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1.
D. J. GALLEY 《The Annals of applied biology》1974,76(2):171-178
Brevicoryne brassicae and Myzus persicae removed similar quantities of 32 P-labelled material from Brussels sprout leaves whether they fed for 24 or 48 h periods. They also removed similar quantities from untreated leaf disks as from leaf disks treated with a sub-lethal dose of menazon. When a lethal dose was used, the uptake of 32 P by B. brassicae was significantly less than by M. persicae. M. persicae excreted a greater proportion of 32 P label in the honeydew than B. brassicae and a greater proportion of the amount absorbed was lost in the progeny of this aphid than in B. brassicae.
B. brassicae was 6.2 times more susceptible than M. persicae to dimethoate acting systemically. When it was applied topically the aphids were equally susceptible.
Considerable variation in uptake of32 P occurred between replicates and the factors that could influence this are discussed. 相似文献
B. brassicae was 6.2 times more susceptible than M. persicae to dimethoate acting systemically. When it was applied topically the aphids were equally susceptible.
Considerable variation in uptake of
2.
Ageing of potato tuber discs markedly increases the rate of phosphate uptake. This increase is partially prevented by the presence of indoleacetic acid (IAA: 50 μ M ) in the ageing medium. 32 P distribution among the various phosphorylated fractions (P1 , organic soluble phosphate, acid-insoluble phosphate) was carried out after 24 h of ageing in the presence of IAA. An equal inhibition of the labelling rates of each of the different fractions is induced by the hormone. No important effect on respiration and ATP content was observed. Moreover, IAA neither changes the total phospholipid content nor the relative distribution of 32 P between the components. These results support the hypothesis that IAA acts specifically on the development of uptake mechanisms during the ageing period. 相似文献
3.
Biochemistry of an Olfactory Purinergic System: Dephosphorylation of Excitatory Nucleotides and Uptake of Adenosine 总被引:2,自引:1,他引:1
Henry G. Trapido-Rosenthal William E. S. Carr Richard A. Gleeson 《Journal of neurochemistry》1987,49(4):1174-1182
Abstract: The olfactory organ of the spiny lobster, Panu-lirus argus , is composed of chemosensory sensilla containing the dendrites of primary chemosensory neurons. Receptors on these dendrites are activated by the nucleotides AMP, ADP, and ATP but not by the nucleoside adenosine. It is shown here that the lobster chemosensory sensilla contain enzymes that dephosphorylate excitatory nucleotides and an uptake system that internalizes the nonexcitatory dephosphorylated product adenosine. The uptake of [3 H]-adenosine is saturable with increasing concentration, linear with time for up to 3h, sodium dependent, insensitive to moderate pH changes and has a K m of 7.1 μ M and a Vmax of 5.2 fmol/sensillum/min (573 fmol/μg of protein/min). Double-label experiments show that sensilla dephosphorylate nucleotides extracellularly; 3 H from adenine-labeled AMP or ATP is internalized, whereas 32 P from phosphate-labeled nucleotides is not. The dephosphorylation of AMP is very rapid; 3 H from AMP is internalized at the same rate as 3 H from adenosine. Sensillar 5'-ectonucleotidase activity is inhibited by ADP and the ADP analog α,β-methylene ADP. Collectively, these results indicate that the enizymes and the uptake system whereby chemosensory sensilla of the lobster inactivate excitatory nucleotides and clear adenosine from extracellular spaces are very similar to those present in the internal tissues of vertebrates, where nucleotides have many neuroactive effects. 相似文献
4.
