scholarly journals EXTRACELLULAR LEVELS OF GLUCOSE IN THE HIPPOCAMPUS AND STRIATUM DURING MAZE TRAINING FOR FOOD OR WATER REWARD IN MALE RATS

2021 ◽  
pp. 113385
Author(s):  
C.J. Scavuzzo ◽  
L.A. Newman ◽  
P.E. Gold ◽  
D.L. Korol
Keyword(s):  
Male Rats ◽  
Water Reward

scholarly journals Extracellular levels of glucose in the hippocampus and striatum during maze training for food or water reward in male rats

2020 ◽  
Author(s):  
C.J. Scavuzzo ◽  
L.A. Newman ◽  
P.E. Gold ◽  
D.L. Korol
Keyword(s):  
Glucose Consumption ◽  
Male Rats ◽  
List Type ◽  
Central Administration ◽  
Water Reward ◽  
Brain Areas ◽  
Glucose Levels ◽  
Learning Tasks ◽  
Extracellular Glucose ◽  
Lactate Levels

AbstractPeripheral and central administration of glucose potently enhance cognitive functions. The present experiments examined changes in brain extracellular glucose levels while rats were trained to solve hippocampus-sensitive place or striatum-sensitive response learning tasks for food or water reward. During the first minutes of either place or response training, extracellular glucose levels declined in both the hippocampus and striatum, an effect not seen in untrained, rewarded rats. Subsequently, glucose increased in both brain areas under all training conditions, approaching asymptotic levels ∼15-25 min into training. Compared to untrained-food controls, training with food reward resulted in significant glucose increases in the hippocampus but not striatum; striatal glucose levels exhibited large increases to food intake in both trained and untrained groups. In rats trained to find water, glucose levels increased significantly above the values seen in untrained rats in both hippocampus and striatum. In contrast to results seen with lactate measurements, the magnitude of training-related increases in hippocampus and striatum glucose levels did not differ by task under either reward condition. The decreases in glucose early in training might reflect an increase in brain glucose consumption, perhaps triggering increased brain uptake of glucose from blood, as evident in the increases in glucose later in training. Together with past findings measuring lactate levels under the same conditions, the initial decreases in glucose may also stimulate increased production of lactate from astrocytes to support neural metabolism directly and/or to act as a signal to increase blood flow and glucose uptake into the brain.HighlightsGlucose levels in hippocampus and striatum decrease at the start of training.Glucose levels increase in both brain areas later in training.Glucose changes in both brain areas were similar for place and response tasks.Glucose levels responded similarly to training for either food and water rewards.Early decreases in glucose may trigger increased production astrocytic lactate.

scholarly journals Metabotropic group II glutamate receptors mediate cue-triggered increases in incentive motivation for reward

2021 ◽  
Author(s):  
Caroline Garceau ◽  
Justine Marsault ◽  
Mike J F Robinson ◽  
Anne-Noël Samaha
Keyword(s):  
Free Water ◽  
Incentive Motivation ◽  
Receptor Activity ◽  
Male Rats ◽  
Sprague Dawley ◽  
Water Reward ◽  
Water Port ◽  
Conditioned Approach ◽  
Lever Pressing ◽  
Group Ii

AbstractRationaleReward-associated cues can acquire incentive motivational properties and invigorate reward-seeking actions via Pavlovian-to-instrumental transfer (PIT). Glutamatergic neurotransmission mediates the appetitive effects of reward-associated cues. We characterized the expression of PIT and its mediation by metabotropic group II glutamate (mGlu2/3) receptor activity in female and male rats.ObjectivesAcross the sexes, we used PIT procedures to determine i) cue-triggered increases in incentive motivation for water reward (Experiment 1), ii) the respective influences of the mGlu2/3 receptor agonist LY379268 and reward devaluation by satiation on this effect (Experiment 2).MethodsWater-restricted male and female Sprague-Dawley rats learned to lever press for water. Separately, they learned that one of two auditory stimuli predicts free water (CS+ vs CS-). On PIT test days, the CS+ and CS- were presented non-contingently, and we measured effects on lever pressing under extinction (no water). In Experiment 1, we characterized PIT across the sexes. In Experiment 2, we measured PIT after systemic LY379268 administration (0, 0.3 and 1 mg/kg), and water satiation, respectively.ResultsFemale and male rats showed similar PIT, with CS+ but not CS- presentations potentiating water-seeking behaviour. LY379268 (1 mg/kg) attenuated CS+ evoked increases in both water-associated lever pressing and conditioned approach to the water port. Reward devaluation attenuated both water-seeking and CS+ evoked conditioned approach behaviour.ConclusionsThe sexes show similar cue-triggered increases in reward ‘wanting’, and water devaluation suppresses both water seeking and cue-triggered anticipation of water reward. Finally, across the sexes, mGlu2/3 receptor activity mediates cue-triggered increases in reward ‘wanting’.

