scholarly journals Effect of sinusoidal electrical cortical stimulation on brain cells

2019 ◽  
Author(s):  
Seungjun Ryu ◽  
Kyung-Tai Kim ◽  
Hyeon Seo ◽  
Jongwook Cho ◽  
Jiyoung Park ◽  
...  
Keyword(s):  
Neurological Diseases ◽  
Cortical Stimulation ◽  
Inhibitory Neurons ◽  
Brain Cells ◽  
Specific Cell ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Different Types ◽  
Dependent Protein ◽  
40 Hz

ABSTRACTBackgroundElectrical cortical stimulation is often used in patients with neurological disorders but it is unclear how it modulates different types of brain cells.ObjectiveThe aim of this study was to determine the effect of sinusoidal electrical brain stimulation (SEBS) on different types of brain cells and to identify the exact types of brain cells that are stimulated.MethodsThe study subjects were 40 male Sprague Dawley rats (weight 300–350 g; age 9 weeks). SEBS was delivered continuously at frequencies of 20, 40, 60, or 100 Hz to the sensory parietal cortex using epidurally placed electrodes for 1 week. Transverse rat brain tissue sections were immunolabeled with calmodulin-dependent protein kinase II and parvalbumin (PV) antibodies and with c-Fos for counting of activated excitatory and inhibitory neurons. Computer simulation was performed to cross-validate the frequency-specific cell stimulation results.ResultsInhibitory neurons were more excited than excitatory neurons after epidural EBS. Most excitatory neural activity was evoked at 40 Hz (p<0.05) and most inhibitory neuronal activity was evoked at 20 Hz (p<0.01). The contralateral sensory cortex was activated significantly more at 40 Hz (p<0.05) and the corticothalamic circuit at 20 Hz (p<0.001). Stimulation-induced excitatory and inhibitory neuronal activation was widest at 20 Hz.ConclusionsEpidural electrical stimulation targets both excitatory and inhibitory neurons and the related neural circuits. Further exploration is needed to identify circuits that promote the plasticity needed for recovery in patients with specific neurological diseases.Graphical Abstract

Acute superoxide scavenging reduces sympathetic vasoconstrictor responsiveness in short-term exercise-trained rats

2013 ◽  
Vol 114 (11) ◽  
pp. 1511-1518 ◽  
Author(s):  
Nicholas G. Jendzjowsky ◽  
Darren S. DeLorey
Keyword(s):  
Nitric Oxide ◽  
Methyl Ester ◽  
Dependent Manner ◽  
Sympathetic Stimulation ◽  
Sprague Dawley ◽  
Vascular Conductance ◽  
Time Control ◽  
Sprague Dawley Rats ◽  
Vasoconstrictor Response ◽  
40 Hz

We hypothesized that acute superoxide (O2−) scavenging would attenuate sympathetic vasoconstrictor responsiveness by augmenting nitric oxide (NO)-mediated inhibition of sympathetic vasoconstriction in exercise-trained rats. Sprague-Dawley rats were randomly assigned to sedentary time control (S; n = 7) or mild- (M: 20 m/min, 5° grade; n = 7) or heavy-intensity (H: 40 m/min, 5° grade; n = 7) exercise training (ET) groups and trained 5 days/wk for 4 wk with matched training volume. Following ET, rats were anesthetized and instrumented for lumbar sympathetic chain stimulation and measurement of femoral vascular conductance. In resting skeletal muscle, the percentage change of femoral vascular conductance in response to continuous (2 Hz) and patterned (20 and 40 Hz) sympathetic stimulation was determined during control conditions, O2− scavenging (TIRON, 1 g·kg−1·h−1 iv) and combined O2− scavenging + nitric oxide synthase blockade ( Nω-nitro-l-arginine methyl ester, 5 mg/kg iv). ET augmented the vasoconstrictor response to sympathetic stimulation in a training intensity-dependent manner ( P < 0.05) (S: 2 Hz: −26 ± 7.1%; 20 Hz: −26.9 ± 7.3%; 40 Hz: −27.7 ± 7.0%; M: 2 Hz: −37.4 ± 8.3%; 20 Hz: −35.9 ± 7.4%; 40 Hz: −38.2 ± 9.4%; H: 2 Hz: −46.9 ± 7.8%; 20 Hz: −48.5 ± 7.2%; 40 Hz: −51.2 ± 7.3%). O2− scavenging did not alter ( P > 0.05) the vasoconstrictor response in S rats (S: 2 Hz: −23.9 ± 7.6%; 20 Hz: −26.1 ± 9.1%; 40 Hz: −27.5 ± 7.2%), whereas the response in ET rats was diminished (M: 2 Hz: −26.3 ± 5.1%; 20 Hz: −28.7 ± 5.3%; 40 Hz: −28.5 ± 5.6%; H: 2 Hz: −35.5 ± 10.3%; 20 Hz: −38.6 ± 6.8%; 40 Hz: −43.9 ± 5.9%, P < 0.05). TIRON + Nω-nitro-l-arginine methyl ester increased vasoconstrictor responsiveness ( P < 0.05) in ET rats (M: 2 Hz: −47.7 ± 9.8%; 20 Hz: −41.2 ± 7.2%; 40 Hz: −50.5 ± 7.9%; H: 2 Hz: −55.8 ± 7.6%; 20 Hz: −55.7 ± 7.8%; 40 Hz: −58.7 ± 6.2%), whereas, in S rats, the response was unchanged (2 Hz: −29.4 ± 8.7%; 20 Hz: −30.0 ± 7.4%; 40 Hz: −35.2 ± 10.3%; P > 0.05). These data indicate that the augmented sympathetic vasoconstrictor responsiveness in ET rats was related to increased oxidative stress and altered nitric oxide-mediated inhibition of vasoconstriction.

