bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neurochemical development of the striatum in a precocial (guinea pig) and an altricial (rat) species
Authors: Kalaria R. N. , Prince A. K. 
Published: April 2003

AbstractIn this study, the developmental patterns of key neurotransmitter marker enzymes, namely choline acetyltransferase (ChAT), glutamate decarboxylase (GAD), and tyrosine hydroxylase (TH) in the corpus striatum were compared between the guinea pig and rat. In an attempt to assess cell acquisition and differentiation, striatal DNA and protein content were also determined during development in the two species. The most outstanding feature apparent from these investigations was a sequential maturation of the three neurotransmitter‐synthesizing enzymes: TH and GAD first, followed by ChAT in striata of both species. The developmental increase in DNA content suggests that cell acquisition in the rat striatum is approximately 50% at birth, whereas in the guinea pig, the total population is present before birth, and thereafter cell numbers decline. The accretion of protein, reflecting the increase in region size, continued into adulthood in both species. With emphasis on cholinergic neurons, the neurochemical findings are assessed in relation to the morphological descriptions of cellular changes during pre‐ and postnatal development of the striatum.
Composition and synthesis of polyunsaturated fatty acyl groups in the embryonic brain of the trisomy‐16 mouse
Authors: Brooksbank B. W. L. , Martinez M. , Balázs R. 
Published: April 2003

AbstractThe trisomy‐16 (T‐16) mouse is considered to be a promising model for human trisomy‐21 (T‐21) (Down's syndrome, DS). Therefore, the fatty acyl (PUFA) compositions of phosphoglycerides in embryonic brains (days E‐17 and E‐18) of T‐16 mice have been compared with those of balanced heterozygotic embryos from the same litters, in order to determine whether similar abnormalities are present as have been found in foetal DS brain (Brooksbank et al., 1985, J. Neurochem.44, 869–874). The analyses revealed that the ratio of (n‐3) to (n‐6) PUFA was significantly increased in ethanolamine (EPG) and in choline phosphoglycerides, as it is in EPG in the foetal T‐21 brain. However, the abnormality was not so marked in the murine as in the human trisomy, and the (n‐3)/(n‐6) ratio in EPG was primarily elevated on account of decreased proportions of 20:4(n‐6) and 22:4(n‐6), there being no significant increase in (n‐3) PUFA. The PUFA composition of the phosphoglycerides of the corresponding trisomic and balanced placentae was also determined, but no relevant differences could be discerned between the genetically different tissues.As 6‐desaturase, the rate‐limiting enzyme system in PUFA synthesis, reacts more readily with (n‐3) than with (n‐6) substrates, the shift in (n‐3)(n‐6) ratio of PUFA might be related to an alteration in 6‐desaturase activity in trisomy. Comparison of the specific activity of 6‐desaturase in fresh brain homogenates of T‐16 embryos with those from balanced litter‐mates revealed, however, no differences.
Circadian patterns of serotonin (5‐HT) accumulation after pargyline treatment in the rat hypothalamus during development
Authors: Jimenez Agnes E. , Walker Richard F. 
Published: April 2003

AbstractThe purpose of this study was to determine if developmental changes in serotonin (5‐HT) synthesis occur during maturation of the 5‐HT circadian rhythm in the rat hypothalamus of 10‐ to 35‐day‐old rats. Pargyline (75 mg/kg, s.c.), a monoamine oxidase (MAO) inhibitor, was administered 30 min prior to decapitation. Hypothalamic 5‐HT concentrations after pargyline treatment were measured at six time points over a 24‐hr interval in male and female rat pups at 10, 20, 30 and 35 days of age.Daily fluctuations in hypothalamic 5‐HT accumulation were detectable as early as 10 days of age in rats of both sexes. Since the influence of MAO on hypothalamic 5‐HT concentrations was eliminated by pargyline treatment, the findings suggest that changes in tryptophan hydroxylase activity contribute significantly to daily and age‐related patterns of 5‐HT accumulation in the rat hypothalamus during development.Circadian rhythms in hypothalamic norepinephrine (NE) and dopamine (DA) also occurred during development; however, sex differences were not detected for these biogenic amines. Since catecholamine catabolism is not exclusively mediated by MAO, our findings are insufficient to conclude whether or not sex differences actually exist in patterns of these monoamines.
Taurine effect on neuritic growth from goldfish retinal explants
Authors: Lima L. , Matus P. , Drujan B. 
Published: April 2003

