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Locus coeruleus

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https://www.readbyqxmd.com/read/28109312/locus-coeruleus-cellular-and-molecular-pathology-during-the-progression-of-alzheimer-s-disease
#1
Sarah C Kelly, Bin He, Sylvia E Perez, Stephen D Ginsberg, Elliott J Mufson, Scott E Counts
A major feature of Alzheimer's disease (AD) is the loss of noradrenergic locus coeruleus (LC) projection neurons that mediate attention, memory, and arousal. However, the extent to which the LC projection system degenerates during the initial stages of AD is still under investigation. To address this question, we performed tyrosine hydroxylase (TH) immunohistochemistry and unbiased stereology of noradrenergic LC neurons in tissue harvested postmortem from subjects who died with a clinical diagnosis of no cognitive impairment (NCI), amnestic mild cognitive impairment (aMCI, a putative prodromal AD stage), or mild/moderate AD...
January 21, 2017: Acta Neuropathologica Communications
https://www.readbyqxmd.com/read/28108977/a-locus-coeruleus-norepinephrine-account-of-individual-differences-in-working-memory-capacity-and-attention-control
#2
Nash Unsworth, Matthew K Robison
Studies examining individual differences in working memory capacity (WMC) have suggested that low WMC individuals have particular deficits in attention control processes compared to high WMC individuals. In the current article we suggest that part of the WMC-attention control relation is due to variation in the functioning of the locus coeruleus-norepinephrine system (LC-NE). Specifically, we suggest that because of dysregulation of LC-NE functioning, the fronto-parietal control network for low WMC individuals is only weakly activated, resulting in greater default-mode network activity (and greater mind-wandering) for low WMC individuals compared to high WMC individuals...
January 20, 2017: Psychonomic Bulletin & Review
https://www.readbyqxmd.com/read/28108647/effects-of-early-life-exposure-to-thip-on-brainstem-neuronal-excitability-in-the-mecp2-null-mouse-model-of-rett-syndrome-before-and-after-drug-withdrawal
#3
Weiwei Zhong, Christopher M Johnson, Ningren Cui, Max F Oginsky, Yang Wu, Chun Jiang
Rett syndrome (RTT) is mostly caused by mutations of the X-linked MECP2 gene. Although the causal neuronal mechanisms are still unclear, accumulating experimental evidence obtained from Mecp2(-/Y) mice suggests that imbalanced excitation/inhibition in central neurons plays a major role. Several approaches may help to rebalance the excitation/inhibition, including agonists of GABAA receptors (GABAAR). Indeed, our previous studies have shown that early-life exposure of Mecp2-null mice to the extrasynaptic GABAAR agonist THIP alleviates several RTT-like symptoms including breathing disorders, motor dysfunction, social behaviors, and lifespan...
January 2017: Physiological Reports
https://www.readbyqxmd.com/read/28105598/clinical-pharmacokinetics-and-pharmacodynamics-of-dexmedetomidine
#4
REVIEW
Maud A S Weerink, Michel M R F Struys, Laura N Hannivoort, Clemens R M Barends, Anthony R Absalom, Pieter Colin
Dexmedetomidine is an α2-adrenoceptor agonist with sedative, anxiolytic, sympatholytic, and analgesic-sparing effects, and minimal depression of respiratory function. It is potent and highly selective for α2-receptors with an α2:α1 ratio of 1620:1. Hemodynamic effects, which include transient hypertension, bradycardia, and hypotension, result from the drug's peripheral vasoconstrictive and sympatholytic properties. Dexmedetomidine exerts its hypnotic action through activation of central pre- and postsynaptic α2-receptors in the locus coeruleus, thereby inducting a state of unconsciousness similar to natural sleep, with the unique aspect that patients remain easily rousable and cooperative...
January 19, 2017: Clinical Pharmacokinetics
https://www.readbyqxmd.com/read/28100828/an-integrated-modelling-framework-for-neural-circuits-with-multiple-neuromodulators
#5
Alok Joshi, Vahab Youssofzadeh, Vinith Vemana, T M McGinnity, Girijesh Prasad, KongFatt Wong-Lin
Neuromodulators are endogenous neurochemicals that regulate biophysical and biochemical processes, which control brain function and behaviour, and are often the targets of neuropharmacological drugs. Neuromodulator effects are generally complex partly owing to the involvement of broad innervation, co-release of neuromodulators, complex intra- and extrasynaptic mechanism, existence of multiple receptor subtypes and high interconnectivity within the brain. In this work, we propose an efficient yet sufficiently realistic computational neural modelling framework to study some of these complex behaviours...
