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Evelyn H Schlenker
The arcuate nucleus of the hypothalamus (ANH) interacts with other hypothalamic nuclei, forebrain regions, and downstream brain sites to affect autonomic nervous system outflow, energy balance, temperature regulation, sleep, arousal, neuroendocrine function, reproduction, and cardiopulmonary regulation. Compared to studies of other ANH functions, how the ANH regulates cardiopulmonary function is less understood. Importantly, the ANH exhibits structural and functional sexually dimorphic characteristics and contains numerous neuroactive substances and receptors including leptin, neuropeptide Y, glutamate, acetylcholine, endorphins, orexin, kisspeptin, insulin, Agouti-related protein, cocaine and amphetamine-regulated transcript, dopamine, somatostatin, components of renin-angiotensin system and gamma amino butyric acid that modulate physiological functions...
October 15, 2016: Respiratory Physiology & Neurobiology
Maryam Farahmandfar, Mehdi Kadivar, Sareh Rastipisheh
Behavioral abnormalities associated with opiate addiction include memory and learning deficits, which are the result of some alterations in the neuromodulatory systems. Recently, orexin has shown to influence drug addiction neural circuitry, specifically in mediating reward-related perception and memory. To explore the possible interaction of orexinergic and opioidergic system on modulation of learning and memory, we have investigated the effects of intra-dorsal hippocampal (intra-CA1) administration of orexin-1 receptor agonist and the competitive orexin-1 antagonist, SB-334867, on morphine-induced memory impairment by using step-down passive avoidance task in mice...
October 11, 2016: Neuropeptides
Thomas Roth, Jed Black, Raymond Cluydts, Pascal Charef, Marzia Cavallaro, Fabrice Kramer, Gary Zammit, James Walsh
OBJECTIVE: Sleep laboratory study to determine the dose-related efficacy and safety of almorexant in elderly patients with primary chronic insomnia. METHODS: Patients aged ≥65 years with primary insomnia were enrolled into a prospective, randomized, double-blind, placebo-controlled, multicenter dose-finding study with a five-period, five-way Latin square cross-over design. Patients were randomized to one of 10 unique sequences of two-night treatment with oral almorexant 25, 50, 100, or 200 mg capsules, or matching placebo...
October 10, 2016: Sleep
Teemu Aitta-Aho, Elpiniki Pappa, Denis Burdakov, John Apergis-Schoute
The hypothalamic hypocretin/orexin (HO) system holds a central role in the regulation of several physiological functions critical for food-seeking behavior including mnemonic processes for effective foraging behavior. It is unclear however whether physiological increases in HO neuronal activity can support such processes. Using a designer rM3Ds receptor activation approach increasing HO neuronal activity resulted in improved short-term memory for novel locations. When tested on a non-spatial novelty object recognition task no significant difference was detected between groups indicating that hypothalamic HO neuronal activation can selectively facilitate short-term spatial memory for potentially supporting memory for locations during active exploration...
October 13, 2016: Neurobiology of Learning and Memory
Amanda C Sharko, Jim R Fadel, Kris F Kaigler, Marlene A Wilson
Identifying the neurobiological mechanisms that underlie differential sensitivity to stress is critical for understanding the development and expression of stress-induced disorders, such as post-traumatic stress disorder (PTSD). Preclinical studies have suggested that rodents display different phenotypes associated with extinction of Pavlovian conditioned fear responses, with some rodent populations being resistant to extinction. An emerging literature also suggests a role for orexins in the consolidation processes associated with fear learning and extinction...
October 13, 2016: Physiology & Behavior
Elham Kordijaz, Ali Moghimi, Masoud Fereidoni, Saeedeh Asadi, Ali Shamsizadeh, Ali Roohbakhsh
Convulsive seizures are due to abnormal synchronous and repetitive neuronal discharges in the central nervous system (CNS). Finding new therapeutics to overcome the side effects of the current drug therapies and to increase their effectiveness is ongoing. Orexin-A and orexin-B are brain neuropeptides originating from postero-lateral hypothalamic neurons. Studies show that orexins, through activation of OX1 and OX2 receptors, have excitatory effects in the CNS. Accordingly, the present study was designed to evaluate the effect of OX1 receptor antagonist (SB-334867) on seizure- and anxiety-related behaviors of pentylenetetrazol (PTZ) kindled rats...
October 14, 2016: Fundamental & Clinical Pharmacology
Idan Elbaz, David Zada, Adi Tovin, Tslil Braun, Tali Lerer-Goldshtein, Gordon Wang, Philippe Mourrain, Lior Appelbaum
Sleep is tightly regulated by the circadian clock and homeostatic mechanisms. Although the sleep/wake cycle is known to be associated with structural and physiological synaptic changes that benefit the brain, the function of sleep is still debated. The hypothalamic hypocretin/orexin (Hcrt) neurons regulate various functions including feeding, reward, sleep, and wake. Continuous imaging of single neuronal circuits in live animals is vital to understanding the role of sleep in regulating synaptic dynamics, and the transparency of the zebrafish model enables time-lapse imaging of single synapses during both day and night...
