Expression of tyrosine kinase A in the cerebral cortex of postnatal developing rat

Tyrosine kinase A (TrkA)is an essential component of the high affinity nerve growth factor (NGF) receptor necessary to the mediate the biological effects of the neurotrophins, NGF. This study examined the distribution of TrkA-immunoreactivity (IR)cells in the postnatal rat cerebral cortex and the changes that occur in postnatal development as a result of the expression of this protein. TrkA-IR was detected at postnatal day (PD)3, PD6, PD9 and PD15. Base upon their somatodendritic morphology, the most commonly labeled cell type was the pyramidal neurons. At PD3 and PD6, layer I, II, III and V was immunopositive for TrkA, at PD9, not only at layer I, II, III, and V but also at layer VI. At PD15, the TrkA-positive cells were distributed in all layers. These TrkA-positive cells were not detected at PD0. In contrast, there was significant increase in the percentage of cells exhibiting TrkA-IR with development and the highest level was detected at PD15. These results suggest that the cerebral cortex expresses TrkA strongly during the postnatal period. Moreover, the postnatal development-related increase in the expression of TrkA-cells shows that NGF may have a trophic effect on these cerebral cortex neurons from the postnatal period.

Distribution of trkA in cerebral cortex and diencephalon of the mongolian gerbil after birth

TrkA is essential components of the high-affinity NGF receptor necessary to mediate biological effects of the neurotrophins NGF. Here we report on the expression of trkA in the cerebral cortex and diencephalon of mongolian gerbils during postnatal development. The expression of trkA was identified by immunohistochemical method. In parietal cortex and piriform cortex, higher levels of trkA-IR (immunoreactivity) were detected at 3 days postnatal (P3) and at P9. Although trkA was not expressed till P3 in the parietal cortex, it was detectable at birth in the piriform cortex. Several regions, such as Layers I, IV & VI, did not show much expression. Layer I showed especially weak labeling. In the hippocampus, thalamus, and hypothalamus, higher levels of trkA-IR were detected at P6 and P12 than earlier days. But trkA was not expressed at birth in the hippocampus, at P3 in the reticular thalamic nucleus (Rt), or neonatally in the dorsomedial hypothalamic nucleus (DM). This data shows that expression of trkA is developmentally regulated and suggests that high affinity neurotrophin-receptors mediate a transient response to neurotrophines in the cerebral cortex and diencephalon during mongolian gerbil brain ontogeny.

A Study on the Spinoreticulocerebellar Tract in Chickens

The spicoreticulocerebellar (SRC) tract is an indirect spinocerebellar tract formed by the reticular formation (RF), which is connected to the cerebellum and spinal cord. The RF receives ascending fibers to both the spinal enlargement and sends descending fibers to the cerebellum. This study demonstrated that the connectivity of the neurons in the RF is concerned to the cerebellum and spinal cord using the anterograde projection with biotinylated dextran amine (BDA) and retrograde labeling with wheat germ agglutinin-horseradish peroxidase (WGA-HRP). Until now, a preliminary study in mammals has dealt with the afferent and efferent pathways in separating groups of neurons in the RF. There are only few reports on chickens. This study examined the SRC tract in chickens. Following bilateral injections we injected BDA into chicken spinal cord (lumbosacral enlargement) and WGA-HRP into the cerebellum. Both of single- and double-labeled cells were found within the RF. The spinoreticular axons were mainly distributed from the potomedullary junction to the rostral medulla in the rostro-caudally RF levels, for example, nucleus of reticularis (n. r.) pontis oralis, locus coeruleus, n. r. pontis caudalis, n. r. pars gigantocellularis, n. r. gigantocellularis and n. r. parvocellualris. Reticulocerebellar labeling by the WGA- HRP was found in the same place as well as that of the BDA-projection. We observed that the proportion and location of double labeling cells in the chicken were almost similar in each level, comparing to the rodents. These results suggest that the reticular formation is strongly related to the spicoreticulocerebellar tract in chickens.

