Behavioral performance and seizure activity of lithium-intoxicated Sprague-Dawley rats treated with theophylline

The effects of sodium phenobarbital on (a) behavior reinforced by electrical stimulation of the brain, (b) behavioral seizures, and (c) EEG seizure activity were observed in seven male Sprague-Dawley rats. Rate of response on placebo day, over a 30-min. continuous reinforcement session, was compared to rate of response on drug day; an increase in response on the drug day over the placebo day was called a positive phenobarbital effect and a decrease a negative phenobarbital effect. For some animals the positive phenobarbital effect disappeared when the animal's rate of response was calculated for seizure-free time, i.e., when the time spent in seizure was subtracted from the 30-min. period. For other animals, however, the phenobarbital effect, whether positive or negative, was not directly related to time gained on the drug day compared to the placebo day. A new concept was advanced, that of seizure-proneness, measured by the number and duration of seizures and spike after-discharges. Significant correlations were found for seizure-proneness and phenobarbital effect.

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Dexmedetomidine Increases the Cocaine Seizure Threshold in Rats

Anesthesiology ◽

10.1097/00000542-200209000-00024 ◽

2002 ◽

Vol 97 (3) ◽

pp. 693-700 ◽

Cited By ~ 44

Author(s):

Robert A. Whittington ◽

Laszlo Virag ◽

Yvonne Vulliemoz ◽

Thomas B. Cooper ◽

Hisayo O. Morishima

Keyword(s):

Nucleus Accumbens ◽

Seizure Activity ◽

Seizure Threshold ◽

Sprague Dawley ◽

Alpha Adrenoceptors ◽

Alpha Adrenoceptor ◽

Sprague Dawley Rats ◽

Adrenoceptor Agonist ◽

Dopaminergic Neurotransmitter ◽

Cocaine Infusion

Background Central alpha adrenoceptors have been demonstrated to play an important role in the control of seizure activity; moreover, alpha adrenoceptors have been linked to electroencephalogram changes associated with cocaine. The purpose of this study was to determine if dexmedetomidine, a highly selective alpha -adrenoceptor agonist, alters the threshold for cocaine-induced seizure activity in rats. Methods Sprague-Dawley rats received a cocaine infusion (1.25 mg x kg(-1) x min(-1)) followed 15 min later by the coinfusion of either dexmedetomidine (20-microg/kg intravenous bolus followed by an infusion of 1 microg x kg(-1) x min(-1), CD group, n = 8) or an equal volume of saline (CS group, n = 8). Dexmedetomidine or saline were coinfused with cocaine until the onset of cocaine-induced seizures. Dopamine concentrations in the nucleus accumbens were measured by microdialysis paired with chromatography. To determine if changes in extracellular dopamine were related to the seizures, dopamine (1 microm) was continuously delivered to the nucleus accumbens in a separate group (DACD group, n = 6) retrograde microdialysis. These rats then received an intravenous cocaine infusion followed by dexmedetomidine in the same manner as the CD group. Results Dexmedetomidine significantly increased the dose of cocaine necessary to produce seizures. Seizures occurred at 25.0 +/- 7.7 and 49.3 +/- 14.8 min in CS and CD, respectively (P < 0.001). The ratio of the percent increase in accumbal dopamine to the cocaine dose at the onset of seizure activity was significantly lower in CD, 39.9 +/- 16.5, compared to CS, 82.2 +/- 46.5 (P = 0.04). Intraaccumbal administration of dopamine prevented the effects of dexmedetomidine on the cocaine seizure threshold. Conclusions These data suggest that dexmedetomidine increases the cocaine-induced seizure threshold possibly a mechanism related to the attenuation of the extracellular dopaminergic neurotransmitter response to cocaine.

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Early Blockade of CB1 Receptors Ameliorates Schizophrenia-like Alterations in the Neurodevelopmental MAM Model of Schizophrenia

Biomolecules ◽

10.3390/biom12010108 ◽

2022 ◽

Vol 12 (1) ◽

pp. 108

Author(s):

Tibor Stark ◽

Fabio Arturo Iannotti ◽

Serena Di Martino ◽

Martina Di Bartolomeo ◽

Jana Ruda-Kucerova ◽

...

