Brain Of Albino Rats Research Articles

The distribution of growth-hormone-releasing factor (GRF) immunoreactivity in the central nervous system of the rat: an immunohistochemical study using antisera directed against rat hypothalamic GRF.

Immunohistochemical methods have been used to chart the distribution of rat hypothalamic growth-hormone-releasing factor (rhGRF) immunoreactivity in the brains of normal and colchicine-treated adult albino rats. The results suggest the existence of at least two distinct rhGRF-containing systems: one responsible for delivery of the peptide to portal vessels in the median eminence, and one whose relationship, if any, to hypophysiotropic function is less direct. A dense plexus of rhGRF-stained fibers was found throughout the external lamina of the median eminence that is the route by which the peptide is delivered to the anterior pituitary. This projection appears to arise primarily from a group of rhGRF-immunoreactive neurons centered in the arcuate nucleus. Some 1,000-1,500 rhGRF-positive neurons were counted on each side of the brain in rats pretreated with colchicine. Colocalization studies, using a sequential double staining technique, indicated that a subset of rhGRF-immunoreactive neurons in the arcuate region contain neurotensin immunoreactivity. No evidence was obtained for colocalization of rhGRF with either of two pro-opiomelanocortin-derived peptides (alpha-melanocyte-stimulating hormone, adrenocorticotropic hormone (1-24)) in individual neurons in the arcuate nucleus. Much smaller groups of neurons were localized in the parvicellular division of the paraventricular nucleus of the hypothalamus and in the dorsomedial nucleus, and it is unclear whether they contribute to the plexus of rhGRF-stained fibers in the median eminence. The only other region in the rat brain in which rhGRF-stained cells were found reliably was in the area that roughly encapsulates the caudal aspect of the ventromedial nucleus of the hypothalamus. Because cells in this region are not known to project to the median eminence, they may be assumed to contribute to the extrahypophysiotropic rhGRF-stained projections outlined below. From the level of the arcuate and ventromedial nuclei, rhGRF-immunoreactive fibers could be traced along the base of the brain and through the periventricular system to discrete terminal fields limited almost exclusively to the hypothalamus and adjoining parts of the basal telencephalon. All parts of the periventricular region of the hypothalamus receive an input, including the preoptic and anterior parts in which somatostatin-containing neurons that project to the median eminence are clustered. Other prominent terminal fields were localized in discrete parts of the dorsomedial, paraventricular, suprachiasmatic, and premammillary nuclei, and in the medial preoptic and lateral hypothalamic areas.(ABSTRACT TRUNCATED AT 400 WORDS)

Anatomy of the inferior colliculus in rat.

This paper defines the pattern of subdivision of the inferior colliculus in rat. It is based on serial sections of brains of albino and hooded rats cut in the frontal, sagittal and horizontal planes using Golgi, Nissl and a combined cell-myelin method. In rat, like in other mammals, the inferior colliculus consists of a central nucleus, an external cortex, and a dorsal cortex. The central nucleus is flattened in the frontal plane and confined to the caudomedial part of the inferior colliculus. It is characterized by a lamellar organization of disc-shaped neurons interspersed with multipolar cells. The cells are small to medium-sized. Although there is a dorsoventral gradient in size and packing density of cells within the nucleus, the overall size is smaller and the packing density larger than in adjacent subdivisions. The two cortices each consists of three layers. The outer-most layer is common to the two cortices, forming a fibrocellular capsule continuous along most of the circumference of the inferior colliculus. The external cortex is located lateral, rostral, ventral and ventrocaudal to the central nucleus. Its second layer, deep to the superficial capsule, is characterized by clusters of many small and a few medium-sized neurons in a myelin-dense neuropil. Layer 3, which constitutes the major portion of the subdivision, consists of relatively scattered, small, medium and large cells, the most characteristic element being large multipolar neurons with coarse Nissl granules. The dorsal cortex is located dorsocaudal and dorsomedial to the central nucleus. Its second layer is composed of small neurons, while the third, deep layer in addition contains medium-sized neurons. The cell density is intermediate to that of the central nucleus and the deep part of the external cortex. We have tried to facilitate the parcellation by reference to easily recognizable, nearby structures and to standard stereotaxic coordinates.

