7-12 Hz High-Voltage Rhythmic Spike Discharges in Rats Evaluated by Antiepileptic Drugs and Flicker Stimulation

2007 ◽  
Vol 97 (1) ◽  
pp. 238-247 ◽  
Author(s):  
Fu-Zen Shaw
Keyword(s):  
Antiepileptic Drugs ◽  
High Voltage ◽  
Wistar Rats ◽  
Barrel Cortex ◽  
Occipital Cortex ◽  
High Dose ◽  
Absence Seizure ◽  
Mu Rhythm ◽  
Flicker Stimulation ◽  
Long Evans

Paroxysmal 7- to 12-Hz high-voltage rhythmic spike (HVRS) or spike-wave discharges often appear in several particular strains of rats. However, functional hypotheses of these 7-12 Hz high-voltage cortical oscillations (absence seizure vs. idling mu rhythm) are inconclusive. The mu rhythm can be provoked by flicker stimulation (FS) in most people, but FS is less effective at eliciting absence epileptic activity. Therefore FS and antiepileptic drugs were used to verify the role of HVRS activity in Long-Evans rats with spontaneous HVRS discharges and Wistar rats without spontaneous HVRS discharges. The occurrence of HVRS discharges was significantly reduced by antiabsence drugs (ethosuximide, valproic acid, and diazepam) in dose-dependent manners, but high-dose carbamazepine displayed little effect. On the other hand, oscillation frequencies and durations of spontaneous HVRS discharges were not altered by FS. Under asynchronous brain activity, many FSs (>60%) elicited small-amplitude mu-rhythm-like activity in the barrel cortex concomitant with FS-related rhythms in the occipital cortex and resulted in significant augmentation of 7-12 Hz power in the parietal region. Furthermore, a large portion of FSs (>60%) revealed increase of 7-12 Hz power of the parietal cortex after ethosuximide administration (100 mg/kg ip) in Long-Evans rats. Similar FS-elicited phenomena also appeared in Wistar rats. Characteristics of FS-elicited mu-rhythm-like activities were consistent with those observed in humans, and they remarkably differed from those of spontaneous HVRS discharges. These results support the hypothesis that HVRS activity in Long-Evans rats may be an absence-like seizure activity rather than the mu rhythm.

Is Spontaneous High-Voltage Rhythmic Spike Discharge in Long Evans Rats an Absence-Like Seizure Activity?

2004 ◽  
Vol 91 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Fu-Zen Shaw
Keyword(s):  
High Voltage ◽  
Slow Wave Sleep ◽  
Seizure Activity ◽  
Spectral Characteristics ◽  
Absence Seizure ◽  
Mu Rhythm ◽  
Behavioral Arousal ◽  
Ongoing Behavior ◽  
Long Evans ◽  
Electrical Stimuli

A distinct high-voltage rhythmic spike (HVRS) discharge characterized by a barrage of negative spikes oscillating at 5–12 Hz was observed in chronically implanted Long Evans rats. Spontaneous HVRS discharges were exhibited in 90% of 40 Long Evans rats and occurred during sudden arrest of ongoing behavior (immobility) with occasional facial/whisker twitching. However, the function of HVRS discharges in Long Evans rats remains inconclusive to date and has been associated with alpha tremor/mu rhythm, attentive mu wave, and absence seizure. To elucidate the function of HVRS discharges in Long Evans rats, several experiments were performed. In a 6-h recording session (12:00–18:00), HVRS activities primarily occurred in several specific vigilance states, being particularly abundant in a short-lasting period before vigilance changes. Several characteristics, such as durations, oscillatory frequencies, and interspike intervals (ISIs) of HVRS discharges, were altered during wake-sleep states. Oscillatory frequencies were negatively correlated with durations of HVRS segments. In addition, ISIs of a HVRS episode exhibited a crescendo-decrescendo pattern. These variable ISIs could explain why a negative correlation was found between oscillatory frequencies and durations of HVRS episodes. Moreover, HVRS discharges were demonstrated to have widespread and near-synchronous distribution to bilateral cortical areas. In addition, innocuous electrical stimuli were unable to stop ongoing HVRS discharges. By contrast, noxious stimuli elicited behavioral arousal and immediately terminated most HVRS discharges. Cortical-evoked potentials in response to mild electrical stimulation under HVRS discharges were different from those under waking state but resemble those under slow-wave sleep with a smaller magnitude. Moreover, the temporal and spectral characteristics of spontaneous HVRS activities were analogous to those of seizure activities induced by penicillin and pentylenetetrazol. The incidence of spontaneous HVRS discharges was significantly decreased by ethosuximide administration. Based on these results, HVRS discharge might not be associated with a voluntary mu-rhythm behavior, instead it behaves as an absence-like seizure activity. These results were also collaborated using other genetic absence-seizure rats, such as WAG/Rij and GAERS rats. Possible mechanisms for the generation and termination of paroxysmal HVRS discharges are also discussed.

