bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential rates of attack, defense, and counterattack during the developmental decrease in play fighting by male and female rats
Authors: Pellis Sergio M. , Pellis Vivien C. 
Published: January 2005

AbstractDuring postweaning development, rats exhibit several well documented trends in their play fighting: (1) It peaks between 30–40 days and then declines with the approach of sexual maturity; (2) males initiate more play fights than females; and (3) the overall complexity of play fights, as expressed by such measures as duration of bouts, also decreases with increasing age. Such trends could arise from changes in attack or defense, or some combination of both. In this article it is shown that (a) the decline in play fighting with the onset of sexual maturity in rats results from a decline in attack, not in defense; (b) the differences in play fighting by male and female rats are due to sex‐specific rates of both attack and defense; (c) the developmental decrease in the complexity of play fighting arises from a decrease in the frequency of counterattacks (i.e., after an animal defends itself, it is less likely to launch an attack). In this way, age and sex differences in play fighting can be traced to differences in its subcomponents.
Weaning in rats: II. Pup behavior patterns
Authors: Thiels Edda , Alberts Jeffrey R. , Cramer Catherine P. 
Published: January 2005

AbstractIn this study, litters of rat pups and their mothers were continuously video‐monitored from Day 14 to Day 35 postpartum in order to describe the behavioral changes that occur during that period. Prior to the onset of solid food intake (Day 18), pups spent most of their active time suckling. During Days 18 to 26, feeding, drinking, grooming, and play‐fighting rapidly became frequent daily activities, while suckling gradually began to decline. By Day 28, pups' food and water intake relative to body weight and time allocated to the new behaviors reached asymptote. Pups nevertheless continued to suckle until Day 34. These results suggest that (1) the transition from milk to solid food is embedded in a multitude of behavioral changes; (2) these behavioral changes have distinct temporal characteristics; and (3) the developmental period between Days 14 and 34 can be divided into three phases.Apart from the fascination and the self education of watching the developing of any form of life from its early protoplasmic simplicity into that complex maturity, there is solid scientific reason that Psychology has much to hope from minute and accurate records of the developmental periods of young animals of all species (Small, 1899).
Innate learning preferences: Signals for communication
Authors: Marler Peter 
Published: January 2005

AbstractResearch on the ways in which different species of birds learn to sing is used to illustrate the necessity of taking innate factors into account in studies of behavioral development. Experiments on two species of songbirds are described that reveal innate species differences in responsiveness to taperecorded songs. Conspecific songs are favored over those of other species. These patterns of innately varying responsiveness provide a basis for the development, not of stereotyped behavior, but of variable, individually learned behavior. The viewpoint is presented that mechanisms that differ innately from species to species, some with general functions, others specialized for particular ontogenetic assignments, provide the necessary substrates with which experience interacts.
Pre‐ and postweaning excretion of puberty‐influencing chemosignals in house mice
Authors: Drickamer Lee C. 
Published: January 2005

AbstractPre‐ and postweaning excretion urinary chemosignals that influence puberty in female house mice were tested. The dependent variable used to assess the effectiveness of urine samples collected from donor mice was the age of first vaginal estrus in young female mice. Preweaning excretion of the puberty‐delaying chemosignal by females was affected by litter sex composition; this effect interacted with the age of the young donor females. In litters of all females, the substance occurred from about the age of 9 days and in litters with 6 females and 2 males the delay substance was released from about the age of 17 days. Grouping dams during gestation but not prior to conception resulted in excretion of the puberty‐delaying substance in the female progeny from the age of 17 days or possibly earlier. Young male mice do not excrete the puberty‐accelerating chemosignal prior to the age of puberty. However, giving young males injections of testosterone resulted in an earlier first excretion of the acceleratory signal, suggesting that the machinery for chemosignal production is operative prior to the time of sexual maturity. Caging young males with an adult female prior to puberty resulted in earlier excretion of the puberty‐accelerating substance, while caging young males with adult males retarded excretion of the substance. The findings are discussed in terms of early hormone effects on behavior and with regard to consequences for the chemosignal systems in house mice. © 1992 Wiley & sons. Inc.
Contextual determinants of auditory learning in bobwhite quail embryos and hatchlings
Authors: Lickliter Robert , Hellewell Timothy B. 
Published: January 2005

