scholarly journals LIGHT DEPREVATION INFLUENCE ON MORPHOFUNCTIONAL STATE OF NEURONS OF THE HYPOTHALAMUS SUPRAOPTIC NUCLEI IN RATS

2021 ◽  
Vol 19 (4) ◽  
Author(s):  
O.V. Smetaniuk ◽  
R.Ye. Bulyk ◽  
T.S. Bulyk ◽  
М.І. Kryvchanska
Keyword(s):  
Supraoptic Nucleus ◽  
Prolonged Exposure ◽  
Maximum Activity ◽  
Constant Darkness ◽  
Endocrine Regulation ◽  
Light Deprivation ◽  
Statistical Research ◽  
White Rats ◽  
Night And Day ◽  
Rna Concentration

The supraoptic nucleus (SON) of the hypothalamus is one of the key neurosecretorylinks that ensure the joining of the nervous and endocrine regulation mechanismsinto the general neuroendocrine system, thereby participating in the realization of thebody’s response to experimental influences. Despite deep and comprehensive studies ofthe hypothalamus, until now there are no unified ideas about its individual reactivityand the degree of involvement of these structures in the stress response, caused by prolonged exposure to constant darkness (light deprivation).The aim of this work is to study the effect of light deprivation on the morphofunctionalstate of the supraoptic nucleus of the hypothalamus in rats.Material and methods. The experiments were carried out on nonlinear male white rats,which were divided into 2 series of studies, biomaterial sampling of which was taken at14.00 and 02.00 h using morphofunctional and statistical research methods.Results. The study of the morphometric characteristics of the neurons of thehypothalamus SON revealed the diurnal dynamics of indices. Under the light regime12.00C:12.00T, a daily rhythm of the morpho-functional activity of SON neurons witha maximum activity is registered in rats in the daytime.When the animals were kept under conditions of constant darkness (00C:24.00T), anincrease in the size of its nucleus 21.1±2.4% (r=0.73), caused by an increase in thearea of the neuron nucleolus (r=0.89), which constituted 61.94±7.07 µm2, was revealedat 14.00. Attention was also drawn to a significant decrease in the nuclear-cytoplasmicratio (NCR) relative to intact animals, which constituted 2.07±0.041 units. Lightdeprivation led at 14.00 to a significant RNA concentration decrease in the nucleus35.3±2.1%, and in the nucleolus 26.6±1.9%.The studies, carried out at 02.00 h, revealed that the area of the neuron nucleuswas 98.33±5.40µm2and significantly larger than that in the intact animals. Thesechanges were accompanied by an increase in the area of the nucleolus, which was48.90±6.892µm2(r=0.87) and the area of the neuron cytoplasm, which was within217.61±7.19 µm2(r=0.91). The NCR of a neuron in the SON of the hypothalamus at02:00 was lower than that in the intact animals 2.67±0.17%. A significant increasein RNA concentration in the nucleus, nucleolus and cytoplasm of neurons in thehypothalamic SON was noted relative to the indices of animals of the previous timeinterval, which were under conditions of constant darkness.Compared to the daytime period (14.00 h), up to 02.90 h, NCR increase was revealedin the nighttime observation period in the neurons under study, which constituted2.55±0.022 units.Conclusions. 1. Photoperiod duration significantly affects the daily activity of thehypothalamus SON. 2. Permanent darkness (light deprivation) does not lead to aninversion of the rhythm of the morphofunctional activity of the neurons under study,the maximum values, as in intact animals, are registered in the daytime interval. 3.Light deprivation causes a significant increase in the area of the neuron, its nucleus,nucleolus in the night and day intervals of observation. At the same time, a decrease inthe nuclear-cytoplasmic ratio, a decrease in the concentration of RNA in the nucleusand nucleolus of the neuron of SON of the hypothalamus of rats in the daytime isobserved.

scholarly journals The biological action of solid solutions (on the example of cadmium-mercury-tellurium alloy)