January 2017: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/28096471/resolving-the-brainstem-contributions-to-attentional-analgesia-in-man
#6
Jonathan C W Brooks, Wendy-Elizabeth Davies, Anthony E Pickering
: Previous human imaging studies manipulating attention or expectancy have identified the periaqueductal gray (PAG) as a key brainstem structure implicated in endogenous analgesia. However, animal studies indicate that PAG analgesia is mediated largely via caudal brainstem structures like the rostral ventromedial medulla (RVM) and locus coeruleus (LC). To identify their involvement in endogenous analgesia, we used brainstem optimised, whole-brain imaging to record responses to concurrent thermal stimulation (left forearm) and visual attention tasks of titrated difficulty in 20 healthy subjects...
January 17, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28093336/peripheral-nerve-injury-potentiates-excitatory-synaptic-transmission-in-locus-coeruleus-neurons
#7
Kambiz Rohampour, Hossein Azizi, Yaghoub Fathollahi, Saeed Semnanian
Peripheral nerve injury (PNI) is believed to cause maladaptive changes at synaptic level, leading to neuropathic pain which is difficult to treat with common analgesic drugs. Noradrenergic locus coeruleus (LC) neurons have a crucial role in neuropathic pain modulation. In this study we examined whether chronic constriction injury (CCI) could affect glutamatergic synaptic transmission in LC neurons. CCI was performed on P10 to P12 Sprague Dawley pups. Seven days after CCI, horizontal slices of brainstem (300μm thick) were prepared and whole-cell patch clamp recording was performed...
January 13, 2017: Brain Research Bulletin
https://www.readbyqxmd.com/read/28093335/intracoerulear-microinjection-of-orexin-a-induces-morphine-withdrawal-like-signs-in-rats
#8
Masoumeh Ghaemi-Jandabi, Hossein Azizi, S Mohammad Ahmadi-Soleimani, Saeed Semnanian
Orexin (hypocretin) neuropeptides play a pivotal role in expression of opioid withdrawal signs. Hypothalamic orexinergic neurons provide dense afferents for the nucleus locus coeruleus (LC). Somatic signs of opioid withdrawal are associated with the enhanced activity of LC neurons. In addition, intra-LC administration of orexin-A leads to the hyperactivity of LC neurons. The present study was an attempt to investigate whether intra-LC microinjection of orexin-A induces morphine withdrawal-like signs in both morphine dependent and control rats...
January 13, 2017: Brain Research Bulletin
https://www.readbyqxmd.com/read/28092095/noradrenergic-transmission-in-the-central-medial-thalamic-nucleus-modulates-the-electroencephalographic-activity-and-emergence-from-propofol-anesthesia-in-rats
#9
Bao Fu, Tian Yu, Jie Yuan, Xingrui Gong, Mazhong Zhang
At present, the mechanisms by which general anesthetics causing loss of consciousness remain unclear. The central medial thalamic nucleus (CMT) is a rarely studied component of the midline thalamic complex, which is deemed to be a part of the nonspecific arousal system. Despite the fact that CMT participates in modulating arousal and receives excitatory noradrenergic projections from locus coeruleus (LC), it remains unknown whether the noradrenergic pathway in the CMT takes part in modulating the arousal system...
January 16, 2017: Journal of Neurochemistry
https://www.readbyqxmd.com/read/28089758/pupil-responses-and-pain-ratings-to-heat-stimuli-reliability-and-effects-of-expectations-and-a-conditioning-pain-stimulus
#10
James C Eisenach, Regina Curry, Carol A Aschenbrenner, Robert C Coghill, Timothy T Houle
BACKGROUND: The locus coeruleus (LC) signals salience to sensory stimuli and these responses can modulate the experience of pain stimuli. The pupil dilation response (PDR) to noxious stimuli is thought to be a surrogate for LC responses, but PDR response to Peltier-controlled noxious heat stimuli, the most commonly used method in experimental pain research, has not been described. NEW METHOD: Healthy volunteers were presented with randomly presented heat stimuli of 5 sec duration and provided pain intensity ratings to each stimulus...