AbstractExplants from retinas from which the optic nerve was previously crushed exhibited neuritic outgrowth after 4–5 days in culture, and up to 10 days in the presence of the same nutrient medium. Intact retinas did not exhibit vigorous outgrowth. Taurine added in the medium to post‐crush explants accelerated the emission of neurites in 1–2 days, and increased the nerve growth index in a concentration‐dependent manner up to 4 mM. Greater concentration did not produce any effect on the nerve growth index. The effect of taurine was produced between 0 and 5 days in culture; from day 5 to day 10 explants did not exhibit further growth in the presence of the amino acid. However, post‐crush control explants exhibited growth between 5 and 10 days. Taurine effect is blocked in the absence of fetal calf serum, and is reduced in the presence of dialysed serum. Providing new medium on days 1 and 2, but not later, elevated the nerve growth index with respect to expiants regenerating in the same medium since day 0. In addition, taurine supplied at various days after plating produced the same pattern of growth as that observed by adding fresh medium, but the nerve growth index was statistically significantly greater in the presence of the amino acid. The mechanisms for these observations remain to be elucidated.
The effects of intrauterine growth retardation on the development of the Purkinje cell dendritic tree in the cerebellar cortex of fetal sheep: A note on the ontogeny of the Purkinje cell
Authors: Rees Sandra , Harding Richard 
Published: April 2003

AbstractThe development of the fetal sheep cerebellum at 80, 100, 120 and 140 days gestation (term = 146 days) and 3 months postnatally was studied using Nissl stained sections and rapid Golgi preparations. The most rapid expansion of the Purkinje cell dendritic tree occurred between 100 and 120 days of gestation (5–6 fold increase in area). By 140 days it had acquired its adult form after which time growth continued mainly in the vertical direction. The effects of intrauterine growth retardation on the growth of granule and Purkinje cell dendrites in the cerebellar cortex of fetal sheep (140 days) were investigated in Golgi preparations. Compared with control cerebella the length (but not the number) of granule cell dendrites was reduced by 14% (P<0.01); the area of the Purkinje cell dendritic field was reduced by 20% (P<0.01); the branching density was reduced by 8% (P<0.01); the total branch length was reduced by 27% (P<0.002); the density of dendritic spines per row was not affected. These factors resulted in a decrease of 26% (P<0.002) in the total number of dendritic spines per row per Purkinje cell.These findings show that the growth of granule cell dendrites and the Purkinje cell dendritic tree have been significantly affected by chronic intrauterine deprivation. Such structural abnormalities could affect the pattern of neuronal connectivity and could be associated with functional deficits.
Developmental expression of proenkephalin a mRNA and phenylethanolamine n‐methyltransferase mRNA in foetal sheep adrenal medulla
Authors: Wan David C.‐C. , Choi Chung‐lit , Livett Bruce G. 
Published: April 2003

AbstractThe ontogenic expression of proenkephalin A (ProEnk A) mRNA and phenylethanolamine N‐methyltransferase (PNMT) mRNA was examined in the foetal sheep adrenal medulla by the use of specific oligodeoxyribonucleotide probes. Northern blot analysis of RNA extracts from foetal adrenals demonstrated that ProEnk A mRNA was expressed as early as 60 days of gestation, a time at which the foetal adrenal is not functionally innervated. In situ hydridization on sections of foetal adrenals revealed that at 110–140 days gestation ProEnk A mRNA was expressed in chromaffin cells at the outer margin of the adrenal medulla but at earlier stages of gestation (e.g. 95 days) appeared to be expressed homogeneously throughout the whole of the adrenal medulla. In comparison, PNMT mRNA was expressed preferentially in cells at the outer margin of the adrenal medulla from the earliest stage detectable. Both PNMT mRNA and ProEnk A mRNA co‐localized in cells at the outer margin of foetal adrenal of late gestations (110–140 days), a similar pattern to that seen in the adult adrenal medulla. These results indicate that, as with adult animals, in foetuses of late gestation, adrenal enkephalins are co‐stored within adrenaline cells. It is likely therefore that enkephalins are co‐released from the foetal adrenal with adrenaline in response to intra‐uterine stress.
Synaptic density of caudate‐putamen and visual cortex following exposure to ethanol in utero
Authors: Lancaster F. , Delaney C. , Samorajski T. 
Published: April 2003