Keyword(s):

Social Withdrawal ◽

Endocannabinoid System ◽

Brain Maturation ◽

Behavioral Performance ◽

Sprague Dawley ◽

Behavioral Alterations ◽

Antimitotic Agent ◽

Sprague Dawley Rats ◽

Cb1 Antagonist ◽

Neurodevelopmental Hypothesis

In agreement with the neurodevelopmental hypothesis of schizophrenia, prenatal exposure of Sprague-Dawley rats to the antimitotic agent methylazoxymethanol acetate (MAM) at gestational day 17 produces long-lasting behavioral alterations such as social withdrawal and cognitive impairment in adulthood, mimicking a schizophrenia-like phenotype. These abnormalities were preceded at neonatal age both by the delayed appearance of neonatal reflexes, an index of impaired brain maturation, and by higher 2-arachidonoylglycerol (2-AG) brain levels. Schizophrenia-like deficits were reversed by early treatment [from postnatal day (PND) 2 to PND 8] with the CB1 antagonist/inverse agonist AM251 (0.5 mg/kg/day). By contrast, early CB1 blockade affected the behavioral performance of control rats which was paralleled by enhanced 2-AG content in the prefrontal cortex (PFC). These results suggest that prenatal MAM insult leads to premorbid anomalies at neonatal age via altered tone of the endocannabinoid system, which may be considered as an early marker preceding the development of schizophrenia-like alterations in adulthood.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053747 ◽

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.

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Early Development of Drug-Induced Hepatic Necrosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100066942 ◽

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.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100077086 ◽

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.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084223 ◽

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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Sarcolemmal permeability changes during early myocardial anoxia

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084089 ◽

1978 ◽

Vol 36 (2) ◽

pp. 642-643

Author(s):

M. Ashraf ◽

L. Landa ◽

L. Nimmo ◽

C. M. Bloor

Keyword(s):

Cell Membrane ◽

Membrane Permeability ◽

Coronary Artery Occlusion ◽

Artery Occlusion ◽

Cell Membrane Permeability ◽

Enzyme Release ◽

Sprague Dawley ◽

Sprague Dawley Rats ◽

Sarcolemmal Permeability ◽

Membrane Changes

Following coronary artery occlusion, the myocardial cells lose intracellular enzymes that appear in the serum 3 hrs later. By this time the cells in the ischemic zone have already undergone irreversible changes, and the cell membrane permeability is variably altered in the ischemic cells. At certain stages or intervals the cell membrane changes, allowing release of cytoplasmic enzymes. To correlate the changes in cell membrane permeability with the enzyme release, we used colloidal lanthanum (La+++) as a histological permeability marker in the isolated perfused hearts. The hearts removed from sprague-Dawley rats were perfused with standard Krebs-Henseleit medium gassed with 95% O2 + 5% CO2. The hypoxic medium contained mannitol instead of dextrose and was bubbled with 95% N2 + 5% CO2. The final osmolarity of the medium was 295 M osmol, pH 7. 4.

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Light and electron microscopic investigation of adenohypophyses of germfree, food-restricted, and germfree-food restricted aging, male lobund-wistar rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103826 ◽

1988 ◽

Vol 46 ◽

pp. 352-353

Author(s):

G. Ilse ◽

K. Kovacs ◽

N. Ryan ◽

T. Sano ◽

L. Stefaneanu ◽

...

Keyword(s):

Wistar Rats ◽

Microscopic Investigation ◽

Electron Microscopic Investigation ◽

Aging Male ◽

Sprague Dawley ◽

Electron Microscopic ◽

Sprague Dawley Rats ◽

Old Rats ◽

Ad Libitum ◽

Microscopic Findings

Germfree state and food restriction have been shown to increase life span and delay tumor occurrence in rats. We report here the histologic, immunocytochemical and electron microscopic findings of adenohypophyses of aging, male Lobund-Wistar rats raised at Lobund Laboratories. In our previous study, the morphologic changes in the adenohypophyses of old rats have been extensively investigated by histology, immunocytochemistry and electron microscopy. Lactotroph adenomas were frequent in Long-Evans and Sprague-Dawley rats, whereas gonadotroph adenomas were frequent in Sprague-Dawley and Wistar rats.Male Lobund-Wistar rats were divided into four groups: 1) conventional, which were raised under normal non-germfree environment and received food ad libitum; 2) germfree-food ad libitum; 3) conventional environment-food restricted and 4) germfree-food restricted. The adenohypophyses were removed from 6-month-, 18-month- and 30-month-old rats. For light microscopy, adenohypophyses were fixed in formalin and embedded in paraffin.

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