neuropeptide-y and Cognition-Disorders

Neuropsychological dysfunction after treatment of spontaneous subarachnoid haemorrhage (sSAH) is common but underreported. The vasoconstrictor neuropeptide Y (NPY) is excessively released after sSAH and in psychiatric disorders. We prospectively analysed the treatment-specific differences in the secretion of endogenous cerebrospinal fluid (CSF) NPY during the acute stage after sSAH and its impact on cognitive processing.. A total of 26 consecutive patients (f:m = 13:8; mean age 50.6 years) with good-grade sSAH were enrolled (drop out n = 5): n = 9 underwent endovascular aneurysm occlusion, n = 6 microsurgery, and n = 6 patients with perimesencephalic SAH received standardized intensive medical care. Ventricular CSF was drawn daily from day 1-10. CSF NPY levels were determined with competitive enzyme immunoassay. All patients underwent neuropsychological self-report assessment [36-Item Short Form Health Survey (SF-36) and ICD-10-Symptom-Rating questionnaire (ISR)] after the onset of sSAH (day 11-35; t. To the best of our knowledge, this study is the first to correlate the levels of endogenous NPY in supratentorial CSF with cognitive outcome in good-grade sSAH patients. Excessive NPY release into CSF may have a short-term influence on the pathogenesis of neuropsychological deficits. The impact of cerebrovascular manipulation on NPY release has to be further elucidated.. ANOVA: analysis of variance; aSAH: aneurysmal subarachnoid haemorrhage; AUC: area under the curve; CBF: cerebral blood flow; CSF: cerebrospinal fluid; CT (scan): computed tomography (scan); CV: cerebral vasospasm; DIND: delayed ischemic neurological deficit; DSA: digital subtraction angiography; EIA: enzyme immunoassay; EV: endovascular aneurysm occlusion; EVD: external ventricular drainage; FU: 6-month follow-up; GCS: Glasgow Coma Scale; Ghp: general health perceptions; GOS: Glasgow Outcome Scale; h: hour/s; HH: Hunt and Hess; ICU: intensive care unit; ISR: ICD-10-Symptom-Rating questionnaire; MCS: mental component summary; Mhi: general mental health; min: minute/s; min-max: minimum - maximum; ml: millilitre; mRS: modified Ranking Scale; MS: microsurgical clipping, microsurgical aneurysm occlusion; ng: nanograms; no. [n]: number; NPY: Neuropeptide Y; p: p value; Pain: bodily pain; PCS: physical component summary; Pfi: physical functioning; pSAH: perimesencephalic subarachnoid haemorrhage; PTSD: posttraumatic stress disorder; QoL: quality of life; Rawhtran: health transition item; Rolem: role limitations because of emotional problems; Rolph: role limitations due to physical health problems; SAH: subarachnoid haemorrhage; SD: standard deviation; SF-36: 36-Item Short Form Health Survey; Social: social functioning; sSAH: spontaneous subarachnoid haemorrhage; TCD: trans-cranial Doppler ultrasound; (test) t

Topics: Adolescent; Adult; Aged; Area Under Curve; Cognition Disorders; Cohort Studies; Female; Glasgow Outcome Scale; Humans; Male; Middle Aged; Neuropeptide Y; Neuropsychological Tests; Pilot Projects; Self Report; Subarachnoid Hemorrhage; Young Adult

Postmenopausal women represent the largest cohort of patients with heart failure with preserved ejection fraction, and vascular dementia represents the most common form of dementia in patients with heart failure with preserved ejection fraction. Therefore, we tested the hypotheses that the combination of cardiac pressure overload (aortic banding [AB]) and the loss of female sex hormones (ovariectomy [OVX]) impairs cerebrovascular control and spatial memory.. Female Yucatan miniswine were separated into 4 groups (n=7 per group): (1) control, (2) AB, (3) OVX, and (4) AB-OVX. Pigs underwent OVX and AB at 7 and 8 months of age, respectively. At 14 months, cerebral blood flow velocity and spatial memory (spatial hole-board task) were lower in the OVX groups (. Mechanistically, impaired cerebral blood flow control in experimental heart failure may be the result of heightened neuropeptide Y-induced vasoconstriction along with reduced vasodilation associated with decreased Ca