January 12, 2017: Journal of Neuroscience Methods
https://www.readbyqxmd.com/read/28089702/the-visible-burrow-system-a-view-from-across-the-hall
#11
REVIEW
James P Herman, Kellie L Tamashiro
The visible burrow system (VBS) is an ethologically relevant social stress model that creates a distinct dominance hierarchy in rats. Randall Sakai's laboratory performed an impressive series of studies documenting the very different impact of VBS exposure on the brain and behavior of dominants (DOM) and subordinates (SUBs). Hierarchy formation causes pronounced changes in metabolism in SUBs relative to both DOMs and unstressed controls, resulting in marked weight loss and metabolic imbalance. Stress testing revealed multiple phenotypes in the VBS, including DOMs, stress-responsive SUBs and stress-non-responsive SUBs...
January 12, 2017: Physiology & Behavior
https://www.readbyqxmd.com/read/28087339/differential-behavioral-sensitivity-to-carbon-dioxide-co2-inhalation-in-rats
#12
Andrew Winter, Rebecca Ahlbrand, Devanshi Naik, Renu Sah
Inhalation of carbon dioxide (CO2) is frequently employed as a biological challenge to evoke intense fear and anxiety. In individuals with panic disorder, CO2 reliably evokes panic attacks. Sensitivity to CO2 is highly heterogeneous among individuals, and although a genetic component is implicated, underlying mechanisms are not clear. Preclinical models that can simulate differential responsivity to CO2 are therefore relevant. In the current study we investigated CO2-evoked behavioral responses in four different rat strains: Sprague-Dawley (SD), Wistar (W), Long Evans (LE) and Wistar-Kyoto, (WK) rats...
January 10, 2017: Neuroscience
https://www.readbyqxmd.com/read/28071709/early-life-peripheral-lipopolysaccharide-challenge-reprograms-catecholaminergic-neurons
#13
Lin Kooi Ong, Erin A Fuller, Luba Sominsky, Deborah M Hodgson, Peter R Dunkley, Phillip W Dickson
Neonatal immune challenge with the bacterial mimetic lipopolysaccharide has the capacity to generate long-term changes in the brain. Neonatal rats were intraperitoneally injected with lipopolysaccharide (0.05 mg/kg) on postnatal day (PND) 3 and again on PND 5. The activation state of tyrosine hydroxylase (TH) was measured in the locus coeruleus, ventral tegmental area and substantia nigra on PND 85. In the locus coeruleus there was an approximately four-fold increase in TH activity. This was accompanied by a significant increase in TH protein together with increased phosphorylation of all three serine residues in the N-terminal region of TH...
January 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28069353/effects-of-chronic-exposure-to-low-dose-thip-on-brainstem-neuronal-excitability-in-mouse-models-of-rett-syndrome-evidence-from-symptomatic-females
#14
Weiwei Zhong, Christopher Mychal Johnson, Ningren Cui, Hao Xing, Yang Wu, Chun Jiang
Rett Syndrome (RTT) is a neurodevelopmental disorder caused by mutations of the MECP2 gene, affecting predominantly females. One of the characteristic features of the disease is defective brainstem autonomic function. In Mecp2(-/Y) mice, several groups of brainstem neurons are overly excitable, which causes destabilization of neuronal networks for the autonomic control. We have previously shown that the extrasynaptic GABAA receptor agonist THIP relieves many RTT-like symptoms in Mecp2(-/Y) mice. Although neuronal activity is inhibited by acute THIP exposure, how a chronic treatment affects neuronal excitability remains elusive...
January 6, 2017: Neuropharmacology
https://www.readbyqxmd.com/read/28053247/heterogeneous-effects-of-noradrenaline-on-spontaneous-and-stimulus-driven-activity-in-the-male-accessory-olfactory-bulb
#15
Wayne I Doyle, Julian P Meeks
Noradrenaline (NA) release has been linked to experience-dependent plasticity in many model systems and brain regions. Among these is the rodent accessory olfactory system (AOS), which is crucial for detecting and processing socially relevant environmental cues. The accessory olfactory bulb (AOB), the first site of chemosensory information processing in the AOS, receives dense centrifugal innervation by noradrenergic (NAergic) fibers originating in the locus coeruleus. Though NA release has been linked to behavioral plasticity through its actions in the AOB, the impacts of NAergic modulation on AOB information processing have not been thoroughly studied...