EFFECTS OF DENERVATION ON THE INCORPORATION OF 32 P INTO PHOSPHATIDYL INOSITOL AND OTHER PHOSPHOLIPIDS OF RAT DIAPHRAGM 总被引:1,自引:0,他引:1
Abstract— At 24 h after denervation of the rat hemidiaphragm, incorporation of 32 P into phosphatidyl inositol was depressed relative to incorporation of 32 P into phosphatidyl choline (measured 75 min after injection of the isotope intraperitoneally). The ratio of the specific radioactivity of phosphatidyl choline to the specific radioactivity of Pi was unaffected by denervation which implies that denervation had depressed incorporation of isotope into phospatidyl inositol. Denervation did not cause a measurable change in the pool size of phosphatidyl inositol relative to that of phosphatidyl choline. The effect of denervation on incorporation of 32 P into phosphatidyl inositol was not entirely a direct consequence of the cessation of ACh release at the motor end-plate since the effect was clearly manifest in strips of muscle not containing motor end-plates, but the magnitude of the denervation effect was slightly greater in the strips of denervated hemidiaphragm which contained motor end-plates. 相似文献
5.
Phosphorus translocation in salt-stressed cotton 总被引:6,自引:0,他引:6
The effect of salinity on plants has usually been studied at high inorganic P concentration ([Pi]) in the nutrient solution, and salinity × Pi interactions have been examined at much higher [Pi] than found in soil solutions. Short-term 32 Pi experiments were carried out to study the effect of salinity (150 m M NaCl) on phosphorus translocation in cotton plants ( Gossypium hirsutum L. cv. Acala SJ-2) grown in nutrient solutions containing 10 μ M [Pi]. The effect of additional Ca to a concentration of 10 μ M was also tested. Salinity inhibited 32 P translocation from root to shoot. This inhibition was more evident at higher [Pi] in the root medium. Increasing [Pi] 33-fold in the solution resulted in a 4.3-fold increase in [32 P] in the root under saline conditions, but only in a 1,8-fold increase in the shoot. In older shoot tissues total [P] was elevated in the salinized plants. In the young tissues, however, total P concentration was higher in control plants. Inhibition of 32 P translocation by salinity was greater from root to young leaves than to mature shoot tissues. Salinity also decreased 32 P recirculation from the cotyledons to the young leaf. Inhibition by salinity of both 32 P translocation and recirculation to young leaves was fully reversed by increasing Ca supply from 1 to 10 相似文献
6.
JOSEPH DONNELLY 《The Annals of applied biology》1958,46(2):243-253
1. A simple method of radioactive labelling of L. sericata larvae is described.
2. More uniform count levels are obtained in individuals which have fed entirely on radioactive foods than in those which first feed on non-active food.
3. The radioactive count rates of the larvae are correlated with larval live weight and the counting rates of resulting imagines correlated both with corresponding larval counting rates and with imaginal live weight.
4. The loss of32 P in the larvae due to causes other than decay of the isotope is traced from the prepupal stage to 3 weeks after emergence. The first and major loss occurs at emergence, when about 10% of the original 31 P is shed as empty puparium and meconium. Adults lose about 1.5% per day.
5. The distribution of32 P in the adult body of L. sericata labelled in the larval stage has been determined. The abdominal tissues have a lower activity than the rest of the body. 相似文献
2. More uniform count levels are obtained in individuals which have fed entirely on radioactive foods than in those which first feed on non-active food.
3. The radioactive count rates of the larvae are correlated with larval live weight and the counting rates of resulting imagines correlated both with corresponding larval counting rates and with imaginal live weight.
4. The loss of
5. The distribution of
7.
Maria Mercedes Fernandez Samperiz Guilherme Blumen Jose Merzel 《Cell proliferation》1985,18(5):493-503
Abstract. The effects of vinblastine on the cell cycle and the migration of ameloblasts were studied in the lower incisors of mice by labelling the cells with 3 H-thymidine ([3 H]TdR) and radioautography. A group of mice received 2 μg/g of body weight vinblastine intraperitoneally and 6 hr after these animals and those of a control group were injected with 1μCi/g body weight of [3 H]TdR, and sacrificed at time intervals from 0.75 hr to 15 days.