Topics: Animals; Aorta; Arterial Pressure; Behavior, Animal; Cerebral Arteries; Cerebrovascular Circulation; Cerebrovascular Disorders; Cognition; Cognition Disorders; Disease Models, Animal; Female; Gonadal Steroid Hormones; Heart Failure; Ligation; Neuropeptide Y; Nitric Oxide; Ovariectomy; Pia Mater; Potassium Channels, Calcium-Activated; Signal Transduction; Spatial Memory; Swine; Swine, Miniature; Time Factors; Vasoconstriction; Vasodilation

The senescence-accelerated mouse prone 8 (SAMP8) strain is considered a neurodegeneration model showing age-related cognitive deficits with little physical impairment. Young SAMP8 mice, however, exhibit signs of disturbances in development such as marked hyperactivity and reduced anxiety well before the onset of cognitive impairment. As the key enzyme in local regulation of thyroid hormone (TH) signaling, type 2 deiodinase, was significantly reduced in the SAMP8 hippocampus relative to that of the normally aging SAM-resistant 1 (SAMR1), we used these two strains to compare the development of the hippocampal GABAergic system, which is known to be strongly affected by hypothyroidism. Among GABAergic components, neuronal K+ /Cl- co-transporter 2 was down-regulated in SAMP8 transiently at 2 weeks. Although distribution of total GABAergic neurons was similar in both strains, 22-30% reduction was observed in the neuropeptide Y (NPY)-positive subpopulation of GABAergic neurons in SAMP8. Electrophysiological studies on hippocampal slices obtained at 4 weeks revealed that epileptiform activity, induced by high-frequency stimulation, lasted four times longer in SAMP8 compared with SAMR1, indicating a dysregulation of excitability that may be linked to the behavioral abnormalities of young SAMP8 and to neurodegeneration later on in life. Local attenuation of TH signaling may thus impact the normal development of the GABAergic system.

Topics: Aging; Animals; Behavior, Animal; Cognition Disorders; Cyclic AMP Response Element-Binding Protein; Electrophysiological Phenomena; gamma-Aminobutyric Acid; Hippocampus; Iodide Peroxidase; K Cl- Cotransporters; Learning Disabilities; Male; Memory Disorders; Mice; Neurodegenerative Diseases; Neurons; Neuropeptide Y; Phosphorylation; Symporters; Thyroid Hormones

In this study, the motor deficit, cognition impairment and the vulnerability of different striatal interneurons to the 6-hydroxydopamine (6-OHDA)-induced excitotoxicity in unilateral medial forebrain bundle (MFB) lesion rats were analyzed by employing behavioral test, immunohistochemistry and Western blot methods. The apomorphine-induced rotation after MFB lesion was used as a valid criterion of motor deficit. The 6-OHDA damaged rats had limb rigidity with longer hang time compared to the controls in the grip strength test. Cognitive and mnemonic deficits of rats with unilateral MFB lesion were observed by the water maze task. The MFB lesion resulted in a significant loss of tyrosine hydroxylase (TH)+ cells in the contralateral striatum or substantia nigra. After dopaminergic depletion, the numbers of calretinin (Cr)+ and choline acetyltransferase (ChAT)+ interneurons were notably reduced while these of neuropeptide Y (NPY)+ were markedly increased in the striatum. No noticeable change in the number of parvalbumin (Parv)+ interneurons was found in 6-OHDA rats. In addition, the fiber densities for each individual interneuron were increased after 6-OHDA treatment, especially for the fiber densities of Parv+ and Cr+ interneurons. The Western blot analysis further confirmed the results described above. In conclusion, the MFB lesion model is suitable to mimic Parkinson's disease (PD), and our results are helpful for further understanding the underlying mechanism and the specific functions of various striatal interneurons in the pathological process of PD.