The Morphology of the Rat Kidney Following Folic Acid Administration

1970 ◽  
Vol 28 ◽  
pp. 200-201
Author(s):  
Aline Byrnes ◽  
Elsa E. Ramos ◽  
Minoru Suzuki ◽  
E.D. Mayfield
Keyword(s):  
Folic Acid ◽  
De Novo ◽  
Specific Activity ◽  
Rat Kidney ◽  
Present Report ◽  
Intracellular Localization ◽  
Male Rats ◽  
Renal Hypertrophy ◽  
Electron Microscopic ◽  
Biochemical Alterations

Renal hypertrophy was induced in 100 g male rats by the injection of 250 mg folic acid (FA) dissolved in 0.3 M NaHCO3/kg body weight (i.v.). Preliminary studies of the biochemical alterations in ribonucleic acid (RNA) metabolism of the renal tissue have been reported recently (1). They are: RNA content and concentration, orotic acid-c14 incorporation into RNA and acid soluble nucleotide pool, intracellular localization of the newly synthesized RNA, and the specific activity of enzymes of the de novo pyrimidine biosynthesis pathway. The present report describes the light and electron microscopic observations in these animals. For light microscopy, kidney slices were fixed in formalin, embedded, sectioned, and stained with H & E and PAS.

Fine Structural Changes in the Adenohypophyses of Rats Following Destruction of the Pituitary Stalk

1977 ◽  
Vol 35 ◽  
pp. 496-497
Author(s):  
K. Kovacs ◽  
E. Horvath ◽  
J. M. Bilbao ◽  
F. A. Laszlo ◽  
I. Domokos
Keyword(s):  
Structural Changes ◽  
Tissue Injury ◽  
Anterior Lobe ◽  
Uranyl Acetate ◽  
Male Rats ◽  
Pituitary Stalk ◽  
Sequence Of Events ◽  
Pituitary Glands ◽  
Electrolytic Lesions ◽  
Ultrathin Sections

Electrolytic lesions of the pituitary stalk in rats interrupt adenohypophysial blood flow and result in massive infarction of the anterior lobe. In order to obtain a deeper insight into the morphogenesis of tissue injury and to reveal the sequence of events, a fine structural investigation was undertaken on adenohypophyses of rats at various intervals following destruction of the pituitary stalk.The pituitary stalk was destroyed electrolytically, with a Horsley-Clarke apparatus on 27 male rats of the R-Amsterdam strain, weighing 180-200 g. Thirty minutes, 1,2,4,6 and 24 hours after surgery the animals were perfused with a glutaraldehyde-formalin solution. The skulls were then opened and the pituitary glands removed. The anterior lobes were fixed in glutaraldehyde-formalin solution, postfixed in osmium tetroxide and embedded in Durcupan. Ultrathin sections were stained with uranyl acetate and lead citrate and investigated with a Philips 300 electron microscope.

Ultrastructural Localization of Acetylcholinesterase in the Arcuate Nucleus and Median Eminence of the Rat

1977 ◽  
Vol 35 ◽  
pp. 440-441
Author(s):  
K.A. Carson ◽  
C.B. Nemeroff ◽  
M.S. Rone ◽  
J.S. Kizer ◽  
J.S. Hanker
Keyword(s):  
Choline Acetyltransferase ◽  
Median Eminence ◽  
Arcuate Nucleus ◽  
Cholinergic Neurons ◽  
Ultrastructural Localization ◽  
Male Rats ◽  
Neonatal Rats ◽  
Good Marker ◽  
Chemical Studies ◽  
High Doses

Biochemical, physiological, pharmacological, and more recently enzyme histo- chemical data have indicated that cholinergic circuits exist in the hypothalamus. Ultrastructural correlates of these pathways such as acetylcholinesterase (AchE) positive neurons in the arcuate nucleus (ARC) and stained terminals in the median eminence (ME) have yet to be described. Initial studies in our laboratories utilizing chemical lesioning and microdissection techniques coupled with microchemical and light microscopic enzyme histo- chemical studies suggested the existence of cholinergic neurons in the ARC which project to the ME (1). Furthermore, in adult male rats with Halasz deafferentations (hypothalamic islands composed primarily of the isolated ARC and the ME) choline acetyltransferase (ChAc) activity, a good marker for cholinergic neurons, was not significantly reduced in the ME and was only somewhat reduced in the ARC (2). Treatment of neonatal rats with high doses of monosodium 1-glutamate (MSG) results in a lesion largely restricted to the neurons of the ARC.

