Nucleo-cytoplasmic relationships of high-molecular-weight ribonucleic acid, including polyadenylated species, in the developing rat brain

The metabolism of high-molecular-weight RNA in the nuclear and cytoplasmic fractions of newborn and adult rat brain was investigated after the intracranial administration of [32P]Pi. In young brain, a considerable proportion of the newly synthesized radioactive RNA is transferred to the cytoplasm, in contrast with the adult brain, where there appears to be a high intranuclear turnover. Electrophoretic analysis of the newly synthesized RNA showed that processing of the rRNA precursor to yield the 28S and 18S rRNA may be more rapid in the adult than in the young, although most of the adult rRNA in the nucleus is not transferred to the cytoplasm. In young brain, processing is probably tightly coupled to transport of rRNA into the cytoplasm, so that 28S and 18S rRNA are not subjected to possible degradation within the nucleus. Polyadenylated RNA turns over in concert with high-molecular-weight RNA in the nuclei of the adult rat brain. In the cytoplasm the polyadenylated RNA has a higher turnover rate relative to rRNA. In the young brain the polyadenylated RNA is transferred to the cytoplasm along with rRNA, although polyadenylated RNA is transported into the cytoplasm at a faster rate. The nuclear and cytoplasmic polyadenylated RNA species of young brain are larger than their corresponding adult counterparts. These results suggest that there are considerable changes in the regulation of the nucleo-cytoplasmic relationship of rRNA and polyadenylated RNA during the transition of the brain from a developing replicative phase to an adult differentiated and non-dividing state.

Download Full-text

The metabolism of high-molecular-weight ribonucleic acid including polyadenylated species, in the developing rat brain

Biochemical Journal ◽

10.1042/bj1540517 ◽

1976 ◽

Vol 154 (2) ◽

pp. 517-527 ◽

Cited By ~ 19

Author(s):

W Berthold ◽

L Lim

Keyword(s):

Molecular Weight ◽

Brain Stem ◽

Rat Brain ◽

High Molecular Weight ◽

Newborn Rats ◽

Total Rna ◽

Adult Rat ◽

Polyadenylated Rna ◽

Old Rats ◽

Developing Rat

High-molecular-weight RNA was isolated from rat brain at various times after the intracranial administration of [32P]Pi. The synthesis of 28S and 18S rRNA could be detected within 1h of the injection of the radioactive precursor and appeared to be more pronounced, relative to other high-molecular-weight RNA, in the brains of older rats compared with those of newborn rats. Polyadenylated RNA, representing most mRNA and their precursors, was isolated by chromatography on oligo(dT)-cellulose. The contribution of this polyadenylated RNA to total RNA synthesis was investigated in the cerebral cortex and the phylogenetically older brain stem at different stages in the development of the rats by using a 5h period of labelling as an arbitrary index of transcription. In the brain stem the proportion of labelled polyadenylated RNA comprised 27-30% of the total RNA. The corresponding values for the cortex decreased from 34% in newborn rats to 23% in 40-150-day-old rats. These data indicated that proportionately more polyadenylated RNA is synthesized in the cortex of the newborn than in the adult rat and that there is a progressive decrease in the synthesis of polyadenylated RNA relative to rRNA during development.

Download Full-text

Pattern of chondroitin sulfate proteoglycan expression after ablation of the sensorimotor cortex of the neonatal and adult rat brain

Archives of Biological Sciences ◽

10.2298/abs0804581d ◽

2008 ◽

Vol 60 (4) ◽

pp. 581-591

Author(s):

Sanja Dacic ◽

Sanja Pekovic ◽

Maja Stojiljkovic ◽

Irena Lavrnja ◽

Danijela Stojkov ◽

...

