Behavioral Effects of Transient Cerebral Ischemia

2000 ◽  
Vol 1 (4) ◽  
pp. 276-286 ◽  
Author(s):  
Tess L. Briones ◽  
Barbara Therrien
Keyword(s):  
Spatial Learning ◽  
Cell Loss ◽  
Female Rats ◽  
Minimal Cell ◽  
Behavioral Impairment ◽  
Learning Deficits ◽  
Ca1 Neurons ◽  
Ischemic Group ◽  
Ca1 Region ◽  
Female Wistar Rats

CA1 neurons in the hippocampus, a brain structure involved in learning and memory, are selectively vulnerable to ischemic effects. In this study, the authors examined if duration of ischemia is directly related to extent of CA1 damage and degree of spatial learning deficit. Adult female Wistar rats received either 5-min or 10-min ischemia or sham surgery. Following recovery, rats were tested in the Morris water maze. Histological analysis showed moderate cell loss in CA1 (31%) and CA3 (12%) and minimal cell loss in CA2 (4%) with 5-min ischemia. Increased cell loss was seen in CA1 (68%), CA2 (16%), and CA3 (23%) with 10-min ischemia. Behavioral testing revealed that animals with 10-min ischemia have greater spatial learning deficits and they remain impaired across the test days compared to the 5-min ischemic group. Furthermore, degree of CA1 cell loss accounted for approximately 45% of the variance in spatial learning deficits in the ischemic group. The authors conclude that cell loss is largely confined to CA1 region in rats who received 5 and 10 min of ischemia and that increased ischemic duration results in persistent learning deficits in female rats; also, the degree of behavioral impairment is related to extent of CA1 cell loss.

scholarly journals Reappearance of Hippocampal CA1 Neurons after Ischemia is Associated with Recovery of Learning and Memory

2005 ◽  
Vol 25 (12) ◽  
pp. 1586-1595 ◽  
Author(s):  
Olof Bendel ◽  
Tjerk Bueters ◽  
Mia von Euler ◽  
Sven Ove Ögren ◽  
Johan Sandin ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Learning And Memory ◽  
Spatial Learning ◽  
Cognitive Functions ◽  
Spatial Learning And Memory ◽  
Neuronal Marker ◽  
Ca1 Neurons ◽  
Ca1 Region ◽  
Hippocampal Ca1 ◽  
The Brain

The pyramidal neurons of the hippocampal CA1 region are essential for cognitive functions such as spatial learning and memory, and are selectively destroyed after cerebral ischemia. To analyze whether degenerated CA1 neurons are replaced by new neurons and whether such regeneration is associated with amelioration in learning and memory deficits, we have used a rat global ischemia model that provides an almost complete disappearance (to approximately 3% of control) of CA1 neurons associated with a robust impairment in spatial learning and memory at two weeks after ischemia. We found that transient cerebral ischemia can evoke a massive formation of new neurons in the CA1 region, reaching approximately 40% of the original number of neurons at 90 days after ischemia (DAI). Co-localization of the mature neuronal marker neuronal nuclei with 5-bromo-2'-deoxyuridine in CA1 confirmed that neurogenesis indeed had occurred after the ischemic insult. Furthermore, we found increased numbers of cells expressing the immature neuron marker polysialic acid neuronal cell adhesion molecule in the adjacent lateral periventricular region, suggesting that the newly formed neurons derive from this region. The reappearance of CA1 neurons was associated with a recovery of ischemia-induced impairments in spatial learning and memory at 90 DAI, suggesting that the newly formed CA1 neurons restore hippocampal CA1 function. In conclusion, these results show that the brain has an endogenous capacity to form new nerve cells after injury, which correlates with a restoration of cognitive functions of the brain.