The generation time of ameloblasts in the progenitor compartment was 14.8 hr in animals treated with vinblastine and 17 hr in the controls, using the FLM curve method; with the grain dilution method the duration was respectively 29.25 hr and 25.96 hr. the thymidine labelling index of the treated animals was 50% higher than the controls. the velocity of ameloblast migration, determined either by the displacement of the most incisally labelled cell or by the grain dilution method, was lower in the experimental group (2.48 cell positions/hr and 9.18 μ/hr respectively) as compared with the control (3.21 cell positions/hr and 18.88 μm/hr respectively).
The results on the ameloblast production rate are contradictory but the slowing down in the velocity of cell migration is compatible with a decrease of the rate of cell production in the progenitor compartment as a vinblastine effect. 相似文献
The generation time of ameloblasts in the progenitor compartment was 14.8 hr in animals treated with vinblastine and 17 hr in the controls, using the FLM curve method; with the grain dilution method the duration was respectively 29.25 hr and 25.96 hr. the thymidine labelling index of the treated animals was 50% higher than the controls. the velocity of ameloblast migration, determined either by the displacement of the most incisally labelled cell or by the grain dilution method, was lower in the experimental group (2.48 cell positions/hr and 9.18 μ/hr respectively) as compared with the control (3.21 cell positions/hr and 18.88 μm/hr respectively).
The results on the ameloblast production rate are contradictory but the slowing down in the velocity of cell migration is compatible with a decrease of the rate of cell production in the progenitor compartment as a vinblastine effect. 相似文献
8.
We investigated the degree to which developing fruit compete directly with leaves for mineral nutrients, e.g. phosphate coming up from the roots. When soybean ( Glycine max (L.) Merrill cv. Anoka) explants cut at mid-late podfill were given a 15-min pulse of 32 Pi via the cut stem and then transferred to distilled water, 75% of the 32 P accumulated in the leaves and 21% in stem and petiole during the first hour. The amount of 32 P entering the seeds was low (1%) initially, but thereafter increased to 30% in 48 h. An accumulation of 32 P in the seed coats preceded its entry into the embryos. Disruption (with hot steam) of the phloem between the leaf and the pods after pulse labelling indicated that more than 80% of the 32 Pi pulse moved to the leaf before redistribution to the pods. Increasing "sink" size by adjusting the pod load from 1 to 2–3 did not increase the 32 P accumulated by the pods proportionally. Conversely, excision of the seeds after pulse labelling did not prevent translocation of 32 P out of the leaves. These results suggest that the rate of transport of phosphate to the pods at mid-late podfill is controlled primarily by factors in the leaves. The results are consistent with the observation that the relative size of the sink (pod load) does not regulate leaf senescence. 相似文献
9.
The Phosphorylation of Proteins in Hippocampal Slices: Effects of Noradrenaline and of Pretreatment with Kainic Acid 总被引:1,自引:1,他引:0
Abstract: Hippocampal slices were incubated in the presence of [32 P]Pi , and protein phosphorylation was examined by means of sodium dodecyl sulfate-gel electrophoresis. Incubation for at least 30 min with 300 μCi of [32 P)Pi /brain slice gave rise to the phosphorylation of 8–10 protein bands. Most of these bands showed enhanced phosphorylation in response to noradrenaline. The basal phosphorylation of kainic acid-pretreated hippocampal slices was enhanced two- to threefold compared with controls. There was also an additional increase in kainic acid-pretreated slices in the response to noradrenaline. 8-Br-Cyclic AMP and phosphodiesterase inhibitors, such as papaverine or isobutylmethyl-xanthine, had no effect on the phosphorylation patterns. 相似文献
10.
Abstract— Guinea pig brain nerve-ending particles (synaptosomes) were incubated with [32 P]orthophosphate in a medium with or without 10−4 M-acetylcholine and 10−4 M-eserine. Phospholipids were then extracted and separated by chromatography. About 60 per cent of the 32 P was found in phosphatidic acid and about 20 per cent in triphosphoinositide. Acetylcholine significantly increased the specific radioactivity of phosphatidic acid but had no effect on that of phosphatidylinositol or the nucleotide fraction. Labelling of the other phospholipids, including diphosphoinositide and triphosphoinositide, was not altered significantly by acetylcholine. Labelling of the nucleotide fraction and the polyphosphoinositides reached a peak at 40 min, that of phosphatidic acid at 80 min, while that of phosphatidylinositol was still rising at 160 min. 相似文献
11.
