bluuebunny/crossref_metadata_2025_split huggingface dataset:
Central projection of sensory fibers from the cat knee joint
Authors: Clark Frank J. 
Published: January 2005

AbstractThe dorsal column projections of individual primary afferent fibers from the posterior articular nerve innervating the cat knee have been studied. The majority of fibers not projecting to cervical levels in the dorsal columns supply slowly adapting receptors. These fibers undergo a reduction in conduction velocity shortly after entering the dorsal columns and terminate in the upper lumbar to lower thoracic region of the spinal cord.
Spreading depression in tissue culture
Authors: Walker Franklin D. , Hild Walther J. 
Published: January 2005

AbstractA method is described to record neuronal activity, steady potential, and the impedance of mammalian neural tissue maintained in culture without the perturbation of explants by the introduction of electrodes into the culture. A phenomenon similar, if not identical, to spreading depression is demonstrated and can be produced by a high concentration of potassium, by mechanical or electrical stimuli. The presence of neurons is not required for the characteristic dc shift and impedance changes recorded during this condition. The rate of neuronal activity in explants from various brain areas can be reduced by small additions of potassium which could be generated by neuroglia during spreading depression.
Neurite development in vitro. I. The effects of adenosine 3′5′‐cyclic monophosphate (cyclic AMP)
Authors: Roisen Fred J. , Murphy Richard A. , Braden Wanda G. 
Published: January 2005

AbstractElevated levels of 3′5′ adenosine monophosphate (cyclic AMP) stimulate a wide variety of cellular events including aggregation, differentiation, morphological expression, pigment migration, and secretion. The role of cyclic AMP in these events prompted our present study of embryonic chick dorsal root ganglia. Test substances were applied to cultures during the routine feeding procedure. Their development was quantitatively evaluated on the basis of explant size, length of glial‐like outgrowth, distribution of growth, neurite number, length, diameter, and degree of arborization. These parameters were all shown to be independent of each other. The high variability of in vitro neurite development necessitated the use of over 100 cultures per treatment group. Cultures treated with 5′ AMP exhibited no significant differences from controls. Those treated with cyclic AMP, dibutyryl cyclic AMP, or Nerve Growth Factor (NGF) exhibited statistically significant increases in area of outgrowth, the number of neurites per culture, and in diameters, lengths, and degree of neurite arborization. The growth promoting activity of dibutyryl cyclic AMP and NGF were greater than those of cyclic AMP. Electron microscopic study shows neurites formed under the influence of cyclic AMP or its dibutyryl derivative to resemble those grown in NGF. These studies suggest the possibility that cyclic AMP stimulates neurite growth by mediating the process of microtubule (MT) assembly. They further prompt us to speculate that one way NGF enhances neurite development is by stimulating MT assembly via a “Second Messenger System”.
Surface culture of fetal mammalian brain cells: Effect of subculture on morphology and choline acetyltransferase activity
Authors: Schrier Bruce K. 
Published: January 2005

AbstractCells from brains of fetal rats were grown in surfece cell culture for up to 46 days and were subjected to two subculturing cycles with mild trypsin treatment. The cells maintained their characteristic morphology into third passage, and some putative neurons developed the ability to abhere directly to plastic surfaces. The specific activity of choline acetyl‐transferase reached higher levels in third than in first passage cultures. An increase of at least 34‐fold was obtained in the total activity of enzyme, the major increments occurring during first and third passages. The data suggest that choline acetyltransferase‐producing cells may be capable of multiplication in culture.
Effects of lidocaine on axonal morphology, microtubules, and rapid transport in rabbit vagus In vitro
Authors: Byers Margaret R. , Fink B. Raymond , Kennedy Ross D. , Middaugh Mical E. , Hendrickson Anita E. 
Published: January 2005

