Free Nucleotides in the Rat Brain During Post‐natal Development

Mandel, P.; Edel‐Harth, S.

doi:10.1111/j.1471-4159.1966.tb11955.x

Cited by 108 publications

(33 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This peak was chosen for two reasons. First, other studies have indicated that ATP and NTP do not change greatly with age (Samson, Balfour & Dahl, 1960;Mandel & Edel-Harth, 1966;Miller & Shamban, 1977). Secondly, ATP concentration is maintained constant during the course ofan experiment by PCr acting as a buffer (see e.g.…”

Section: Resultsmentioning

confidence: 99%

Changes in brain phosphorus metabolites during the post‐natal development of the rat.

Tofts¹,

Wray²

1985

The Journal of Physiology

100

View full text Add to dashboard Cite

SUMMARY1. Changes in brain phosphorus metabolites during the post-natal development of the rat and in neonatal and adult guinea-pigs have been studied in vivo using 31P nuclear magnetic resonance spectroscopy (n.m.r.s.).2. The brain spectra showed clear differences with age, particularly during the first 3 weeks post-partum.3. The spectra from 4-day-old rats resembled those of new-born human infants. We suggest that the differences between human and animal brains seen in previously published spectra arise because of an age difference rather than a species difference.4. The phosphocreatine (PCr) to nucleoside triphosphate (NTP) ratio increased from around 1-0 in 3-day-old rats to 1P8 in adult animals. The adult ratio is larger than that previously reported from in vitro chemical analyses.5. An unknown compound in the phosphomonoester (PME) region of the spectra predominated in young animals, but decreased in concentration relative to NTP with age and reached adult values by around 2 weeks post-partum.6. Neonatal guinea-pigs, which are much more developed at birth than the rat, had a significantly greater PCr/NTP ratio than the neonatal rat, but their brain spectra also contained the large PME peak.7. The intracellular pH of cerebral tissue was estimated to be 7-21 +0-02 and did not show any change with age.8. The changes we find in the phosphorus compounds in the brain may be of importance in post-natal development, and the possible functional significance of these results is discussed.

show abstract

Section: Resultsmentioning

confidence: 99%

Changes in brain phosphorus metabolites during the post‐natal development of the rat.

Tofts¹,

Wray²

1985

The Journal of Physiology

100

View full text Add to dashboard Cite

show abstract

“…These levels are lower than those described in brain samples obtained from rats killed differently (i .e ., by freezing the brain before decapitation and, thereafter, not subjecting the tissues to incubation) (Mandel and Edel-Harth, 1966 ; Abe et al ., 1987) . Dose-dependent increases in tissue CTP levels were observed after striatal slices were incubated with cytidine for l h (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The rate of PC biosynthesis apparently depends upon the activity of CTP :phosphocholine cytidylyltransferase, which catalyzes the formation of CDP-choline from phosphocholine and CTP (Pelech and Vance, 1984) . Brain CTP levels are low (Mandel and Edel-Harth, 1966 ;Abe et al ., 1987) and below this enzyme's apparent K , for the nucleotide (Pelech and Vance, 1984 ;Mages et al, 1988) . Hence, we suspected that exogenous cytidine might, by increasing intracellular CTP levels, affect brain phospholipid synthesis .…”

mentioning

confidence: 99%

Effect of Cytidine on Membrane Phospholipid Synthesis in Rat Striatal Slices

Savci

Wurtman

1995

Journal of Neurochemistry

View full text Add to dashboard Cite

Concurrent exposure to cytidine (200^and ethanolamine (20^also caused significantly greater elevations (p < 0.05) in tissue PE levels than those caused by cytidine alone. In contrast, the addition of serine (500 did not enhance cytidine's effects on any membrane phospholipid . Exposure to serine alone, however, like exposure to sufficient choline, increased levels of all three membrane phospholipids significantly (p < 0.01) . These data show that exogenous cytidine, probably acting via CTP and the Kennedy cycle, can increase the synthesis and levels of membrane PC and PE in brain cells.