Receptor-mediated increases in phosphatidylinositol turnover in neuron-like cell lines 总被引:6,自引:4,他引:2
Abstract: Muscarinic receptors found in the N IE-115 mouse neuroblastoma cell line were tested for their ability to mediate stimulation of phosphatidylinositol (PI) turnover. This study was facilitated by the development of a new solvent system (acetone: butanol: acetic acid: water, 5: 5: 1: 1) for the rapid and consistent separation of PI by one-dimensional thin-layer chromatography. Cholinergic stimulation caused as much as a 680% increase in the incorporation of 32 P into PI. Enhanced incorporation of 32 P into PI could be measured as early as 4 min after stimulation began. By 20 min, the rate of incorporation by stimulated cells had decreased to that of unstimulated cells, indicating desensitization. The magnitude of the response was dependent on the extent of receptor occupancy and the response elicited by a saturating dose of carbamylcholine was blocked completely by 10−7 M at-ropine, a specific muscarinic antagonist. Chronic stimulation, known to cause a loss of receptor binding sites, led to a 90% decrease in the maximum response even after a 40-min withdrawal period. Replacement of Na+ ions in the medium with choline or K+ severely impaired the ability of the cells to incorporate added 32 P into PI (90 and 50%, respectively). Removal of the putative second messenger Ca2+ for short periods of time by the addition of excess EGTA did not alter either basal or muscarinic-stimulated PI turnover. 相似文献
12.
1. Phosphorus (P) uptake by macrophytes and epiphytes from the LaPlatte River (VT) was examined in the laboratory by adding 32 PO4 ‐P to recirculating stream microcosms.
2. Water, plugs of sediment and plants were removed from the river and placed into the microcosms.32 PO4 ‐P was then added either to the water or the sediment, and its incorporation into plants and epiphytes was monitored over 3 days. Uptake was examined at both ambient (5 μg L–1 ) and increased (50 μg L–1 ) soluble reactive phosphorus (SRP) concentrations. A computer program was developed to fit curves to the radiotracer data and calculate rate constants for the simultaneous transfer of 32 P among compartments.
3. Both macrophytes and epiphytes removed P from the water, but epiphyte uptake of P was more rapid. Phosphate enrichment stimulated P uptake by both macrophytes and epiphytes. Macrophytes also obtained P from the sediment. The relative contribution of P to macrophytes from the water vs. that from the sediment appeared to vary with SRP in the overlying water. Accurate estimates of rates of P uptake from sediments by macrophytes were difficult to obtain however, due to very low and highly variable unit rate constants for P uptake and uncertainty about the magnitude of the phosphate pool available for uptake.
4. SRP concentrations were greater in the overlying water than in the sediment pore water of stream microcosms in the present study. Numerous reports in the literature have suggested that this condition favours uptake by macrophyte stems and leaves rather than by roots.
5. Phosphate uptake from the water by macrophytes in shallow streams may be more common than for macrophytes in lakes. 相似文献
2. Water, plugs of sediment and plants were removed from the river and placed into the microcosms.
3. Both macrophytes and epiphytes removed P from the water, but epiphyte uptake of P was more rapid. Phosphate enrichment stimulated P uptake by both macrophytes and epiphytes. Macrophytes also obtained P from the sediment. The relative contribution of P to macrophytes from the water vs. that from the sediment appeared to vary with SRP in the overlying water. Accurate estimates of rates of P uptake from sediments by macrophytes were difficult to obtain however, due to very low and highly variable unit rate constants for P uptake and uncertainty about the magnitude of the phosphate pool available for uptake.
4. SRP concentrations were greater in the overlying water than in the sediment pore water of stream microcosms in the present study. Numerous reports in the literature have suggested that this condition favours uptake by macrophyte stems and leaves rather than by roots.
