scholarly journals Transient Changes of Cortical Interhemispheric Responses After Repeated Caffeine Administration in Immature Rats

2011 ◽  
pp. 961-969 ◽  
Author(s):  
J. TCHEKALAROVA ◽  
H. KUBOVÁ ◽  
P. MAREŠ
Keyword(s):  
Developmental Changes ◽  
Adult Rats ◽  
Frequency Responses ◽  
Transient Nature ◽  
Rat Pups ◽  
Wistar Strain ◽  
Opposite Change ◽  
Frequency Stimulation ◽  
Old Rats ◽  
Epileptic Afterdischarges

Repeated postnatal caffeine treatment of rat pups led to transient developmental changes in cortical epileptic afterdischarges. To know if physiological cortical functions are also affected transcallosal evoked potentials were studied. Rat pups of the Wistar strain were injected daily with caffeine (10 or 20 mg/kg s.c.) from postnatal day (P) 7 to P11, control siblings received saline. Cortical interhemispheric responses were tested at P12, 18, 25 and in young adult rats. Amplitude of initial monosynaptic components was evaluated in averaged responses. Single pulses as well as paired and frequency (five pulses) stimulations were used. Developmental rules – highest amplitude of responses in 25-day-old rats, potentiation with paired and frequency stimulation present since P18 – were confirmed. Caffeine-treated rats exhibited transient changes: single responses were augmented in P25 if high stimulation intensity was used, paired-pulse and frequency responses were higher in experimental than in control animals at P12, the opposite change was observed in 18- and more markedly in 25-day-old rats. No significant changes were found in adult animals, monosynaptic transcallosal responses represent a simple and robust system. The developmental profile of described changes did not exactly correspond to changes in epileptic afterdischarges supporting the possibility that afterdischarges did not arise from early monosynaptic components of responses. In spite of transient nature of changes they can reflect delayed or more probably modified brain development.

DEVELOPMENTAL CHANGES IN THE DEGRADATION OF THYROTROPHIN RELEASING HORMONE BY THE SERUM AND BRAIN TISSUES OF THE MALE RAT

1977 ◽  
Vol 74 (2) ◽  
pp. 339-340 ◽  
Author(s):  
C. OLIVER ◽  
C. R. PARKER ◽  
J. C. PORTER
Keyword(s):  
Medical School ◽  
Developmental Changes ◽  
Male Rats ◽  
Male Rat ◽  
Obstetrics And Gynecology ◽  
Adult Rats ◽  
Thyrotrophin Releasing Hormone ◽  
Releasing Hormone ◽  
Old Rats ◽  
Phosphate Buffered Saline

*Laboratoire de Médecine Expérimentale, UER Médecine Nord, Boulevard Pierre Dramard, 13326 Marseille Cedex 3, France and †Department of Obstetrics and Gynecology, Southwestern Medical School, 5323 Harry Hines Boulevard, Dallas, Texas 75235, U.S.A. (Received 15 March 1977) Thyrotrophin releasing hormone (TRH) is rapidly degraded when incubated at 37 °C with plasma (Redding & Schally, 1969) or brain homogenates (Bassiri & Utiger, 1974) from adult rats. However, immunoreactive TRH is stable in serum obtained from rats less than 2 weeks old (Oliver, Taurog & Porter, 1974). No loss of biological or immunological TRH activity occurs during incubation with serum from 4- or 16-day-old rats (Neary, Kieffer, Federico, Mover, Maloof & Soodak, 1976). In this report, we have determined the TRH degrading activity of brain homogenates and serum obtained from male rats at various stages of development after birth. Synthetic TRH (1 ng, Beckman Instruments, Inc.) diluted in 50 μl phosphate-buffered saline (0·01

scholarly journals Polyamine metabolism in liver of young rats

1978 ◽  
Vol 174 (3) ◽  
pp. 727-732 ◽  
Author(s):  
M E Brosnan ◽  
G W Symonds ◽  
D E Hall ◽  
D L Symonds
Keyword(s):  
Fold Increase ◽  
Polyamine Metabolism ◽  
Decarboxylase Activity ◽  
Adult Rats ◽  
Adenosylmethionine Decarboxylase ◽  
Dna And Rna ◽  
Rat Pups ◽  
Old Rats ◽  
Rna Accumulation ◽  
Number Of Cells

Rat liver undergoes a phase of rapid growth during weaning. We followed the changes in polyamine metabolism occurring during this period of natural growth, and compared them with changes in DNA and RNA accumulation. There was a 2.5-fold increase in the number of cells per liver between suckling (18–19 days old) and weaning (30–32 days old) rats. Ornithine decarboxylase activity increased from the low value in 18-day-old rat pups and remained significantly higher (approx. 5–10-fold) than that in adult rats from day 21 to day 34. Putrescine-dependent S-adenosylmethionine decarboxylase activity was slightly but significantly increased during most of this period. Spermidine and RNA concentrations fluctuated in concert, whereas spermine content per cell doubled during the period from day 23 to day 30.