AbstractThis study examined the ability of bobwhite quail embryos and hatchlings to learn an individual bobwhite maternal call. Results revealed that embryos could learn an individual maternal call and remember that call for at least 24 hr following exposure. In contrast, hatchlings reared socially in groups of same‐age chicks during postnatal exposure to a maternal call did not demonstrate a preference for that familiar call at 24 hr following exposure. However, individual auditory recognition was exhibited by hatchlings reared in social isolation, suggesting that the perceptual and social complexity of the postnatal situation can disrupt or interfere with early auditory learning. Additional support for this view was the finding that embryos exposed to unusually early visual stimulation during prenatal exposure to a maternal call also failed to prefer that familiar maternal call in subsequent choice tests. The idea that early auditory learning capacity is determined more by context and experience rather than the organism's specific age or stage of development is discussed. © 1992 Wiley & sons. Inc.
Intrauterine position effects on sexually dimorphic asymmetries of Mongolian gerbils: Testosterone, eye opening, and paw preference
Authors: Clark Mertice M. , Robertson Rohan K. , Galef Bennett G. 
Published: January 2005

AbstractA series of experiments was undertaken to both discover and explore the causes of sexually dimorphic phenotypic asymmetries in infant and adult Mongolian gerbils. We found that (1) the order in which the eyes of individual gerbil pups opened varied with their gender; right eyes of female pups opened before left eyes, while left eyes of male pups opened before right eyes, and (2) the paw that adult gerbils held in the air while maintaining a species‐typical tripedal stance varied with gender; female gerbils held their right paws in the air significantly more often than did male gerbils. Both order of eye opening and laterality of paw use while in a tripedal stance varied significantly as a function of the intrauterine position which subjects had occupied as fetuses. These data implicate exposure to testosterone as a mediator of the development of asymmetries exhibited by Mongolian gerbils. © 1993 John Wiley & Sons, Inc.
Naturalistic evaluation
Authors: Guba Egon G. 
Published: January 2005

AbstractTwo forms of naturalistic evaluation have appeared in the literature within the past decade. One form treats this perspective as a collection of usually qualitative techniques that are complementary with conventional quantitative methods. The second form represents an alternative paradigm for evaluation. It emphasizes the negotiation of multiple socially‐constructed realities, interdependence of facts and values, and the emergent character of the evaluation process.
Examining racial discrimination with fair housing audits
Authors: Yinger John 
Published: January 2005

AbstractFair housing audits, an innovative quasi‐experimental technique, have made it possible to study the incidence and intensity of housing discrimination faced by minority families. Results from the application of this technique indicate that groups such as black, Hispanic, and Asian Americans face substantial discrimination in terms of the number, types, and location of housing units they are shown by realtors.
Coexpression of glial fibrillary acidic protein and vimentin in the central and peripheral nervous systems of the twitcher mutant
Authors: Chiu F.‐C. , Sacchi R. S. , Claudio L. , Kobayashi S. , Suzuki K. 
Published: January 2005

AbstractA method to purify glial fibrillary acidic protein (GFAP) from mouse spinal cord is described, which permits the measurement of GFAP in the sciatic nerve of the twitcher mutant and control mouse. Cytoskeletal proteins from sciatic nerves and purified GFAP standards were electrophoresed on gel, transferred to nitrocellulose paper, and immunostained with anti‐GFAP antibody. From the immunostained, 51,000‐dalton band, we estimated about 200 ng GFAP per 50 μg of cytoskeletal protein in the twitcher sciatic nerve. The control nerve showed no detectable GFAP. Double‐labeled fluorescence immunocytochemistry showed that in the brainstem of twitcer mutant, GFAP and vimentin were coexpressed in the majority of astrocytes.
Distribution of orthogonal arrays of particles in the Müller cell membrane of the mouse retina
Authors: Wolburg Hartwig , Berg Karin 
Published: January 2005