5. Phosphate uptake from the water by macrophytes in shallow streams may be more common than for macrophytes in lakes. 相似文献
13.
Chemosensory Adaptation to Lysozyme and GTP Involves Independently Regulated Receptors in Tetrahymena thermophila 总被引:1,自引:0,他引:1
HEATHER G. KURUVILLA MARK Y. KIM TODD M. HENNESSEY 《The Journal of eukaryotic microbiology》1997,44(3):263-268
ABSTRACT. Chemosensory adaptation is seen in Tetrahymena thermophila following prolonged exposure (ten minutes) to micromolar concentrations of the chemorepellents lysozyme or guanosine triphosphate (GTP). Since these cells initially show repeated backward swimming episodes (avoidance reactions) in these repellents, behavioral adaptation is seen as a decrease in this repellent-induced behavior. The time course of this behavioral adaptation is paralleled by decreases in the extents of surface binding of either [32 P]GTP or [3 H]lysozyme in vivo. Scatchard plot analyses of repellent binding in adapted cells suggests the behavioral adaptation is due to a dramatic decrease in the number of surface binding sites, as represented by decreased Bmax values. The estimated KD values for nonadapted cells are 6.6 μM and 8.4 μM for lysozyme and GTP binding, respectively. Behavioral adaptation and decreased surface receptor binding are specific for each repellent. The GTP adapted cells (20 μM for ten minutes) still respond behaviorally to 50 μM lysozyme and bind [3 H]lysozyme normally. Lysozyme adapted cells (50 μM for ten minutes) still bind [32 P]GTP and respond behaviorally to GTP. All the behavioral and binding changes seen are also reversible (deadaptation). Neomycin was shown to be a competitive inhibitor of [3 H]lysozyme binding and lysozyme-induced avoidance reactions, but it had no effect on either [32 P]GTP binding or GTP-induced or avoidance reactions. These results are consistent with the hypothesis that there are two separate repellent receptors, one for GTP and the other for lysozyme, that are independently downregulated during adaptation to cause specific receptor desensitization and consequent behavioral adaptation. 相似文献
14.
CHRISTY SUSHEELA KUNTHALA JAYARAMAN 《Differentiation; research in biological diversity》1976,5(1):29-33
Activation of the dormant embryos of Artemia salina was marked by a rapid increase in 32 P uptake which reached a stationary phase after 6 h of activation. The increase in 32 P uptake by whole cysts was paralleled by its incorporation into nucleotides. Fractionation of acid-soluble nucleotides and alkaline hydrolysate of nucleic acids on Dowex-1-formate column revealed the 32 P radioactivity to be exclusively localised in AMP. Analysis of the labelled RNA species extracted at different stages of development indicated a preferential labelling of small molecular weight species till the emergence of the embryos, followed by the de novo synthesis of messenger and stable RNA species in later stages of development. During early development, polyadenylated RNA species were localised in the par-ticulate fraction sedimenting at 16,000 rpm and their location shifted to the soluble fraction as development proceeded. Activation of preformed messengers by phosphorylation of the adenylate residue of their poly A stretches and translocation of the capacitated messengers to the cytosol via a RNP-membrane complex is proposed as a trigger of embryonic differentiation. 相似文献
15.
