whereas it decreased Tb during the light phase only when injected at 5:00 p.m. This effect was blocked by the selective MT2 receptor antagonist 4P-PDOT and the non-selective MT1/MT2 receptor antagonist, luzindole, but not by the α1/MT3 receptors antagonist prazosin. However, unlike MLT, neither the selective MT1 receptor partial agonist UCM871 (14 mg/kg) nor the selective MT2 partial agonist UCM924 (40 mg/kg) altered Tb during the light phase. In contrast, UCM871 injected at 5:00 p.m. increased Tb at the beginning of the dark phase, whereas UCM924 injected at 5:00 a.m. decreased Tb at the end of the dark phase. These effects were blocked by luzindole and 4P-PDOT, respectively. The MT3 receptor agonist GR135531 (10 mg/kg) did not affect Tb. These data suggest that the simultaneous activation of both MT1 and MT2 receptors is necessary to regulate Tb during the light phase, whereas in a complex but yet unknown manner, they regulate Tb differently during the dark phase. Overall, MT1 and MT2 receptors display complementary but also distinct roles in modulating circadian fluctuations of Tb.

Locomotor activity responses in juvenile sockeye salmon, Oncorhynchus nerka, to melatonin and serotonin

1970 ◽  
Vol 48 (6) ◽  
pp. 1425-1427 ◽  
Author(s):  
John E. Byrne
Keyword(s):  
Locomotor Activity ◽  
Sockeye Salmon ◽  
Oncorhynchus Nerka ◽  
Dark Phase ◽  
Light Phase ◽  
Selective Activity

Intraperitoneal injections administered for 3 consecutive days to juvenile sockeye salmon resulted in selective activity responses to either the light or the dark phase of the photoperiodic cycle. Serotonin increased locomotor activity only during the dark phase, while melatonin decreased locomotor activity only during the light phase.

Circadian and estrous cycle-dependent variations in blood pressure and heart rate in female rats

1994 ◽  
Vol 267 (5) ◽  
pp. R1250-R1256 ◽  
Author(s):  
H. Takezawa ◽  
H. Hayashi ◽  
H. Sano ◽  
H. Saito ◽  
S. Ebihara
Keyword(s):  
Heart Rate ◽  
Estrous Cycle ◽  
Female Rats ◽  
Constant Darkness ◽  
Dark Phase ◽  
Daily Rhythms ◽  
Abrupt Decrease ◽  
Internal Phase ◽  
Free Running ◽  
Cycle Dependent

To determine whether cardiovascular functions are controlled by the endogenous circadian system and whether they change with the estrous cycle in female rats, we measured mean arterial pressure (MAP), heart rate (HR), and spontaneous activity (ACT) of female rats using an implantable radiotelemetry device and a computerized data-collecting system. Under a 12:12-h light-dark (LD) cycle, these parameters exhibited daily rhythms that were entrained to the photic cycle. The patterns of the daily rhythms varied with estrous cycles, and variations were particularly marked in the proestrous stage. During the dark period of this stage, ACT levels were significantly higher, but HR was significantly lower than in other stages. Although the peak MAP occurred within 2 h after the onset of the dark phase in three of the estrous stages, it occurred around midnight in the proestrous stage. Such estrous cycle-dependent variations were eliminated by ovariectomy. The implantation of 17 beta-estradiol produced a gradual increase in MAP and an abrupt decrease in HR. During constant darkness, all three parameters were free running, maintaining the same internal phase relationships with each other as during LD cycles. These results indicate that daily variations in these parameters were controlled by the endogenous circadian oscillating system, that they vary with the estrous cycle in female rats, and that estrogen may be responsible for these estrous cycle-dependent variations.

scholarly journals Algae-Assisted Microbial Desalination Cell: Analysis of Cathode Performance and Desalination Efficiency Assessment

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 2011
Author(s):  
David Ewusi-Mensah ◽  
Jingyu Huang ◽  
Laura Katherin Chaparro ◽  
Pau Rodenas ◽  
Marina Ramírez-Moreno ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Chlorella Vulgaris ◽  
Coulombic Efficiency ◽  
Geobacter Sulfurreducens ◽  
Dark Phase ◽  
Water Production ◽  
Light Phase ◽  
Experimental Conditions ◽  
Residual Concentration ◽  
Microbial Desalination Cell

