scholarly journals The Transfer Coefficients for L-Valine and the Rate of Incorporation of L-[1-14C] Valine into Proteins in Normal Adult Rat Brain

1988 ◽  
Vol 8 (4) ◽  
pp. 598-605 ◽  
Author(s):  
M. Kirikae ◽  
M. Diksic ◽  
Y. L. Yamamoto

An autoradiographic method for the measurement of the rate of valine incorporation into brain proteins is described. The transfer coefficients for valine into and out of the brain and the rate of valine incorporation into normal rat brain proteins are given. The valine incorporation and the transfer constants of valine between different biological compartments are provided for 14 gray matter and 2 white matter structures of an adult rat brain. The rate of valine incorporation varies between 0.52 ± 0.19 nmol/g/min in white matter and 1.94 ± 0.47 in inferior colliculus (gray matter). Generally, the rate of valine incorporation is about three to four times higher in the gray matter than in the white matter structures.

1970 ◽  
Vol 117 (2) ◽  
pp. 325-331 ◽  
Author(s):  
H. C. Agrawal ◽  
A. H. Bone ◽  
A. N. Davison

1. Inhibition of the rate of incorporation of [35S]methionine into protein by phenylalanine was more effective in 18-day-old than in 8-day-old or adult rat brain. 2. Among the subcellular fractions incorporation of [35S]methionine into myelin proteins was most inhibited in 18-day-old rat brain. 3. Transport of [35S]methionine and [14C]leucine into the brain acid-soluble pool was significantly decreased in 18-day-old rats by phenylalanine (2mg/g body wt.). The decrease of the two amino acids in the acid-soluble pool equalled the inhibition of their rate of incorporation into the protein. 4. Under identical conditions, entry of [14C]glycine into the brain acid-soluble pool and incorporation into protein and uptake of [14C]acetate into lipid was not affected by phenylalanine. 5. It is proposed that decreased myelin synthesis seen in hyperphenylalaninaemia or phenylketonuria may be due to alteration of the free amino acid pool in the brain during the vulnerable period of brain development. Amyelination may be one of many causes of mental retardation seen in phenylketonuria.


1969 ◽  
Vol 115 (5) ◽  
pp. 1051-1062 ◽  
Author(s):  
N. L. Banik ◽  
A. N. Davison

1. Subcellular fractions and myelin were isolated from developing and adult rat brain. 2. Measurements of chemical composition and enzyme activities indicate the presence of a second myelin-like fraction mainly in the brain of developing rats. 3. This membrane fraction has a different lipid composition from myelin, but resembles myelin in its content of phosphohydrolase and aminopeptidase activity. 4. It is suggested that the second myelin-like fraction may be a submicrosomal contaminant or it may be derived from oligodendroglial plasma membrane during myelinogenesis.


1993 ◽  
Vol 41 (4) ◽  
pp. 481-487 ◽  
Author(s):  
A Bertolotto ◽  
B Caterson ◽  
G Canavese ◽  
A Migheli ◽  
D Schiffer

We used six monoclonal antibodies (MAb) recognizing epitopes within keratan sulfate (KS) chains for an immunocytochemical study of adult rat brain. One of the MAb selectively stained microglia and their ramified processes. KS-positive cells were found throughout the CNS in both paraffin-embedded and cryostat sections; the greatest number were present in hippocampus and brainstem. In the cortex the positive processes of some cells surrounded neuronal somata. In the white matter the processes were both parallel and perpendicular to the axon bundles. Double staining showed that KS-positive cells did not express astrocytic or oligodendroglial markers. By immunoelectron microscopy, the positivity was localized around the perikarya and cell processes of small cells with peripheral chromatin clumps and dark cytoplasm, which often contained secondary lysosomes. The KS-positive cells did not contribute to myelin sheaths and were not surrounded by a basal membrane. In addition to the cellular staining, three other MAb stained the white matter diffusely. Anti-KS MAb are therefore proposed as immunohistochemical markers for ramified microglia in both paraffin and cryostat sections of adult rat brain.


2018 ◽  
Author(s):  
Ahmet S. Asan ◽  
Sinan Gok ◽  
Mesut Sahin

AbstractTranscranial electrical stimulation (tES) is rapidly becoming an indispensable clinical tool with its different forms. Animal data are crucially needed for better understanding of the underlying mechanisms of tES. For reproducibility of results in animal experiments, the electric fields (E-Fields) inside the brain parenchyma induced by the injected currents need to be predicted accurately. In this study, we measured the electrical fields in the rat brain perpendicular to the brain surface, i.e. vertical electric field (VE-field), when the stimulation electrode was placed over the skin, skull, or dura mater through a craniotomy hole. The E-field attenuation through the skin was a few times larger than that of the skull and the presence of skin substantially reduced the VE-field peak at the cortical surface near the electrode. The VE-field declined much quicker in the gray matter underneath the pial surface than it did in the white matter, and thus the large VE-fields were contained mostly in the gray matter. The transition at the gray/white matter border caused a significant peak in the VE-field, as well as at other local inhomogeneties. A conductivity value of 0.57 S/m is predicted as a global value for the whole brain by matching our VE-field measurements to the field profile given by analytical equations for volume conductors. Finally, insertion of the current return electrode into the shoulder, submandibular, and hind leg muscles had virtually no effects on the measured E-field amplitudes in the cortex underneath the epidural electrodes.


2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Karin Warfvinge ◽  
Diana Krause ◽  
Lars Edvinsson

Abstract Background Recent work, both clinical and experimental, suggests that the hypothalamic hormone oxytocin (OT) and its receptor (OTR) may be involved in migraine pathophysiology. In order to better understand possible central actions of OT in migraine/headache pathogenesis, we mapped the distribution of OT and OTR in nerve cells and fibers in rat brain with a focus on areas related to migraine attacks and/or shown previously to contain calcitonin gene related peptide (CGRP), another neuropeptide involved in migraine. Methods Distribution of OT and OTR in the adult, rat brain was qualitatively examined with immunohistochemistry using a series of well characterized specific antibodies. Results As expected, OT was extensively localized in the cell somas of two hypothalamic nuclei, the supraoptic (SO or SON) and paraventricular nuclei (Pa or PVN). OT also was found in many other regions of the brain where it was localized mainly in nerve fibers. In contrast, OTR staining in the brain was mainly observed in cell somas with very little expression in fibers. The most distinct OTR expression was found in the hippocampus, the pons and the substantia nigra. In some regions of the brain (e.g. the amygdala and the hypothalamus), both OT and OTR were expressed (match). Mismatch between the peptide and its receptor was primarily observed in the cerebral and cerebellar cortex (OT expression) and hippocampus (OTR expression). Conclusions We compared OT/OTR distribution in the CNS with that of CGRP and identified regions related to migraine. In particular, regions suggested as “migraine generators”, showed correspondence among the three mappings. These findings suggest central OT pathways may contribute to the role of the hypothalamus in migraine attacks.


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