THE SELECTIVE NEURONAL UPTAKE AND RELEASE OF [3 H]DL-2,4-DIAMINOBUTYRIC ACID BY RAT CEREBRAL CORTEX 总被引:2,自引:0,他引:2
Abstract— At 25°C the accumulation of [3 H] dl -2,4-diaminobutyric acid (DABA) into small rat cortical slices was linear with time and a tissue: medium ratio of 35:1 was attained after 60 min. At 37°C the uptake was no longer linear and the tissue: medium ratio at 60 min was 66:1. Uptake was unaffected by the addition of 10 μ m -AOAA and dependent on the presence of Na+ in the incubation media. The uptake was shown to have a high affinity component with a K m of 20.7 μ m and a V max of 28.6 nmol/g/min. IC50's for the inhibition of [3 H]DABA uptake by dl -DABA, l -DABA and GABA were 80, 40 and 17 μ m respectively. Two m m β -alanine, however, caused less than 13% inhibition of [3 H]DABA uptake. Electron microscopic autoradiographs showed the [3 H]DABA to be accumulated by 22% of the identifiable nerve terminals and, after 14 days exposure, the density of silver grains over nerve terminals was 36–38 times higher than that over the rest of the electron micrograph. On the other hand, [3 H]DABA was not taken up into rat sensory ganglia and light level autoradiography showed the small amount of [3 H]DABA accumulated by the ganglia to be evenly distributed throughout the tissue. Both electrical stimulation for 30 s and exposure of the tissue to a medium containing 47 m m -K+ for 2 min caused a marked increase in the efflux of [3 H]DABA from the tissue. Both these effects were abolished by a reduction in Ca2+ concentration and an increase in the Mg2+ concentration of the superfusing medium. These results suggest that l -DABA acts as a 'false transmitter' for the neuronal uptake, storage and release of GABA. 相似文献
16.
UPTAKE OF CALCIUM BY SUBCELLULAR FRACTIONS ISOLATED FROM OUABAIN-TREATED CEREBRAL TISSUES 总被引:2,自引:1,他引:1
Abstract— Slices of cerebral cortex were incubated in medium containing 0·75 or 2·8 mM 45 CaCl2 , in the presence or absence of 0·01–0·1 m m -ouabain. Ouabain induced accumulation of calcium by slices to a maximum of 4 μmoles/g of tissue/hr (0·75 m m -CaCl2 in the medium) and to 8 μmoles/g of tissue/hr (2·8 m m -CaCl2 in the medium). Accumulation of Ca2+ occurred more slowly than loss of K+ from the slices and more closely resembled the pattern of Na+ uptake.
Mitochondrial fractions isolated from ouabain-treated slices contained significantly more calcium than controls. Inclusion of EDTA in the homogenization medium resulted in decreased amounts of particulate-bound calcium.
The effect of ouabain on accumulation of calcium is discussed with regard to possible relationships to processes of active and passive transport. 相似文献
Mitochondrial fractions isolated from ouabain-treated slices contained significantly more calcium than controls. Inclusion of EDTA in the homogenization medium resulted in decreased amounts of particulate-bound calcium.
The effect of ouabain on accumulation of calcium is discussed with regard to possible relationships to processes of active and passive transport. 相似文献
17.
NOREPINEPHRINE INCREASES THE [32 P]LABELLING OF A SPECIFIC PHOSPHOLIPID FRACTION OF POST-SYNAPTIC PINEAL MEMBRANES 总被引:2,自引:0,他引:2
Abstract— Cultured pineal glands incorporated 32 P into membrane phospholipids. Treatment of cultured glands with norepinephrine, which is known to stimulate membrane- bound pineal adenyl cyclase and to increase the production and secretion of melatonin, stimulated the incorporation of 32 P into a phospholipid fraction of membranes and particulates containing phosphatidyl serine and phosphatidyl inositol. The labelling of other phospholipid fractions and the total 32 P in the gland were not changed by norepinephrine treatment. Experiments with chronically-denervated pineal glands indicated that the effect of norepinephrine on the [32 P]labelling of phospholipids occurred at a postsynaptic site. When norepinephrine-stimulated secretion of melatonin was partially inhibited by p -chlorophenylalanine (a compound which blocks the synthesis of melatonin precursors), the norepinephrine-stimulated labelling of phospholipids was still observed. Conversely, when melatonin secretion was stimulated in the absence of norepinephrine by treatment with the immediate precursor of melatonin, N -acetylserotonin, a stimulation of 32 P- labelling of phospholipids did not occur. These observations suggest that the increased [32 P]- labelling of a phospholipid fraction caused by the norepinephrine treatment is not related to the secretion of melatonin. This effect on phospholipids may be associated with the interaction of norepinephrine with a membrane-bound postsynaptic receptor. Stimulation by norepinephrine of [32 P]-incorporation into phospholipids has not been previously reported to occur in a tissue in which cholinergic fibres are absent. 相似文献
18.