AbstractIn the present study we investigated the Müller cell membrane of the mouse retina by freeze‐fracturing. The mouse retina is vascularized and the vessels running outside the nerve fiber layer are completely encased by Müller cell endfeet. Orthogonal arrays of particles (OAP) reside in all membrane areas of the Müller cells. The paravitreous as well as the pericapillary endfeet reveal a considerably higher density of OAP than the nonendfoot membranes including the perikaryal ones. This is in contrast to the Müller cell membrane of the rabbit retina studied previously (Wolburg and Berg: Neurosci. Lett., 82:273–277, 1987). There we found a completely different distribution of OAP; practically all OAP reside in the endfoot membrane facing the vitreous body. The nonendfoot and perikaryal membranes were devoid of OAP. The OAP distribution in both species corresponds roughly to the distribution of the K+ conductances measured by Newman (J. Neurosci., 7:2423–2432, 1987). The putative relationship between OAP and K+ channels, including functional aspects, is discussed.
Neurons from substantia nigra increase the efficacy and potency of second messenger arising from striatal astroglia dopamine receptor
Authors: Hansson Elisabeth , Rönnbäck Lars 
Published: January 2005

AbstractDopamine (D1) receptors were demonstrated to be present on astroglial cells from striatum in primary culture. In a cocultivation system, the astrocytes were influenced by neurons from one of their natural projection areas (substantia nigra) to increase the efficacy and potency of second messenger (cyclic AMP) from the dopamine receptor. This provides evidence for a heterogeneity among astroglia from the various brain regions with respect to the expression of receptors.
Astroglial differentiation in the opossum superior colliculus
Authors: Barradas Penha C. , Cavalcante Leny A. , Mendez‐Otero Rosalia , Vieira Alex M. 
Published: January 2005

AbstractGlial markers, namely, vimentin, glial fibrillary acidic protein (GFAP), and glycogen, as well as accumulation of axon‐borne horseradish peroxidase (HRP), were used to visualize radial glial cells in the developing opossum superior colliculus (SC) and to follow changes in young astrocytes of the superficial layers. Vimentin, GFAP, and glycogen are relatively abundant in elements of the median ventricular formation (MVF), which persists at least as late as weaning time, i.e., postconception day 103, postnatal day 90 (PND90). Radial profiles and end‐feet in the remaining collicular sectors (main radial system, MRS) are also vimentin‐positive but show little or no glycogen or anti‐GFAP staining. The numeric density of MRS profiles is very high at the final stages of neuronal migration (PND12) but falls to vestigial numbers by PND 56–60. Antivimentin staining and filling of MRS profiles by axon‐borne HRP disappear in parallel. Before total regression of MRS profiles, young astrocytes of the superficial gray layer exhibit a transiently high GFAP expression that is not found in those of the subjacent layers. The results suggest that (1) radial glia at or near the collicular midline are well equipped for a mechanical supportive role, and their abundant glycogen accumulation may reflect their eventual transformation in cells with high glycolytic metabolism, including tanycytes; (2) in most collicular sectors, some radial glia cells persist for long periods after cessation of neuronal migration and may interact with afferent fibers coursing through the superficial neuropil; (3) radially oriented astrocytes of the superficial gray layer exhibit a transiently high GFAP expression that is temporally correlated with late transformations of the retinocollicular projections.
Uptake, metabolism, and release of [3H]‐histamine by glial cells in primary cultures of chicken cerebral hemispheres
Authors: Huszti Zsuzsanna , Rimanóczy Ágnes , Juhász Anna , Magyar Kálmán 
Published: January 2005

AbstractLabelled histamine was taken up into cultured glial cells of chick embryonic brain by a system with high affinity for histamine and diffusion. The active uptake, occurring at low concentrations of the amine, was Na+ dependent and gave an apparent Km of 0.24 μM and a Vmax of 0.31 pmol X mg protein−1 X min−1. The uptake was completely blocked by desmethylimipramine (Ki = 2.5 μM) and partially by the histamine agonists and histamine‐N‐methyltransferase blockers 4‐methylhistamine and 2‐methylhistamine (I30 values obtained were 2 μM and 5 μM). Other psychoactive drugs were either ineffective (imipramine) or they showed moderate inhibitory effects (amitryptyline and cocaine). Ouabain (100 μM) inhibited uptake by ∼50%. Diffusion occurred at high concentrations of the amine, was insensitive to extracellular Na+, and was proportional to histamine concentration up to 1 mM.[3H]‐Histamine, taken up into the cells, was metabolized and/or released. The spontaneous efflux of the radioactivity measured after 10 min of exposure to [3H]‐histamine (when most of it was still unmetabolized), was moderately Ca++ dependent, accelerated by both reduced concentrations of extracellular Na+ and enhanced concentrations of K+ and inhibited by desmethylimipramine. After prolonged (60 min) incubation, histamine metabolites detected in the cells presented 78% of the chromatogram radioactivity and consisted of Nτ‐methylhistamine and Nτ‐methylimidazole acetic acid.These results indicate that at low nM concentrations, histamine is taken up and metabolized by (and released from) glial cells by an Na+‐dependent system, and the intracellular metabolism seems to serve an increased uptake of the amine.
Glutamine synthetase immunoreactivity is present in oligodendroglia of various regions of the central nervous system
Authors: D'Amelio Fernando , Eng Lawrence F. , Gibbs Michael A. 
Published: January 2005