Topics: Adrenergic Agents; Animals; Apomorphine; Choline O-Acetyltransferase; Cognition Disorders; Corpus Striatum; Creatine; Interneurons; Male; Maze Learning; Medial Forebrain Bundle; Movement Disorders; Muscle Strength; Neuropeptide Y; Oxidopamine; Parvalbumins; Rats; Rats, Sprague-Dawley; Spatial Behavior; Tyrosine 3-Monooxygenase

BACE1 is the rate-limiting enzyme that cleaves amyloid precursor protein (APP) to produce the amyloid β peptides that accumulate in Alzheimer's disease (AD). BACE1, which is elevated in AD patients and APP transgenic mice, also cleaves the β2-subunit of voltage-gated sodium channels (Navβ2). Although increased BACE1 levels are associated with Navβ2 cleavage in AD patients, whether Navβ2 cleavage occurs in APP mice had not yet been examined. Such a finding would be of interest because of its potential impact on neuronal activity: previous studies demonstrated that BACE1-overexpressing mice exhibit excessive cleavage of Navβ2 and reduced sodium current density, but the phenotype associated with loss of function mutations in either Navβ-subunits or pore-forming α-subunits is epilepsy. Because mounting evidence suggests that epileptiform activity may play an important role in the development of AD-related cognitive deficits, we examined whether enhanced cleavage of Navβ2 occurs in APP transgenic mice, and whether it is associated with aberrant neuronal activity and cognitive deficits. We found increased levels of BACE1 expression and Navβ2 cleavage fragments in cortical lysates from APP transgenic mice, as well as associated alterations in Nav1.1α expression and localization. Both pyramidal neurons and inhibitory interneurons exhibited evidence of increased Navβ2 cleavage. Moreover, the magnitude of alterations in sodium channel subunits was associated with aberrant EEG activity and impairments in the Morris water maze. Together, these results suggest that altered processing of voltage-gated sodium channels may contribute to aberrant neuronal activity and cognitive deficits in AD.

Topics: Alzheimer Disease; Amyloid beta-Protein Precursor; Amyloid Precursor Protein Secretases; Animals; Aspartic Acid Endopeptidases; Biotinylation; Cognition Disorders; Disease Models, Animal; Electroencephalography; Gene Expression Regulation; Glutamate Decarboxylase; Humans; Maze Learning; Mice; Mice, Transgenic; Mutation; NAV1.1 Voltage-Gated Sodium Channel; Nerve Tissue Proteins; Neurons; Neuropeptide Y; Sodium Channels

Levels of educational and occupational attainment, as components of cognitive reserve, may modify the relationship between the pathological hallmarks and cognition in Alzheimer's disease (AD). We examined whether exposure of a Tg2576 transgenic mouse model of AD to environmental enrichment (EE) at a specific period during the amyloidogenic process favored the establishment of a cognitive reserve. We found that exposure to EE during early adulthood of Tg2576 mice--before amyloidogenesis has started--reduced the severity of AD-related cognitive deficits more efficiently than exposure later in life, when the pathology is already present. Interestingly, early-life exposure to EE, while slightly reducing forebrain surface covered by amyloid plaques, did not significantly impact aberrant inhibitory remodeling in the hippocampus of Tg2576 mice. Thus, transient early-life exposure to EE exerts long-lasting protection against cognitive impairment during AD pathology. In addition, these data define the existence of a specific life time frame during which stimulatory activity most efficiently builds a cognitive reserve, limiting AD progression and favoring successful aging.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Amyloidosis; Analysis of Variance; Animals; Calbindins; Cognition Disorders; Disease Models, Animal; Environment; Exploratory Behavior; Humans; Maze Learning; Mice; Mice, Inbred C57BL; Mice, Transgenic; Mutation; Neuropeptide Y; Recognition, Psychology; S100 Calcium Binding Protein G; Spatial Behavior; Statistics, Nonparametric