scholarly journals Proconvulsant Action of Two GABAB Receptor Antagonists Is Age-Dependent

2013 ◽  
pp. S109-S114 ◽  
Author(s):  
P. MAREŠ
Keyword(s):  
Gabab Receptor ◽  
Water Soluble ◽  
Gabab Receptors ◽  
Implanted Electrodes ◽  
Rat Pups ◽  
Age Dependent ◽  
Old Rats ◽  
Gabab Receptor Antagonists ◽  
Epileptic Afterdischarges

Antagonists of GABAB receptors are expected to have proconvulsant action also in developing brain. Two antagonists (CGP55845 and CGP46381) were tested in a model of cortical epileptic afterdischarges (ADs) in 12-, 18- and 25-day-old rat pups with implanted electrodes. CGP55845 was dissolved in dimethylsulfoxide and the results demonstrated marked proconvulsant action of this solvent which masked possible action of the antagonist. Water soluble antagonist CGP46381 led to marked potentiation of ADs in 12-day-old animals, its action decreased with age, it was negligible in 25-day-old rats. Our results demonstrated important inhibitory role of GABAB receptors at very early stages of maturation.

Homeostatic control of manganese excretion in the neonatal rat

1987 ◽  
Vol 252 (5) ◽  
pp. R842-R847 ◽  
Author(s):  
N. Ballatori ◽  
E. Miles ◽  
T. W. Clarkson
Keyword(s):  
Trace Metal ◽  
Biliary Excretion ◽  
Intraperitoneal Injection ◽  
Neonatal Rat ◽  
Abrupt Increase ◽  
Adult Rats ◽  
Tracer Dose ◽  
Diminished Capacity ◽  
Carrier Free ◽  
Old Rats

Previous studies in neonatal and suckling animals showed that immature animals have a greatly diminished capacity to excrete manganese and therefore were considered to be unable to regulate tissue manganese concentrations. In contrast, the present studies indicate that suckling rats have the capacity to excrete excess manganese at rates nearly comparable to those of adults. Eight- to 10-day-old rats given a tracer dose of 54MnCl2 (essentially carrier free), either via gavage or by intraperitoneal injection showed little elimination of the 54Mn until the 18-19th day of life, when there was an abrupt increase in the rate of the metal's excretion. However, when manganese was given in doses of 1 and 10 mg/kg, the young animals excreted from 30-70% of the dose in only 4 days, at which time a new rate of excretion was achieved. This enhanced rate of excretion remained constant until the 18-19th day of life, when it was again accelerated. Biliary excretion of manganese, the primary route for the elimination of the metal, was only 30-60% lower in 14-day-old rats compared with adults at doses ranging from tracer to 10 mg 54Mn/kg. For both the 14-day-old and adult rats, an apparent biliary transport maximum was reached at a dose of 10 mg Mn/kg. These studies indicate that the excretory pathways for manganese are well developed in the neonatal rat. The avid retention of tracer quantities of manganese by the neonate may be a consequence of the scarcity of this essential trace metal in its diet.

scholarly journals The association of the sulphogalactosylglycerolipid of rat brain with myelination

1977 ◽  
Vol 166 (3) ◽  
pp. 421-428 ◽  
Author(s):  
Joanne Pieringer ◽  
G. Subba Rao ◽  
Paul Mandel ◽  
Ronald A. Pieringer
Keyword(s):  
Rat Brain ◽  
Adult Life ◽  
Developmental Pattern ◽  
Adult Rats ◽  
Jimpy Mouse ◽  
Myelin Fraction ◽  
Old Rats

The sulphogalactosylglycerolipid of rat brain is closely associated with the process of myelination, as demonstrated by the following observations. 1. The lipid is barely detectable in rat brain before 10 days of age, accumulates rapidly between age 10 and 25 days, and remains relatively constant in amount (between 0.3 and 0.4μmol per brain) thereafter into adult life. 2. The activity of adenosine 3′-phosphate 5′-sulphatophosphate–galactosyldiacylglycerol sulphotransferase is almost absent before 10 days of age, attains a maximum at age 20 days, and slowly decreases thereafter with increasing age. This developmental pattern correlates well with that of other myelin-specific metabolites. 3. Both the concentration of the sulphogalactosylglycerolipid and the activity of sulphotransferase are greatly decreased in the non-myelinating jimpy mouse. 4. The myelin fraction of rat brain contains most of the sulphogalactosylglycerolipid. The lipid occurs in a diacyl and an alkylacyl form. Determinations of the relative amount of each type in brain showed about a 1:1 mixture in both 21-day-old and adult rats. Rats injected with H235SO4 at 20 days of age lost35S from the diacyl form at a higher rate than from the alkylacyl compound over a 21-day period. These data suggest that the diacyl form has a higher turnover than the alkylacyl derivative. The percentage of the total sulpholipid content of brain contributed by the sulphogalactosylglycerolipid is 16% in 21-day-old rats and 8.4% in adult rats.