AbstractGlutamine synthetase immunoreactive oligodendrocytes were identified in the cerebral cortex, cerebellum, brain stem, and spinal cord. They were mostly confined to the gray matter, particularly close to neurons and processes. The white matter showed few immunoreactive oligodendroglia. It was suggested that some type of oligodendrocytes, specially those in perineuronal location, might fulfill a functional role more akin to astrocytes than to the normally myelinating oligodendroglia.
Extracellular potassium influences DNA and protein syntheses and glial fibrillary acidic protein expression in cultured glial cells
Authors: Canady Karen S. , Ali‐Osman Francis , Rubel Edwin W. 
Published: January 2005

AbstractPrevious reports of increases in glial cell number and expression of glial fibrillary acidic protein (GFAP) in stimulated brain regions or epileptic tissue have implicated a role for increases in extracellular potassium concentration ([K+]o) in glial reactions. We examined the effects of altered [K+]o on DNA and protein syntheses and GFAP expression of cultured glial cells isolated from the posthatch chick brain stem. [K+]o was varied by adding both KCl and NaCl to K+, NaCl‐free medium to achieve final [K+] of 1–50 mM. DNA and protein syntheses were measured by incorporation of 3H‐thymidine and 3H‐leucine, respectively, into acid‐insoluble material. GFAP expression was measured by a dot‐immunoblotting assay. DNA synthesis in glial cells cultured in high (5–50 mM) K+o was 45–60% less than that of cells cultured in low (1–3 mM) K+o. Protein synthesis per cell was increased 34–44% in cells cultured in high K+ as compared to those cultured in low K+. GFAP expression was inversely related to [K+]o over the 1–10 mM range. Compared to the baseline of 3 mM K+o, GFAP per cell was increased 65% at 1 mM and decreased 45% at 10 mM. These data suggest that increases in glial cell number and GEAP immunoreactivity found in sites of increased neuronal activity and in pathological tissues may not be caused solely by persistent increases in [K+]o. Instead, these results suggest that neuronal activity, through the release of K+, may have an inhibitory influence on glial proliferation and GFAP expression. In light of work by others implying a relationship between GFAP immunoreactivity and rigidity of astroglial processes together with the data presented here, we suggest that the elevated [K+]o accompanying neuronal activity, by inhibiting GFAP expression, may facilitate the morphological plasticity of glial cells. Conversely, conditions of low [K+]o may contribute to rigidity of astrocytic processes.
Stretch‐activated channels in human retinal muller cells
Authors: Puro Donald G. 
Published: January 2005

AbstractThe cell‐attached and excised patch configurations of the patch clamp technique were used to study stretch‐activated ion channels in Muller glial cells that were obtained from postmortem adult human retinas and were maintained in culture. A stretch‐activated channel permeable to monovalent and divalent cations was found. Ion channels of this type have not been demonstrated previously in glial cells, though indirect evidence has suggested that such stretch‐activated channels may help mediate a compensatory response of glia to swelling. Consistent with a possible role for volume regulation is the finding that the activation of calcium‐permeable stretch‐sensitive channels is associated with an increase in the activity of calcium‐activated potassium channels. Activation of potassium channels to produce an efflux of potassium with a subsequent loss of anions and cell water could be an effective mechanism to decrease glial cell volume.
Uptake of [3H]serotonin and [3H]glutamate by primary astrocyte cultures. II. Differences in cultures prepared from different brain regions
Authors: Amundson R. H. , Goderie S. K. , Kimelberg H. K. 
Published: January 2005