Diverse Patterns of Perilymphatic Space Enhancement in the Rat Inner Ear after Intratympanic Injection of Two Different Types of Gadolinium: A 9.4-Tesla Magnetic Resonance Study

2015 ◽  
Vol 20 (2) ◽  
pp. 112-116 ◽  
Author(s):  
Mina Park ◽  
Ho Sun Lee ◽  
Jun-Jae Choi ◽  
Hyeonjin Kim ◽  
Jun Ho Lee ◽  
...  
Keyword(s):  
Inner Ear ◽  
Sprague Dawley ◽  
Mr Images ◽  
Basal Turn ◽  
Sprague Dawley Rats ◽  
Different Types ◽  
Intratympanic Injection ◽  
The Right ◽  
Perilymphatic Space

Objective: To compare the quality of perilymphatic enhancement in the rat inner ear after intratympanic injection of two types of gadolinium with a 9.4-tesla micro-MRI. Materials and Methods: Gadolinium was injected into the middle ear in 6 Sprague-Dawley rats via the transtympanic route. The left ear was injected with Gd-DO3A-butrol first, and then the right ear was injected with Gd-DOTA. MR images of the inner ear were acquired 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4 h after intratympanic (IT) injection using an Agilent MRI system 9.4T/160/AS. The normalized signal intensity was quantitatively analyzed at the scala vestibuli (SV), scala media, and scala tympani (ST) using a Marosis M-view system. Then the normalized signal intensities (SIs) were compared between the two contrast agents. Results: For Gd-DO3A-butrol, the SI was as low as 1.0-1.5 throughout 1-4 h at the SV and ST of the basal turn. The maximum SI was 1.5 ± 0.5 at the SV (2 h) and 1.3 ± 0.5 at the ST (2 h). For Gd-DOTA, the 1-hour postinjection SI at the basal turn was 2.5 ± 0.5 at the SV, 1.6 ± 0.3 at the ST, and 1.2 ± 0.3 at the scala media. In the apical turn, the maximum SI was reached after 2.5 h. The maximum SI in the apical turn was 1.8 ± 0.4 at the SV (3.5 h), 1.8 ± 0.4 at the ST (4 h), and 1.4 ± 0.3 at the scala media (4 h). Conclusions: We were able to clearly visualize and separate the ST and SV using IT Gd and 9.4-tesla micro-MRI. We recommend using Gd-DO3A-butrol over Gd-DOTA and to perform the MRI 2.5 h after using IT Gd in the rat inner ear.

scholarly journals Infraslow coordination of slow wave activity through altered neuronal synchrony

SLEEP ◽  
2019 ◽  
Vol 42 (12) ◽  
Author(s):  
Michael B Dash
Keyword(s):  
Slow Wave ◽  
Critical Role ◽  
Wave Activity ◽  
Slow Wave Activity ◽  
Inhibitory Neurons ◽  
Sprague Dawley ◽  
Data Set ◽  
Neuronal Synchrony ◽  
Sprague Dawley Rats ◽  
Cortical Regions