scholarly journals Differential effects of targeted tongue exercise and treadmill running on aging tongue muscle structure and contractile properties

2013 ◽  
Vol 114 (4) ◽  
pp. 472-481 ◽  
Author(s):  
Heidi Kletzien ◽  
John A. Russell ◽  
Glen E. Leverson ◽  
Nadine P. Connor
Keyword(s):  
Young Adult ◽  
Exercise Group ◽  
Contractile Properties ◽  
Treadmill Running ◽  
Brown Norway ◽  
Middle Aged ◽  
Adult Rats ◽  
Tongue Muscle ◽  
Muscle Structure ◽  
Old Rats

Age-associated changes in tongue muscle structure and strength may contribute to dysphagia in elderly people. Tongue exercise is a current treatment option. We hypothesized that targeted tongue exercise and nontargeted exercise that activates tongue muscles as a consequence of increased respiratory drive, such as treadmill running, are associated with different patterns of tongue muscle contraction and genioglossus (GG) muscle biochemistry. Thirty-one young adult, 34 middle-aged, and 37 old Fischer 344/Brown Norway rats received either targeted tongue exercise, treadmill running, or no exercise (5 days/wk for 8 wk). Protrusive tongue muscle contractile properties and myosin heavy chain (MHC) composition in the GG were examined at the end of 8 wk across groups. Significant age effects were found for maximal twitch and tetanic tension (greatest in young adult rats), MHCIIb (highest proportion in young adult rats), MHCIIx (highest proportion in middle-aged and old rats), and MHCI (highest proportion in old rats). The targeted tongue exercise group had the greatest maximal twitch tension and the highest proportion of MHCI. The treadmill running group had the shortest half-decay time, the lowest proportion of MHCIIa, and the highest proportion of MHCIIb. Fatigue was significantly less in the young adult treadmill running group and the old targeted tongue exercise group than in other groups. Thus, tongue muscle structure and contractile properties were affected by both targeted tongue exercise and treadmill running, but in different ways. Studies geared toward optimizing dose and manner of providing targeted and generalized tongue exercise may lead to alternative tongue exercise delivery strategies.

scholarly journals In vitro analysis of the origin and maintenance of O-2Aadult progenitor cells.

1992 ◽  
Vol 116 (1) ◽  
pp. 167-176 ◽  
Author(s):  
D Wren ◽  
G Wolswijk ◽  
M Noble
Keyword(s):  
Adult Life ◽  
Cell Types ◽  
Adult Rats ◽  
Optic Nerves ◽  
Limited Life ◽  
Old Rats ◽  
Vitro Analysis

We have been studying the differing characteristics of oligodendrocyte-type-2 astrocyte (O-2A) progenitors isolated from optic nerves of perinatal and adult rats. These two cell types display striking differences in their in vitro phenotypes. In addition, the O-2Aperinatal progenitor population appears to have a limited life-span in vivo, while O-2Aadult progenitors appear to be maintained throughout life. O-2Aperinatal progenitors seem to have largely disappeared from the optic nerve by 1 mo after birth, and are not detectable in cultures derived from optic nerves of adult rats. In contrast, O-2Aadult progenitors can first be isolated from optic nerves of 7-d-old rats and are still present in optic nerves of 1-yr-old rats. These observations raise two questions: (a) From what source do O-2Aadult progenitors originate; and (b) how is the O-2Aadult progenitor population maintained in the nerve throughout life? We now provide in vitro evidence indicating that O-2Aadult progenitors are derived directly from a subpopulation of O-2Aperinatal progenitors. We also provide evidence indicating that O-2Aadult progenitors are capable of prolonged self renewal in vitro. In addition, our data suggests that the in vitro generation of oligodendrocytes from O-2Aadult progenitors occurs primarily through asymmetric division and differentiation, in contrast with the self-extinguishing pattern of symmetric division and differentiation displayed by O-2Aperinatal progenitors in vitro. We suggest that O-2Aadult progenitors express at least some properties of stem cells and thus may be able to support the generation of both differentiated progeny cells as well as their own continued replenishment throughout adult life.

