scholarly journals Structural changes in rat colon under obesity conditions and its correction by morning and evening injection of melatonin

2019 ◽  
Vol 79 (3) ◽  
pp. 27-31
Author(s):  
I. Vareniuk ◽  
N. Shevchuk ◽  
N. Roslova ◽  
M. Dzerzhynsky
Keyword(s):  
Mast Cells ◽  
Large Intestine ◽  
Colonic Mucosa ◽  
Structural Changes ◽  
Goblet Cells ◽  
Rat Colon ◽  
Functional Changes ◽  
Calorie Diet ◽  
Morning Administration ◽  
Evening Administration

The effect of morning and evening administrations of melatonin on structural and functional changes in the large intestine of rats with obesity under conditions of the spring-autumn photoperiod (12L:12D) was studied in this work. The obesity was caused with a high-calorie diet for 6 weeks. After that, the morning or evening melatonin administrations were given to normal and obese animals at a dose of 30 mg/kg for 7 weeks. After 13 weeks, two specimens of the colon 1 cm each were taken at a distance of 3 cm from the anus; fixed in 10% formalin and in Carnua solution; paraffin sections of the large intestine were made; stained them with hematoxylin-eosin, alcian blue-carmine, or toluidine blue. Microscopic and morphometric analysis of these sections was performed. It has been shown, that obesity cause hyperactivation of the colonic mucosa, reduction of colonocytes, hypertrophy of goblet cells and overaccumulation of granules in mast cells. Morning administration of melatonin to obese animals normalizes the colonic mucosa, decreases the reduction of colonocytes, but causes the hypotrophy of goblet cells. Evening administration of melatonin significantly decreases the reduction of colonocytes, but does not eliminate other changes caused by obesity. The administration of melatonin (both morning and evening) to animals without obesity causes an activation of the mucosa, hypertrophy of goblet cells, reduction of colonocytes, and does not change the state of mast cells. Consequently, it cannot make a clear conclusion about the possibility of correction of all structural-functional changes in the large intestine during obesity by melatonin. Although, the morning administration of melatonin had some normalizing effects on the colon and it was more effective than evening administration.

scholarly journals Influence of morning and evening melatonin administration on the mucosa and crypts of a small intestine in rats with obesity

2019 ◽  
Vol 78 (2) ◽  
pp. 50-53
Author(s):  
I. Vareniuk ◽  
N. Shevchuk ◽  
N. Roslova ◽  
M. Dzerzhynsky
Keyword(s):  
Small Intestine ◽  
Structural Changes ◽  
Goblet Cells ◽  
Functional Changes ◽  
Melatonin Administration ◽  
Calorie Diet ◽  
Mucosal Edema ◽  
Morning Administration ◽  
Evening Administration ◽  
High Calorie

The aim of this work was to determine structural and functional changes in a small intestine of rats after morning and evening administration of melatonin in obese animals during the spring-autumn photoperiod (12L:12D). The obesity was caused with a high-calorie diet for 6 weeks. After that, morning or evening melatonin administrations were given to normal and obese animals at a dose of 30 mg/kg for 7 weeks. After that, paraffin sections of the small intestine were made, on which a state of the mucosa, enterocytes and goblet cells in crypts was morphometrically and visually examined under a microscope. It has been shown, that obesity causes swelling and an increase of thickness of a mucosa, reduction of crypts, a decrease of activity of enterocytes and goblet cells of the small intestine. Introduction of melatonin to animals without obesity causes an increase in thickness of mucosa and a decrease in area of goblet cells. Additionally, after morning melatonin administration a depth of crypts and a height of enterocytes increases. Morning administration of melatonin to obese animals partially recovers crypts and their goblet cells, but doesn't prevent mucosal edema and worsens a state of enterocytes. The evening administration of melatonin partially normalizes all structural changes, caused by obesity. It was concluded, that melatonin may partially correct morpho-functional changes in the small intestine, caused by obesity in the spring and autumn seasons. The evening administration of melatonin to animals with obesity is more effective, than morning administrations. Also, the evening administration of melatonin causes fewer changes in the small intestine of animals without obesity, compared with morning administration.