show abstract

“…These results indicate that cGMP and cAMP levels in retina are influenced by the light adaptational state, that ischemia markedly modifies these processes, and that the effects of both light exposure and ischemia are regionally selective. Previous studies have detected the existence of adenosine 3': 5'-cyclic monophosphate (cAMP) and guanosine 3':5'-cyclic monophosphate (cGMP) in mammalian retina and have demonstrated that this tissue is uniquely rich in cGMP (1,2). Dark adaptation increases cGMP in outer segments of mammalian photoreceptor cells in vitro (3)(4)(5)(6)(7), and Fletcher and Chader (8) emia was studied.…”

mentioning

confidence: 99%

Distribution of 3':5'-cyclic AMP and 3':5'-cyclic GMP in rabbit retina in vivo: selective effects of dark and light adaptation and ischemia.

Orr¹,

Lowry²,

Cohen³

et al. 1976

Proc. Natl. Acad. Sci. U.S.A.

110

View full text Add to dashboard Cite

By use of highly sensitive radioimmunoassays, 3':5'-cyclic AMP (cAMP) and 3':5'-cyclic GMP (cGMP) were measured in individual layers of light-and dark-adapted rabbit retinas, and the effects of ischemia were determined. In lightadapted retinas, cGMP levels ranged 50-fold, with over 90% of the total concentrated in the photoreceptor cells. The layer of outer segments contained 95 gmol/kg of dry weight, or three times the concentration present in the remainder of the photoreceptor cell layers. By contrast, levels of cAMP varied only 4-fold; the lowest level (6 gmol/kg of dry weight) was found in the outer segment layer and the highest level (22 ;mol/kg of dry weight) in the inner segment layer of the photoreceptor cells. Dark adaptation elevated cGMP levels only in retinal layers containing photoreceptor cells, and the greatest proportional increase was observed in the synaptic layer of photoreceptor cells. Dark adaptation also caused increases of cAMP that were restricted to the outer plexiform and outer nuclear layers. Ischemia lowered cGMP levels, but only in retinal layers containing photoreceptor cells, and elevated cAMP levels, primarily in the inner layers of the retina. emia was studied. The findings demonstrate that the cyclic nucleotides are discretely localized in retinas and that both light exposure and ischemia produce regionally selective changes in their levels. MATERIALS AND METHODS Tissue Preparation. Randomly bred, 6-month-old pigmented rabbits were obtained locally. Light adaptation consisted of 1 hr of exposure to two 100-watt tungsten bulbs about 25 cm above the rabbits. After the photopic stimulation, the rabbits were killed by decapitation. The eyes were removed, and after various ischemic periods in room light, were quickly frozen in liquid N2 cooled to its freezing point by partial evaporation under reduced pressure. Consequently, the liquid N2 does not boil when the eyes are immersed, and freezing is quicker. Dark adaptation consisted of an overnight period in cages wrapped with black cloth and placed in a completely dark room. After decapitation in this room, the dark-adapted eyes were dissected free with the aid of an infrared light source and an infrared image converter, and after various periods, were frozen in the dark as above. Under the most ideal conditions it required 1 min (46-69 sec) to remove and freeze either the light-or dark-adapted eyes. All eyes were stored at -70°until sectioned. Tangential sections (6 ,m) of the retinas were cut at -20°and dried at -400 under reduced pressure. Sections were taken from the paracentral regions of the retina, and care was taken to avoid that portion underlying the myelinated fiber bundle. Paracentral areas of rabbit retina are poorly vacularized (9). Samples (0.03-0.9 ,g dry weight) were dissected from the individual retinal layers and weighed on a quartz-fiber balance (10). Stained, undissected retinal sections were used to help identify individual layers.Assay of cGMP and cAMP. The procedures used for extraction and radioimmunoas...

show abstract

Free Nucleotides in the Rat Brain During Post‐natal Development

Cited by 108 publications

References 5 publications

Changes in brain phosphorus metabolites during the post‐natal development of the rat.

Changes in brain phosphorus metabolites during the post‐natal development of the rat.

Effect of Cytidine on Membrane Phospholipid Synthesis in Rat Striatal Slices

Distribution of 3':5'-cyclic AMP and 3':5'-cyclic GMP in rabbit retina in vivo: selective effects of dark and light adaptation and ischemia.

Contact Info

Product

Resources

About