2020 ◽  
Vol 64 (3) ◽  
pp. 158-162
Author(s):  
Natalia I. Nikolayeva ◽  
Andrey S. Filin ◽  
Ekaterina A. Guseva ◽  
Lubov’ G. Ivanova
Keyword(s):  
Solid Solution ◽  
Solid Solutions ◽  
Biological Effect ◽  
Prolonged Exposure ◽  
Biological Effects ◽  
Experimental Studies ◽  
Mercury Vapor ◽  
The Body ◽  
Hazard Class ◽  
Statistical Research

Solid solutions are widely used in various industries. Experimental studies have been conducted to study the biological effects of warm-blooded animals (rat, mouse) solid solution based on cadmium (7%) mercury (52%) and tellurium (41%) (CMT). The purpose of the study: To investigate the biological effect of the solid solution (CMT) on the body of experimental animals. Material and methods. On the models of acute and subchronic exposure, the biological effect of CMT on the organism of warm-blooded animals (rats, mice) was evaluated. Studies have been carried out to establish toxicometry parameters (acute toxicity, the threshold for acute inhalation and intragastric effects, cumulative properties). In subchronic experiments, local and general toxic effects were investigated. The work used biochemical, physiological, toxicological, pathomorphological, statistical research methods. Results. According to acute experiments, the investigated substance belongs to the 4th hazard class (low-hazard compound). The threshold of acute inhalation action for rats is 46.20 mg/m3, and the intragastric effect for rats is 5000 mg/kg. CMT has moderate cumulation (Kcum = 4.79), does not irritate the skin. The compound was found to have a general toxic effect, which is based on functional disorders of the nervous system, liver, and kidneys. Discussion. The results of the study indicate that solid CMT solution has a polytropic effect on the warm-blooded organism. Conclusion. With prolonged exposure, the CMT aerosol can harm the body of workers, it is necessary to provide general preventive measures that prevent the aerosol of solid solutions from entering the body: automation, mechanization, sealing of production, adequate ventilation of production rooms, the use of personal protective equipment, the passage of mandatory periodic medical examinations by workers, and monitoring the concentration of CMT in the air of the working area should be carried out according to the MPC - 1.0 mg / m3 (mercury vapor).

scholarly journals The influence of melatonin on stress-induced ultramicroscopic changes of the neurons of the supraoptic nuclei of the rat hypothalamus

2021 ◽  
Vol 25 (3 (99)) ◽  
pp. 25-32
Author(s):  
R. Bulyk ◽  
T. Bulyk ◽  
O. Smetanuik
Keyword(s):  
Immobilization Stress ◽  
Prolonged Exposure ◽  
Neurosecretory Cells ◽  
Ultrastructural Organization ◽  
Neurosecretory Granules ◽  
Electron Microscopic ◽  
Relative Improvement ◽  
White Rats ◽  
Hypothalamic Nuclei ◽  
Supraoptic Nuclei

The aim: to study the effect of melatonin on the ultrastructural state of the supraoptic nuclei of the hypothalamus of rats under immobilization stress.Materials and methods. The experiments were performed on non-linear male white rats weighing 200-220 g. The animals were divided into 3 study series, in each of which the biomaterial was collected at 2 p.m. and at 2 a.m. using electron microscopic method. Long immobilization stress was simulated by keeping rats in special plastic penal cages for 6 hours daily for 7 consecutive days. Melatonin (Sigma, USA, 99.5% purification degree) at a dose of 0.5 mg/kg, in 1.0 ml of solvent (0.9% ethanol solution on physiologic saline) was injected daily, intraperitoneally.Results. When the animals were kept under the standard light regime, the ultrastructural organization of the hypothalamic nuclei at 2 p.m. indicated their low functional activity in comparison with the studies carried out at 2 a.m. Prolonged exposure of rats to immobilization stress was reflected in a significant rearrangement of the ultrastructural organization of supraoptic nuclei of the hypothalamus. The established changes can be considered as a manifestation of neurosecretory activity suppression, a decrease in neurosecretase production by hypothalamic neurons. Melatonin injections against the background of immobilization stress resulted in relative normalization of ultrastructural state of neurons of supraoptic nuclei of the hypothalamus of animals. In particular, studies at 2 a.m. revealed light neurosecretory cells containing a large nucleus, it was pyknotically altered. Karyolema invaginations, euchromatin dominance in the nucleus were observed. Heterogeneous changes were observed on the part of mitochondria. Enlarged tubules of granular endoplasmic reticulum were seen. At the same time, a small number of ribosomes and few hormonal granules were noticeable in neuroplasm. The mentioned picture of neurosecretory cells reflects a relative improvement in their electron microscopic state, which is evidenced by the appearance of neurosecretory granules. However, the ultrastructure of other organelles of the studied neurons indicates a depleted state caused by prolonged immobilization.Conclusions. 1. In animals under standard photoperiod conditions, the structural organization of supraoptic neurons of the hypothalamic nuclei during the nighttime of the experiment reflects the intensity of intracellular synthesizing processes (at 2 a.m.). A decrease in the activity of the structures under study is noted during the daytime. 2. Under immobilization stress, the ultrastructural organization of the above neurons indicates a pronounced disturbance of reactive nature with the signs of decreased functional ability of the structures and the phenomena of edema and destruction during the period of observation. 3. Melatonin injections against the background of immobilization stress led to a relative improvement in the ultrastructural state of the animals’ hypothalamic nuclei neurons, which is evidenced by the appearance of neurosecretory granules. However, the ultrastructure of other organelles of the studied neurons indicated a depleted state caused by prolonged immobilization.