Abstract Slow wave activity (SWA; the EEG power between 0.5 and 4 Hz during non-rapid eye movement sleep [NREM]) is the best electrophysiological marker of sleep need; SWA dissipates across the night and increases following sleep deprivation. In addition to these well-documented homeostatic SWA trends, SWA exhibits extensive variability across shorter timescales (seconds to minutes) and between local cortical regions. The physiological underpinnings of SWA variability, however, remain poorly characterized. In male Sprague-Dawley rats, we observed that SWA exhibits pronounced infraslow fluctuations (~40- to 120-s periods) that are coordinated across disparate cortical locations. Peaks in SWA across infraslow cycles were associated with increased slope, amplitude, and duration of individual slow waves and a reduction in the total number of waves and proportion of multipeak waves. Using a freely available data set comprised of extracellular unit recordings during consolidated NREM episodes in male Long-Evans rats, we further show that infraslow SWA does not appear to arise as a consequence of firing rate modulation of putative excitatory or inhibitory neurons. Instead, infraslow SWA was associated with alterations in neuronal synchrony surrounding “On”/“Off” periods and changes in the number and duration of “Off” periods. Collectively, these data provide a mechanism by which SWA can be coordinated across disparate cortical locations and thereby connect local and global expression of this patterned neuronal activity. In doing so, infraslow SWA may contribute to the regulation of cortical circuits during sleep and thereby play a critical role in sleep function.

Effect of central amiloride infusion on mineralocorticoid hypertension

1994 ◽  
Vol 267 (5) ◽  
pp. E754-E758 ◽  
Author(s):  
E. P. Gomez-Sanchez ◽  
C. E. Gomez-Sanchez
Keyword(s):  
Blood Pressure ◽  
Urine Volume ◽  
Na Channel ◽  
Sprague Dawley ◽  
Cellular Mechanisms ◽  
Subcutaneous Infusion ◽  
Intracerebroventricular Infusion ◽  
Sprague Dawley Rats ◽  
Different Types ◽  
The Brain

There is strong evidence from different types of studies, including the discrete infusion of agonists and antagonists and ablation of specific brain areas or transmitter-type neurons, that mineralocorticoids, in excess, act in the brain to elevate blood pressure. Aldosterone enhances the entry of Na+ through amiloride-sensitive Na+ channels in some mineralocorticoid-sensitive transport epithelial cells. To define possible cellular mechanisms involved in central mineralocorticoid action, benzamil, an amiloride analogue with selective affinity for the Na+ channel, was continuously infused intracerebroventricularly in three mineralocorticoid-dependent hypertension models in Sprague-Dawley rats, the continuous subcutaneous infusion of aldosterone, the intracerebroventricular infusion of aldosterone, and the ingestion of carbenoxolone, a synthetic licorice analogue. The intracerebroventricular infusion of 0.3 and 0.5 micrograms/h of benzamil, doses that did not have an adverse effect on growth and that had no effect on the blood pressure when infused subcutaneously, prevented the increase in blood pressure in these models. The infusion of these levels of benzamil had no effect on urine volume even in those animals in which it prevented an increase in blood pressure. These data suggest that the central effects of mineralocorticoids on blood pressure are mediated, at least in part, by the effects of mineralocorticoids on amiloride-sensitive sodium transport.

scholarly journals The Effect of Prophylactic Anticoagulation with Heparin on the Brain Cells of Sprague-Dawley Rats in a Cardiopulmonary-Cerebral Resuscitation Model

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Wenxun Liu ◽  
Yun Wang ◽  
Xiaohong Zhou ◽  
Kerong Hai ◽  
Danting Jia ◽  
...  
Keyword(s):  
Heparin Therapy ◽  
Brain Cells ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Need To Evaluate ◽  
Basic Parameters ◽  
Ca Model ◽  
Microcirculatory Disturbances ◽  
Prophylactic Anticoagulation ◽  
The Brain

