2,600 research outputs found
Central oxytocin and food intake: focus on macronutrient-driven reward
Centrally acting oxytocin (OT) is known to terminate food consumption in response to excessive stomach distension, increase in salt loading, and presence of toxins. Hypothalamic-hindbrain OT pathways facilitate these aspects of OT-induced hypophagia. However, recent discoveries have implicated OT in modifications of feeding via reward circuits: OT has been found to differentially affect consumption of individual macronutrients in choice and no-choice paradigms. In this mini-review, we focus on presenting and interpreting evidence that defines OT as a key component of mechanisms that reduce eating for pleasure and shape macronutrient preferences. We also provide remarks on challenges in integrating the knowledge on physiological and pathophysiological states in which both OT activity and macronutrient preferences are affected
Tim Bartness, Ph.D. (1953-2015)
Tim Bartness (Fig. 1) was a friend, mentor, collaborator and leader to many scientists, younger and older, across a
variety of disciplines. He died September 24, 2015 at the age of 62 after a one-year battle with multiple myeloma.
Tim not only helped educate many of us, but also challenged us to think critically and to laugh heartily about
both the bad and the good we experienced in life. Tim was dedicated to science and to those around him. He
worked diligently on his research right up the very end until he no longer could
Glutamate, aspartate and nucleotide transporters in the SLC17 family form four main phylogenetic clusters: evolution and tissue expression
<p>Abstract</p> <p>Background</p> <p>The SLC17 family of transporters transports the amino acids: glutamate and aspartate, and, as shown recently, also nucleotides. Vesicular glutamate transporters are found in distinct species, such as <it>C. elegans</it>, but the evolutionary origin of most of the genes in this family has been obscure.</p> <p>Results</p> <p>Our phylogenetic analysis shows that the SLC17 family consists of four main phylogenetic clades which were all present before the divergence of the insect lineage. One of these clades has not been previously described and it is not found in vertebrates. The clade containing Slc17a9 had the most restricted evolutionary history with only one member in most species. We detected expression of Slc17a1-17a4 only in the peripheral tissues but not in the CNS, while Slc17a5- Slc17a9 are highly expressed in both the CNS and periphery.</p> <p>Conclusions</p> <p>The <it>in situ </it>hybridization studies on vesicular nucleotide transporter revealed high expression throughout the cerebral cortex, certain areas in the hippocampus and in specific nuclei of the hypothalamus and thalamus. Some of the regions with high expression, such as the medial habenula and the dentate gyrus of the hippocampus, are important sites for purinergic neurotransmission. Noteworthy, other areas relying on purine-mediated signaling, such as the molecular layer of the dentate gyrus and the periaqueductal gray, lack or have a very low expression of Slc17a9, suggesting that there could be another nucleotide transporter in these regions.</p
Does wage rank affect employees' well-being?
How do workers make wage comparisons? Both an experimental study and an analysis of 16,000 British employees are reported. Satisfaction and well-being levels are shown to depend on more than simple relative pay. They depend upon the ordinal rank of an individual's wage within a comparison group. “Rank” itself thus seems to matter to human beings. Moreover, consistent with psychological theory, quits in a workplace are correlated with pay distribution skewness
A Model for the Elasticity of Compressed Emulsions
We present a new model to describe the unusual elastic properties of
compressed emulsions. The response of a single droplet under compression is
investigated numerically for different Wigner-Seitz cells. The response is
softer than harmonic, and depends on the coordination number of the droplet.