Effects of phenobarbital on monoamine levels of rat brains and convulsion induced by procaine hydrochloride.

The role of monoamines was examined by measuring noradrenaline(NA), dopamine (DA) and serotonin(5-HT) in brain of male albino rats weighing 200-250g administered with the hydrochloride of procaine at 190 mg/kg (i.p) and pretreated with phenobarbital at 25 mg/kg (s.c), producing 100% anticonvulsant action against procaine-induced convulsion. In addition, effects of doperminergic agents on procaine-induced convulsion in rats were invesigated, and the role of brain monoamines in the anticonvulsant action of phenobarbital against procaine-induced convulsion was examined. Brains were dissected into hypothalamus, midbrain (included striatum, hippocampus), cortex, cerebellum (included pons, medullaoblongata) according to Glowinsky. Brain monoamines analyses were carried out by high pressure liquid chromatography with electrochemical detection. The following results were obtained : 1) When convulsive doses of procaine hydrochloride were administered to the rats, an increase of NA, DA and 5-HT was observed in each of the brain regions, phenobarbital treatment caused a little increse of 5-HT and significant increse of DA. Procaine with pretreatment of phenobarbital caused a significant decrease of DA levels in cerebellum, compared to procaine treatment. 2) The onset time of procaine-induced convulsion was shortened apparently by pretreatment of L-DOPA (200mg/kg) and slightly by pretreatment of apomorphine (0.5 mg/kg). However, it was delayed markedly by pretreatment with haloperidol (5 mg/kg) and chlorpromazine (2 mg/kg). However, reserpine (5mg/kg) pretreated rats produced no effect. The results suggest that the anticonvulsant action of phenobar bital against procaine induced convulsion is dependent on deple tion of brain DA.

Effect of pyrroxan and butyroxan on noradrenalin storage and release in the albino rat brain

Effect of pyrroxan and butyroxan on noradrenalin storage and release in the albino rat brain

Monosodium glutamate-induced lesions in the rat cingulate cortex.

The brains of neonate albino rats were examined with the light and electron microscope following subcutaneous administration of monosodium glutamate (MSG). In addition to lesions in areas known to be vulnerable to glutamate, such as the arcuate nucleus of the hypothalamus, distinct areas of necrotic tissue were detected in the granular portion of the retrosplenial cingulate cortex. The affected cells display the cytological features characteristic of MSG-lesioned brain tissue, including vacuolization of the endoplasmic reticulum and clumping of chromatin. Numerous pyknotic nuclei can be detected as early as 3 h following treatment. The possible causes of the lesion, particularly the role that may be played by astrocytes, are discussed.

Horizontal stereotaxic atlas of the albino rat brain

An atlas of the albino rat brain was prepared in the horizontal plane, extending from the olfactory bulbs through the hind brain. It was drawn to the scale of König and Klippel's rat brain atlas so as to be used in conjunction with their atlas. Corresponding histological sections were also prepared.

Changes in the phospholipid spectrum and activity of some enzyme systems of phospholipid synthesis in the brain and liver of albino rats with alloxan diabetes

Changes in the phospholipid spectrum and activity of some enzyme systems of phospholipid synthesis in the brain and liver of albino rats with alloxan diabetes

Seasonal variations in the catecholamine concentration in the albino rat brain

Seasonal changes in the concentrations of dopamine (DA), noradrenalin (NA), and homovanillic acid (HVA) in the forebrain and diencaphalon were studied in 258 Wistar albino rats. Experiments were carried out montly for six years. The concentrations of DA, NA, and HVA in the brain changed significantly in the course of the year, and in both parts of the brain the changes were in the same direction. The DA concentration in the winter and spring months was higher than the average for the year, whereas in summer it was lower. The NA concentration was much higher in spring (by one-third in the diencephalon) than the mean values. In the summer months (June–August) the average NA concentration corresponded to more rapid metabolism of DA (a decrease in DA and an increase in HVA).

Experimental infections of laboratory rodents with recently isolated stocks of Trypanosoma brucei gambiense. 2. Histopathological investigations.