After a cardiac arrest (CA) of 5 to 10 min, a marked activation of blood coagulation occurs and microthrombi are found in the cerebral vessels. These microcirculatory disturbances directly affect the outcome on cardiopulmonary resuscitation (CPR). The purpose of this study was to investigate the effects and potential mechanisms of prophylactic anticoagulation on rat brain cells after cerebral CPR. After setting up an asphyxial CA model, we monitored the basic parameters such as the vitals and survival rate of the rats and assessed the respective neurological deficit (ND) and histological damage (HD) scores of their brain tissues. We, furthermore, investigated the influence of heparin on the expressions of TNF-α, IL-1β, CD40, NF-κB, and HIF-1α after asphyxial CA. The results showed that anticoagulation with heparin could obviously improve the outcome and prognosis of brain ischemia, including improvement of neurological function recovery and prevention of morphological and immunohistochemical injury on the brain, while significantly increasing the success rate of CPR. Treatment with heparin significantly inhibited the upregulation of CD40, NF-κB, and HIF-1α induced by asphyxial CA. Thrombolysis treatment may improve the outcome and prognosis of CPR, and future clinical studies need to evaluate the efficacy of early heparin therapy after CA.

scholarly journals Clofibrate and di(2-ethylhexyl)phthalate increase ubiquinone contents without affecting cholesterol levels.

1994 ◽  
Vol 41 (3) ◽  
pp. 321-329
Author(s):  
F Aberg ◽  
E L Appelkvist
Keyword(s):  
Peroxisome Proliferator ◽  
Sprague Dawley ◽  
Beta Oxidation ◽  
Cholesterol Levels ◽  
Sprague Dawley Rats ◽  
Different Types ◽  
Low Toxicity ◽  
Fatty Acid Beta Oxidation ◽  
Ethylhexyl Phthalate ◽  
The Brain

Induction studies were performed on liver, muscle, heart, brain and blood by feeding Sprague-Dawley rats a diet containing a peroxisome proliferator, clofibrate or di(2-ethylhexyl)phthalate. Ingestion of these drugs resulted in an increase in the amount of two different types of ubiquinone homologues UQ9 and UQ10 found in rat. Phthalate proved to be the more effective drug, leading to a highly increased amount of ubiquinone in the liver. Increases were also found in all the above-mentioned organs except the brain. The UQ9 levels were raised to 400, 200, 120 and 120%, of the respective normal values. The antioxidant and hypolipidemic agent, probucol, was used as a control to evaluate whether the increased ubiquinone level constituted a response to the elevated hydrogen peroxide pressure, resulting from the induced increase in fatty acid beta-oxidation. In the presence of probucol, ubiquinone levels were decreased in all the above-mentioned organs except heart and brain. Probucol had limited effects on the amount of cholesterol and did not significantly alter the amount of dolichol. The two peroxisome proliferators differed in their effects on cholesterol, as well as on dolichol levels which was induced by phthalate but not by clofibrate. The possible mechanisms involved, and the importance of low toxicity drugs which could elevate ubiquinone levels in various tissues, are discussed.

Ultrastructural Investigation of Spontaneous Pituitary Adenomas in Aging Sprague-Dawley Rats

1982 ◽  
Vol 40 ◽  
pp. 216-217
Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs
Keyword(s):  
Microscopic Study ◽  
Pituitary Adenomas ◽  
Wistar Rats ◽  
Microscopic Level ◽  
Sprague Dawley ◽  
Prolactin Cells ◽  
Light Microscopic Level ◽  
Ultrastructural Investigation ◽  
Sprague Dawley Rats ◽  
Long Evans

Investigation of the spontaneous pituitary adenomas in rat have been limited mainly to light microscopic study. Furth et al. (1973) described them as chromophobic, secreting prolactin. Kovacs et al. (1977) in an ul trastructural investigation of adenomas of old female Long-Evans rats, found that they were composed of prolactin cells. Berkvens et al. (1980) using immunocytochemistry at the light microscopic level, demonstrated that some spontaneous tumors of old Wistar rats could contain GH, TSH or ACTH as well as PRL.

Early Development of Drug-Induced Hepatic Necrosis

1971 ◽  
Vol 29 ◽  
pp. 576-577
Author(s):  
F. G. Zaki ◽  
E. Detzi ◽  
C. H. Keysser
Keyword(s):  
Early Development ◽  
Hepatic Necrosis ◽  
Screening Tests ◽  
Dense Matrix ◽  
Sprague Dawley ◽  
Electron Microscopic ◽  
Drug Induced ◽  
Hepatocellular Damage ◽  
Sprague Dawley Rats ◽  
Microscopic Studies