Glutamate and GABA concentrations in the cerebellum of novel ataxic mutant Pogo mice

The Pogo mouse is an autosomal recessive ataxic mutant that arose spontaneously in the inbred KJR/MsKist strain derived originally from Korean wild mice. The ataxic phenotype is characterized by difficulty in maintaining posture and side to side stability, faulty coordination between limbs and trunk, and the consequent inability to walk straight. In the present study, the cerebellar concentrations of glutamate and GABA were analyzed, since glutamate is a most prevalent excitatory neurotransmitter whereas gammar-aminobutyric acid (GABA) is one of the most abundant inhibitory neurotransmitters, which may be the main neurotransmitters related with the ataxia and epilepsy. The concentration of glutamate of cerebellum decreased significantly in ataxic mutant Pogo mouse compared to those of control mouse. However, GABA concentration was not decrease. These results suggested that the decrease in glutamate concentration may contribute to ataxia in mutant Pogo mouse.

Immunohistochemical Localization of Nerve Growth Factor, Glial Fibrillary Acidic Protein and Ciliary Neurotrophic Factor in Mesencephalon, Rhombencephalon, and Spinal Cord of Developing Mongolian Gerbil

The distribution of the nerve growth factor (NGF), the glial fibrillary acidic protein (GFAP) and the ciliary neurotrohic factor (CNTF) was performed in coronal sections of the mesencephalon, rhombencephalon and spinal cord in the developing Mongolian gerbils. Generally, NGF specifically recognizes neurons with the NGF receptor, whereas GFAP does the glia, and CNTF does the motor neurons. The receptor expression was examined separately in gerbils between embryonic days 15 (E15) and postnatal weeks 3 (PNW 3). The NGF-IR was first observed in the spinal cord at E21, which might be related to the maturation. The GFAP reactivity was peaked at the postnatal days 2 (PND2), while the highest CNTF-reaction was expressed at PNW 2. The GFAP stains were observed in the aqueduct and the spinal cord, which appeared to project laterally at E19. The CNTF was observed only after the birth and found in both the neurons and neuroglia of the substantia nigra, mesencephalon, cerebellum and the spinal cord from PND1 to PNW3. These results suggest that NGF, GFAP and CNTF are important for the development of the neurons and the neuroglia in the central nervous system at the late prenatal and postnatal stages.

Morphological Studies of the Neuropeptide Y Immunoreactiive Neurons in the Cerebral Cortex and the Corpus Striatum of Striped Field Mouse (apodemus agrarius coreae) / 대한해부학회지

Neuropeptide Y(NPY) was first isolated from porcine brain. This discovery has led some workers to study the distribution of this peptide in the central nervous system of various mammals. In this study examined the distribution pattern of NPY-immunoreactive (NPY-IR) neurons in the Striped Field Mouse (Apodemus agrarius coreae) cerebral cortex and striatum, using immunohistochemical method. The results obtained in this study were summarized as followings. 1. NPY-IR neurons distributed in all layer of cerebral cortex. The number of neurons were higher in layer V and VI than in layer I and IV. 2. The shape of neurons was predominantly round or oval in layer I and II, and triangular in layer V and VI. And the processes were parallel to pia mater in layer I and II and were vertical in layer III. 3. The highest number of NPY-IR neurons were found in the perirhinal cortex but a few distinct population were found in the retrosplenial cortex. 4. In stiatum NPY-IR neurons were observed only in caudate-putamen nucleus. 5. The Immunoreactive neurons in caudate-putamen varied in their shape, but most of them were triangular or multiform neurons had omnidirectional processes.

Morphological study of neuropeptide Y immunoreactive neurons (NPY-IR) of telencephalon in developing chick / 대한해부학회지