The ultrastructure of acinar cells in the external orbital gland of young and old male rats

1978 ◽  
Vol 36 (2) ◽  
pp. 276-277
Author(s):  
R. Carriere
Keyword(s):  
Young Adulthood ◽  
Acinar Cells ◽  
Cell Number ◽  
Male Rats ◽  
Polyploid Cell ◽  
Secretory Cells ◽  
Age Changes ◽  
Albino Rat ◽  
Golgi Membranes ◽  
Diploid Cells

The external orbital gland of the albino rat exhibits both sexual dimorphism and histological age changes. In males, many cells attain a remarkable degree of polyploidy and an increase of polyploid cell number constitutes the major age change until young adulthood. The acini of young adults have a small lumen and are composed of tall serous cells. Subsequently, many acini acquire a larger lumen with an irregular outline while numerous vacuoles accumulate throughout the secretory cells. At the same time, vesicular acini with a large lumen surrounded by pale-staining low cuboidal diploid cells begin to appear and their number increases throughout old age. The fine structure of external orbital glands from both sexes has been explored and in considering acinar cells from males, emphasis was given to the form of the Golgi membranes and to nuclear infoldings of cytoplasmic constituents.

The Effect of Androgen Depletion and Replacement on the Epithelium of the Seminal Vesicle of the Aging Rat

1975 ◽  
Vol 33 ◽  
pp. 590-591
Author(s):  
Venita F. Allison
Keyword(s):  
Cell Proliferation ◽  
Seminal Vesicle ◽  
Male Rats ◽  
Target Cells ◽  
Cell Regeneration ◽  
Secretory Function ◽  
Electron Microscopic ◽  
Aging Rat ◽  
Microscopic Studies ◽  
Androgen Depletion

In 1930, Moore, Hughes and Gallager reported that after castration seminal vesicle epithelial cell atrophy occurred and that cell regeneration could be achieved with daily injections of testis extract. Electron microscopic studies have confirmed those observations and have shown that testosterone injections restore the epithelium of the seminal vesicle in adult castrated male rats. Studies concerned with the metabolism of androgens point out that dihydrotestosterone stimulates cell proliferation and that other metabolites of testosterone probably influence secretory function in certain target cells.Although the influence of androgens on adult seminal vesicle epithelial cytology is well documented, little is known of the effect of androgen depletion and replacement on those cells in aging animals. The present study is concerned with the effect of castration and testosterone injection on the epithelium of the seminal vesicle of aging rats.

Aortic lesions in copper deficiency: Modification by dietary carbohydrates

1986 ◽  
Vol 44 ◽  
pp. 358-359
Author(s):  
U. Bielenberg
Keyword(s):  
Copper Deficiency ◽  
Male Rats ◽  
Dietary Carbohydrates ◽  
Dietary Copper ◽  
Serum Ceruloplasmin ◽  
Hepatic Copper ◽  
Dietary Treatments ◽  
Feeding Diets ◽  
Ceruloplasmin Activity ◽  
Simple Carbohydrate

Copper deficiency can cause cardiovascular lesions in experimental animals. Previous experiments have shown that the biochemical and itDrphologic lesions induced by deprivation of dietary copper can be suppressed by feeding diets containing starch or can be magnified by a high sucrose diet. In a recent study it was found that the more severe signs of copper deficiency in rats fed sucrose as compared to starch were due to the fructose moiety of sucrose. Although fructose as compared to starch markedly enhanced the symptoms of copper deficiency, the possibility that an effect of dietary carbohydrates due to the nature of the simple carbohydrate (fructose vs glucose) cannot be excluded. The present study was designed to determine if the severity of copper deficiency in rats fed sucrose as compared to starch is due to the glucose as well as the fructose moiety of sucrose. This portion of the study assessed the morphologic changes in aortas of seventy weanling male rats who were fed, for 9 weeks, copper deficient or copper supplemented diets containing either 62% starch, fructose or glucose. The starch-fed copper supplemented group served as the most normal controls. Rats were sacrificed after 9 weeks of dietary treatments. Copper deficiency was verified by reduced serum ceruloplasmin activity and serum and hepatic copper concentration.

Sign in / Sign up

Export Citation Format

Share Document