Hippocampal Sclerosis in Pilocarpine Epilepsy: Survival of Peptide-Containing Neurons and Learning and Memory Disturbances in the Adult NMRI Strain Mouse

The present experiments reveal the alterations of the hippocampal neuronal populations in chronic epilepsy. The mice were injected with a single dose of pilocarpine. They had status epilepticus and spontaneously recurrent motor seizures. Three months after pilocarpine treatment, the animals were investigated with the Barnes maze to determine their learning and memory capabilities. Their hippocampi were analyzed 2 weeks later (at 3.5 months) with standard immunohistochemical methods and cell counting. Every animal displayed hippocampal sclerosis. The neuronal loss was evaluated with neuronal-N immunostaining, and the activation of the microglia was measured with Iba1 immunohistochemistry. The neuropeptide Y, parvalbumin, and calretinin immunoreactive structures were qualitatively and quantitatively analyzed in the hippocampal formation. The results were compared statistically to the results of the control mice. We detected neuronal loss and strongly activated microglia populations. Neuropeptide Y was significantly upregulated in the sprouting axons. The number of parvalbumin- and calretinin-containing interneurons decreased significantly in the Ammon’s horn and dentate gyrus. The epileptic animals displayed significantly worse learning and memory functions. We concluded that degeneration of the principal neurons, a numerical decrease of PV-containing GABAergic neurons, and strong peptidergic axonal sprouting were responsible for the loss of the hippocampal learning and memory functions.

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Pathological and non-pathological aging, SAMP8 and SAMR1. What do hippocampal neuronal populations tell us?

10.1101/598599 ◽

2019 ◽

Author(s):

MJ Lagartos-Donate ◽

J Gonzáles-Fuentes ◽

P Marcos-Rabal ◽

R Insausti ◽

MM Arroyo-Jiménez

Keyword(s):

Learning And Memory ◽

Hippocampal Formation ◽

Neurological Diseases ◽

Accelerated Aging ◽

Neural Population ◽

Neuronal Populations ◽

Pathological Aging ◽

Local Circuitry ◽

Samp8 Mice ◽

Senescence Accelerated Mouse

ABSTRACTAlterations of cognitive processes and memory are one of the most important manifestations related to aging. However, not all memory types are affected in the same way. Learning and spatial memory are susceptible to these changes. The hippocampus represents the anatomical substrate of this type of memory, affected by structural and functional alterations along the normal aging and neurological diseases such as Alzheimer’s disease, Parkinson’s, schizophrenia and epilepsy. Some of the alterations related to aging are associated with alterations in the hippocampal interneuron populations and with an increase in excitability in the hippocampal circuit.In order to understand better the underlying processes in normal and pathological aging mechanisms, a murine model (Senescence-Accelerated Mouse Prone, SAMP8) and its respective controls (Senescence-Accelerated Mouse Resistant, SAMR1) have been used. While SAMP8 is a naturally occurring mouse line that displays a phenotype of accelerated aging with learning and memory impairment and these changes of learning and memory might be linked to some alterations in neuronal populations of the hippocampus. Thus, we analyzed the distribution and density of PV, CR and STT interneurons in the hippocampus of young and old mice as well as possible morphological and cholinergic changes in hippocampal formation. Comparing SAMR1 and SAMP8 we did not find any neural population that was specifically affected by aging in both groups. Interestingly, CR immunoreactivity and STT immunoreactivity showed changes in SAMP8 mice when they were compared to their controls. In SAMP8 CR+ and STT+ neurons decreased significantly along aging which suggests that CR and STT interneurons play a more important role than PV neurons in the pathological aging of the brain. In the case of SAMP8 mice the neural changes might be related to changes of the cholinergic system that might be affecting the wiring into the hippocampus formation through the perforant pathway. Further studies of this local circuitry will help to comprehend better how different inputs into these neural populations of the hippocampus could be affecting the development of neurodegerative diseases.

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The effect of electronic cigarettes exposure on learning and memory functions: behavioral and molecular analysis

Inhalation Toxicology ◽

10.1080/08958378.2021.1954732 ◽

2021 ◽

pp. 1-10

Author(s):

Karem H. Alzoubi ◽

Rahaf M. Batran ◽

Nour A. Al-Sawalha ◽

Omar F. Khabour ◽

Nareg Karaoghlanian ◽

...

Keyword(s):

Learning And Memory ◽

Molecular Analysis ◽

Electronic Cigarettes ◽

Memory Functions

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Postnatal Development of the Hippocampus in Male Albino Rats: A Histomorphometric Study

QJM ◽

10.1093/qjmed/hcaa040 ◽

2020 ◽

Vol 113 (Supplement_1) ◽

Author(s):

A A A Baraka ◽

K A Hafez ◽

A I A Othman ◽

A M M Sadek

Keyword(s):

