699 research outputs found
Localization of dopamine D2 receptor in rat spinal cord identified with immunocytochemistry and in situ hybridization
In the present study the distribution of dopamine D2 receptors in rat spinal cord was determined by means of immunocytochemistry using an anti-peptide antibody, directed against the putative third intracellular loop of the D2 receptor and in situ hybridization (ISH) using a [35S]UTP labelled anti-sense riboprobe. With the immunocytochemical technique, labelling was confined to neuronal cell bodies and their proximal dendrites. Strongest labelling was present in the parasympathetic area of the sacral cord and in two sexually dimorphic motor nuclei of the lumbosacral cord, the spinal nucleus of the bulbocavernosus and the dorsolateral nucleus. Moderately labelled cells were present in the intermediolateral cell column, the area around the central canal and lamina I of the dorsal horn. Weak labelling was present in the lateral spinal nucleus and laminae VII and VIII of the ventral horn. Except for the two sexually dimorphic motornuclei of the lumbosacral cord labelled motoneurons were not encountered. With the ISH technique radioactive labelling was present in many neurons, indicating that they contained D2 receptor mRNA. The distribution of these neurons was very similar to the distribution obtained with immunocytochemistry, but with ISH additional labelled cells were detected in laminae III and IV of the dorsal horn, which were never labelled with immunocytochemistry. The present study shows that the De receptor is expressed in specific areas of the rat spinal cord. This distribution provides anatomical support for the involvement of D2 receptors in modulating nociceptive transmission and autonomic control. Our data further indicate that D2 receptors are not directly involved in modulating motor functions with the exception, possibly, of some sexual motor functions
Temperature control of local magnetic anisotropy in multiferroic CoFe/BaTiO3
This paper reports on the temperature evolution of local elastic interactions between ferromagnetic CoFe films and ferroelectric BaTiO3 substrates. Polarization microscopy measurements indicate that growth-induced stripe domains in the CoFe films are preserved and strengthened during cooling and heating through the structural phase transitions of BaTiO3. Moreover, rotation of the magnetic easy axes at the tertragonal-to-orthorhombic transition (T = 278 K) and at T  ≈  380 K simultaneously switches the local magnetization of both uniaxial domains by 90° . Irreversible changes in the ferromagnetic domain pattern are induced when the room-temperature ferroelectric domain structure is altered after temperature cycling.Peer reviewe
Steering effect on the shape of islands for homoepitaxial growth of Cu on Cu(100)
The steering effect on the growth of islands is investigated by combining
molecular dynamics (MD) and kinetic Monte Carlo (KMC) simulations. Dynamics of
depositing atoms and kinetics of atoms on a substrate are realized by MD and
KMC, respectively. The reported experimental results on the asymmetric island
growth [van Dijken {\it et al.}, Phys. Rev. Lett. {\bf 82}, 4038 (1999).] is
well reproduced. A salient phenomenon, the reversal of the asymmetry, is found
as the island size increases, and attributed to the asymmetric flux on the
lower terrace of island.Comment: 5 figur
Field Tuning of Ferromagnetic Domain Walls on Elastically Coupled Ferroelectric Domain Boundaries
We report on the evolution of ferromagnetic domain walls during magnetization
reversal in elastically coupled ferromagnetic-ferroelectric heterostructures.
Using optical polarization microscopy and micromagnetic simulations, we
demonstrate that the spin rotation and width of ferromagnetic domain walls can
be accurately controlled by the strength of the applied magnetic field if the
ferromagnetic walls are pinned onto 90 degrees ferroelectric domain boundaries.
Moreover, reversible switching between magnetically charged and uncharged
domain walls is initiated by magnetic field rotation. Switching between both
wall types reverses the wall chirality and abruptly changes the width of the
ferromagnetic domain walls by up to 1000%.Comment: 5 pages, 5 figure
The Dopaminergic Innervation Of The Brain Stem And Spinal Cord: An Anatomical Study on the Distribution of the Neurotransmitter Dopamine and Its D2 Receptor
Until the first half of the 19th century, the anatomy of
the nervous system was studied mainly by means of
macroscopic methods, like dissection, while
microscopy was hampered by the lack of adequate
staining techniques. However, when reliable fixation
and staining techniques (like the Weigert and Golgi
stains and the silver impregnation technique for
degenerating fibers) became available, the knowledge
of the nervous system rapidly increased. Since then a
multitude of new research methods employed by an
ever increasing number of scientists involved in
studying the nervous system, have led to a rapid
progress in our knowledge and - to some extent - our
understanding of the nervous system.
The classical anatomical studies and especially the
findings of Ramon y Cajal (1909), the great advocate of
the neuron theory, have laid the foundation of our
present knowledge of the nervous system.
Cytoarchitectonic studies of this period, made a big
impact on neuroscience and served as the basis of the
nomenclature of the central nervous system as it is still
used today. Data on the chemical identity and the
specific function of (groups of) nerve cells became
available more recently. Often the data complemented,
but sometimes it conflicted with, the cytoarchitecture
based subdivisions of the brain. This induced the
introduction of alternative nomenclatures, not based on
cytoarchitecture, but on pharmacological or functional
characteristics. This thesis, which describes an
anatomical study of the dopamine innervation of the
brain stem and spinal cord and one of the receptors
involved, i.e. of a chemically identified system
characterized by containing the transmitter dopamine,
reflects some of these great changes, which transformed
classical neuroanatomy into a dynamic, functional
science. In this chapter the subject will be introduced by
a short description of the anatomy of the spinal cord and
the brainstem, followed by a description of the chemical
anatomy of the nervous system, with the main emphasis
on the doparninergic system and its receptors.
Subsequently, we will provide insight into the scope of this thesis
Carbonic anhydrases CA1 and CA4 function in atmospheric CO2-modulated disease resistance
Main conclusion Carbonic anhydrases CA1 and CA4 attenuate plant immunity and can contribute to altered disease resistance levels in response to changing atmospheric CO2 conditions. Abstract β-Carbonic anhydrases (CAs) play an important role in CO2 metabolism and plant development, but have also been implicated in plant immunity. Here we show that the bacterial pathogen Pseudomonas syringae and application of the microbe-associated molecular pattern (MAMP) flg22 repress CA1 and CA4 gene expression in Arabidopsis thaliana. Using the CA double-mutant ca1ca4, we provide evidence that CA1 and CA4 play an attenuating role in pathogen- and flg22-triggered immune responses. In line with this, ca1ca4 plants exhibited enhanced resistance against P. syringae, which was accompanied by an increased expression of the defense-related genes FRK1 and ICS1. Under low atmospheric CO2 conditions (150 ppm), when CA activity is typically low, the levels of CA1 transcription and resistance to P. syringae in wild-type Col-0 were similar to those observed in ca1ca4. However, under ambient (400 ppm) and elevated (800 ppm) atmospheric CO2 conditions, CA1 transcription was enhanced and resistance to P. syringae reduced. Together, these results suggest that CA1 and CA4 attenuate plant immunity and that differential CA gene expression in response to changing atmospheric CO2 conditions contribute to altered disease resistance levels
Ultrastructural localization of cholinergic muscarinic receptors in rat brain cortical capillaries
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