AbstractPregnant Long‐Evans rats were fed a liquid diet containing ethanol (30% of total calories) during days 3–19 of gestation. Controls were given ad libitum access to liquid diet lacking ethanol, or pair‐fed isocaloric amounts based on consumption by the animals in the ethanol group. Brain development of female offspring was evaluated by analysis of electron micrographs of caudate‐putamen and visual cortex. Numbers of presynaptic terminals and synaptic junctions (synaptic density) per unit area were compared for 14‐ and 28‐day‐old offspring of dams from the three treatment groups. Synaptic density of the caudate‐putamen and visual cortex was not affected by ethanol at 14 or 28 days. Although exposure to ethanol during a period comparable to the first two trimesters of human development with minimal or no undernutrition did not affect numerical density of synapses in visual cortex or caudateputamen, synaptogenesis of caudate‐putamen was altered in offspring of pair‐fed animals.
Sexual differentiation of mesencephalic neurons in vitro: Effects of sex and gonadal hormones
Authors: Engele Jürgen , Pilgrim Christoph , Reisert Ingrid 
Published: April 2003

AbstractIn order to study the influence of gender on the development of transmitter uptake by dopaminergic neurons, dissociated cell cultures were raised separately from male and female midbrains of gestational day 14 rats. It was ascertained by use of specific inhibitors and by autoradiography that the uptake of [3H]dopamine was restricted to neurons immunoreactive for tyrosine hydroxylase and that these neurons have dopaminergic properties. The uptake capacity was higher in male than in female dopaminergic neurons by a factor of 1.5. This sexual dimorphism in dopamine uptake was present in cultures of tissue removed before the perinatal rise of testosterone occurs in males and was present even in the absence of hormonal additives to the culture medium. It therefore appears to be independent of the presence of gonadal steroids. It occurred likewise in cultures raised with serum‐supplemented and serum‐free medium, which may indicate that glia are not decisive in generating these differences. In addition, sexual differences were found regarding hormone responsiveness. Whereas testosterone and dihydrotestosterone were ineffective, estradiol was seen to promote dopamine uptake in female but not in male neurons. The results would suggest that mesostriatal and/or mesolimbic dopaminergic systems assume an early role in the development of some sexual dimorphisms of the brain.
Premetamorphic effects of thyroid hormones on tadpole sensory ganglia
Authors: Ando Masato , Hammerschlag Richard 
Published: April 2003

AbstractTadpoles at premetamorphic stages of development were used to compare the precocious responses of lumbar dorsal root ganglia (DRG) and hindlimb bud (tissues destined for growth) with the responses of tail DRG and tail muscle (tissues destined for resorption) following exogenous administration of triiodothyronine (T3) and thyroxine (T4). Responses to intraperitoneal (i.p.) hormone treatment were assessed at varying times by injection of [3H]leucine i.p. and determination of 3H‐labeled protein in tissues after an additional 1.5 hr. Incorporation of [3H]leucine in lumbar DRG and hindlimb bud was markedly stimulated by either hormone. T3 and T4 effects were both maximal at 0.3 nmol/g body wt although, as examined in lumbar DRG, the response to T4 was more rapid and of lesser magnitude than that to T3. By contrast, incorporation in tail DRG and tail muscle was significantly depressed in response to T3 and was unaffected by T4. Co‐injection of T3 and T4 (either 1:1 or 1:6 as occurs during the peak surge of circulating thyroid hormones during metamorphic climax) did not produce an additive effect; the hindlimb bud response was reduced while the lumbar DRG, tail DRG and tail muscle responses to the individual hormones were virtually eliminated. The present data suggest that the responses of lumbar and tail sensory neurons to thyroid hormones parallel the responses of their peripheral target tissues.
Developmental changes in the chemosensitivity of rat brain synaptoneurosomes to excitatory amino acids, estimated by inositol phosphate formation
Authors: Guiramand Janique , Sassetti Isabelle , Recasens Max 
Published: April 2003