Cell kinetic parameters of cells in the crypt of the jejunum of the mouse were obtained autoradiographically. A number of different methods used in cell proliferation studies were applied to the same animal strain kept under constant conditions. In order to avoid effects of geometrical factors, squashes of isolated crypts were used.
The generation time was determined by the per cent labelled mitoses method of Quastler, modified by double labelling with3 H- and 14 C-TdR. This modified method permits a more exact determination of the generation time. The duration of the cycle was 14 hr.
Double labelling experiments in which an injection of3 H-TdR was followed by an injection of 14 C-TdR after 1 hr showed that the cell flux was 7.0%/hr at the beginning of the S-phase and 7.68%/hr at the end. Assuming steady state growth a constant cell flux of 7.15%/hr within the whole cycle can be derived from the measured generation time of 14 hr. These results clearly show that the crypt epithelia constitute a steady state system with constant frequency distribution of the cells throughout the cycle.
The per cent labelled mitoses method after a single injection of3 H-TdR as well as double labelling experiments with 3 H- and 14 C-TdR give an estimate of the S-phase of 8.0 or 7.4 hr respectively. Double determinations lead to a value of 0.54 or 0.52 hr respectively for the duration of mitosis and to values of 77% and 72% 相似文献
The generation time was determined by the per cent labelled mitoses method of Quastler, modified by double labelling with
Double labelling experiments in which an injection of
The per cent labelled mitoses method after a single injection of
19.
MEASUREMENT OF THE RATE OF GLUCOSE UTILIZATION BY RAT BRAIN IN VIVO 总被引:17,自引:15,他引:2
Abstract— A method is described by which the rate of glucose utilization by whole brain of conscious rats may be measured. The basis is the uptake of 14 C derived front [2-14 C] glucose into the acid-soluble metabolite pool of brain. Catheters are placed in the femoral artery and vein under light ether anesthesia. After full recovery of consciousness a single intravenous injection of [2-14 C] glucose is given and arterial blood samples taken at intervals. Simultaneous with the last sample the brain is removed and frozen within 1 s. The accumulation of 14 C into the acid-soluble metabilite pool is measured and the rate of glucose utilization is calculated according to the equation:
The integral is calculated from the plasma glucose specific activity curve and evidence is presented to justify this procedure. The rate of glucose utilization measured by this method was 0·62 μmol/min per g in conscious rats and 0·28 μmol/min per g in sodium pentobarbital anesthetized rats. 相似文献
The integral is calculated from the plasma glucose specific activity curve and evidence is presented to justify this procedure. The rate of glucose utilization measured by this method was 0·62 μmol/min per g in conscious rats and 0·28 μmol/min per g in sodium pentobarbital anesthetized rats. 相似文献
20.
Abstract— Glial cells isolated from rabbit cerebral cortex contained approximately one-third more phospholipids per unit protein than the neuronal cell bodies. The pattern of individual phospholipids was rather similar in both cell types. The incorporation of intracisternally administered 32 P into neuronal and glial phospholipid classes of rabbit brain was studied at intervals ranging from 5 to 60min. In general, for all investigated phospholipids the incorporation of the label was somewhat faster in neurons than in glial cells. Phosphatidylinositol showed the fastest and ethanolamine plasmalogen the slowest incorporation of 32 P in both neurons and glial cells. A lag phase of about 10 min could be observed before labelling of the glial phosphatidylcholine, phosphatidylethanolamine, ethanolamine plasmalogen, phosphatidylserine and sphingomyelin had occurred. Among the neuronal phospholipids a lag phase was found only for the labelling of the ethanolamine plasmalogen. Norepinephrine increased the incoropration of 32 P into phosphatidylinositol of both glia and neurons but had no effect on the specific radioactivity of ethanolamine plasmalogen and sphingomyelin. Labelling of phosphatidylcholine was slightly inhibited in both cell types by the administration of norepinephrine. 相似文献