October 12, 2016: Molecular Neurobiology
S Cohen, G Ifergane, E Vainer, M A Matar, Z Kaplan, J Zohar, A A Mathé, H Cohen
Pharmacotherapeutic intervention during traumatic memory consolidation has been suggested to alleviate or even prevent the development of posttraumatic stress disorder (PTSD). We recently reported that, in a controlled, prospective animal model, depriving rats of sleep following stress exposure prevents the development of a PTSD-like phenotype. Here, we report that administering the wake-promoting drug modafinil to rats in the aftermath of a stressogenic experience has a similar prophylactic effect, as it significantly reduces the prevalence of PTSD-like phenotype...
October 11, 2016: Translational Psychiatry
Raouf Amin, Narong Simakajornboon, Rhonda Szczesniak, Thomas Inge
BACKGROUND: Obstructive sleep apnea (OSA) associated with obesity is known to improve after bariatric surgery, but little is known about early changes in this condition after surgery. OBJECTIVES: To study the clinical course of OSA after bariatric surgery SETTING: Children's hospital in the United States METHODS: Adolescents and young adults with obstructive sleep apnea undergoing vertical sleeve gastrectomy (n = 6) or gastric bypass (n = 1) were enrolled in this prospective study...
May 30, 2016: Surgery for Obesity and related Diseases: Official Journal of the American Society for Bariatric Surgery
Aimee Chan, SiHan Li, Ahn R Lee, Joseph Leung, Alissa Yip, Jaimie Bird, Kyle E Godden, Dolores Martinez-Gonzalez, Niels C Rattenborg, Evan Balaban, Maria Pompeiano
Coordinated activity in different sets of widely-projecting neurochemical systems characterize waking (W) and sleep (S). How and when this coordination is achieved during development is not known. We used embryos and newborns of a precocial bird species (chickens) to assess developmental activation in different neurochemical systems using cFos expression, which has been extensively employed to examine cellular activation during S and W in adult mammals. Similarly to adult mammals, newborn awake chicks showed significantly higher cFos expression in W-active hypocretin/orexin (H/O), serotonergic Dorsal Raphe, noradrenergic Locus Coeruleus and cholinergic Laterodorsal and Pedunculopontine Tegmental (Ch-LDT/PT) neurons when compared to sleeping chicks...
October 4, 2016: Neuroscience
Hélène Volkoff, Rafael Esatevan Sabioni, Luiz Lehmann Coutinho, José Eurico Possebon Cyrino
The pacu Piaractus mesopotamicus is an omnivorous fish considered a promising species for aquaculture. Little is known about the endocrine regulation of feeding in this species. In this study, transcripts for orexin, cocaine and amphetamine regulated transcript (CART), cholecystokinin (CCK) and leptin were isolated in pacu. Orexin, CCK and leptin have widespread mRNA distributions in brain and periphery, CART is limited to the brain. To examine the role of these peptides in the regulation of feeding and energy status, mRNA expression levels were compared between fed and fasted fish and around feeding time...
October 4, 2016: Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology
Tobias Hofmann, Ulf Elbelt, Verena Haas, Anne Ahnis, Burghard F Klapp, Matthias Rose, Andreas Stengel
While physical hyperactivity represents a frequent symptom of anorexia nervosa and may have a deleterious impact on the course of the disease, the underlying mechanisms are poorly understood. Since several food intake-regulatory hormones affect physical activity, the aim of the study was to investigate the association of physical activity with novel candidate hormones (kisspeptin, ghrelin, oxyntomodulin, orexin-A, FGF-21, R-spondin-1) possibly involved in patients with anorexia nervosa. Associations with psychometric parameters and body composition were also assessed...
September 28, 2016: Appetite
Olga Dergacheva, Akihiro Yamanaka, Alan R Schwartz, Vsevolod Y Polotsky, David Mendelowitz
Orexin neurons are known to augment the sympathetic control of cardiovascular function, however the role of orexin neurons in parasympathetic cardiac regulation remains unclear. To test the hypothesis that orexin neurons contribute to parasympathetic control we selectively expressed channelrhodopsin-2 (ChR2) in orexin neurons in orexin-Cre transgenic rats and examined postsynaptic currents in cardiac vagal neurons (CVNs) in the dorsal motor nucleus of the vagus (DMV). Simultaneous photostimulation and recording in ChR2-expressing orexin neurons in the lateral hypothalamus resulted in reliable action potential firing as well as large whole-cell currents suggesting a strong expression of ChR2 and reliable optogenetic excitation...
