bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of apomorphine and isoproterenol on the ‘transport response’ in the white rat
Authors: Wilson Christopher 
Published: April 2003

AbstractIn a series of four experiments, the ability of specific catecholaminergic agonists to intensify the ‘transport response’ was investigated in 19‐, 32‐, 36‐ and 40‐day‐old rats. The dopaminergic agonist, apomorphine, was able to intensify the response in a dose‐dependent fashion. The beta‐noradrenergic agonist, isoproterenol, was unable to alter the intensity of the response. These results indicate a central dopaminergic involvement in the transport response.
Interplexiform, horizontal and bipolar‐like cells of the rabbit retina take up exogenous serotonin during early developmental stages
Authors: Osborne N.N. 
Published: April 2003

AbstractA subpopulation of amacrine cells which have the ability to take up exogenous serotonin occur in the rabbit retina at all stages during postnatal development. However, during the initial stages of the retina's development some serotonin‐accumulating neurons are also associated with the outer plexiform layer in the form of interplexiform and/or bipolar and/or horizontal cells. These neurons could have an additional function of their own or simply be misplaced serotonin‐accumulating neurons destined to degenerate in the process of synaptogenesis.
Neural transplantation: Autoradiographic analysis of histogenesis in neocortical transplants
Authors: Das Gopal D. , Ross Douglas T. 
Published: April 2003

AbstractNcurohistogenesis in neoeortical transplants obtained from 15‐, 16‐. 17‐, 18‐, 19‐, 20‐ and 21 day‐old embryos, was studied employing [3H]thymidine autoradiography. The neural tissues were transplanted in the midvcrmis of cerebellum of the host animals. Following transplantation the host animals in different groups were injected with the radiochemical at 6 hr. 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 day intervals, to label the neurons forming on different days in the developing transplants. Analysis of auto radiograms showed that all the neoeortical transplants did undergo histogenesis in the host cerebellum and that it was similar to that seen in a normally developing neocortex. Transplants from the 15‐day embryos showed histogenesis lasting for 9 days and at the other extreme transplants from the 21‐day embryos showed histogenesis lasting only for 1 day. Histogenesis in other transplants fell between these two extremes in a graded fashion in relation to the age of the donor embryos. The magnitude of histogenesis in transplants from different donor embryos was closely related to the final size of the transplants. Transplants from 15‐day embryos were the largest in size and they were followed by those from 16‐, 17‐, 18‐, 19‐, 20‐ and 21‐day donor embryos in a graded fashion. All transplants were intraparenchymal and histologically appeared normal. They contained fully differentiated neurons and were anatomically integrated with the host cerebellum without any glial scar tissue or necrotic tissue intervening between them.
Long‐term consequence of early iron‐deficiency on dopaminergic neurotransmission in rats
Authors: Ben‐Shachar Dorit , Ashkenazi Ruth , Youdim Moussa B.H. 
Published: April 2003

AbstractNutritional iron‐deficiency (ID) induced in rats caused a reduction in peripheral as well as central iron metabolism. This effect was markedly greater in the liver than the brain. Although the decrease in the rate of brain non‐haem iron was slower than that of serum and liver, significant diminutions of behavioral response to apomorphine (2 mg/kg) and maximum [3H]spiperone binding (Bmax) in caudate nucleus were noted in these animals. These effects of ID can be reserved byron supplementation in young (21‐day‐old) and adult (48‐day‐old) rats. In contrast, if ID is induced in new born (10‐day‐old) animals, the diminished brain non‐haem iron, behavioral response to apomorphine and [3H]‐spiperone binding in caudate nucleus will not recover even after 6 weeks of iron supplementation. However, these animals have normal serum iron, haemoglobin and liver iron. These data point to the profound effect early ID can have on the development of dopaminergic neurotransmission, since brain iron concentration increases its maximum in the 4–5 weeks after birth. The implications of the present finding is that the prevalence of ID in children occurs in the first decade of life, when brain iron accumulation reaches values observed in adults. The profound cognitive changes associated with ID in children is thought to be dopamine‐dependent and is not always reversible with iron therapy.
Cytotoxic effects of monodansylcadaverine and methylamine in primary cultures of rat cerebellar neurons
Authors: Gilad Gad M. , Gilad Varda H. 
Published: April 2003