Relation Between Activities of the Cortex and Vibrissae Muscles During High-Voltage Rhythmic Spike Discharges in Rats

2005 ◽  
Vol 93 (5) ◽  
pp. 2435-2448 ◽  
Author(s):  
Fu-Zen Shaw ◽  
Yi-Fang Liao
Keyword(s):  
High Voltage ◽  
Muscle Activity ◽  
Oscillation Frequency ◽  
Muscular Activity ◽  
Simultaneous Recording ◽  
Absence Seizure ◽  
Mu Rhythm ◽  
Oscillation Frequencies ◽  
Peripheral Sensory

Paroxysmal 5- to 12-Hz high-voltage rhythmic spike (HVRS) activities, which are accompanied by whisker twitching (WT), are found in Long Evans rats, but the function of these HVRS activities is still debated. In four major functional hypotheses of HVRS discharges, i.e., alpha tremor, attention/mu rhythm, idling/mu rhythm, and absence seizure, the first two hypotheses emphasize WT behavior in HVRS bouts. Whisker movement is primarily determined by activation of intrinsic and extrinsic muscles. To clarify the role of WT in HVRS activities, simultaneous recording of the activities from the cortex and intrinsic/extrinsic and neck muscles were performed. Most HVRS bouts (68.8%) revealed no time-locked WT behavior in a 2-h recording session. In addition, WT primarily arose from active protraction due to activation of intrinsic muscles followed by passive retraction. A small portion of WT resulted from activation of both vibrissae muscles with dynamic frequency-dependent phase shifts. Onset of the rhythmic vibrissae EMG significantly lagged behind HVRS onset, and the mean duration of vibrissae muscle activity was one-third to a one-half of a HVRS bout. Moreover, a greater number of HVRS bouts were associated with a longer HVRS duration and higher oscillation frequency. Oscillation frequencies of HVRS activities without WT behavior were significantly lower than those with WT. Under peripheral sensory/motor blockade by xylocaine injection, oscillation frequencies of HVRS bouts significantly decreased, but no remarkable changes in the number or duration of HVRS bouts were observed. Compared with vibrissa muscle activity during WT and exploratory whisking, the duration of muscular activity in each cycle was apparently longer during whisking bouts. Based on these results, overemphasis of the role of WT on HVRS activities might not be appropriate. Instead, HVRS discharges may be associated with absence seizure or idling state. In addition, peripheral inputs, including WT, may elevate the oscillation frequency of HVRS bouts. Moreover, different muscular controls may exist between WT and whisking.

Mozart K.448 attenuates spontaneous absence seizure and related high-voltage rhythmic spike discharges in Long Evans rats

2013 ◽  
Vol 104 (3) ◽  
pp. 234-240 ◽  
Author(s):  
Lung-Chang Lin ◽  
Chun-Ting Juan ◽  
Hsueh-Wen Chang ◽  
Ching-Tai Chiang ◽  
Ruey-Chang Wei ◽  
...  
Keyword(s):  
High Voltage ◽  
Absence Seizure ◽  
Long Evans

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.

scholarly journals The fertility assessment of normal cyclic Wistar rats following the administration of methanolic extract of Portulaca oleracea: an experimental study

2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Izuchukwu Azuka Okafor ◽  
Uchenna Somtochukwu Nnamah ◽  
Jude Nnaka
Keyword(s):  
Estrous Cycle ◽  
Adult Female ◽  
Wistar Rats ◽  
Major Effect ◽  
Reproductive Hormones ◽  
Portulaca Oleracea ◽  
High Dose ◽  
Methanolic Extracts ◽  
Cycle Arrest ◽  
Female Wistar Rats

Abstract Background Purslane is a widely distributed shrub used for the treatment of different ailments. The increasing reproductive complications associated with herbal treatments have led to the need to critically evaluate the safety and/or reproductive potentials of commonly used plant extracts. This study investigated the reproductive effect of methanolic extracts of Portulaca oleracea (MEPO) in adult female Wistar rats. Results Group C showed a significant decrease both in relative ovarian weight (p = 0.000), and relative uterine weight (p = 0.037), when compared with the control. There were no significant (p ˃ 0.05) changes in the levels of follicle-stimulating hormone, luteinizing hormone, progesterone, and estradiol. When compared to the control, groups B and C showed abnormal estrous cycle and cycle arrest especially at the metestrus phase with mild congestion of a few blood vessels in the ovary and uterus. Conclusions MEPO may possess some anti-fertility effect, as it disrupts the estrous cycle of adult female Wistar rats; although it has no major effect on the reproductive hormones, uterus, and ovarian histology of adult female Wistar rats. However, high dose consumption should be taken with precaution.