Subacute melamine exposure disrupts task-based hippocampal information flow via inhibiting the subunits 2 and 3 of AMPA glutamate receptors expression

2020 ◽  
pp. 096032712097582
Author(s):  
Wei Sun ◽  
Xiaoliang Li ◽  
Dongxin Tang ◽  
Yuanhua Wu ◽  
Lei An
Keyword(s):  
Information Flow ◽  
Spatial Learning ◽  
Phase Synchronization ◽  
Neural Function ◽  
Learning Deficits ◽  
Postsynaptic Receptors ◽  
Ca1 Region ◽  
Hippocampal Ca1 ◽  
Neural Information ◽  
Hippocampal Ca3

Although melamine exposure induces cognitive deficits and dysfunctional neurotransmission in hippocampal Cornus Ammonis (CA) 1 region of rats, it is unclear whether the neural function, such as neural oscillations between hippocampal CA3–CA1 pathway and postsynaptic receptors involves in these effects. The levels of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) subunit glutamate receptor (GluR) 1 and GluR2/3 in CA1 region of melamine-treated rats, which were intragastric treated with 300 mg/kg/day for 4 weeks, were detected. Following systemic or intra-hippocampal CA1 injection with GluR2/3 agonist, spatial learning of melamine-treated rats was assessed in Morris water maze (MWM) task. Local field potentials were recorded in CA3–CA1 pathway before and during behavioral test. General Partial Directed Coherence approach was applied to determine directionality of neural information flow between CA3 and CA1 regions. Results showed that melamine exposure reduced GluR2/3 but not GluR1 level and systemic or intra-hippocampal CA1 injection with GluR2/3 agonist effectively mitigated the learning deficits. Phase synchronization between CA3 and CA1 regions were significantly diminished in delta, theta and alpha oscillations. Coupling directional index and strength of CA3 driving CA1 were marked reduced as well. Intra-hippocampal CA1 infusion with GluR2/3 agonist significantly enhanced the phase locked value and reversed the melamine-induced reduction in the neural information flow (NIF) from CA3 to CA1 region. These findings support that melamine exposure decrease the expression of GluR2/3 subunit involved in weakening directionality index of NIF, and thereby induced spatial learning deficits.

NEW DATA CONCERNING THE ROLE PLAYED BY PROGESTERONE IN THE CONTROL OF FOLLICULAR GROWTH IN THE RAT

1974 ◽  
Vol 75 (3) ◽  
pp. 569-578 ◽  
Author(s):  
G. Buffler ◽  
S. Roser
Keyword(s):  
Wistar Rats ◽  
Venous Blood ◽  
Oestrous Cycle ◽  
Female Rats ◽  
Cycle Duration ◽  
Follicular Growth ◽  
The Third ◽  
Female Wistar Rats

ABSTRACT The mechanisms involved in the prolongation of the oestrous cycle following LH administration were studied in 4-day cyclic female Wistar rats. In females injected with LH on the morning of dioestrus I there was an increase in ovarian venous blood progesterone as compared with non-injected animals. In both LH-treated females, and those injected with progesterone on the morning of dioestrus I, a slowing up in follicular growth was observed from the afternoon of dioestrus I. The size of follicles greater than 400 urn present in LH or progesterone injected animals on the third day of cycle was similar to the size reached by the same range of follicles in non-injected animals on the second day of the cycle. Hence, the increase in endogenous ovarian progesterone elicited by LH was considered as the cause of the slowing up of follicular growth and therefore of the lengthening of the oestrous cycle duration in female rats injected with LH at the beginning of 4-day cycle.

Intrahippocampal co-administration of nicotine and O-acetyl-L-carnitine prevents the H-89-induced spatial learning deficits in Morris water maze

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mahmoud Hashemzaei ◽  
Najmeh Baratzadeh ◽  
Iraj Sharamian ◽  
Sahar Fanoudi ◽  
Mehdi Sanati ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Spatial Memory ◽  
Morris Water Maze ◽  
Spatial Learning ◽  
Water Maze ◽  
Synergistic Effects ◽  
Deionized Water ◽  
Learning Deficits ◽  
Learning Impairments ◽  
Morris Water Maze Task

