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Chronic prenatal restraint stress induced memory impairment in passive avoidance task in post weaned male and female Wistar rats

Cherian SB, Bairy KL, Rao MS

Indian J Exp Biol, 2009 Nov;47(11):893-9.
PMID: 20099462

With a view to examine the effect of chronic maternal stress on cognitive function in the offspring during young age, pregnant Wistar rats were subjected to restraint stress from embryonic day 11 till delivery. Male and female pups born to these stressed rats were subjected to passive avoidance test on postnatal day 30 and 31. Results were compared with rats of the same age and sex born to control mothers, which were not stressed. The results showed that prenatal maternal restraint stress impairs the memory retention during young age in both sexes. The memory retention deficit induced by maternal restraint stress was evident in the decreased latency to enter the dark compartment of passive avoidance apparatus by the rats born to stressed mothers. The observed behavioral deficit may be due to the insult of stress on the developing hippocampus, a structure of the brain concerned with learning and memory. The results suggest that prolonged prenatal stress leads to long lasting malfunction in the behavioral development during young age in both male and female young rats. However when compared to their respective stress naïve controls, it seems evident that prenatal restraint stress has a less effect on females which could be due to their oesterogenic effects. These data reinforce the view that prenatal stress affects cognitive development in a sex-specific manner.

Matched MeSH terms: Memory Disorders/etiology*
Red flags in patients presenting with headache: clinical indications for neuroimaging

Sobri M, Lamont AC, Alias NA, Win MN

Br J Radiol, 2003 Aug;76(908):532-5.
PMID: 12893694

Headache is a very common patient complaint but secondary causes for headache are unusual. Neuroimaging is both expensive and has a low yield in this group. Most patients with intracranial pathology have clinical features that would raise a "red flag". Appropriate selection of patients with headache for neuroimaging to look for secondary causes is very important. Red flags act as screening tools to help in identifying those patients presenting with headache who would benefit from prompt neuroimaging, and may increase the yield. The aim of this study is to evaluate clinical features in patients with headache using neuroimaging as a screening tool for intracranial pathology. 20 red flags were defined. A retrospective study of 111 patients was performed and the outcomes were divided into positive and negative. Abnormal neuroimaging was present in 39 patients. Results were analysed using the Logistic Regression model. Sensitivity and specificity of red flags were analysed to establish the cut-off point to predict abnormal neuroimaging and a receiver operating characteristic (ROC) curve plotted to show the sensitivity of the diagnostic test. Three red flag features proved to be statistically significant with the p-value of less than 0.05 on both univariate and multivariate analysis. These were: paralysis; papilloedema; and "drowsiness, confusion, memory impairment and loss of consciousness". In addition, if three or more red flags from the list were present, this showed strong indication of abnormal neuroimaging, from cut-off point of ROC curve (area under the curve =0.76).

Matched MeSH terms: Memory Disorders/etiology
Chronic cerebral hypoperfusion-induced memory impairment and hippocampal long-term potentiation deficits are improved by cholinergic stimulation in rats

Damodaran T, Müller CP, Hassan Z

Pharmacol Rep, 2019 Jun;71(3):443-448.
PMID: 31003155 DOI: 10.1016/j.pharep.2019.01.012

BACKGROUND: Chronic cerebral hypoperfusion (CCH) can induce the accumulation of reactive oxygen species, which leads to oxidative damage, neuronal injury, and central cholinergic dysfunction in vulnerable regions of the brain, such as the hippocampus and cerebral cortex. These effects can lead to significant cognitive impairments in clinical populations of vascular dementia (VaD). The present studies aimed to investigate the role of the cholinergic system in memory functions and hippocampal long-term potentiation (LTP) impairments induced by CCH in rats.
METHODS: Male Sprague Dawley rats were subjected to permanent bilateral occlusion of common carotid arteries (PBOCCA) or sham surgery. Then, PBOCCA rats received ip injections with, either vehicle (control group), the muscarinic receptor agonist oxotremorine (0.1 mg/kg), or the acetylcholinesterase inhibitor physostigmine (0.1 mg/kg). Cognitive functions were evaluated using a passive avoidance task and the Morris water maze test. In addition, hippocampal LTP was recorded in vivo under anaesthesia.
RESULTS: The PBOCCA rats exhibited significant deficits in passive avoidance retention and spatial learning and memory tests. They also showed a suppression of LTP formation in the hippocampus. Oxotremorine and physostigmine significantly improved the learning and memory deficits as well as the suppression of LTP in PBOCCA rats.
CONCLUSIONS: The present data suggest that the cholinergic system plays an important role in CCH-induced cognitive deficits and could be an effective therapeutic target for the treatment of VaD.