Effects of high-dose antiepileptic drugs on event-related potentials in epileptic children

1996 ◽  
Vol 25 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Hideo Enoki ◽  
Satoshi Sanada ◽  
Eiji Oka ◽  
Shunsuke Ohtahara
Keyword(s):  
Antiepileptic Drugs ◽  
Event Related Potentials ◽  
High Dose ◽  
Epileptic Children ◽  
Related Potentials

Pregnancy in women with epilepsy

2017 ◽  
pp. 61-64
Author(s):  
Shahla Yagub Melikova ◽  
Keyword(s):  
Key Words ◽  
Antiepileptic Drugs ◽  
Congenital Malformations ◽  
Social Problems ◽  
Neurological Diseases ◽  
Epileptic Seizures ◽  
Conclusive Evidence ◽  
High Dose ◽  
Key Words Pregnancy

Epilepsy is one of the most common serious neurological diseases. Many publications relating to interaction of epilepsy and pregnancy have been studied. Women with epilepsy experience a number of physical and social problems associated with obstetric risk, the risk of seizures during pregnancy. Generalized epileptic seizures may have a direct damaging effect on the fetus, although there is no conclusive evidence for a significant increase in the incidence of complications during pregnancy in women with epilepsy. Antenatal exposure to antiepileptic drugs, especially in high-dose and polytherapy, increases the risk of congenital malformations. There are concerns regarding the effects of antiepileptic drugs on infants during breastfeeding. However, the risk of complications associated with the epilepsy and the effects of antiepileptic drugs on the fetus may be reduced by joint monitor by neurologist-epileptologist and obstetrician. Key words: pregnancy, antiepileptic drugs, epilepsy, monotherapy, polytherapy.

scholarly journals Lead-Induced Toxicity in Wistar Rats: Amelioration by Palm Wine

2020 ◽  
pp. 1-9
Author(s):  
Femi A. Egbeleke ◽  
Kehinde O. Shittu ◽  
Ayobola A. Iyanda
Keyword(s):  
Body Weight ◽  
Total Protein ◽  
Wistar Rats ◽  
Histological Study ◽  
Lead Nitrate ◽  
Lead Toxicity ◽  
Study Groups ◽  
High Dose ◽  
Palm Wine ◽  
Antioxidant Agents

Lead a free-radical generating agent is a multi-systemic toxicant which affects major body systems especially the hepatic axis. Several natural products rich in antioxidant agents have been used to ameliorate lead toxicity. Vitamin C present abundantly in palm wine has been noted for its ability to modulate oxidative stress. This study investigated the ameliorative effects of palm wine in lead-induced hepatotoxicity in Wistar rats. Adults Wistar rats randomly divided into Groups A-H, consisting of 7 rats per group were used for the study. Groups A and B were administered with distilled water and palm wine respectively. Groups C, E, and G were dosed daily with lead nitrate at dosage levels of 50 (low dose), 150 (intermediate dose) and 600 (high dose) mg/kg body weight (BW). On the other hand, Groups D, F, and H were administered daily with lead nitrate at dosage levels of 50, 150 and 600 mg/kg body weight (BW) as well as palm wine (10 mL/kg BW). All experimental animals were allowed access to standard feed and water without any form of restriction. Estimation of biochemical parameters i.e. total protein, albumin, alkaline phosphatase and aminotransferases (ALT; AST) took place using standard biochemical methods. The liver was harvested and processed for histological study using haematoxylin and eosin staining techniques. Statistical analysis was done using one-way analysis of variance (ANOVA) and Student’s t-test. P< 0.05 was considered significant. While albumin concentrations were not significantly different, both total protein and globulin concentrations in lead administered rats were significantly reduced compared with control. Periportal and interstitial hepatitis and necrosis occurred from lead exposure at different levels suggesting hepatotoxicity. Meanwhile, lead and palm wine-administered rats featured similar histologic results. In conclusion, the results of the study, therefore, indicate that palm wine does not possess an ameliorative effect on lead-induced hepatotoxicity.

scholarly journals Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease Presenting as Recurrent and Migrating Focal Cortical Encephalitis

2020 ◽  
Vol 7 ◽  
pp. 2329048X2096617
Author(s):  
Xinran Maria Xiang ◽  
Rachel Evans ◽  
Jesus Lovera ◽  
Rashmi Rao
Keyword(s):  
Brain Mri ◽  
Occipital Cortex ◽  
Myelin Oligodendrocyte Glycoprotein ◽  
New Right ◽  
High Dose ◽  
Antibody Testing ◽  
Leptomeningeal Enhancement ◽  
The Right ◽  
Work Up ◽  
New Onset

Although pediatric myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease is increasingly well-recognized, its full clinical spectrum is still being defined. Cortical encephalitis is emerging as a distinct clinico-radiologic syndrome of adult MOG antibody-associated disease. We describe a 12-year-old girl who presented with new onset seizures and left-sided hemiparesis. Brain MRI showed edema of the right temporal-parietal-occipital cortex with associated focal leptomeningeal enhancement. Patient received high-dose corticosteroids and 21 days of acyclovir despite negative infectious work-up due to the focal nature of encephalitis. Patient remained seizure-free for 20 months before presenting with new right hemiclonic seizures with right-sided hemiparesis and edema of the left temporal-parietal cortex with associated leptomeningeal enhancement. Patient’s MOG antibody titer was 1:40. She completed high-dose corticosteroids and intravenous immunoglobulin. Our patient highlights the importance of MOG antibody testing in pediatric focal cortical encephalitis to avoid unnecessary anti-viral agents and provide more appropriate immunotherapy and a more informed prognosis.

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