AbstractThe effects of dansylcadaverine and methylamine, competitive inhibitors of transglutaminase. were examined in primary cultures of dissociated rat cerebellar neurons. Addition of the drugs at plating time resulted 24 hr later in irreversible cytotoxic effects evidenced by failure of aggregation and neurite formation. Cytotoxicity was dose‐dependent with methylamine being more potent (1C50 = 20μm) than dansylcadaverine (IC50 = 30μM). The cytotoxic effects were less potent when drugs were added 24 hr after plating, the time when neurons had already begun to extend neurites. Drugs were effective in the various sera and heat‐inactivated sera tested. We concluded that low doses of methylamine and dansylcadaverine have potent toxic effects on primary neuronal cultures.
Are the effects of gestational stress on motor development and cerebellar cholinesterase activity mediated prenatally?
Authors: Fride Ester , Soreq Hermona , Weinstock Marta 
Published: April 2003

AbstractPrenatal random noise and light stress retards early motor development in the rat. To determine whether this delay is pre‐ or postnatally mediated and whether the developing cerebellum may play a role in the delay, rats were subjected to this form of stress and their offspring were fostered or cross‐fostered onto control rats and vice versa. Their motor development was assessed by a series of behavioral tests between birth and day 10 of life.Prenatally stressed pups (Eo). whether reared by stressed (Em) or control mothers (Cm), showed a retardation in motor development. However, stressed pups matured earlier when reared by a control mother than by a stressed dam. Control pups (Co) raised by stressed mothers showed normal behavioral development.Cerebellar cholinesterase activity, which has been shown to undergo characteristic alterations with normal maturation, did not differ between stressed and control pups at birth. However, on day 10, cholinesterase activity was lower in EmCo than in CmCo pups, whereas that in CmEo and EmEo pups did not differ significantly from controls.It is concluded that three effects of random noise and light stress during pregnancy may be distinguished: (1) A prenatal effect as expressed by a delay in motor development, (2) a postnatal (rearing) effect on motor development and (3) a rearing effect expressed as a decrease in cerebellar ChE activity.
Early olfactory deprivation and the mitral cells of the olfactory bulb: A Golgi study
Authors: Meisami Esmail , Noushinfar Elaheh 
Published: April 2003

AbstractGolgi impregnation was used to study the morphology, morphometry and number of mitral cells in control and stimulus‐deprived olfactory bulbs (OB) of 25‐day‐old albino rats. The rats were made unilaterally anosmic by closure of one nostril in the early neonatal period. The previously described reductions in the size of OB and thickness of OB layers were confirmed. Quantitative comparison of the control and anosmic OB revealed that in the odor deprived OB the number of Golgi impregnated mitral cells was 40% less and the impregnation of dendritic neuropil in the external plexiform layer was greatly reduced. Of the remaining mitral cells of the odor‐deprived OB, a small portion exhibited an ‘atrophic’ appearance with markedly reduced impregnation of the intracellular material, while the majority showed relatively ‘normal’ morphology. Morphometric measurements and statistical comparison of the means revealed that in the remaining ‘normal’ mitral cells, there were significant reductions in the following parameters: (1) the size of the cell soma as measured by the vertical and transverse diameters (17 and 12%); (2) length of the apical dendrite (27%); (3) diameter of the glomerular tuft (22%); (4) total length of the basal dendrites (18%); (5) diameter of the dendritic field of the basal dendrites (22%). The pattern of impregnation did not differ between the control OB of the experimental rats and the normal OB of normal rats. The results indicate that an absence of olfactory stimulation during the postnatal period exerts deleterious transneuronal influences on the developing mitral neurons, leading to atrophy and loss for some and diminished somatic and dendritic growth for others.
Ocular changes in the mouse embryo following acute maternal ethanol intoxication
Authors: Kennedy L. A. , Elliott M. J. 
Published: April 2003