AbstractRegional astrocyte cultures were derived by dissecting six regions; brain stem, cerebellum, mesencephalon, basal ganglia plus diencephalon, cerebral cortex, and hippocampus, from 3 to 4‐day‐old neonatal rat brains. Glial fibrillary acidic protein (GFAP) immunocytochemistry was used to confirm the astrocyte composition of the cultures. The percentage of GFAP (+) cells between regions varied from 75% to 100%. Once confluent these cultures were incubated with radiolabeled serotonin or glutamate for uptake and autoradiographic studies. For the different brain regions Na+‐dependent, [3H] L‐glutamate, and fluoxetine‐sensitive [3H] 5‐HT uptake varied markedly. The relative order of uptake for [3H] 5‐HT was MS (mesencephalon) > CC (cerebral cortex) > BG + DI (basal ganglia + diencephelon) > HP (hippocampus) > BS (brain stem) > CB (cerebellum). For [3H] L‐glutamate the order was HP > CC > BG + DI > MS = BS > CB. For [3H] 5‐HT this essentially corresponds to the reported order of binding in situ of the [3H] 5‐HT‐specific uptake ligand [3H] citalopram. For [3H] L‐glutamate regional variation of the uptake for the different cultures corresponds to the regional uptake reported for different regions of rat brain. Double‐label studies with GFAP and radiolabeled neurotransmitters were also used to study uptake into GFAP(+) astrocytes by autoradiography. Flat GFAP cells with or without processes comprised 65–98% of the cultures and represented most of the uptake. The percentage of all GFAP(+) cells that were positive for uptake of ARG varied from 50% to 90% and also showed differences in grain density both intra‐ and inter‐regionally. These differences in transmitter uptake by GFAP(+) astrocytes in primary culture, which are dependent on the region of origin and correspond to regional differences in situ, suggest that such uptake in vitro may reflect uptake by astrocytes in vivo. Implied in this is that uptake by astrocytes represents a significant component of serotonin uptake in vivo. © 1992 Wiley‐Liss, Inc.
Intracellular pH regulation in single cultured astrocytes from rat forebrain
Authors: Boyarsky Gregory , Ransom Bruce , Schlue Wolf‐R. , Davis Marion B. E. , Boron Walter F. 
Published: January 2005

AbstractWe used the fluorescent pH‐sensitive dye 2′,7′‐bis(carboxyethyl)‐5,6‐carboxyfluorescein (BCECF) to monitor intracellular pH (pHi) in single astrocytes cultured from the forebrain of neonatal rats. When exposed to a nominally CO2/HCO3− ‐free medium buffered to pH 7.40 with HEPES at 37°C, the cells had a mean pHi of 6.89. Switching to a medium buffered to pH 7.40 with 5% CO2 and 25 mM HCO3− caused the steady‐state pHi to increase by an average of 0.35, suggesting the presence of a HCO3− ‐dependent acid‐extrusion mechanism. The sustained alkalinization was sometimes preceded by a small transient acidification. In experiments in which astrocytes were exposed to nominally HCO3−‐free (HEPES‐buffered) solutions, the application and withdrawal of 20 mM extracellular NH4+ caused pHi to fall to a value substantially below the initial one. pHi spontaneously recovered from this acid load, stabilizing at a value ∼ 0.1 higher than the one prevailing before the application of NH4+. In other experiments conducted on cells bathed in HEPES‐buffered solutions, removing extracellular Na+ caused pHi to decrease rapidly by 0.5. Returning the Na+ caused pHi to increase rapidly, indicating the presence of an Na+‐dependent/HCO3−‐independent acid‐extrusion mechanism; the final pHi after returning Na+ was ∼ 0.08 higher than the initial value. This pHi recovery elicited by returning Na+ was not substantially affected by 50 μM ethylisopropylamiloride (EIPA), but was speeded up by 50 μM 4,4′‐diisothiocyanostilbene‐2,2′‐disulfonate (DIDS). Increasing [K+]− from 5 to 25 mM caused pHi to increase reversibly by ∼ 0.2 in nominally CO2/HCO3−‐free solutions, and by ∼ 0.1 in CO2/HCO3−‐containing solutions, although the initial pHi was ∼ 0.17 higher in the presence of CO2/HCO3‐. These results suggest the presence of a depolarization‐induced alkalinization. Our results suggest the presence of both HCO3− dependent and ‐independent acid‐base transport systems in cultured mammalian astrocytes, and indicate that astrocyte pHi is sensitive to changes in either membrane voltage or [K+]0 per se. © 1993 Wiley‐Liss, Inc.