Chick pineal serotonin acetyltransferase: a diurnal cycle maintained in vitro and its regulation by light

1979 ◽  
Vol 57 (6) ◽  
pp. 700-709 ◽  
Author(s):  
S. D. Wainwright ◽  
Lillian K. Wainwright
Keyword(s):  
Enzyme Activity ◽  
Diurnal Cycle ◽  
Prolonged Exposure ◽  
Continuous Illumination ◽  
Constant Darkness ◽  
Light Cycle ◽  
Acetyltransferase Activity ◽  
Lighting Conditions

We have reproduced in vitro the diurnal cycles in levels of serotonin acetyltransferase activity found in the chick pineal gland in vivo. The more closely the lighting conditions of culture matched those under which the birds were raised, the closer was the similarity between cycles in levels of enzyme activity in vitro and in vivo. Repetitive cycles in levels of acetyltransferase activity persisted in culture for at least 4 days under a diurnal cycle of illumination, and at least 2 days in continuous darkness. When glands were explanted into culture in the light phase of a cycle, short periods of further exposure to light markedly stimulated subsequent increase of acetyltransferase in the dark (after a short lag). Prolonged exposure to light in culture markedly inhibited increase of enzyme activity. Cycles in the levels of enzyme activity in glands cultured under altered light cycles were regulated primarily by changes in illumination. However, the endogenous biological 'clock' remained at least partly entrained to the original light cycle. Increase of acetyltransferase activity in vitro was markedly stimulated by theophylline plus compound Ro. 20.1724 (4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone) under all lighting conditions. Kinetics (to the time of attaining maximum levels in situ) of the increase under diurnal lighting and in constant darkness were indistinguishable from those in vivo. A high concentration of dl-propranolol markedly stimulated an increase in acetyltransferase activity in glands cultured in constant darkness but had little effect on glands under diurnal lighting or continuous illumination.

scholarly journals Metaproteomic Discovery and Characterization of a Novel Lipolytic Enzyme From an Indian Hot Spring

2021 ◽  
Vol 12 ◽  
Author(s):  
Dennis Sander ◽  
Yanfei Yu ◽  
Premankur Sukul ◽  
Sina Schäkermann ◽  
Julia E. Bandow ◽  
...  
Keyword(s):  
Chain Length ◽  
Prolonged Exposure ◽  
Hot Spring ◽  
Hydrolytic Activity ◽  
Industrial Applications ◽  
Maximum Activity ◽  
Lipolytic Enzyme ◽  
Lipolytic Enzymes ◽  
Optimum Activity ◽  
Solvent Stable