Abstract P604: Astrocyte-dependent Regulation of Vascular Tone: Role in Hypertension

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Juan Manuel Ramiro-Diaz ◽  
Ki Jung Kim ◽  
Jessica A Filosa
Keyword(s):  
Vascular Tone ◽  
Structural Changes ◽  
Neurovascular Unit ◽  
Brain Slices ◽  
Vascular Cognitive Impairment ◽  
Vascular Density ◽  
Aqp4 Expression ◽  
Functional Changes ◽  
Functional Studies ◽  
Underlying Mechanisms

Clinical studies support that untreated hypertension (HT) accelerates the development of vascular cognitive impairment (VCI). Yet, the underlying mechanisms for VCI are not known. In a recent study we demonstrated the role of astrocytes in the regulation of parenchymal arteriole (PA) steady-state vascular tone. Here we hypothesized hypertension results in structural and functional changes to the neurovascular unit resulting in enhanced astrocytic TRPV4 channel-dependent Ca 2+ increases contributing to augmented pressure-induced PA constriction . Functional studies were conducted in brain slices from angiotensin II (AngII) treated mice (600 ng/Kg/min, 28 days). PA arterioles within brain slices were perfused and pressurized and myogenic-evoked diameter changes measured using video microscopy. In addition, using the GLAST-CreERT2 ; R26-lsl-GCaMP3 mice we measure myogenic-evoked Ca 2+ changes in perivascular astrocytes. We demonstrate that HT increases pressure-induced PA tone by 11.14% at 30 mmHg and 12.97% at 60 mmHg (10.88 to 22.02 and 15.46 to 28.43% of tone, P<0.05 and P<0.01, respectively). In ANG II-treated mice, PA myogenic-evoked responses significantly increased astrocytic Ca 2+ oscillations frequency (119.4%, 0.0366 to 0.0803 Hz, P<0.0001). A significant increase in astrocytic Ca 2+ oscillation frequency was also observed after 2 min of AngII (500 nM) bath application (44.8%, 0.0366 to 0.053 Hz, P<0.01) in brain slices from AngII treated mice. Furthermore, using the model of spontaneous hypertensive rat (SHR) we observed that HT differentially increases vascular density and the number of vascular pericytes in cortical layers with highest neuronal densities (L III-V). Finally, while aquaporin 4 (AQP4) expression pattern was not different in the gray matter of SHR compared with WKY rats, a significant increase in unpolarized AQP4 expression was observed in the white matter of SHR. Taken together, this evidence indicates that HT induces functional and structural changes to the neurovascular unit favoring the development of regional brain hypoperfusion likely contributing to the development of VCI.

scholarly journals Retinal functional imager (RFI): Non-invasive functional imaging of the retina

2013 ◽  
Vol 5 (2) ◽  
pp. 250-257 ◽  
Author(s):  
Sunil Ganekal
Keyword(s):  
Functional Imaging ◽  
Structural Changes ◽  
Imaging System ◽  
Retinal Blood Flow ◽  
Capillary Perfusion ◽  
Functional Changes ◽  
Non Invasive ◽  
Retinal Disorders ◽  
Retinal Blood Flow Velocity ◽  
Perfusion Maps

Retinal functional imager (RFI) is a unique non-invasive functional imaging system with novel capabilities for visualizing the retina. The objective of this review was to show the utility of non-invasive functional imaging in various disorders. Electronic literature search was carried out using the websites www.pubmed.gov and www.google.com. The search words were retinal functional imager and non-invasive retinal imaging used in combination. The articles published or translated into English were studied. The RFI directly measures hemodynamic parameters such as retinal blood-flow velocity, oximetric state, metabolic responses to photic activation and generates capillary perfusion maps (CPM) that provides retinal vasculature detail similar to flourescein angiography. All of these parameters stand in a direct relationship to the function and therefore the health of the retina, and are known to be degraded in the course of retinal diseases. Detecting changes in retinal function aid early diagnosis and treatment as functional changes often precede structural changes in many retinal disorders. Nepal J Ophthalmol 2013; 5(10): 250-257 DOI: http://dx.doi.org/10.3126/nepjoph.v5i2.8738