AbstractTreatment with lidocaine, at exposures which completely block impulse conduction and rapid axonal transport, resulted in a sequence of morphological effects on rabbit vagus never in vitro. Low exposures (0.3% for 90 min, 0.4% for 45 min, 0.6% for 25 min) caused a reorientation and proliferation of smooth endoplasmic reticulum (SER); the number of axonal microtubules either remained normal or was increased. Intermediate exposures (0.4% for 90 min, 0.6% for 45 min) Produced a similar effect on the SER, as well as causing a 50% reduction in microtubule number and some swelling of axons and Schwann cells. The highest exposure (0.6% for 75 min) caused over 90% reduction in microtubule number, a partial loss of neurofilaments, and severe swelling of axons, Schwann call, and mitochondria. Reversibility of these effects was tested in lidocaine‐treated nerves that had been washed with fresh culture medium. There was good recovery of nerve exposures. After intermediate exposures, there was only partial return of rapid transport, even though imposures, there was morphological, and no recovery occured throughout the excised vagus nerve in efferent and afferent axons as well as Schwann cells, and these events did not coincide with changes in the functional state of rapid axonal transport.
Incorporation of [35S] sulfate into chondroitin sulfates by organized cultures of murine peripheral, sympathetic and central nervous tissues
Authors: Uzman Betty G. , Murray Margaret R. , Saito Hidehiko 
Published: January 2005

AbstractOrganized cultures of mouse dorsal root ganglia (PNS), cerebellum (CNS), and sympathetic chain ganglia (ANS) were exposed to feeding media containing radioactive Na235SO4 for 10 day periods beginning either at the onset of myelination or during myelin maintenance. During this period, the used medium was collected at each of three feedings and frozen. Some cultures were frozen and together with the collected medium were analyzed for mucopolysaccharides (MPS). Sister cultures were fixed in ruthenium red‐glutaraldehyde and processed for [35S] radioautography by light microscopy, and cellular localization of MPS by electron microscopy. [35S] MPS were isolated from both cultures and medium (by alkali treatment, proteolytic digestion, TCA treatment, and dialysis, followed by precipitation with cetylpyridinium chloride and ethanol). Isolated MPS were analysed by paper chromatography after digestion with chondroitinase‐ABC and testicular hyarulonidase. Fifty‐five to seventy‐five percent of the total sulfated MPS formed in all types of cultures were chondroitin sulfates (Ch‐S) A, B, and C, ChS‐A, ChS‐B, and ChS‐C are used throughout to indicate chondroitin ‐4‐ sulfate, dermatan sulfate, and chondroitin ‐6‐ sulfate, respectively
chondroitin sulfate A accounting for 50 to 60% of the total MPS. PNS and ANS exceeded CNS cultures in total sulfated MPS formed by 10:1.Qualitatively, CNS cultures produced a higher proportion of ChS‐C and a lower proportion of ChS‐B compared to PNS and ANS. Rutheniumred positive material covered all types of cell surfaces, collagen fibers, and the surfaces of enveloped axons; the layers of compact myelin and its underlying axon‐Schwann cell interface showed no such staining, though it appeared regularly in the external mesaxon.
Axoplasmic transport of RNA
Authors: Bondy Stephen C. , Madsen Carol Jean 
Published: January 2005

AbstractThe transport of RNA from the ganglion cell bodies within the retina to the contralateral optic tectum has been studied in the chick following intraocular injection of radioactive uridine. By tracing the appearance of labeled RNA at the proximal end of the optic nerve as it leaves the eyeball and comparing this to the time of arrival of RNA within the optic tectum, the migratory velocity of axonal RNA has been calculated to be around 12 mm per day. The continuation of RNA migration to the optic tectum in the presence of intracerebrally injected actinomycin‐D but not in the presence of the intraocularly injected drug, suggests a retinal site of synthesis of the excess RNA found in the tectum innervated by the injected eye. A study of the rate of disppearance of radioactivity of the transported RNA in the optic lobes, suggested that this RNA turns over more rapidly than the bulk of tectal RNA. The destination of migrating RNA within the optic tectum has been autoradiographically examined. Most radioactive RNA is found in the outer tectal layers in which are found the afferent fibers of the optic tract and most of their synaptic terminations. Label is not confined to these areas however but is also present in the deeper layers of the optic tectum which are not known to contain any primary synapses of the axons from retinal ganglion cells.
Interconversion of glycine and serine in a synaptosome fraction isolated from the spinal cord, medulla oblongata, telencephalon, and cerebellum of the rat
Authors: McBride W. J. , Daly E. , Aprison M. H. 
Published: January 2005