Dentate Gyrus ◽

Postnatal Development ◽

Learning And Memory ◽

Hippocampal Formation ◽

Critical Role ◽

Mammalian Brain ◽

Albino Rats ◽

Ammon's Horn ◽

Hippocampus Proper ◽

Ammon’S Horn

Abstract Introduction In recent year deterioration in cognitive, learning, and memory become one of the significant problems in human life. Hippocampus is a pivotal part of the brain’s limbic system which serves a critical role in memory, learning process and regulating the emotions. In most regions of the brain, neurons are generated only at specific periods of early development, and not born in the adulthood. In contrast, hippocampal neurons are generated throughout development and adult life. The hippocampal dentate gyrus was reported to be one of the few regions of the mammalian brain where neurogenesis continue to occur throughout adulthood. The neurogenesis in the dentate gyrus was thought to play an important role in hippocampus-dependent learning and memory. The hippocampal formation is composed of the hippocampus proper, the dentate gyrus and the subiculum. The hippocampus proper is the largest part and is subdivided into fields designated as Cornu Ammonis or Ammon’s horn (CA) from CA1 to CA4. Ammon's horn is continuous with the subiculum, which acts as the main output source of the hippocampal formation. Aim of the Study To study the postnatal development of the hippocampal formation. Materials and Methods Five male albino rats from the following postnatal ages day 1, week 1, week 2, week3 and week 4 were studied by histological, immunohistochemical, and morphometric methods. Results The general architecture of the hippocampus proper with its polymorphic, pyramidal, and molecular layers was present at day1, whereas the details of the adult structure appeared at week 2. In the dentate gyrus, distinct lamination appeared at week 1 and its maturation continued with the production of neurons at the interhilar zone that peaked at week 2. The number and density of pyramidal axons and dendrites increase by age. Astrocytes increased in size and staining affinity for glial filaments, and acquired a stellate shape with age. Furthermore, the number of granule cell layers increased concomitantly with the increase in thickness of the molecular and polymorphic layers of both the hippocampus proper and the dentate gyrus. Conclusion The important sequences of events in the growth and maturation of the hippocampal formation in male albino rat occurred in the first 2 postnatal weeks.

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P.1.12 Interaction between neuropeptide Y, Y1 and Y2 receptor protein in the mouse hippocampal formation and amygdaloid complex

European Neuropsychopharmacology ◽

10.1016/s0924-977x(07)70013-5 ◽

2007 ◽

Vol 17 ◽

pp. S12

Author(s):

D. Stanic ◽

T. Hökfelt

Keyword(s):

Neuropeptide Y ◽

Hippocampal Formation ◽

Amygdaloid Complex ◽

Receptor Protein ◽

Y2 Receptor

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Effects of Walnuts (Juglans regia) on Learning and Memory Functions

Plant Foods for Human Nutrition ◽

10.1007/s11130-011-0260-2 ◽

2011 ◽

Vol 66 (4) ◽

pp. 335-340 ◽

Cited By ~ 25

Author(s):

Saida Haider ◽

Zehra Batool ◽

Saiqa Tabassum ◽

Tahira Perveen ◽

Sadia Saleem ◽

...

Keyword(s):

Learning And Memory ◽

Juglans Regia ◽

Memory Functions

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Review for "The effects of dietary edible bird nest supplementation on learning and memory functions of multigenerational mice"

10.1002/brb3.1817/v1/review1 ◽

2020 ◽

Keyword(s):

Learning And Memory ◽

Memory Functions ◽

Bird Nest

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Influence of Corticosterone and ACTH on the Postnatal Development of Learning and Memory Functions

Hormones and Brain Function ◽

10.1007/978-1-4684-2007-4_8 ◽

1973 ◽

pp. 83-89 ◽

Cited By ~ 2

Author(s):

Cs. Nyakas

Keyword(s):

Postnatal Development ◽

Learning And Memory ◽

Memory Functions

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Hippocampal sclerosis dementia: An amnesic variant of frontotemporal degeneration

Dementia & Neuropsychologia ◽

10.1590/s1980-57642013dn70100013 ◽

2013 ◽

Vol 7 (1) ◽

pp. 83-87 ◽

Cited By ~ 7

Author(s):

Chiadi U. Onyike ◽

Olga Pletnikova ◽

Kelly L. Sloane ◽

Campbell Sullivan ◽

Juan C. Troncoso ◽

...

Keyword(s):

Psychiatric Disorder ◽

Clinical Diagnosis ◽

Hippocampal Sclerosis ◽

Neuronal Loss ◽

Executive Dysfunction ◽

Convenience Sample ◽

Illness Onset ◽

Work Support ◽

Resource Center ◽

Johns Hopkins University

ABSTRACT Objective: To describe characteristics of hippocampal sclerosis dementia. Methods: Convenience sample of Hippocampal sclerosis dementia (HSD) recruited from the Johns Hopkins University Brain Resource Center. Twenty-four cases with post-mortem pathological diagnosis of hippocampal sclerosis dementia were reviewed for clinical characterization. Results: The cases showed atrophy and neuronal loss localized to the hippocampus, amygdala and entorrhinal cortex. The majority (79.2%) had amnesia at illness onset, and many (54.2%) showed abnormal conduct and psychiatric disorder. Nearly 42% presented with an amnesic state, and 37.5% presented with amnesia plus abnormal conduct and psychiatric disorder. All eventually developed a behavioral or psychiatric disorder. Disorientation, executive dysfunction, aphasia, agnosia and apraxia were uncommon at onset. Alzheimer disease (AD) was the initial clinical diagnosis in 89% and the final clinical diagnosis in 75%. Diagnosis of frontotemporal dementia (FTD) was uncommon (seen in 8%). Conclusion: HSD shows pathological characteristics of FTD and clinical features that mimic AD and overlap with FTD. The findings, placed in the context of earlier work, support the proposition that HSD belongs to the FTD family, where it may be identified as an amnesic variant.

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