Histopathological findings on brain, heart, liver, and spleen of albino rats and white mice, infected with different stocks of Trypanosoma brucei gambiense of human origin are presented. Classical brain lesions, including chronic inflammation of the choroid plexuses, were observed in all infected animals, the severity of which increased with the chronicity of the disease. Parasite stocks which gave rise to a less acute course of the disease more often induced myocarditis, while brain lesions were less pronounced, suggesting that virulence of the parasites is more closely related to the advent of myocarditis than to the appearance of brain lesions. Liver lesions were not obvious. In spleens, a variable and often very pronounced degree of lymphoid hyperplasia was observed.

Rat brain melanin at different ages and after various treatments

Melanin was measured by a spectrophotofluorometric method in the brains of albino rats from birth to 20 months of age. The concentration of brain melanin increased from Day 1 until adult levels were reached at 1 month. Between 1 and 20 months of age no significant differences were found in brain melanin. Daily injections of α-MSH, MIF-I, melatonin, or diluent did not consistently alter the concentration of brain melanin and a high (40%) protein diet did not appear to increase it. After concurrent injections of α-MSH and theophylline, an initial elevation of the level of melanin in the brain of newborn rats was found beginning at Day 8 but by age 1 month the values had returned to control levels. The results show that the largest changes in the concentrations of melanin in the brains of rats occur with age during the first month after birth.

Effects of gamma-butyrolactone on local cerebral glucose utilization in the rat.

Abstract— The effects of graded doses of γ‐butyrolactone on the rates of glucose utilization in 29 structural components of the albino rat brain were studied by means of the [14C]deoxyglucose technique. The γ‐butyrolactone in doses of 75, 150, 300, and 600 mg/kg of body weight was administered intravenously in divided doses, two‐thirds 45min and one‐third 15min before the administration of the pulse of [14C]deoxyglucose. Electroencephalographic recordings were carried out in some of the rats administered each of the above doses. The results demonstrate dose‐dependent changes in the level of consciousness, electroencephalographic activity, and the rates of local cerebral glucose utilization. At the two lower doses there were no notable effects on behavior, but there was significant slowing of the electroencephalogram. The higher doses caused a trance‐like state associated with long periods of electroencephalographic silence punctuated by bursts of polyspike and wave activity. At all doses there was significant depression of the rates of cerebral glucose utilization throughout the brain, the greater the dose the greater the magnitude of the depression. The effects were greater in gray structures than in white matter. At the maximum doses local cerebral glucose utilization was profoundly depressed to mean values of 32% and 58% of control values in gray and white matter, respectively. There was no apparent selectivity or specificity in the effects of γ‐butyrolactone on glucose utilization in the various gray structures of the brain; all 26 gray structures studied exhibited similar dose‐response relationships. Animals similarly treated with γ‐butyrolactone and left undisturbed regained completely normal behavior and electroencephalographic activity in several hours. These results suggest that γ‐butyrolactone profoundly depresses cerebral energy metabolism throughout the brain and that it might prove useful in clinical conditions in which a temporary reversible reduction in cerebral energy demand is desired.

Melanin in the rat brain

Melanin was measured in various parts of the rat brain by a spectrophotofluorometric assay. This method could detect natural, Sepia melanin as well as melanin synthesized from L-DOPA. Contrary to published expectations of other investigators, measurable amounts of melanin were found in the brain of albino as well as pigmented rats. The highest concentrations of melanin occurred in the pons-medulla and midbrain, but all regions within the blood-brain barrier contained greater concentrations than samples from many other tissues in the body. No significant change in the melanin content was found after various endocrine manipulations such as removal of the pituitary, pineal, adrenals, thyroid, testes, or ovaries, exposure to constant illumination or darkness, and daily injection for 5 weeks of α-MSH, Pro-Leu-Gly-NH 2 (MIF-I) or melatonin. As expected, retinal tissue from black-hooded rats contained extremely high levels of melanin whereas that from albino rats contained no melanin. It is thought that the presence of melanin in the brain of albino and pigmented rats may have a function which is still unknown.

Role of ethanolamine, phosphoethanolamine, and phosphatidylethanolamine in oxidative phosphorylation of albino rat brain mitochondria

Addition of ethanolamine, phosphoethanolamine, or phosphatidylethanolamine in concentrations of 0.5 μM to the brain mitochondrial fraction increases endogenous respiration and the P/O ratio. In insulin hypoglycemia, addition of these substances leads to a proportional increase in the level of respiration and inorganic phosphorus, so that the supply of energy remains at the characteristic level for intact rats.