Neuropeptide Y (NPY) was a 36-amino acid peptide that biochemical structure to be resemble the pancreatic polypeptide in mammalian and it was first isolated from porcine brain by Tatemoto et al. (1982). It is now known to neurotransmitter or neuromodulator as well as it has important effects to sexual precocity, regulation of feeding behavior and function of pituitary gland in avians. The distribution and morphological study of NPY-immunoreactive neurons (NPY-IR) is studied in many experimental animal but in developing chick brain have been not studied. The present study provided the distribution and morphological study of NPY-IR in developing chick brain. The developing brain of Korean native chicks embryos at E8, E10, E12, E14, E16, E18, and E20 days of incubation were used. Experimental animals were perfused with 4% paraformaldehyde through the left ventricle and aorta. The brains were removed and transferred 30% sucrose, and then cut on a cryostat into 60 mm-thick. The tissue immunostained with free-floating and avidin-biotin complex (ABC) method. The results obtained in this study are that followings. The numerous of NPY-IR first observed at E8 days in the telencephalon of neostriatum, ectostriatum, archistriatum intermedium pars ventralis, nucleus taeniae and paleostriatum agumentatum, at E12 days in telencephalon of hippocampus, at E14 days in telencephalon of hyperstriatum. In the telencephalon, NPY-IR distributed predominantly in neostriatum and ectostriatum. shape of neuron's that E8 days of incubation were oval shape neurons and increased days of chicks was sphere, oval and many multigonal shapes. Their processes were also omnidirectional. The process of neuron's that E8 days of incubation was observed a few and weak immunity and increased days of chicks was numerous and strong immunity. According to increasing the days the morphology of NPY-IR showed the tendency to increase their sizes and numbers. We suggest that the regional differences in the distribution of NPY-containing neuron types may reflect adaptations of local neuronal circuits for specialized functions.

Morphological Study of GFAP Immunoreactive Cells on Fetuses and Neonate Telencephalon of Korean Native Goat / 대한해부학회지

GFAP (Glial Fibrillary Acidic Protein) was one of the intermediate filament group and used as an astrocyte marker. The numerous studies about GFAP immunoreactive cell's distribution were investigated for fetus, neonate and aged brains. There are several reports about that GFAP immunoreactive cells were appeared at early fetus or after birth. In cases of mammalian fetus radial glia cells migrated toward pial surface at early stage and revealed GFAP immunoreactivity by the immunostain. But in cases of rodents, they migrated last gestation or after birth. This study, the GFAP immunoreactive cells' localizations and distribution in the fetuses (the 30th, 45th, 60th, 90th, 95th, 105th 120th of gestation) and neonate telencephalon of Korean native goat were investigated by immunohisto-chemistry (ABC method). The results obtained in this study were summarized as followings; 1. Multipolar astrocytes of 60 days of gestation were found cerebral cortex, in 95 days of gestation were found cerebral medulla, in 105 days of gestation were found lateral ventricle. 2. Radial glial cell presented 45 days of gestation and process of GFAP immunoreactive was to stretch out from ventricular to pia mater. And the nonpolar immunoreactive cells were transformed bipolar immunoreactive cells and they were transformed to monopolar and multipolar immunoreactive cell. 3. The number of GFAP immunoreactive cells of a field were gradually increased from 45 days of gestation till 90 days of gestation and decreased from 90 days of gestation till 105 days of gestation. But in 120 days of gestation and newborn were slightly increased. 4. Immunoreactivity of GFAP immunoreactive cells were gradually decreased from 95 days of gestation till 120 days of gestatioin. However, most pia mater areas and ventricles had high immunoreactivity and medulla part had low immunoreactivity. These results were suggested that radial glial cell of cerebral cortex and cerebral medulla were developed faster than lateral ventricle.

The study of dopaminergic immunoreactive cell change in mesencephalon and pons of mongolian gerbil by water deprived day / 대한해부학회지

Mongolian gerbil (Meriones unguiculatus) has been as an model animal for studing the neurologic disease because of the long-term survival in the condition of water-deprived desert condition. In order to accomplish the this research, first of all another divided the laboratory animals 10groups. In this study of the long term water deprived condition investigated catecholamine synthetic enzymes, tyrosine hydroxylase(TH), dopamine-beta-hydroxylase (DBH), and phenylethanolamine-N- methyltransferase(PNMT) in the brain by using immunohistochemical stain. The results obtained in this study were summarized as following. 1. It were observed TH-IR cells in substantia nigra pars compacta, ventral tegmental area and substantia nigra pars reticular of Midbrian. Most of them were presented in pars compacta and ventral tegmental area, but a few in pars reticular. TH-IR cell decreased until the 5th water-deprived day, increased from the 10th water-deprived day to the 15th water-deprived day and redecreased in the 20th water-deprived day 2. In locus ceruleus and rubrospinal tract were observed TH-IR cells and a few DBH-IR cell. Therefore there was composed of dopaminergic neuron and noradrenergic neuron. 3. The quantity of dopamin in serum were decreased until the 4th water-deprived day, increased from the 5th water-deprived day, redecreased on the 15th water-deprived day and reincreased from the 20th water-deprived day.