Lipolytic enzymes are produced by animals, plants and microorganisms. With their chemo-, regio-, and enantio-specific characteristics, lipolytic enzymes are important biocatalysts useful in several industrial applications. They are widely used in the processing of fats and oils, detergents, food processing, paper and cosmetics production. In this work, we used a new functional metaproteomics approach to screen sediment samples of the Indian Bakreshwar hot spring for novel thermo- and solvent-stable lipolytic enzymes. We were able to identify an enzyme showing favorable characteristics. DS-007 showed high hydrolytic activity with substrates with shorter chain length (<C8) with the maximum activity observed against p-nitrophenyl butyrate (C4). For substrates with a chain length >C10, significantly less hydrolytic activity was observed. A preference for short chain acyl groups is characteristic for esterases, suggesting that DS-007 is an esterase. Consistent with the high temperature at its site of isolation, DS-007 showed a temperature optimum at 55°C and retained 80% activity even after prolonged exposure to temperatures as high as 60°C. The enzyme showed optimum activity at pH 9.5, with more than 50% of its optimum activity between pH 8.0 and pH 9.5. DS-007 also exhibited tolerance toward organic solvents at a concentration of 1% (v/v). One percent of methanol increased the activity of DS-007 by 40% in comparison to the optimum conditions without solvent. In the presence of 10% methanol, DMSO or isopropanol DS-007 still showed around 50% activity. This data indicates that DS-007 is a temperature- and solvent-stable thermophilic enzyme with reasonable activity even at lower temperatures as well as a catalyst that can be used at a broad range of pH values with an optimum in the alkaline range, showing the adaptation to the habitat’s temperature and alkaline pH.

scholarly journals GENDER-SPECIFIC DIFFERENCES OF CARDIAC VEGETATIVE CONTROL IN ADRENALINE-INDUCED NECROSIS AND LIGHT DEPRIVATION

2020 ◽  
Vol 5 (2) ◽  
pp. 137-144
Author(s):  
H. O. Bezkorovaina ◽  
I. M. Klishch ◽  
M. R. Khara ◽  
V. Ye. Pelykh
Keyword(s):  
Cardiovascular Disease ◽  
Myocardial Necrosis ◽  
Heart Rhythm ◽  
Light Deprivation ◽  
Cardiac Effects ◽  
White Rats ◽  
Gender Specific Differences ◽  
Parasympathetic Control ◽  
Males And Females ◽  
Gender Specific

Background. Cardiovascular disease is the main cause of morbidity predominantly in males. Stress is one of the crucial factors, especially with light desynchronosis. Objective of the study was to assess gender-specific characteristics of cardiac vegetative control in myocardial necrosis in cases of light deprivation. Methods. Cardiac vegetative control in adrenaline-induced myocardial necrosis (AIMN) in a setting of light deprivation (LD) was assessed in 72 mature white rats of both sexes. The animals were divided into 2 groups: G1 – the animals kept under day/night cyclic balance (12 hours/12 hours); G2 – the animals kept at LD (illumination 0.5-1 LX) for 10 days. On Day 11, AIMN caused by adrenaline (0.5 mg/kg) and heart rate variability (HRV) was assessed in 1 hour and 24 hours. Results. The development of AIMN at LD in the ♂G2 led to HRV increase that was caused by augmentation of parasympathetic and reduction of sympathetic cardiac effects. In cases of AIMN, changes of CVC in the ♀G2 were similar to the ♀G1. However, in 1 hour of AIMN, parasympathetic cardiac effects were more significant than in the ♀G1. While the ♀G2 AIMN animals experienced balanced sympathetic and parasympathetic actions, the predominance of the sympathetic component was evidenced in the ♀G1 AIMN animals. Conclusions. Light deprivation has different effects on baseline sympathetic/parasympathetic balance in males and females, i.e. increased parasympathetic control of heart rhythm in males and maintenance of sympathetic/ parasympathetic balance in females.