High levels of Aβ impair neuronal function at least in part by disrupting normal synaptic transmission and causing dysfunction of neural networks. This network dysfunction includes abnormal synchronization of neuronal activity resulting in epileptiform activity. Over time, this aberrant network activity can lead to the depletion of calcium-dependent proteins, such as calbindin, Fos, and Arc, and compensatory inhibitory remodeling of hippocampal circuits, including GABAergic sprouting and ectopic expression of the inhibitory neuropeptide Y (NPY) in dentate granule cells. Here we present detailed protocols for detecting and quantifying these alterations in mouse models of Alzheimer's disease (AD) by immunohistochemistry. These methods are useful as surrogate measures for detecting chronic aberrant network activity in models of AD and epilepsy. In addition, since we have found that the severity of these changes relates to the degree of Aβ-dependent cognitive impairments, the protocols are useful for quantifying biomarkers of cognitive impairment in mouse models of AD.

Topics: Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; Biomarkers; Cognition Disorders; Hippocampus; Humans; Immunohistochemistry; In Vitro Techniques; Mice; Mice, Transgenic; Neuropeptide Y

Severe malnutrition resulting from anorexia nervosa or involuntary starvation leads to low weight, cognitive deficits and increased mortality rates. In the present study, we examined whether fish oil supplementation, compared with that of canola oil, would ameliorate the morbidity and mortality associated with these conditions by normalizing endocannabinoid and monoaminergic systems as well as other systems involved in satiety and cognitive function within the hypothalamus and hippocampus. Female Sabra mice restricted to 40% of their daily food intake exhibited decreased body weight, were sickly in appearance, displayed cognitive deficits and had increased mortality rates. Strikingly, fish oil supplementation that contains high omega-3 fatty acids levels decreased mortality and morbidity, and normalized the expression of genes and neurotransmitters in the hippocampus and hypothalamus. Fish oil supplementation, but not canola oil, increased survival rates, improved general appearance and prevented cognitive decline, despite the facts that both diets contained an equivalent number of calories and that there were no differences in weight between mice maintained on the two diets in 100% but decrease in the 40%. In the hypothalamus, the beneficial effects of fish oil supplementation were related to normalization of the endocannabinoid 2-arachidonylglycerol, serotonin (5-HT) (P<.056), dopamine, neuropeptide Y (NPY) and Ca(2+)/calmodulin (CaM)-dependent protein kinase (Camkk2). In the hippocampus, fish oil supplementation normalized 5-HT, Camkk2, silent mating type information regulation 1 and brain-derived neurotrophic factor. In conclusion, dietary supplements of fish oil, as source of omega-3 fatty acids, may alleviate cognitive impairments associated with severe diet restriction and prolong survival independently of weight gain by normalizing neurochemical systems.

Topics: Animals; Body Weight; Brain-Derived Neurotrophic Factor; Calcium-Calmodulin-Dependent Protein Kinase Kinase; Cognition Disorders; Dopamine; Fatty Acids, Monounsaturated; Female; Fish Oils; Gene Expression; Hypothalamus; Malnutrition; Mice; Neuropeptide Y; Polymerase Chain Reaction; Rapeseed Oil; Receptor, Cannabinoid, CB1; Receptors, Serotonin, 5-HT1; Satiation; Sirtuin 1