AbstractThe evolution of excitatory amino acids‐(EAA) stimulated inositol phosphates (IPs) turnover during postnatal development was investigated in synaptoneurosomes prepared from rat forebrains. The two main EAA agonists which induce the IPs synthesis were quisqualate (QA) and N‐methyl‐d‐aspartate (NMDA). The QA and NMDA stimulations of IPs formation present a particular developmental pattern, characterized by an active phase during rat synaptogenesis. The QA‐evoked IPs accumulation peaked in synaptoneurosomes prepared from 8‐day‐old rat forebrains while that evoked by NMDA peaked in synaptoneurosomes from 12‐day‐old rats. These two developmental patterns are specific of the EAA agonists since the other various neuroactive substances tested (carbachol (Carb), noradrenaline, and high concentrations of potassium) induced an IPs accumulation, which increases during development and reaches a maximum in synaptoneurosomes of adult animals. Aging leads to a decrease in the capability of EAAs and muscarinic agonists to stimulate IPs formation in synaptoneurosomes, whereas the stimulation of IPs turnover by noradrenaline remains constant.Taken together, these results suggest that EAAs play a key role during brain development by sequentially activating two receptor subtypes, a new QA receptor, and a NMDA receptor, linked to the phosphoinositide metabolism. They may also indicate that these EAA‐induced IPs responses are related to neuronal plastic events, the amplitude of which decreases with aging.
The effects of intrauterine growth retardation on the structural development of cranial nerves (optic, trochlear) in fetal sheep
Authors: Rees Sandra , Clark Malcolm , Snowden Michael , Harding Richard 
Published: April 2003

AbstractA quantitative morphometric study of the development of myelinated fibres in the optic and trochlear nerves has been made in growth‐retarded fetal sheep at 140 days gestation (term = 146 days). Intrauterine growth retardation was induced as a result of the reduction of placental mass, by prior removal of placentation sites in six ewes. In the optic nerve (central nervous system) the mean diameter of myelinated fibres was not significantly reduced but the thickness of the myelin sheath relative to axon diameter was disproportionately reduced. In the trochlear nerve (peripheral nervous system) there was a significant reduction of 23% (p < 0.01) in the mean diameter of myelinated fibres; however the normal axon:myelin ratio was maintained. The total number of myelinated fibres in the trochlear nerve did not differ between the normal and growth‐retarded group, indicating that there was not a greater than normal incidence of cell death during intrauterine growth retardation in the nucleus of the trochlear nerve.The differential effect of intrauterine growth retardation on myelination in the central and peripheral nervous systems suggests that chronic intrauterine deprivation affects oligodendrocyte activity but does not markedly affect the capacity of Schwann cells to produce myelin.
Localization of dipeptidylpeptidase IV and alkaline phosphatase in developing spinal cord meninges and peripheral nerve coverings of the rat
Authors: Haninec Pavel , Grim Miloš 
Published: April 2003

AbstractLocalization of dipeptidylpeptidase IV was studied in the spinal cord meninges and peripheral nerve coverings of fetal and postnatal rats. In the same sections, the localization of alkaline phosphatase was monitored.In the prenatal period, dipeptidylpeptidase (DPP) IV activity in the differentiating meninges appeared at the time of cerebrospinal fluid spaces formation (on day 16 in the cervical region and on day 18 in the lumbar region).In adult animals DPP IV was found in cells of those meningeal lamellae which delineated the cerebrospinal fluid spaces (the outer, intermediate and inner lamellae), in the perineurium, in Schwann cells and in some fibroblasts of the bulk of dura mater. It is suggested that DPP IV plays a role in the metabolism of neuropeptides by their interaction with cerebrospinal fluid.Alkaline phosphatase activity was detectable earlier than DPP IV activity. Positivity was first observed in some cells of the meninx primitiva and, later on, in the ectomeninx and also in the differentiating endomeninx where it disappeared postnatally.The developing ectomeninx exhibited activities of both enzymes. Alkaline phosphatase occupied its external layers, while DPP IV was localized in its inner layers. This enzymatic heterogeneity of the ectomeningeal layers suggests that the ectomeninx gives rise not only to dura mater (which in adult animals exhibits alkaline phosphatase activity) but also to the outer arachnoid layer (positive for DPP IV in adult rats).
Cortical neuron sensitivity to neurotransmitters following neonatal noradrenaline depletion
Authors: Mirmiran M. , Dijcks F. A. , Bos N. P. A. , Gorter J. A. , Van der Werf D. 
Published: April 2003