Relationship between sulfhydryl reactivity and toxicity of vinyl sulfone molluscicidal agents

Vinyl sulfone was tested to determine (a) sulfhydryl reactivity, ascertained by monitoring the color-forming reaction between 5,5′-dithiobis(2-nitrobenzoic acid) and cysteine, (b) inhibition of malic dehydrogenase, (c) inhibition of in vitro endogenous respiration in the snail Australorbis glabratus, (d) the in vitro effect on endogenous respiration and pyruvate metabolism of liver and brain of albino rats, and (e) pyruvate metabolism in liver, kidney, and brain homogenates of male rats treated in vivo with vinyl sulfone. The effects of sublethal doses of vinyl sulfone on albino rats were also investigated. A series of vinyl sulfone molluscicidal agents was shown to exhibit a positive correlation between sulfhydryl reactivity and molluscicidal potency. High concentrations (>2 m m) of vinyl sulfone were required to inhibit the activity of malic dehydrogenase. No effect on endogenous respiration was observed in snails. Similarly, no effects on endogenous respiration or pyruvate metabolism was observed in rats. An ip LD50 of 3 mg/kg vinyl sulfone was found in female rats. A sublethal dose of vinyl sulfone increased blood urea nitrogen and decreased urinary output while producing no effect on SGOT and SGPT activity or on hematocrit values in rats. These data indicate that the toxicity of vinyl sulfone is not related to the inhibition of endogenous respiration in either snails or rats. The toxicity of sublethal doses of vinyl sulfone was postulated to be caused by impairment of normal renal function.

Demonstration of mast cells in the albino rat brain.

Des cellules «mast» ont ete observees dans les lobes olfactifs, dans le thalamus et dans la region de l'habenula de l'epithalamus chez le rat adulte, et dans la pie-mere dorsale du diencephale chez le rat nouveau-ne de 6 jours. La teneur en histamine de ces cellules pourrait expliquer la presence de la plus grande partie de l'histamine observee par d'autres auteurs dans la region du thalamus chez le rat adulte et au moins la moitie de la teneur totale en histamine dans la cervelle des rats nouveau-nes.

Effect of hydrocortisone on respiration and physphorylation in the brain and liver mitochondria of albino rats

Effect of hydrocortisone on respiration and physphorylation in the brain and liver mitochondria of albino rats

Mast cells in the central nervous system of several rodents.

AbstractMast cells were detected in the brains of kangaroo rats, gerbils and albino rats. They were most numerous in diencephalic structures (leptomeninges, choroid plexuses, nuclei, tracts); moderately abundant in telencephalic and mesencephalic structures (leptomeninges, choroid plexuses, nuclei, tracts); and least plentiful in metencephalic and myelencephalic structures. They were not detected in the spinal cord. In all cases the mast cells were closely associated with the blood vessels in these regions.

Electron Microscopy of Mitochondrial DNA From Rat Brain

The presence of deoxyribonucleic acid (DJNA) in the mitochondria of cells and tissues of vertebrates, invertebrates and plants is now well-established. The conformation of DNA has been extensively studied from highly purified preparations of mitochondria from liver, heart muscle and flight muscle and rarely from brain tissue. The present work has been conducted to study the structural form and length of DNA molecules of mitochondria from brain of albino rats.

Changes in content of catecholamines in the brain of albino rats during stress produced by running in a revolving drum

Changes in content of catecholamines in the brain of albino rats during stress produced by running in a revolving drum

Distribution of carboxylesterase activities in different tissues of albino rats

1. 1. Esterase activities on indophenyl acetate were determined in extracts of livers, kidneys, brain, thigh muscles and testes of albino rats. 2. 2. Livers and kidneys had higher esterase activity than brain, muscles or testes. 3. 3. No significant loss of esterase activities was observed when the tissues were left untouched in the body 1–24 hr after decapitation. 4. 4. Analyses of tissues from the same liver on 5 successive days or at 1- to 60-day intervals were reproducible. 5. 5. The method was also used to demonstrate esterase activities in tissues of DDT-fed rats and progeny and in necropsy samples of human livers.