Abstract Objectives H-89 (a protein kinase AII [PKA II] inhibitor) impairs the spatial memory in the Morris water maze task in rats. In the present study, we aimed to study the protective effects of nicotine and O-acetyl-L-carnitine against H-89-induced spatial memory deficits. Methods Spatial memory impairment was induced by the bilateral intrahippocampal administration of 10 µM H-89 (dissolved in dimethyl sulfoxide, DMSO) to rats. The rats then received bilateral administrations of either nicotine (1 μg/μL, dissolved in saline) or O-acetyl-L-carnitine (100 μM/side, dissolved in deionized water) alone and in combination. Control groups received either saline, deionized water, or DMSO. Results The H-89-treated animals showed significant increases in the time and distance travelled to find hidden platforms, and there was also a significant decrease in the time spent in the target quadrant compared to DMSO-treated animals. Nicotine and O-acetyl-L-carnitine had no significant effects on H-89-induced spatial learning impairments alone, but the bilateral intrahippocampal co-administration of nicotine and O-acetyl-L-carnitine prevented H-89-induced spatial learning deficits and increased the time spent in the target quadrant in comparison with H-89-treated animals. Conclusions Our results indicated the potential synergistic effects of nicotine and O-acetyl-L-carnitine in preventing protein kinase AII inhibitor (H-89)-induced spatial learning impairments.

scholarly journals Folic Acid Affects Iron Status in Female Rats with Deficiency of These Micronutrients

2019 ◽  
Vol 195 (2) ◽  
pp. 551-558 ◽  
Author(s):  
Joanna Suliburska ◽  
Katarzyna Skrypnik ◽  
Agata Chmurzyńska
Keyword(s):  
Folic Acid ◽  
Iron Status ◽  
Iron Concentration ◽  
Folic Acid Supplementation ◽  
Female Rats ◽  
Control Group ◽  
Standard Diet ◽  
Study Group ◽  
Female Wistar Rats ◽  
Iron And Folic Acid

Abstract Although simultaneous supplementation with iron and folic acid is justified, the potential interactions between these micronutrients are unknown. The aim of this study was to determine the effects of oral iron and folic acid, administered together or separately, on iron concentration in tissues in rats with a deficiency of both these micronutrients. In the first stage of the experiment (28 days), 150 8-week-old female Wistar rats were randomly assigned to a control group (C; n = 30) fed the standard diet and to a study group (n = 120) fed a diet deficit in iron and folate. The study group was then randomly divided to four groups: D group fed a deficit diet, FE group fed a deficit diet with iron gluconate, the FOL group fed a deficit diet with folate acid, and the FEFOL group fed a deficit diet with iron gluconate and folate acid. After 2, 10, and 21 days of supplementation, ten animals from each group were killed. Morphological parameters were measured in whole blood. Iron concentration was assayed in serum, liver, spleen, pancreas, heart, and kidneys. Folic acid supplementation more significantly decreased iron concentrations in the pancreas and spleen than in the D group after 10 and 21 days of supplementation. Moreover, the combination of iron with folic acid markedly decreased iron levels in the liver and spleen, in comparison with iron alone, after 10 and 21 days of the experiment. In conclusion, folic acid affects iron status in female rats deficient in these micronutrients in moderate and long-term supplementation.

Spatial Learning Deficits in Preschool Children of Alcoholics

1995 ◽  
Vol 19 (4) ◽  
pp. 1067-1072 ◽  
Author(s):  
Steven L. Schandler ◽  
Connie S. Thomas ◽  
Michael J. Cohen
Keyword(s):  
Preschool Children ◽  
Spatial Learning ◽  
Children Of Alcoholics ◽  
Learning Deficits

Hypothalamo-pituitary regulation of the c-myc gene in rat liver

1990 ◽  
Vol 5 (3) ◽  
pp. 267-274 ◽  
Author(s):  
I. Porsch Hällstöm ◽  
J.-Å. Gustafsson ◽  
A. Blanck
Keyword(s):  
Rat Liver ◽  
Female Rats ◽  
Male Rats ◽  
Female Rat ◽  
Continuous Administration ◽  
Gh Secretion ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
Female Wistar Rats ◽  
Myc Gene