AbstractIn order to test the functional significance of rapid eye movement (REM)‐sleep and noradrenergic activity for cerebral cortex maturation, rat pups were daily injected with clonidine from 8 to 21 days of life. Previous studies have shown that this treatment reduces the amount of time spent in REM‐sleep and the level of noradrenaline turnover in the brain. For long‐term consequences of such treatment in adulthood, cortical neuron responses to micro‐iontophoretically applied neurotransmitters were studied. No significant differences were found in the single cell responses to glutamate, GABA or noradrenaline in the cerebral cortex of clonidine treated rats as compared with age matched controls. However, the magnitude of GABAergic depression of glutamate induced neuronal responses was greater in the clonidine than in the control group.
Structural and neurochemical effects in mouse cerebellum following neonatal methylazoxymethanol and 6‐hydroxydopamine treatment
Authors: Luthman J. , Eriksdotter‐Nilsson M. , Jonsson G. 
Published: April 2003

AbstractThe effects of neonatal treatment with the antimitotic agent methylazoxymethanol and the catecholamme neurotoxin 6‐hydroxydopamine on cerebellar morphology and monoamine innervation in the N.M.R.I. mouse has been studied. Methylazoxymethanol (25 mg/kg s.c.) treatment induced a cerebellar weight reduction of 40% as observed in the adult stage, while other CNS regions analysed were unaffected. An obvious atrophy of the cerebellar cortex was found, with an irregular distribution of the Purkinje cells, while Bergmann glia fibers deviated from their normal radial configuration and showed a tendency to form clusters. A 65% increase of tyrosine hydroxylase immunoreactive fiber density was found in the cerebellar cortex and 3H‐5‐hydroxytryptamine in vitro synaptosomal uptake was increased by 55%. Noradrenaline and 5‐hydroxytryptamine concentrations in the cerebellum increased by 50 and 30%, respectively, whereas the total content of both neurotransmitters in cerebellum was approximately unchanged after methylazoxymethanol treatment. A significant reduction in total cerebellar in vitro binding of 3H‐WB‐4101 and 3H‐dihydroalprenolol was also found, indicating compensatory receptor alterations following methylazoxymethanol treatment. The effect of combined treatment of methylazoxymethanol and the neurotoxin 6‐hydroxydopamine (50 mg/kg s.c., day 1) showed a very pronounced reduction of noradrenaline concentration in cortex cerebri, while the noradrenaline concentration in cerebellum was increased by 185% and the tyrosine hydroxylase immunoreactive fiber density by 125%, indicating an additional relative hyperinnervation of cerebellar noradrenaline fiber due to a “pruning effect” of the 6‐hydroxydopamine treatment. The results imply a relatively rigid development of terminal arborization of central nervous system monoamine neurons, relatively independent of neuronal and glial arrangement in the target area.
A developmental study of soluble L1
Authors: Nybroe Ole , Dalseg Anne‐Marie , Bock Elisabeth 
Published: April 2003

AbstractL1 is a neural cell adhesion molecule expressed by neurons and it is involved in cell interactions during axon elongation and fasciculation. L1 from rat brain consists of a membrane‐inserted Mr 200,000 polypeptide from which two polypeptides of Mr 180,000 and Mr 140,000 can be derived. These latter polypeptides appear both as membrane‐associated and as soluble molecules. In this report, both total and soluble L1 in rat brain have been quantified by an enzyme‐linked immunosorbent assay. The amount of total L1 per gram brain varies with postnatal age showing a peak value at postnatal day 7. The variation in soluble L1 coincides with the changes in total L1. Thus, soluble L1 constitutes ca 2% of total L1 at all ages investigated. The soluble Mr 140,000 and 180,000 L1 polypeptides are also present in cerebrospinal fluid. Studies of membrane L1 catabolism in cultured fetal rat brain neurons show that the half‐life of membrane L1 is less than 24 hr. As a part of membrane L1 catabolism, small amounts of soluble L1 polypeptides are released to include cell surroundings.
Spontaneous neuronal firing patterns in the occipital cortex of developing rats
Authors: Corner M. A. , Mirmiran M. 
Published: April 2003

AbstractSpontaneous action potentials have been recorded in the cerebral cortex of developing rats under chloral hydrate anaesthesia. These “spike‐trains” were subjected to a multivariate analysis of parameters describing different aspects of temporal patterning within each train. Three parameters which reflected clustering of action potentials in, respectively, the range of: (i) milliseconds (the modal interval, derived from the interval histograms); (ii) seconds (the mean “burst period”, i.e. the time elapsing between the onset of successive clusters of relatively short intervals); and (iii) minutes (the coefficient of variation for the number of spikes in consecutive 2 min time bins) showed distinctive developmental patterns.