AbstractThe metabolism of glycine was studied in vitro using preparations of synaptosomes (P2) isolated from the spinal cord, medulla oblongata, telencephalon, and cerebellum of the rat. The content of aspartate, glutamate, glutamine, serine, threonine, glycine, and alanine was determined in the crude synaptosomal fraction (P2) from the four regions of the CNS. In general, the content of the amino acids in the subcellular fraction from the medulla oblongata and spinal cord resembled one another whereas the same was true for the telencephalon and cerebellum. Significantly greater amounts of glutamate, aspartate, glutamine, and serine were found in the synaptosomal fraction of the telencephalon and cerebellum than in similar P2 fractions from the medulla oblongata and spinal cord. On the other hand, glycine had a higher content in the latter two preparations than in the P2 fractions from the telencephalon and cerebellum. [U‐14C]‐serine and [U‐14C]‐glycine were readily taken up by the crude synaptosomal fractions. The rate of conversion of serine to glycine appeared to be 18.5, 3.9, 2.9, and 2.7 times greater than the conversion of glycine to serine in the incubated synaptosomal fractions from the cerebellum, spinal cord, medulla oblongata, and telencephalon, respectively. The conversion of serine carbons into glycine appeared to be 2.5, 1.9 and 1.6 times greater in the synaptosomal fraction from the cerebellum, spinal cord, and medulla oblongata than in similar preparations from the telencephalon. The data are discussed in terms of the possible synthesis pathway for the pool of glycine used as a transmitter.
The cholinergic excitatory and inhibitory postsynaptic responses of Aplysia ganglion cells during and after lithium‐ringer perfusion
Authors: Ono Hirohisa , Sato Makoto , Maruhashi Juro 
Published: January 2005

AbstractThe excitatory and inhibitory postsynaptic responses of Aplysia ganglion cells were elicited by either stimulating cholinergic afferent fibers or by topically applying acetylcholine (ACh) to the cell under study. The responses were evaluated as an increase in membrane conductance and compared before, during, and after perfusion with Li+‐Ringer. Excitatory postsynaptic responses were significantly depressed during 30–60 min of Li+‐Ringer perfusion. Upon return to normal Ringer, they increased sharply beyond the control, showing post‐Li+ augmentation.Inhibitory postsynaptic responses were augmented during 30–60 min of Li+‐Ringer perfusion when the cells were examined before treatment with anticholinesterase. After treatment with neostigmine, however, they were found to be also depressed in Li+‐Ringer. This finding suggested a suppressing effect of Li+‐Ringer on the acetylcholinesterase (AChE) activity.The reversal potential of ACh‐induced depolarizing response was altered from the normal value of –25 mV to –5 mV during 1–2 hr of Li+‐Ringer perfusion and gradually returned to normal value in 2–3 hr after return to normal Ringer. The reversal potential of ACh‐induced hyperpolarizing response remained practically unchanged (–62 mV) during 1–2 hr of Li+‐Ringer perfusion.Post‐Li+ augmentation of ACh‐induced depolarizing responses was explained by an increase in driving force for Na+ movement resulting from a depletion of intracellular Na+. The systematic shift of the dose‐response curves during Li+‐Ringer perfusion suggested that the affinities of both excitatory and inhibitory receptors to ACh are depressed and the effect is greater on the excitatory receptors.
Some chemical and electrophysiological effects of glutamate in cerebral cortex
Authors: Kaczmarek L. K. , Adey W. R. 
Published: January 2005

AbstractThe efflux of 45Ca2+ and 3H‐GABA from cat cerebral cortex has been measured in vivo by a superfusion technique. Under control conditions, the efflux of both these isotopes is sensitive to increments in the calcium concentration of the superfusion medium but insensitive to the addition of 25 mM GABA. After 40 min of contact with medium containing 25 mM glutamate, however, neither 45Ca2+ nor 3H‐GABA efflux is affected by added Ca2+ but 3H‐GABA efflux becomes considerably enhanced by 25 mM GABA. The mean membrane potentials at this time were found to be less than controls. Depolarization generally continued past this time, recovery beginning 150 min after superfusion with glutamate. Peaks in 45Ca2+ efflux were also correlated with seizure activity which was sometimes elicited by topical glutamate. It is suggested that the transport systems for Ca2+ and GABA may be sensitive to states of neural activity, such as spreading depression.
Physiological and pharmacological properties of Purkinje cells in rat cerebellum degranulated by postnatal X‐irradiation
Authors: Woodward D. J. , Hoffer B. J. , Altman J. 
Published: January 2005