ABSTRACT Expression of the c-myc gene was studied in the livers of male and female Wistar rats. Furthermore, the effects on hepatic c-myc expression of neonatal and adult castration, with or without testosterone supplementation, as well as of continuous administration of GH to intact males, were analysed. Expression of c-myc was low in 6-day-old animals of both sexes, reached a maximum at 35 days of age and declined to the level of adult animals at 70 days. In prepubertal animals, expression was higher in females, but was higher in males after the onset of puberty, the postpubertal female rat liver exhibiting 50–70% of the expression in males. Treatment of adult male rats with bovine GH in osmotic minipumps for 1 week reduced c-myc expression to the level of female rats. Castration, both neonatally and of adults, also feminized hepatic c-myc expression. Testosterone supplementation of the castrated animals increased the expression towards the level in sham-operated controls. These results indicate that the c-myc gene is regulated by the hypothalamo-pituitary-liver axis via the sex-differentiated pattern of GH secretion, in analogy with other sex-differentiated hepatic functions, such as metabolism of steroids and xenobiotics. Neuroendocrine regulation of a gene such as c-myc, which is involved in the control of cell proliferation and differentiation, represents another aspect of the complex influence of GH on various somatic functions.

Mice lacking hippocampal left-right asymmetry show non-spatial learning deficits

2018 ◽  
Vol 336 ◽  
pp. 156-165 ◽  
Author(s):  
Akihiro Shimbo ◽  
Yutaka Kosaki ◽  
Isao Ito ◽  
Shigeru Watanabe
Keyword(s):  
Spatial Learning ◽  
Learning Deficits ◽  
Left Right Asymmetry

Regulation of hepatic growth

1986 ◽  
Vol 66 (3) ◽  
pp. 499-541 ◽  
Author(s):  
M. R. Alison
Keyword(s):  
Cell Mass ◽  
Growth Inhibitor ◽  
Cell Loss ◽  
Regenerative Process ◽  
Chemical Mechanism ◽  
Cell Renewal ◽  
Minimal Cell ◽  
Liver Size ◽  
Success Stories ◽  
Isolation And Characterization

The liver is a conditional renewal system, which in the adult organism undergoes minimal cell production and/or cell renewal. However, a reduction in liver cell mass, because of either actual cell loss or cell atrophy, evokes a rapid regenerative response tailored to replace the lost tissue. Synthesis of DNA begins as early as 15 h after a two-thirds hepatectomy, and the fact that all the remaining hepatocytes enter DNA synthesis within the next 48 h does indicate they are all potentially proliferative, and it is unlikely that a distinct stem cell compartment exists. The temporal sequelae of events can be best explained by the semisynchronous passage of cells from G0 into the proliferative cycle (see Fig. 2) where they undergo one or more rounds of cell division before decycling back into the proliferatively quiescent G0 state. The age of the animal and its nutritional and hormonal status are all important modifiers of the response, but none of them is critical to the regenerative process. Experiments involving the administration of sera or the transfer of blood between animals strongly favor the existence of humoral regulatory factors; the liver is apparently capable of producing both inhibitory and stimulatory molecules that act by negative and positive feedback mechanisms, respectively, to control tissue homeostasis, whereas other organs, notably the pancreas, are important sources of facilitatory molecules. A chemical mechanism of self inhibition is a very intellectually appealing hypothesis, but at present there is no consistent message as to the identity of the inhibitory molecule, although most studies suggest the target site for its action is the G1-S transition. Unless the whole field is one of multilateral analysis of an artifact, then endogenous growth inhibitors do exist, but the problem now is one of biochemical isolation and characterization. The field compares rather badly with the many success stories in recent years in which new hormones and peptides have been speedily isolated and purified. A reduction in liver size appears to be associated with a decrease in the concentration of an hepatic growth inhibitor and the production and/or unmasking of a stimulatory factor(s) that is also of hepatic origin. Once again, there is little information about the biochemical nature of the principle and much less on its mode of action. We all assume that such stimulators, and for that matter inhibitors as well, act on "restriction points" or "mitosis operons" and so on.(ABSTRACT TRUNCATED AT 400 WORDS)

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