Airway smooth muscle tone modulates mechanically induced cytoskeletal stiffening and remodeling

2005 ◽  
Vol 99 (2) ◽  
pp. 634-641 ◽  
Author(s):  
Linhong Deng ◽  
Nigel J. Fairbank ◽  
Darren J. Cole ◽  
Jeffrey J. Fredberg ◽  
Geoffrey N. Maksym
Keyword(s):  
Smooth Muscle ◽  
Mechanical Stress ◽  
Applied Stress ◽  
Airway Smooth Muscle ◽  
Cell Activation ◽  
Structural Changes ◽  
Muscle Tone ◽  
Residual Effects ◽  
Cell Stiffness ◽  
Functional Changes

The application of mechanical stresses to the airway smooth muscle (ASM) cell causes time-dependent cytoskeletal stiffening and remodeling (Deng L, Fairbank NJ, Fabry B, Smith PG, and Maksym GN. Am J Physiol Cell Physiol 287: C440–C448, 2004). We investigated here the extent to which these behaviors are modulated by the state of cell activation (tone). Localized mechanical stress was applied to the ASM cell in culture via oscillating beads (4.5 μm) that were tightly bound to the actin cytoskeleton (CSK). Tone was reduced from baseline level using a panel of relaxant agonists (10−3 M dibutyryl cAMP, 10−4 M forskolin, or 10−6 M formoterol). To assess functional changes, we measured cell stiffness (G′) using optical magnetic twisting cytometry, and to assess structural changes of the CSK we measured actin accumulation in the neighborhood of the bead. Applied mechanical stress caused a twofold increase in G′ at 120 min. After cessation of applied stress, G′ diminished only 24 ± 6% (mean ± SE) at 1 h, leaving substantial residual effects that were largely irreversible. However, applied stress-induced stiffening could be prevented by ablation of tone. Ablation of tone also inhibited the amount of actin accumulation induced by applied mechanical stress ( P < 0.05). Thus the greater the contractile tone, the greater was applied stress-induced CSK stiffening and remodeling. As regards pathobiology of asthma, this suggests a maladaptive positive feedback in which tone potentiates ASM remodeling and stiffening that further increases stress and possibly leads to worsening airway function.

Myosin thick filament lability induced by mechanical strain in airway smooth muscle

2001 ◽  
Vol 90 (5) ◽  
pp. 1811-1816 ◽  
Author(s):  
Kuo-Hsing Kuo ◽  
Lu Wang ◽  
Peter D. Paré ◽  
Lincoln E. Ford ◽  
Chun Y. Seow
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Cross Sections ◽  
Structural Changes ◽  
Isometric Force ◽  
Mechanical Strain ◽  
Thick Filament ◽  
Functional Changes ◽  
Thick Filaments ◽  
Length Changes

Airway smooth muscle adapts to different lengths with functional changes that suggest plastic alterations in the filament lattice. To look for structural changes that might be associated with this plasticity, we studied the relationship between isometric force generation and myosin thick filament density in cell cross sections, measured by electron microscope, after length oscillations applied to the relaxed porcine trachealis muscle. Muscles were stimulated regularly for 12 s every 5 min. Between two stimulations, the muscles were submitted to repeated passive ±30% length changes. This caused tetanic force and thick-filament density to fall by 21 and 27%, respectively. However, in subsequent tetani, both force and filament density recovered to preoscillation levels. These findings indicate that thick filaments in airway smooth muscle are labile, depolymerization of the myosin filaments can be induced by mechanical strain, and repolymerization of the thick filaments underlies force recovery after the oscillation. This thick-filament lability would greatly facilitate plastic changes of lattice length and explain why airway smooth muscle is able to function over a large length range.