Keyword(s):

Chondroitin Sulfate ◽

Rat Brain ◽

Sensorimotor Cortex ◽

Immunohistochemical Analysis ◽

Recovery Process ◽

Adult Brain ◽

Sulfate Proteoglycan ◽

Adult Rats ◽

Adult Rat ◽

Adult Rat Brain

The central nervous system has a limited capacity for self-repair after damage. However, the neonatal brain has agreater capacity for recovery than the adult brain. These differences in the regenerative capability depend on local environmental factors and the maturational stage of growing axons. Among molecules which have both growth-promoting and growth-inhibiting activities is the heterogeneous class of chondroitin sulfate proteoglycans (CSPGs). In this paper, we investigated the chondroitin-4 and chondroitin-6 sulfate proteoglycan expression profile after left sensorimotor cortex ablation of the neonatal and adult rat brain. Immunohistochemical analysis revealed that compared to the normal uninjured cortex, lesion provoked up regulation of CSPGs showing a different pattern of expression in the neonatal vs. the adult brain. Punctuate and membrane-bound labeling was predominate after neonatal lesion, where as heavy deposition of staining in the extracellular matrix was observed after adult lesion. Heavy deposition of CSPG immunoreactivity around the lesionsite in adult rats, in contrast to a less CSPG-rich environment in neonatal rats, indicated that enhancement of the recovery process after neonatal injury is due to amore permissive environment.

Download Full-text

Activity of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in brains of adult and 7-day-old rats

Biochemical Journal ◽

10.1042/bj1540559 ◽

1976 ◽

Vol 154 (2) ◽

pp. 559-560 ◽

Cited By ~ 9

Author(s):

M M. Sudjic ◽

R Booth

Keyword(s):

Rat Brain ◽

Coenzyme A ◽

Reductase Activity ◽

Cholesterol Biosynthesis ◽

Adult Brain ◽

Adult Rat ◽

Adult Rat Brain ◽

Old Rats ◽

Coa Reductase ◽

Coenzyme A Reductase

Rat brain contains 3-hydroxy-3-methylglutaryl-CoA reductase activity, but this enzyme is far more active in 7-day-old brain than in adult brain. This difference may partly explain why cholesterol biosynthesis is more rapid in growing than in adult rat brain.

Download Full-text

Demonstration of poly-N-acetyl lactosamine residues in ameboid and ramified microglial cells in rat brain by tomato lectin binding.

Journal of Histochemistry & Cytochemistry ◽

10.1177/42.8.8027523 ◽

1994 ◽

Vol 42 (8) ◽

pp. 1033-1041 ◽

Cited By ~ 152

Author(s):

L Acarin ◽

J M Vela ◽

B González ◽

B Castellano

Keyword(s):

Rat Brain ◽

Glial Cells ◽

Lectin Histochemistry ◽

Adult Brain ◽

Microglial Cells ◽

Electron Microscopic Level ◽

Sugar Residue ◽

Adult Rat ◽

Tomato Lectin ◽

Adult Rat Brain

This study was designed to demonstrate the localization of poly-N-acetyl lactosamine residues in postnatal and adult rat brain, visualized by their specific binding to a lectin obtained from Lycopersicon esculentum (tomato). Lectin histochemistry was carried out on cryostat, paraffin, and vibratome sections and was examined by light microscopy. Selected vibratome sections were processed for electron microscopy. Our results showed that tomato lectin histochemistry was found in relation to blood vessels and glial cells in both postnatal and adult rat brain. Since tomato lectin-positive glial cells did not show GFAP immunoreactivity and displayed the same morphological features and overall distribution as nucleoside diphosphatase (NDPase)-positive cells, they were consequently identified as microglial cells. At the electron microscopic level, both ameboid and ramified microglial cells displayed intracytoplasmic and plasma membrane lectin reactivity. In postnatal brain, ameboid microglial cells always showed stronger binding of tomato lectin compared with ramified microglial cells in the adult brain. The putative significance of this decrease in poly-N-acetyl lactosamine from ameboid to ramified microglial cells and the possible role(s) of this sugar residue are discussed.