Excess neural activity in the CA3 region of the hippocampus has been linked to memory impairment in aged rats. We tested whether interventions aimed at reducing this excess activity would improve memory performance. Aged (24 to 28 months old) male Long-Evans rats were characterized in a spatial memory task known to depend on the functional integrity of the hippocampus, such that aged rats with identified memory impairment were used in a series of experiments. Overexpression of the inhibitory neuropeptide Y 13-36 in the CA3 via adeno-associated viral transduction was found to improve hippocampal-dependent long-term memory in aged rats, which had been characterized with impairment. Subsequent experiments with two commonly used antiepileptic agents, sodium valproate and levetiracetam, similarly produced dose-dependent memory improvement in such aged rats. Improved spatial memory with low doses of these agents was observed in both appetitve and aversive spatial tasks. The benefits of these different modalities of treatment are consistent with the concept that excess activity in the CA3 region of the hippocampus is a dysfunctional condition that may have a key role underlying age-related impairment in hippocampal-dependent memory processes. Because increased hippocampal activation occurs in age-related memory impairment in humans as observed in functional neuroimaging, the current findings also suggest that low doses of certain antiepileptic drugs in cognitively impaired elderly humans may have therapeutic potential and point to novel targets for this indication.

Topics: Age Factors; Aging; Animals; Anticonvulsants; CA3 Region, Hippocampal; Cognition Disorders; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Combinations; Levetiracetam; Male; Maze Learning; Neuropeptide Y; Peptide Fragments; Piracetam; Rats; Rats, Long-Evans; Space Perception; Transduction, Genetic; Valproic Acid

Rheumatoid arthritis (RA) is associated with enhanced pro-inflammatory cytokine levels, pain, anorexia, and cognitive changes. The enhanced production of cytokines appears before the full manifestation of the disease. So far, any experimental data on behavioral effects of early arthritis are lacking. In the present series we describe anorexia early changes in, pain hyper-sensitivity and altered cognitive behavior during the first four days of adjuvant arthritis in rats (AA), when no clinical signs are yet apparent.. AA was induced to male Lewis rats by a single injection of complete Freund's adjuvant (cFA) at the base of the tail. Plasma leptin and ghrelin were measured using specific RIA methods. Gene expressions for food-regulatory peptides, neuropeptide-Y (NPY) and interleukin-1β (IL-1β) in the hypothalamic arcuate nuclei (nARC), were quantitated by TaqMan real-time PCR. Pain sensation was measured on all four limbs and tail by the plantar test. Cognitive functions were tested in the Morris water maze (MWM).. Levels of orexigenic ghrelin as well as mRNA expression of orexigenic NPY in nucleus arcuatus (nRC)re significantly enhanced on day 2 of AA only. Reduced body weight and food intake persisted by day 4 with the most profound reduction on day 2. The mRNA for anorexigenic IL-1β in the nARC was significantly enhanced on days 2 and 4. Enhanced pain sensitivity was observed on day 2, as was the cognitive impairment given by longer time to find the hidden platform, longer time spent in thigmotaxis zone, and longer trajectory. The less effective strategy used to find the hidden platform was observed up to the day 4 of AA.. Early stage of AA brings about reduced body weight, food intake, and activation of central orexigenic pathways. The observed anorexia could be ascribed to the over-expression of anorexigenic IL-1β which dominates over the NPY orexigenic effects. On day 2 of AA higher pain sensitivity and cognitive impairment appear. All the observed change tend to recover by day 4 of the disease.

Topics: Animals; Anorexia; Arcuate Nucleus of Hypothalamus; Arthritis, Experimental; Cognition Disorders; Gene Expression; Ghrelin; Hyperalgesia; Interleukin-1beta; Leptin; Male; Neuropeptide Y; Rats; RNA, Messenger; Time Factors

Alzheimer's disease is a devastating neurological disorder. The role of hyperexcitability in the disease's cognitive decline is not completely understood. In this issue of Neuron, Palop et al. report both limbic seizures and presumed homeostatic responses to seizures in an animal model of Alzheimer's.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Animals; Cognition Disorders; Dentate Gyrus; Disease Models, Animal; Epilepsy; Homeostasis; Humans; Mutation; Neural Inhibition; Neuropeptide Y