Prolonged exposure of young rats to an oxygen atmosphere at reduced pressure

1964 ◽  
Vol 19 (1) ◽  
pp. 17-20 ◽  
Author(s):  
John H. Dines ◽  
Edwin P. Hiatt
Keyword(s):  
Prolonged Exposure ◽  
Young Male ◽  
Hemoglobin Concentration ◽  
Ambient Air ◽  
Pure Oxygen ◽  
Consistent Difference ◽  
Free Atmosphere ◽  
Reduced Pressure ◽  
White Rats ◽  
Urine Production

The effect was studied of exposing 12 young male white rats to an atmosphere almost free of nitrogen but with an alveolar Po2 the same as that of the 12 control animals breathing ambient air. This was achieved by keeping the experimental animals in almost pure oxygen at a reduced pressure. Experimental and control animals were in closed chambers with oxygen being supplied from a spirometer while Co2 was absorbed. Humidity and temperature were closely regulated. Provision was made for handling the animals and supplying them with food and water without changing the chamber environment. A successful experiment lasting 24 days was completed, not including observation periods of 6 days be-before and 8 days after the experiment when both groups were kept in air. No consistent difference was noted in rate of growth, oxygen consumption, food consumption, water intake, hemoglobin concentration, or behavior of the two groups. A decreased rate of urine production by the rats in the experimental group was attributed to an increased evaporative loss of water in the rarified atmosphere. nitrogen-free atmosphere; growth rate; O2 consumption; reduced pressure; oxygen low pressure atmosphere Submitted on March 20, 1963

scholarly journals Daily blue-light exposure shortens lifespan and causes brain neurodegeneration in Drosophila

2019 ◽  
Vol 5 (1) ◽  
Author(s):  
Trevor R. Nash ◽  
Eileen S. Chow ◽  
Alexander D. Law ◽  
Samuel D. Fu ◽  
Elzbieta Fuszara ◽  
...  
Keyword(s):  
Blue Light ◽  
Prolonged Exposure ◽  
Light Exposure ◽  
Model Organism ◽  
Accelerated Aging ◽  
Health Concern ◽  
Constant Darkness ◽  
Long Term Effects ◽  
Light Emitting

Abstract Light is necessary for life, but prolonged exposure to artificial light is a matter of increasing health concern. Humans are exposed to increased amounts of light in the blue spectrum produced by light-emitting diodes (LEDs), which can interfere with normal sleep cycles. The LED technologies are relatively new; therefore, the long-term effects of exposure to blue light across the lifespan are not understood. We investigated the effects of light in the model organism, Drosophila melanogaster, and determined that flies maintained in daily cycles of 12-h blue LED and 12-h darkness had significantly reduced longevity compared with flies maintained in constant darkness or in white light with blue wavelengths blocked. Exposure of adult flies to 12 h of blue light per day accelerated aging phenotypes causing damage to retinal cells, brain neurodegeneration, and impaired locomotion. We report that brain damage and locomotor impairments do not depend on the degeneration in the retina, as these phenotypes were evident under blue light in flies with genetically ablated eyes. Blue light induces expression of stress-responsive genes in old flies but not in young, suggesting that cumulative light exposure acts as a stressor during aging. We also determined that several known blue-light-sensitive proteins are not acting in pathways mediating detrimental light effects. Our study reveals the unexpected effects of blue light on fly brain and establishes Drosophila as a model in which to investigate long-term effects of blue light at the cellular and organismal level.

scholarly journals Regulation of trypsin-like enzyme activity in the tissues of white rats with thiamine

2016 ◽  
Vol 71 (1) ◽  
pp. 77-81
Author(s):  
O. Ustjansky ◽  
S. Petrov ◽  
O. Budnyak ◽  
S. Gozhenk
Keyword(s):  
Enzyme Activity ◽  
Small Intestine ◽  
Protease Activity ◽  
Maximum Activity ◽  
Parenteral Administration ◽  
White Rats ◽  
Intact Rats

The effect of intramuscular thiamine injection on the activity of trypsin-like enzymes in the liver, kidneys, stomach and small intestine of white rats has been researched. In the organs of intact rats, the maximum activity of trypsin-like proteases has been established in the small intestine, and the minimum one in the liver. Thiamine parenteral administration leads to the decrease of trypsin-like protease activity in the liver, kidney and stomach, and the increase of the enzyme activity in the small intestine that suggests the possibility of non-coenzyme thiamine effect on the trypsin-like enzyme activity.

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