Download Full-text

The BDNF content of postnatal and adult rat brain: the effects of 6-hydroxydopamine lesions in adult brain

Developmental Brain Research ◽

10.1016/s0165-3806(96)00159-9 ◽

1996 ◽

Vol 97 (2) ◽

pp. 297-303 ◽

Cited By ~ 49

Author(s):

Jiawei Zhou ◽

Bernardo Pliego-Rivero ◽

Henry F. Bradford ◽

Gerald M. Stern

Keyword(s):

Rat Brain ◽

Adult Brain ◽

Adult Rat ◽

Adult Rat Brain ◽

6 Hydroxydopamine

Download Full-text

Acetoacetate metabolism in infant and adult rat brain in vitro

Biochemical Journal ◽

10.1042/bj1160641 ◽

1970 ◽

Vol 116 (4) ◽

pp. 641-655 ◽

Cited By ~ 112

Author(s):

T. Itoh ◽

J. H. Quastel

Keyword(s):

Rat Brain ◽

Brain Cortex ◽

Brain Slices ◽

Adult Brain ◽

Adult Rat ◽

Infant Rat ◽

Rat Brain Cortex ◽

Adult Rat Brain ◽

Brain Cortex Slices ◽

Cortex Slices

1. Acetoacetate or dl-β-hydroxybutyrate increases the rate of oxygen consumption to a smaller extent than that brought about by glucose or pyruvate in adult rat brain-cortex slices but to the same extent as that in infant rat brain-cortex slices. 2. The rate of 14CO2 evolution from [1-14C]glucose considerably exceeds that from [6-14C]glucose in respiring infant rat brain-cortex slices, in contrast with adult brain-cortex slices, suggesting that the hexose monophosphate shunt operates at a greater rate in the infant rat brain than in the adult rat brain. 3. The rate of 14CO2 evolution from [3-14C]acetoacetate or dl-β-hydroxy[3-14C]butyrate, in the absence of glucose, is the same in infant rat brain slices as in adult rat brain slices. It exceeds that from [2-14C]glucose in infant rat brain but is less than that from [2-14C]glucose in adult rat brain. 4. Acetoacetate is oxidized in the brain through the operation of the citric acid cycle, as shown by the accelerating effect of glucose on acetoacetate oxidation in adult brain slices, by the inhibitory effects of malonate in both infant and adult brain slices and by its conversion into glutamate and related amino acids in both tissues. 5. Acetoacetate does not affect glucose utilization in adult or infant brain slices. It inhibits the rate of 14CO2 formation from [2-14C]glucose or [U-14C]-glucose the effect not being wholly due to isotopic dilution. 6. Acetoacetate inhibits non-competitively the oxidation of [1-14C]pyruvate, the effect being attributed to competition between acetyl-CoA and CoA for the pyruvate-oxidation system. 7. Acetoacetate increases the rate of aerobic formation of lactate from glucose with both adult and infant rat brain slices. 8. The presence of 0.1mm-2,4-dinitrophenol diminishes but does not abolish the rate of 14CO2 formation from [3-14C]acetoacetate in rat brain slices. This points to the participation of ATP in the process of oxidation of acetoacetate in infant or adult rat brain. 9. The presence of 5mm-d-glutamate inhibits the rate of 14CO2 formation from [3-14C]acetoacetate, in the presence or absence of glucose. 10. Labelled amino acids are formed from [3-14C]acetoacetate in both adult and infant rat brain-cortex slices, but the amounts are smaller than those found with [2-14C]glucose in adult rat brain and greater than those found with [2-14C]glucose in infant rat brain. 11. Acetoacetate is not as effective as glucose as a precursor of acetylcholine in adult rat brain but is as effective as glucose in infant rat brain slices. 12. Acetoacetate or β-hydroxybutyrate is a more potent source of acetyl-CoA than is glucose in infant rat brain slices but is less so in adult rat brain slices.

Download Full-text