Matched MeSH terms: Memory Disorders/etiology
Modulation of the Nitrergic Pathway via Activation of PPAR-γ Contributes to the Neuroprotective Effect of Pioglitazone Against Streptozotocin-Induced Memory Dysfunction

Prakash A, Kumar A, Ming LC, Mani V, Majeed AB

J Mol Neurosci, 2015 Jul;56(3):739-50.
PMID: 25854775 DOI: 10.1007/s12031-015-0508-7

Alzheimer's disease (AD) is a neurodegenerative disease characterized by impaired memory function and oxidative damage. NO is a major signaling molecule produced in the central nervous system to modulate neurological activity through modulating nitric oxide synthase. Recently, PPAR-γ agonists have shown neuroprotective effects in neurodegenerative disorders. However, there have been only a few studies identifying mechanisms through which cognitive benefits may be exerted. The present study was designed to investigate the possible nitric oxide mechanism in the protective effect of pioglitazone against streptozotocin (STZ)-induced memory dysfunction. Wistar rats were intracerebroventricularly (ICV) injected with STZ. Then rats were treated with pioglitazone, NO modulators [L-arginine and nitro-L-arginine methyl ester (L-NAME)] for 21 days. Behavioral alterations were assessed in between the study period. Animals were sacrificed immediately after behavioral session, and mito-oxidative parameters, TNF-α, IL-6, and caspase-3 activity were measured. STZ-treated rats showed a memory deficit and significantly increased in mito-oxidative damage and inflammatory mediators and apoptosis in the hippocampus. Chronic treatment of pioglitazone significantly improved memory retention and attenuated mito-oxidative damage parameters, inflammatory markers, and apoptosis in STZ-treated rats. However, L-arginine pretreatment with lower dose of pioglitazone has not produced any protective effect as compared to per se. Furthermore, pretreatment of L-NAME significantly potentiated its protective effect, which indicates the involvement of nitric oxide for activation of PPAR-γ action. These results demonstrate that pioglitazone offers protection against STZ-induced memory dysfunction possibly due to its antioxidant, anti-inflammatory, and anti-apoptotic action mediating nitric oxide pathways and, therefore, could have a therapeutic potential in AD.

Matched MeSH terms: Memory Disorders/etiology
Development of the clinical assessment scale in autoimmune encephalitis

Lim JA, Lee ST, Moon J, Jun JS, Kim TJ, Shin YW, et al.

Ann Neurol, 2019 03;85(3):352-358.
PMID: 30675918 DOI: 10.1002/ana.25421

OBJECTIVE: There is no scale for rating the severity of autoimmune encephalitis (AE). In this study, we aimed to develop a novel scale for rating severity in patients with diverse AE syndromes and to verify the reliability and validity of the developed scale.
METHODS: The key items were generated by a panel of experts and selected according to content validity ratios. The developed scale was initially applied to 50 patients with AE (development cohort) to evaluate its acceptability, reproducibility, internal consistency, and construct validity. Then, the scale was applied to another independent cohort (validation cohort, n = 38).
RESULTS: A new scale consisting of 9 items (seizure, memory dysfunction, psychiatric symptoms, consciousness, language problems, dyskinesia/dystonia, gait instability and ataxia, brainstem dysfunction, and weakness) was developed. Each item was assigned a value of up to 3 points. The total score could therefore range from 0 to 27. We named the scale the Clinical Assessment Scale in Autoimmune Encephalitis (CASE). The new scale showed excellent interobserver (intraclass correlation coefficient [ICC] = 0.97) and intraobserver (ICC = 0.96) reliability for total scores, was highly correlated with modified Rankin scale (r = 0.86, p

Matched MeSH terms: Memory Disorders/etiology