Algae-assisted microbial desalination cells represent a sustainable technology for low-energy fresh water production in which microalgae culture is integrated into the system to enhance oxygen reduction reaction in the cathode chamber. However, the water production (desalination rate) is low compared to conventional technologies (i.e., reverse osmosis and/or electrodialysis), as biocathodes provide low current generation to sustain the desalination process. In this sense, more research efforts on this topic are necessary to address this bottleneck. Thus, this study provides analysis, from the electrochemical point of view, on the cathode performance of an algae-assisted microbial desalination cell (MDC) using Chlorella vulgaris. Firstly, the system was run with a pure culture of Chlorella vulgaris suspension in the cathode under conditions of an abiotic anode to assess the cathodic behavior (i.e., cathode polarization curves in light-dark conditions and oxygen depletion). Secondly, Geobacter sulfurreducens was inoculated in the anode compartment of the MDC, and the desalination cycle was carried out. The results showed that microalgae could generate an average of 9–11.5 mg/L of dissolved oxygen during the light phase, providing enough dissolved oxygen to drive the migration of ions (i.e., desalination) in the MDC system. Moreover, during the dark phase, a residual concentration of oxygen (ca. 5.5–8 mg/L) was measured, indicating that oxygen was not wholly depleted under our experimental conditions. Interestingly, the oxygen concentration was restored (after complete depletion of dissolved oxygen by flushing with N2) as soon as microalgae were exposed to the light phase again. After a 31 h desalination cycle, the cell generated a current density of 0.12 mA/cm2 at an efficiency of 60.15%, 77.37% salt was removed at a nominal desalination rate of 0.63 L/m2/h, coulombic efficiency was 9%, and 0.11 kWh/m3 of electric power was generated. The microalgae-assisted biocathode has an advantage over the air diffusion and bubbling as it can self-sustain a steady and higher concentration of oxygen, cost-effectively regenerate or recover from loss and sustainably retain the system’s performance under naturally occurring conditions. Thus, our study provides insights into implementing the algae-assisted cathode for sustainable desalination using MDC technology and subsequent optimization.

scholarly journals Aging Alters Daily and Regional Calretinin Neuronal Expression in the Rat Non-image Forming Visual Thalamus

2021 ◽  
Vol 13 ◽  
Author(s):  
Felipe P. Fiuza ◽  
José Pablo G. Queiroz ◽  
Antônio Carlos Q. Aquino ◽  
Diego A. Câmara ◽  
Luiz Eduardo M. Brandão ◽  
...  
Keyword(s):  
Calcium Binding ◽  
Brain Dysfunction ◽  
Dark Phase ◽  
Light Phase ◽  
Dark Light ◽  
Visual Thalamus ◽  
Age Related ◽  
Spatial Domains ◽  
Subcortical Regions ◽  
Daily Changes

Aging affects the overall physiology, including the image-forming and non-image forming visual systems. Among the components of the latter, the thalamic retinorecipient inter-geniculate leaflet (IGL) and ventral lateral geniculate (vLGN) nucleus conveys light information to subcortical regions, adjusting visuomotor, and circadian functions. It is noteworthy that several visual related cells, such as neuronal subpopulations in the IGL and vLGN are neurochemically characterized by the presence of calcium binding proteins. Calretinin (CR), a representative of such proteins, denotes region-specificity in a temporal manner by variable day–night expression. In parallel, age-related brain dysfunction and neurodegeneration are associated with abnormal intracellular concentrations of calcium. Here, we investigated whether daily changes in the number of CR neurons are a feature of the aged IGL and vLGN in rats. To this end, we perfused rats, ranging from 3 to 24 months of age, within distinct phases of the day, namely zeitgeber times (ZTs). Then, we evaluated CR immunolabeling through design-based stereological cell estimation. We observed distinct daily rhythms of CR expression in the IGL and in both the retinorecipient (vLGNe) and non-retinorecipient (vLGNi) portions of the vLGN. In the ZT 6, the middle of the light phase, the CR cells are reduced with aging in the IGL and vLGNe. In the ZT 12, the transition between light to dark, an age-related CR loss was found in all nuclei. While CR expression predominates in specific spatial domains of vLGN, age-related changes appear not to be restricted at particular portions. No alterations were found in the dark/light transition or in the middle of the dark phase, ZTs 0, and 18, respectively. These results are relevant in the understanding of how aging shifts the phenotype of visual related cells at topographically organized channels of visuomotor and circadian processing.

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