This study represents the first in a series of investigations carried out to elucidate the mechanism(s) of early hepatocellular damage induced by drugs and other related compounds. During screening tests of CNS-active compounds in rats, it has been found that daily oral administration of one of these compounds at a dose level of 40 mg. per kg. of body weight induced diffuse massive hepatic necrosis within 7 weeks in Charles River Sprague Dawley rats of both sexes. Partial hepatectomy enhanced the development of this peculiar type of necrosis (3 weeks instead of 7) while treatment with phenobarbital prior to the administration of the drug delayed the appearance of necrosis but did not reduce its severity.Electron microscopic studies revealed that early development of this liver injury (2 days after the administration of the drug) appeared in the form of small dark osmiophilic vesicles located around the bile canaliculi of all hepatocytes (Fig. 1). These structures differed from the regular microbodies or the pericanalicular multivesicular bodies. They first appeared regularly rounded with electron dense matrix bound with a single membrane. After one week on the drug, these vesicles appeared vacuolated and resembled autophagosomes which soon developed whorls of concentric lamellae or cisterns characteristic of lysosomes (Fig. 2). These lysosomes were found, later on, scattered all over the hepatocytes.

Ultrastructural investigation of spontaneous pituitary gonadotroph cell adenomas in aging Sprague-Dawley rats

1983 ◽  
Vol 41 ◽  
pp. 702-703
Author(s):  
D. J. McComb ◽  
J. Beri ◽  
F. Zak ◽  
K. Kovacs
Keyword(s):  
Electron Microscopy ◽  
Animal Model ◽  
Epoxy Resin ◽  
Immunoelectron Microscopy ◽  
Tumor Type ◽  
Gonadal Function ◽  
Sprague Dawley ◽  
Male And Female ◽  
Reticulin Fibers ◽  
Sprague Dawley Rats

Gonadotroph cell adenomas of the pituitary are infrequent in human patients and are not invariably associated with altered gonadal function. To date, no animal model of this tumor type exists. Herein, we describe spontaneous gonadotroph cell adenomas in old male and female Sprague-Dawley rats by histology, immunocytology and electron microscopy.The material consisted of the pituitaries of 27 male and 38 female Sprague Dawley rats, all 26 months of age or older, removed at routine autopsy. Sections of formal in-fixed, paraffin-embedded tissue were stained with hematoxylin-phloxine-saffron (HPS), the PAS method and the Gordon-Sweet technique for the demonstration of reticulin fibers. For immunostaining, sections were exposed to anti-rat β-LH, anti-ratβ-TSH, anti-rat PRL, anti-rat GH and anti-rat ACTH 1-39. For electron microscopy, tissue was fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4 and embedded in epoxy-resin. Tissue fixed in 10% formalin, embedded in epoxy resin without osmification, was used for immunoelectron microscopy.

Freeze-etch studies of epiphyseal growth plate cartilage reveal matrix vesicles associated with calcification

1978 ◽  
Vol 36 (2) ◽  
pp. 670-671
Author(s):  
Russell N. A. Cecil ◽  
H. Clarke Anderson
Keyword(s):  
Chromic Acid ◽  
Light And Electron Microscopy ◽  
Matrix Vesicles ◽  
Matrix Vesicle ◽  
Glycerol Solution ◽  
Sprague Dawley ◽  
Epiphyseal Growth Plate ◽  
Growth Plates ◽  
Sprague Dawley Rats ◽  
Tibial Epiphyseal

Unfixed proximal tibial epiphyseal growth plates were studied by freeze-etch to confirm the presence of extracellular calcifying matrix vesicles and to determine the substructure of matrix vesicle membranes as compared to plasma and other membranes of intact chondrocytes. Growth plates from 6-10 week old Sprague-Dawley rats were cut into 1x3 mm blocks whose long dimension was oriented either perpendicular or parallel to the long axis of the tibia. Some blocks were fixed at pH 7. 0 in 0. 2M cacodylate - buffered 2. 5% glutaraldehyde for 1 hour at 4ÅC. The blocks were immersed in 30% glycerol solution at 4ÅC for 1 hour, frozen in liquid nitrogen, and then fractured, etched for 2 minutes, and coated with platinum, carbon and 0. 2% Formvar solution. The replicas were cleaned with chromic acid, floated onto Formvar coated grids, and examined with a Phillips EM 300 electron microscope.Fixed and unfixed specimens appeared similar in ultrastructure. Chondrocytes, matrix, and matrix vesicles were identified. In specimens fractured parallel to the long axis of the tibia, the reserve, proliferative, hypertrophic, and calcifying zones could be discerned as described by light and electron microscopy.

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