AbstractThe development of the eye was investigated in the mouse embryo following a single administration of ethanol plus [3H]thymidine to the dam on day 13 of gestation. After 1 hr there was no difference in the number of labelled cells/100 μm2 in the neural layer of the retina compared to controls, but there was an alcohol‐related reduction in labelling density. After 24 hr there was an increase in the numbers of both pyknotic cells and mitotic figures, breaks occurred in the inner surface of the retina and cell debris was being extruded into the posterior chamber. At 48 hr the increase in pyknotic cells persisted, but there was less evidence of cell debris and the borders had been repaired. The estimated cell cycle time in the neural progenitor cells following maternal alcohol administration was increased 7‐fold compared to controls. Morphometric analysis revealed that after 48 hr there were significant alcoholrelated reductions in the width and depth of the eye, in the thickness of the neural layer and in the interocular distance. It appears that many of the ophthalmic abnormalities reported in human fetal alcohol syndrome can be produced in the mouse embryo following a single episode of acute maternal intoxication during a critical period of ocular ontogeny, and that they evolve primarily from disturbances in the normal patterns of recruitment and loss of neural progenitor cells in the developing retina.
Astroglial development in microencephalic rat brain after fetal methylazoxymethanol treatment
Authors: Eriksdotter‐Nilsson M. , Jonsson G. , Dahl D. , Björklund H. 
Published: April 2003

AbstractTreatment of pregnant rats on gestation day 15 with methylazoxymethanol (MAM) leads to a marked microencephaly in the offspring with a considerable atrophy in cerebral cortex, hippocampus and striatum. The development of the astrocytic populations in these atrophic regions was studied by means of immunohistochemistry using an antiserum against glial fibrillary acidic protein (GFA). The distribution and density of GFA‐positive structures were not notably altered in the parietal cortex, hippocampal formation and striatum after prenatal MAM‐treatment as compared to control. Also the individual astrocytes were morphologically similar in experimental and control animals in all regions analyzed. We suggest that an adjustment of the astrocytic development has occurred in response to the changed neuronal environment. Alternatively, MAM‐treatment may affect neuronal and glial precursor cells leading to a seemingly normal astrocytic cell density.
Acquisition of acoustic startle shows a dose‐response to serum free T4
Authors: Schneider Bernard F. , Golden Wendy L. 
Published: April 2003

AbstractMethimazole, administered to rats in drinking water (0.1 and 0.05%) from embryonic day 17 to postnatal day 10, caused a dose‐dependent decrease in serum Free T4 and an accompanying dose‐dependent delay in acquisition of acoustic startle reflex. In conjunction with other studies showing the specific dependence of acoustic startle development on thyroid hormone, this study suggests that the acoustic startle system may be a useful model for determining thyroid hormone requirements for normal neurologic development.
Alterations in gastric acid secretion following hepatic vagotomy at a stage of development in rats
Authors: Ohtake Masahiro , Sakaguchi Takeo 
Published: April 2003

AbstractThe relation of gastric acid secretion to the hepatic vagal section was examined in consideration of developmental stages of a rat. Acid outputs in rats deprived of food for 22 hr before the experiment were estimated with or without insulin. The animals were classified into five groups according to their body weights at the experiments (50, 100, 200, 300 and 400 g). Hepatic vagotomy was effective in decreasing acid output in all of the groups treated with food deprivation and insulin, and it was found that there was a close relationship between the output and glucose concentration in the portal blood. In rats treated only with food deprivation, hepatic vagotomy produced different effects for the five groups; the vagotomy failed to cause acid response when the rats weighed about 300 and 400 g, while in the animals weighing about 50, 100 and 200 g acid outputs were reduced following the vagotomy. It was noted that the sensitivity to hypoglycemia in the acid output was greater in the young rats than the older ones. Results suggest that function of the hepatic vagal nerve may be prominent in modulating acid secretion in an earlier stage of development when the animals are most sensitive to hypoglycemia.
Normal zinc and iron concentrations in mice after early exposure to phenobarbital
Authors: Pick Chaim G. , Statter Marian , Shachar Dorit Ben , Youdim Moussa B. H. , Yanai Joseph 
Published: April 2003