AbstractElimination of most granule, basket, and stellate interneurons in the rat cerebellum was achieved by repeated doses of low level x‐irradiation applied during the first two weeks of postnatal life. Purkinje neurons in these rats, studied when adults, exhibited sustained spiking activity in Halothane anesthetized preparations. Mean firing rates were 35‐‐40/sec, no different from normal. Spontaneous bursts presumed to be generated by climbing fiber synaptic activity differed from normal by often consisting of full sized spikes rather than characteristic inactivation responses. Intracellularly observed correlates of bursts consisted of epsp's of several discretely different amplitudes appearing independently in time. Stimulation of white matter revealed evidence for, (a) graded synaptic excitation of Purkinje cells indicating more than one converging excitatory synapse, and (b) inhibitory actions on Purkinje cells either through a few remaining inhibitory interneurons or through Purkinje cell recurrent collaterals. Iontophoretic drug application studies showed normal chemosensitivity of the Purkinje cell membrane, i.e., excitation by glutamate and inhibition by gamma‐amino butyric acid, serotonin, norepinephrine, and 3′5′ cyclic AMP.These studies indicate considerable autonomy of Purkinje cell ontogenesis in the absence of normal interneuronal input. A unique synaptic relation only rarely found in normal cerebellum is the innervation of single Purkinje cells by more than one climbing fiber.
Electrolyte‐ and fluid‐spaces of rat brain in situ after infusion with dinitrophenol
Authors: Baethmann A. , Sohler K. 
Published: January 2005

AbstractChemical distribution measurements of radioactive sodium‐thiosulfate (35S) and of the brain water indicate that infusion of 2.4‐dinitrophenol into a carotid artery of rats caused a water uptake and fluid shifts from the extra‐ into the intracellular compartments in the central nervous system.The extracellular marker compound was administered to the brain via ventriculo‐cisternal perfusion and intravenous injection yielding almost equal concentrations in plasma‐ water and perfusate. In order to prevent an active efflux of the label from the tissue, high concentrations were utilized in the perfusate to saturate potential outward transport mechanisms. The indicator space (based on total brain water) was 16% in controls and 12% in experimental animals when marker equilibrium had been attained, which is equivalent in reduction of the extracellular space of about 1/4. Intracellular water and Na+ rose after DNP, while K+ remained all but unchanged.The fluid shift into the intracellular compartment was found to relate closely with a cellular uptake of Na+. The Na+ concentration both in plasma and in the perfusion fluid leaving the ventricular system was consistently reduced in experimental animals. The K+ concentration was significantly elevated in the plasma of experimental animals but virtually unchanged in the cisternal effluate.
Biosynthesis of catecholamines in organotypic cultures of the peripheral autonomic nervous system: Modifications by biopterin and other agents
Authors: Cöté L. J. , Benitez H. H. , Murray M. R. 
Published: January 2005

AbstractOrganotypic cultures of chick‐embryo sympathetic ganglion chains maintained in vitro for 3–4 weeks rapidly synthesized catecholamines, as demonstrated by the conversion of L‐[U‐14C]tyrosine to catechol derivatives and by histofluorescence assay. The biosynthesis of catechols from radioactive L‐tyrosine leveled off at 6 hr of incubation and dropped slightly at 10 hr. The addition of DL‐α‐methyl‐p‐tyrosine to the culture medium did not affect protein synthesis, but produced a complete block in the synthesis of catecholamines from L‐tyrosine, with consequent loss of fluorescence in the bodies and proximal processes of adrenergic neurons in 2 hr, and essentially complete loss in 6 hr. Our observations suggest that a major portion of the catecholamines were synthesized in the perikarya and transported via neuronal processes to their terminals. The addition of monoamine oxidase inhibitors to the incubation medium produced a moderate to pronounced increase in fluorescence; reserpine caused a rapid and profound loss of catecholamines. When added to the culture medium, crude biopterin produced an increase in the synthesis of catechol derivatives from radioactive L‐tyrosine and a marked increase in fluorescence, beginning in the neuronal perikarya. This effect was completely blocked by DL‐α‐methyl‐p‐tyrosine. The mechanism of biopterin's action in the synthesis of catecholamines in cultures of sympathetic ganglia is not completely elucidated from these studies, but may be related to the role it plays as cofactor for tyrosine hydroxylase.
Cooperative interaction of glutamate and aspartate with receptors in the neuromuscular excitatory membrane in walking limbs of the lobster
Authors: Shank R. P. , Freeman A. R. 
Published: January 2005