Using these results, we propose a new effective inter-droplet potential which
is used to determine the elastic response of a monodisperse collection of
disordered droplets as a function of volume fraction. Our results are in
excellent agreement with recent experiments. This suggests that anharmonicity,
together with disorder, are responsible for the quasi-linear increase of
and observed at .Comment: RevTeX with psfig-included figures and a galley macr
Effects of streptozotocin-induced diabetes on feeding stimulated by centrally administered opioid agonists
The potencies of several opioid agonists are reduced in diabetic animals and in animals made hyperglycemic via injections of glucose. In this report we examined the effects of streptozotocin-induced diabetes on the feeding responses to centrally administered opioid agonists with differing receptor selectivities. The selective mu receptor agonist Tyr-D-Ala-Gly-(Me)Phe-Gly-ol (DAGO) caused a larger increase in intake in diabetic rats than in controls. In both groups feeding responses were greater on the fourth day of daily injections than on the first day. The delta receptor agonist [D-Ser2,Leu5]-enkephalin-Thr6 (DSLET) stimulated intake in controls but not in diabetics. However, the elevated baseline and large variability in intake of the diabetics in this experiment prevent drawing a conclusion on diabetes-induced changes in the potency of this peptide. No differences between controls and diabetics were apparent in the feeding responses to U50,488H, a selective kappa receptor agonist. These data suggest that diabetes may differentially affect the classes of opioid receptors or the binding of ligands to these receptors.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28109/1/0000558.pd
Behavioral effects of corticotropin-releasing factor: localization and characterization of central effects
Corticotropin-releasing factor (CRF) has potent behavioral effects when administered intracerebroventricularly to rats. CRF and its receptors are found in an uneven distribution in the brain. In an effort to localize the site of the anorectic effect of CRF, exogenous CRF or saline was injected into cannulas directed toward the paraventricular hypothalamic nucleus (PVN), lateral hypothalamus, ventromedial hypothalamus, globus pallidus, or striatum of rats. CRF decreased food intake only when injected into the PVN. In subsequent experiments PVN injections of CRF were shown to (1) increase grooming and movement; (2) not induce a conditioned taste aversion to saccharin in a single bottle test; and (3) inhibit the increase in feeding induced by injections of norepinephrine into the PVN. These results suggest that CRF induces not only anorexia, but also increased movement and grooming by action in the PVN.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27370/1/0000396.pd
Infrared Excess in the Be Star Delta Scorpii
We present infrared photometric observations of the Be binary system delta
Scorpii obtained in 2006. The J,H and K magnitudes are the same within the
errors compared to observations taken 10 months earlier. We derive the infrared
excess from the observation and compare this to the color excess predicted by a
radiative equilibrium model of the primary star and its circumstellar disk. We
use a non-LTE computational code to model the gaseous envelope concentrated in
the star's equatorial plane and calculate the expected spectral energy
distribution and Halpha emission profile of the star with its circumstellar
disk. Using the observed infrared excess of delta Sco, as well as Halpha
spectroscopy bracketing the IR observations in time, we place constraints on
the radial density distribution in the circumstellar disk. Because the disk
exhibits variability in its density distribution, this work will be helpful in
understanding its dynamics.Comment: 12 pages, 14 figures, to be published in PASP May 200
New constraints on dark energy from the observed growth of the most X-ray luminous galaxy clusters
We present constraints on the mean matter density, Omega_m, the normalization
of the density fluctuation power spectrum, sigma_8, and the dark-energy
equation-of-state parameter, w, obtained from measurements of the X-ray
luminosity function of the largest known galaxy clusters at redshifts z<0.7, as
compiled in the Massive Cluster Survey (MACS) and the local BCS and REFLEX
galaxy cluster samples. Our analysis employs an observed mass-luminosity
relation, calibrated by hydrodynamical simulations, including corrections for
non-thermal pressure support and accounting for the presence of intrinsic
scatter. Conservative allowances for all known systematic uncertainties are
included, as are standard priors on the Hubble constant and mean baryon
density. We find Omega_m=0.28 +0.11 -0.07 and sigma_8=0.78 +0.11 -0.13 for a
spatially flat, cosmological-constant model, and Omega_m=0.24 +0.15 -0.07,
sigma_8=0.85 +0.13 -0.20 and w=-1.4 +0.4 -0.7 for a flat, constant-w model.
Future work improving our understanding of redshift evolution and observational
biases affecting the mass--X-ray luminosity relation have the potential to
significantly tighten these constraints. Our results are consistent with those
from recent analyses of type Ia supernovae, cosmic microwave background
anisotropies, the X-ray gas mass fraction of relaxed galaxy clusters, baryon
acoustic oscillations and cosmic shear. Combining the new X-ray luminosity
function data with current supernova, cosmic microwave background and cluster
gas fraction data yields the improved constraints Omega_m=0.269 +- 0.016,
sigma_8=0.82 +- 0.03 and w=-1.02 +- 0.06. (Abridged)Comment: Submitted to MNRAS. 15 pages, 15 figures. v2: Improved modeling of
the mass-luminosity relation, including additional systematic allowances for
evolution in the scatter and non-thermal pressure support. Constraints are
somewhat weaker, but overall conclusions are unchanged
Immunocytochemical localization of the intrinsic factor-cobalamin receptor in dog-ileum: distribution of intracellular receptor during cell maturation.
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