AbstractZinc and iron levels were studied in mice with early (pre/neonatal) exposure to phenobarbital, as the levels of these trace metals are known to be correlated with specific behaviors shown in our previous and present experiment to be affected by early phenobarbital administration. Mice were exposed to phenobarbital prenatally or neonatally. At adulthood they showed marked reduction from control in all parameters of eight‐arm maze performance (P < 0.001). Since zinc is known to be correlated with this behavior, it was subsequently studied in barbiturate exposed animals. The differences between barbiturate exposed and control offspring for zinc levels in plasma, brain and hippocampus did not reach statistical significance. Our previous studies have shown that the number of dopamine receptors and the resulting apomorphine‐induced climbing behavior is altered after early exposure to phenobarbital. The effect of iron level on dopamine receptors is now well established. Subsequently, a group of mice were tested for iron levels in their brain and liver. No significant differences were found.It is suggested that deficits in the hippocampal behaviors, mainly eight‐arm maze, after early exposure to phenobarbital are not related to changes in zinc levels. Similarly, early phenobarbital‐induced alternation in dopamine receptors and the resulting dopaminergic behaviors are not related to changes in iron levels.
Effects of nerve growth factor on autonomic neurons in the chick embryo: A stereological study
Authors: Dimberg Yvonne , Ebendal Ted 
Published: April 2003

AbstractQuantitative effects of nerve growth factor (NGF) on the sympathetic, Remak and ciliary ganglia in chicken embryos were investigated. Purified mouse βNGF was injected (80 μg per day for three or four consecutive days) into the yolk sac at different stages (starting on days 6, 8, 10 and 13) of embryonic development. Ganglia were taken for fixation and embedding one day after the last NGF injection. The number of neurons belonging to the different size classes was determined by a computer aided stereological method based on unfolding of cell diameter frequencies. The volume of sympathetic ganglia was increased at all stages with a maximum of 8‐fold occurring on day 10. The ganglion of Remak showed a 3‐fold volume increase up to embryonic days 10 and 12. Ciliary ganglia did not exhibit any differences in volume or neuron size between the controls and the embryos injected with NGF. The number of neurons was increased in younger sympathetic and Remak ganglia in response to NGF, as was the recruitment of neurons to the larger size classes.
Acetylcholine and choline levels in rabbit fetuses exposed to anticholinergics
Authors: McBride William G. , Hicks L. J. 
Published: April 2003

AbstractIt has been hypothesized that acetylcholine, choline acetylase and acetylcholinesterase may have an ontogenic and trophic influence in the embryo, and that therefore certain drugs may produce malformations via their effect on the acetylcholine and choline levels in the fetus. Thalidomide and the anticholinergics, scopolamine hydrobromide and orphenadrine hydrochloride, and doxylamine succinate, an antihistamine with secondary anticholinergic action, were administered to pregnant New Zealand White rabbit does from day 8 to day 15 of gestation. Ceasarean sections were performed on gestational day 16, the fetuses removed and the acetylcholine and choline contents of the fetuses and placentas were estimated by organic extraction and derivation for injection into a GCMS. These acetylcholine and choline levels were compared with those of the fetuses and placentas of the control animals mated with the same buck on the same day as the treated animals.Thalidomide (50 mg/kg) did not affect acetylcholine or choline levels in the fetuses or the placentas obtained from the treated animal. Scopolamine (approximately 100 μg/kg) reduced the choline level in the placenta and fetus but not the acetylcholine levels. Orphenadrine (approximately 24 mg/kg) reduced acetylcholine and choline levels in the fetus and choline levels in the placenta. Doxylamine succinate (10 mg/kg) reduced the acetylcholine levels in the fetus and the choline levels in the placenta.The placenta is a fetal organ and the significance of acetylcholine production by the placenta is as yet unknown. The reduction in acetylcholine levels in the fetus exposed to drugs with an anticholinergic action may be of significance in the production of malformations. However, it appears that thalidomide does not produce malformations through a change in acetylcholine levels in the fetus.
Role of glial cells in the differentiation and function of myelinated axons
Authors: Rosenbluth Jack 
Published: April 2003