January 4, 2017: Journal of Neurophysiology
https://www.readbyqxmd.com/read/28052779/neural-indicators-of-interpersonal-anger-as-cause-and-consequence-of-combat-training-stress-symptoms
#16
G Gilam, T Lin, E Fruchter, T Hendler
BACKGROUND: Angry outbursts are an important feature of various stress-related disorders, and commonly lead to aggression towards other people. Findings regarding interpersonal anger have linked the ventromedial prefrontal cortex (vmPFC) to anger regulation and the locus coeruleus (LC) to aggression. Both regions were previously associated with traumatic and chronic stress symptoms, yet it is unclear if their functionality represents a consequence of, or possibly also a cause for, stress symptoms...
January 5, 2017: Psychological Medicine
https://www.readbyqxmd.com/read/28042095/reduced-noradrenergic-innervation-of-ventral-midbrain-dopaminergic-cell-groups-and-the-subthalamic-nucleus-in-mptp-treated-parkinsonian-monkeys
#17
Gunasingh Jeyaraj Masilamoni, Olivia Groover, Yoland Smith
There is anatomical and functional evidence that ventral midbrain dopaminergic (DA) cell groups and the subthalamic nucleus (STN) receive noradrenergic innervation in rodents, but much less is known about these interactions in primates. Degeneration of NE neurons in the locus coeruleus (LC) and related brainstem NE cell groups is a well-established pathological feature of Parkinson's disease (PD), but the development of such pathology in animal models of PD has been inconsistent across species and laboratories...
December 30, 2016: Neurobiology of Disease
https://www.readbyqxmd.com/read/28013000/galanin-contributes-to-monoaminergic-dysfunction-and-to-dependent-neurobehavioral-comorbidities-of-epilepsy
#18
Jesus-Servando Medel-Matus, Don Shin, Raman Sankar, Andrey Mazarati
Status epilepticus (SE) in rats, along with chronic epilepsy, leads to the development of behavioral impairments resembling depressive disorder and/or attention deficit/hyperactivity disorder (ADHD), thus reflecting respective comorbidities in epilepsy patients. Suppressed neurotransmitter tone in the raphe nucleus (RN)-prefrontal cortex (PFC) serotonergic pathway and in the locus coeruleus (LC)-PFC noradrenergic pathway underlies depressive- and impulsive-like behavioral deficits respectively. We examined possible mechanisms leading to the monoamine dysfunction in brainstem efferents, namely modulatory effects of the neuropeptide galanin on serotonin (5-HT) and norepinephrine (NE) signaling...
December 22, 2016: Experimental Neurology
https://www.readbyqxmd.com/read/27992510/noradrenaline-improves-behavioral-contrast-sensitivity-via-the-%C3%AE-adrenergic-receptor
#19
Ryo Mizuyama, Shogo Soma, Naofumi Suemastu, Satoshi Shimegi
Noradrenaline (NA) is released from the locus coeruleus in the brainstem to almost the whole brain depending on the physiological state or behavioral context. NA modulates various brain functions including vision, but many questions about the functional role of its effects and mechanisms remain unclear. To explore these matters, we focused on three questions, 1) whether NA improves detectability of a behavior-relevant visual stimulus, 2) which receptor subtypes contribute to the NA effects, and 3) whether the NA effects are specific for visual features such as spatial frequency (SF)...
2016: PloS One
https://www.readbyqxmd.com/read/27988321/sex-differences-in-emotional-perception-meta-analysis-of-divergent-activation
#20
REVIEW
Megan M Filkowski, Rachel M Olsen, Bryant Duda, Timothy J Wanger, Dean Sabatinelli
Behavioral and physiological sex differences in emotional reactivity are well documented, yet comparatively few neural differences have been identified. Here we apply quantitative activation likelihood estimation (ALE) meta-analysis across functional brain imaging studies that each reported clusters of activity differentiating men and women as they participated in emotion-evoking tasks in the visual modality. This approach requires the experimental paradigm to be balanced across the sexes, and thus may provide greater clarity than previous efforts...
December 15, 2016: NeuroImage
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