Plasma constituents and mortality in rat pups given chronic insulin via injection, pellet, or osmotic minipump

2002 ◽  
Vol 80 (3) ◽  
pp. 180-192 ◽  
Author(s):  
Carl I Thompson ◽  
John W Munford ◽  
Edward H Buell ◽  
Robert J Karry ◽  
Charles T Lee ◽  
...  
Keyword(s):  
Age Differences ◽  
Plasma Glucose ◽  
Rapid Development ◽  
Daily Injection ◽  
Subcutaneous Insulin ◽  
Insulin Administration ◽  
Osmotic Minipump ◽  
Plasma Triglycerides ◽  
Rat Pups ◽  
Old Rats

Two studies compared the glucose responses of 9-day-old rats given subcutaneous insulin, either continuously or via daily injection, for 10 days. In Experiment 1, implanted pellets released a total of 0, 1.9, or 5.7 U insulin/kg the first 24 h. Injected doses were larger, 0 or 8 U/kg. Injections caused no deaths, but insulin-releasing pellets caused high mortality within 24 h. Pups surviving the pellets were normoglycemic by treatment day 8. In Experiment 2, pups received 0.184 U of insulin daily, approximately 8 U/kg at 9 days, via either injection or osmotic minipump. All pups survived. Injected pups were hypoglycemic 2 h postinjection through treatment day 10, whereas pups with insulin minipumps were normoglycemic by day 5. Insulin injections, but not minipumps, lowered plasma triglycerides on day 10. To examine age differences in response to insulin, additional pups and adults received daily injections of 0 or 8 U/kg for 10 days. All survived. Insulin lowered plasma glucose more in pups than in adults and reduced triglycerides in pups but not in adults. The rapid development of normoglycemia in pups with insulin minipumps, compared with pups injected daily with the same dose, suggests that continuous early insulin may produce insulin resistance.Key words: route of insulin administration, insulin resistance, mortality, plasma glucose, development.

scholarly journals Phosphatidylcholine synthesis in the developing small intestine

1980 ◽  
Vol 186 (2) ◽  
pp. 399-403 ◽  
Author(s):  
P G Holtzapple ◽  
C M Starr ◽  
T Morck
Keyword(s):  
Small Intestine ◽  
Oleic Acid ◽  
Steady State ◽  
Adult Rats ◽  
Acyltransferase Activity ◽  
Acid Incorporation ◽  
Old Rats ◽  
Phosphatidylcholine Synthesis

1. Phosphatidylcholine synthesis in the foetal, newborn and adult small intestine of rats was studied by determination of cytidine diphosphocholine-1,2-diacylglycerocholine phosphotransferase (cholinephosphotransferase) and acyl-CoA-1-acyl-sn-glycerol-3-phosphocholine acyltransferase (lysophosphatidylcholine acyltransferase) activities and the incorporation of [1-14C]oleic acid into phosphatidylcholine. 2. Cholinephosphotransferase activity was low in foetal jejunum and ileum, increased 3-4 fold in the ileum by 6 days of age and by 12 days in the jejunum. Jejunal activity remained constant throughout weaning; ileal activity gradually decreased to values 25% of that of the jejunum. 3. Lysophosphatidylcholine acyltransferase activity was high in foetal jejunum and ileum, decreased 70% immediately after birth in the jejunum and increased to adult values by 12 days of age. Ileal activity decreased by 20% after birth, but decreased more rapidly at weaning to 30% of the activity in jejunum. 4. Initial rates and steady-state incorporation of [1-14C]oleic acid into phosphatidylcholine by jejunal rings of 10 day-old rats exceeded that observed in jejunal rings from adult rats by 2-4-fold. 5. In the postnatal jejunum, neither cholinephosphotransferase and lysophosphatidylcholine acyltransferase activities nor oleic acid incorporation were stimulated by cortisone administration in vivo.

Peculiarities of the ultrastructure of neurons of the neocortex of 5-day-day rats under conditions of prenatal alcoholization

2021 ◽  
Vol 23 (1) ◽  
pp. 35-38
Author(s):  
L. I. Bon ◽  
◽  
S. M. Zimatkin ◽  
Keyword(s):  
Oxidative Stress ◽  
Pyramidal Neurons ◽  
Direct Action ◽  
Ultrastructural Changes ◽  
Initial Weight ◽  
Rat Pups ◽  
White Rats ◽  
Old Rats ◽  
Antenatal Alcoholization

The aim of this work was to study the ultrastructure of the internal pyramidal neurons of the neocortex of 5-day-old rat pups after antenatal alcoholization. The studies were carried out on female outbred white rats with an initial weight of 230 ± 20 g and their offspring. Prenatal alcoholization causes deep and varied ultrastructural changes in pyramidal neurons in the neocortex of 5-day-old rats. Moreover, these violations of direct action not only as a consequence of the damaging effect of alcohol, its metabolite acetehyde or the oxidative stress they cause on the membranes and organelles of neurons during embryogenesis, but also as a violation of the normal "program" of development" of neurons in the cortex.

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