AbstractMyelinated axons are highly differentiated in the vicinity of the node of Ranvier, both structurally and with respect to ion channel distribution. Evidence is reviewed showing that axonal differentiation depends upon two distinct types of interaction between glial cells and the axolemma, one at the node itself, with astrocyte processes, and the second, more extensive one, in the paranodal region, with oligodendrocyte processes. In the peripheral nervous system, Schwann cells fulfill both roles. Glial or Schwann cell abnormalities, due to genetic deficiencies, diseases or experimental procedures, result in corresponding abnormalities in the axolemma and can have devastating effects on nerve fiber function. An example, the myelin‐deficient mutant rat, is presented, and the defects underlying the profound and ultimately lethal neurological abnormalities seen in this mutant are discussed in relation to abnormalities in its axoglial interactions.
Substrate effects on the dynamics of neurite growth in vitro: A quantitative multi‐parametric analysis
Authors: Saxod Raymond , Bizet Marie‐Claude 
Published: April 2003

AbstractEmbryonic chick dorsal root ganglia were cultured in serum‐free medium on natural (collagen, fibronectin and hyaluronic acid) and artificial (polylysine and polyornithine) substrata. The movement of individual growth cones was quantified by measuring five parameters using time‐lapse cinematography combined with a digitizing‐computer system, and the neurite behaviour was compared between the different substrata with multivariate statistical methods. For each substratum, the morphometry of the growth cone was quantified by measuring six morphological parameters. The most discriminative parameters proved to be mean velocity and straightness index for neurite extension, and projected area and cumulated length of filopodia for growth cone morphometry. A good correlation was obtained between behavioural and morphological parameters and the larger the cone area and the filopodia length, the faster and the straighter the neuritic growth. Both quantitative analyses showed highest values for polyornithine and the lowest for hyaluronic acid, and divided the substrata into two opposite groups, artificial and natural. It is concluded that growth cone behaviour and conformation is modulated by substratum properties.
The effect of exogenous human ras and myc oncogenes in morphological differentiation of the rat pheochromocytoma pc12 cells
Authors: Spandidos Demetrios A. 
Published: April 2003

AbstractAn electroporation technique was employed to study the effect of oncogenes H‐ras and c‐myc after their short‐term expression in the rat pheochromocytoma PC12 cells. It was found that within 6 days after electroporation the mutant T24 H‐ras 1 gene induced differentiation of PC12 cells whereas the c‐myc blocked NGF‐induced differentiation. The induction of differentiation by the T24 H‐ras gene may suggest a physiological role of the ras gene in cell differentiation as well as in cell proliferation.
Correlated ultrastructural damage between cerebellum cells after early anticonvulsant treatment in mice
Authors: Fishman Rachelle H. B. , Ornoy Asher , Yanai Joseph 
Published: April 2003

AbstractThe anticonvulsants phenobarbital and diphenylhydantoin administered early in life to mice resulted in significant and long‐lasting ultrastructural damage, including abnormalities of mitochondria, myelin sheaths and lamellar inclusion bodies inside identified cells throughout the cortical layers of the cerebellum in treated vs control mice. The magnitude, distribution and duration of damage was age and treatment specific. No differences were detected in density of parallel fiber processes nor in synapse density within the molecular layer. Neuron profiles containing damaged organelles were not homogeneously distributed but made up only a small fraction of the total cell population examined. In our experiments, there was an overall within‐animal correlation explaining 45% of the magnitude of damage in different cerebellar regions, but between synaptically connected cells, specifically mossy fiber axon varicosities and granule cell dendrite profiles, the subset population ratio of damaged‐to‐total mitochondria was highly significantly correlated (70–90%; P<0.001). We hypothesized that some correlated transneuronal degeneration and death in the central nervous system may have a transynaptically regulated component that first appears as correlated damage between synaptically connected cells, perhaps regardless of the degree of toxicity. The orderly cytoarchitecture and cell connections of the cerebellar cortex can be used to study these patterns of degeneration.