scholarly journals Regional synapse gain and loss accompany memory formation in larval zebrafish

2022 ◽  
Vol 119 (3) ◽  
pp. e2107661119
Author(s):  
William P. Dempsey ◽  
Zhuowei Du ◽  
Anna Nadtochiy ◽  
Colton D. Smith ◽  
Karl Czajkowski ◽  
...  
Keyword(s):  
Classical Conditioning ◽  
Structural Changes ◽  
Memory Formation ◽  
Excitatory Synapses ◽  
Microscopy Imaging ◽  
Functional Changes ◽  
Larval Zebrafish ◽  
Before And After ◽  
Synaptic Changes ◽  
With Memory

Defining the structural and functional changes in the nervous system underlying learning and memory represents a major challenge for modern neuroscience. Although changes in neuronal activity following memory formation have been studied [B. F. Grewe et al., Nature 543, 670–675 (2017); M. T. Rogan, U. V. Stäubli, J. E. LeDoux, Nature 390, 604–607 (1997)], the underlying structural changes at the synapse level remain poorly understood. Here, we capture synaptic changes in the midlarval zebrafish brain that occur during associative memory formation by imaging excitatory synapses labeled with recombinant probes using selective plane illumination microscopy. Imaging the same subjects before and after classical conditioning at single-synapse resolution provides an unbiased mapping of synaptic changes accompanying memory formation. In control animals and animals that failed to learn the task, there were no significant changes in the spatial patterns of synapses in the pallium, which contains the equivalent of the mammalian amygdala and is essential for associative learning in teleost fish [M. Portavella, J. P. Vargas, B. Torres, C. Salas, Brain Res. Bull. 57, 397–399 (2002)]. In zebrafish that formed memories, we saw a dramatic increase in the number of synapses in the ventrolateral pallium, which contains neurons active during memory formation and retrieval. Concurrently, synapse loss predominated in the dorsomedial pallium. Surprisingly, we did not observe significant changes in the intensity of synaptic labeling, a proxy for synaptic strength, with memory formation in any region of the pallium. Our results suggest that memory formation due to classical conditioning is associated with reciprocal changes in synapse numbers in the pallium.

scholarly journals Pairing Cholinergic Enhancement with Perceptual Training Promotes Recovery of Age-Related Changes in Rat Primary Auditory Cortex

2016 ◽  
Vol 2016 ◽  
pp. 1-18 ◽  
Author(s):  
Patrice Voss ◽  
Maryse Thomas ◽  
You Chien Chou ◽  
José Miguel Cisneros-Franco ◽  
Lydia Ouellet ◽  
...  
Keyword(s):  
Auditory Cortex ◽  
Structural Changes ◽  
Primary Auditory Cortex ◽  
Auditory Training ◽  
Tone Frequency ◽  
Perceptual Training ◽  
Adult Rats ◽  
Functional Changes ◽  
Age Related ◽  
Old Rats

We used the rat primary auditory cortex (A1) as a model to probe the effects of cholinergic enhancement on perceptual learning and auditory processing mechanisms in both young and old animals. Rats learned to perform a two-tone frequency discrimination task over the course of two weeks, combined with either the administration of a cholinesterase inhibitor or saline. We found that while both age groups learned the task more quickly through cholinergic enhancement, the young did so by improving target detection, whereas the old did so by inhibiting erroneous responses to nontarget stimuli. We also found that cholinergic enhancement led to marked functional and structural changes within A1 in both young and old rats. Importantly, we found that several functional changes observed in the old rats, particularly those relating to the processing and inhibition of nontargets, produced cortical processing features that resembled those of young untrained rats more so than those of older adult rats. Overall, these findings demonstrate that combining auditory training with neuromodulation of the cholinergic system can restore many of the auditory cortical functional deficits observed as a result of normal aging and add to the growing body of evidence demonstrating that many age-related perceptual and neuroplastic changes are reversible.

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