September 28, 2016: Neuroscience
Fagen Li, Shaodan Li, Yi Liu, Ke Cao, Minghui Yang
Objective. To study the effect of Heweianshen decoction (HAD) on orexin-A and cholecystokinin-8 (CCK-8) expression in rat models of insomnia caused by injecting parachlorophenylalanine (PCPA) intraperitoneally. Methods. Fifty male Wistar rats were randomly divided into five groups (10 rats in each group): blank group, model group, and low-, medium-, and high-dose HAD-treated groups. A rat model of insomnia was established by injecting intraperitoneally with PCPA (300 mg/kg body weight). Rats were given normal saline (10 mL/kg) or 5...
2016: Evidence-based Complementary and Alternative Medicine: ECAM
Masaru Ishibashi, Iryna Gumenchuk, Kenichi Miyazaki, Takafumi Inoue, William N Ross, Christopher S Leonard
UNLABELLED: Orexins (hypocretins) are neuropeptides that regulate multiple homeostatic processes, including reward and arousal, in part by exciting serotonergic dorsal raphe neurons, the major source of forebrain serotonin. Here, using mouse brain slices, we found that, instead of simply depolarizing these neurons, orexin-A altered the spike encoding process by increasing the postspike afterhyperpolarization (AHP) via two distinct mechanisms. This orexin-enhanced AHP (oeAHP) was mediated by both OX1 and OX2 receptors, required Ca(2+) influx, reversed near EK, and decayed with two components, the faster of which resulted from enhanced SK channel activation, whereas the slower component decayed like a slow AHP (sAHP), but was not blocked by UCL2077, an antagonist of sAHPs in some neurons...
September 28, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Xiao-Bing Gao, Tamas L Horvath
A report on the rapid change of activity of hypocretin/orexin cells in response to contact rather than digestion of food delivers new insights into the behavioral control of food intake and systemic energy expenditure.
September 26, 2016: Current Biology: CB
Giovanni Messina, Giovanni Di Bernardo, Andrea Viggiano, Vincenzo De Luca, Vincenzo Monda, Antonietta Messina, Sergio Chieffi, Umberto Galderisi, Marcellino Monda
BACKGROUND: The purpose of this research was to study the effects of exercise on the concentration of plasma orexin A, a peptide regulating several physiological functions. METHODS: Blood samples were collected from participants (men, n=10; age: 24.4±2.93 years) 15, 0 min before the start of exercise, and 30, 45, 60 min after a cycle ergometer exercise at 75 W for 15 min. Also heart rate (HR), galvanic skin response (GSR), and rectal temperature were monitored...
September 26, 2016: Journal of Basic and Clinical Physiology and Pharmacology
Joanna Czerwinska, Katarzyna Chojnowska, Tadeusz Kaminski, Iwona Bogacka, Nina Smolinska, Barbara Kaminska
Orexins are hypothalamic neuropeptides acting via two G protein-coupled receptors in mammals: orexin receptor 1 (OX1R) and orexin receptor 2 (OX2R). In European beavers, which are seasonally breeding animals, the presence and functions of orexins and their receptors remain unknown. Our study aimed to determine the expression of OXR mRNAs and the localization of OXR proteins in hypothalamic-pituitary-adrenal/gonadal (HPA/HPG) axes in free-living beavers. The expression of OXR genes (OX1R, OX2R) and proteins was found in all analysed tissues during three periods of beavers' reproductive cycle (April, July, November)...
September 21, 2016: General and Comparative Endocrinology
Kevin G Burfeind, Vijayshree Yadav, Daniel L Marks
Signs and symptoms of multiple sclerosis are usually attributed to demyelinating lesions in the spinal cord or cerebral cortex. The hypothalamus is a region that is often overlooked yet controls many important homeostatic functions, including those that are perturbed in multiple sclerosis. In this review we discuss how hypothalamic dysfunction may contribute to signs and symptoms in people with multiple sclerosis. While dysfunction of the hypothalamic-pituitary-adrenal axis is common in multiple sclerosis, the effects and mechanisms of this dysfunction are not well understood...
November 2016: Current Neurology and Neuroscience Reports
Abba J Kastin, Weihong Pan
Pertinent to pandemic obesity, the discovery of endogenous peptides that affect the ingestion of food has led to the question of how these ingestive peptides exert their actions in the brain. Whereas peripheral sources provide a ready reserve, the availability of ingestive peptides to their central nervous system targets can be regulated by the blood-brain barrier (BBB). Some of the peptides/polypeptides are transported by saturable mechanisms from blood to brain. Examples include leptin, insulin, mahogany, and pancreatic polypeptide...
September 20, 2016: CNS & Neurological Disorders Drug Targets
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