AbstractWhen applied to lobster muscle fibers, L‐glutamate, L‐aspartate, and combinations of the two amino acids can induce membrane depolarization. Under normal conditions, a quantitative analysis of the depolarization response or change in membrane conductance was precluded by nonlinearities in the voltage—current relationship of the membrane. By including γ‐aminobutyrate (GABA) in the bathing medium, the voltage—current relationship was made linear in the depolarizing direction over a range of 15–20 mV from the resting potential. However, a meaningful examination of the increase in membrane conductance caused by glutamate and aspartate was still not possible. Therefore, the depolarization responses caused by the excitatory amino acids were taken as a quantitative reflection of receptor activation in the excitatory postsynaptic membrane. In the presence of GABA, aspartate by itself, at concentrations up to 10 mM, had little excitatory activity, whereas glutamate effected an appreciable membrane depolarization at concentrations of 0.1 to 0.2 mM. Aspartate, at concentrations which exhibited no activity alone, markedly enhanced the excitatory action of glutamate. Aspartate shifted the glutamate dose‐response curve to the left, but did not appear to affect the maximum depolarization response elicited by glutamate. These observations are consistent with the concept that aspartate increases the affinity between glutamate and the glutamate binding sites. Limiting slopes of log‐dose versus log‐response curves for the excitatory action of glutamate suggest that the interaction of glutamate with excitatory receptors is a cooperative process. The possibility exists that individual receptors contain multiple and distinct glutamate and aspartate binding sites. These results support the view that neuromuscular excitation in the lobster is mediated by glutamate and asparate functioning synergistically.
Axonal transport of RNA during regeneration of the optic nerves of goldfish
Authors: Ingoglia Nicholas A. , Weis Peddrick , Mycek John 
Published: January 2005

AbstractThe distribution of radioactive RNA and RNA precursors in the goldfish optic tecta following intraocular injection of 3H‐uridine has been studied during various stages of optic nerve regeneration. 3H‐uridine was injected into the posterior chamber of the right eye 17, 30, or 60 days after both optic nerves were crushed. Fish were sacrificed at time intervals ranging from 0.5 to 21 days after injection. One day prior to sacrificing, 14C‐proline was also injected into the right eye as a marker of fast axonal protein transport. Seventeen to 23 days after crushing, the approximate time of nerve reconnection, the amount of radioactive RNA appearing in the left optic tectum was increased by more than ten times control values. Approximately 30 days after crushing the nerve, when the reconnected nerve is maturing, RNA values were still elevated, but significantly decreased from the earlier stage. By 60 days after crushing the optic nerve, the amounts of RNA in the left tectum was close to normal. Evidence suggesting that, at least, some of the radioactive RNA in the tectum originated from RNA transported along optic axons rather than from RNA synthesized locally in the tectum was provided by autoradiographic experiments. Autoradiograms of paraffin sections taken from the goldfish optic tecta after the intraocular injection of 3H‐uridine showed a distribution of grains in a linear pattern, suggesting a distribution over the incoming fibers during the reconnection stage of regeneration. Electron microscopic autoradiography of glutaraldehyde fixed epoxy sections confirmed that a significant number of grains (shown to be 3H‐RNA) were, in fact, over regenerating optic axons. Intracranial injection of 3H‐uridine, during the same stage of regeneration, on the other hand, resulted in a distribution of grains, specifically over cell perikarya. These experiments suggest that during the reconnection phase of nerve regeneration, large amounts of RNA may be carried within regenerating optic axons as they enter the optic tectum.