Pulmonary absorption of drugs in the neonatal rat

1978 ◽  
Vol 234 (5) ◽  
pp. C191-C197 ◽  
Author(s):  
J. A. Hemberger ◽  
L. S. Schanker
Keyword(s):  
Neonatal Rat ◽  
Phosphate Solution ◽  
Pulmonary Absorption ◽  
Newborn Rats ◽  
Solution Ph ◽  
Adult Rats ◽  
Straight Line ◽  
Insoluble Drugs ◽  
Old Rats ◽  
Procaine Amide

To compare the pulmonary absorption of drugs in newborn rats (3-27 days old) with that in adults, 0.01-0.1 ml of Krebs-Ringer phosphate solution (pH 7.4) containing a drug was administered to anesthetized animals by way of a catheter introduced through a tight-fitting tracheal cannula. After various times, lungs and trachea were removed and assayed for drug that remained. Semilogarithmic plots of percent drug remaining against time yielded a straight line for each compound. The lipid-soluble drugs procaine amide and sulfisoxazole were absorbed at similar rates in newborn and adult rats. In contrast, the lipid-insoluble drugs tetraethylammonium, p-aminohippuric acid, and mannitol were absorbed approximately 2 times more rapidly in younger rats (3-12 days) than in older animals (18 day, 27 day, or adult). The results suggested that the respiratory tract membranes of 3- to 12-day-old rats have a greater porosity than those of older animals.

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.

Pituitary-adrenal response to bacterial endotoxin in developing rats

1988 ◽  
Vol 255 (4) ◽  
pp. E525-E530 ◽  
Author(s):  
L. Witek-Janusek
Keyword(s):  
Plasma Corticosterone ◽  
Neonatal Rat ◽  
Bacterial Endotoxin ◽  
Plasma Acth ◽  
Adult Rats ◽  
Age Related ◽  
Corticosterone Response ◽  
Adrenal Response ◽  
Old Rats ◽  
Related Pattern

The neonatal rat is very sensitive to the lethal effects of bacterial endotoxin. Because of the adaptive importance of pituitary-adrenal secretions to stress, this study examined the ontogeny of the plasma corticosterone and adrenocorticotropic hormone (ACTH) responses to endotoxin. The lethal sensitivity of young rats to endotoxin ranged from 0.5 to 30 mg/kg (ip) in the 1- to 21-day-old rat. After endotoxin treatment, the 1- and 2-day-old rat showed marked elevations of corticosterone similar in magnitude to that seen in 21-day-old and adult rats; however, significantly depressed corticosterone increments were observed in the 5-, 10-, and 14-day-old rats. This age-related pattern of adrenocortical secretion was correlated with the developing rat's corticosterone response to exogenous ACTH. In contrast, endotoxin administered to 5-, 10-, and 14-day-old rats resulted in increments of plasma ACTH similar to those observed in the 21-day-old and adult rats. Although plasma ACTH levels increased by 84-127% in the 1- and 2-day-old rats, these increases were significantly less than those of rats at all other ages tested. Thus the newborn rat mounts an effective corticosterone response to endotoxin, loses this ability between ages 5-14 days, and regains this response at 21 days of age. Because the hyporesponsive ages exhibit a marked increase in ACTH secretion, the loss of the adrenocortical response to endotoxin appears to be a result of a depressed responsiveness of the adrenal cortex to ACTH.

Developmental pattern of glucuronide formation in rat and guinea pig liver

1963 ◽  
Vol 205 (4) ◽  
pp. 663-666 ◽  
Author(s):  
Lawrence M. Gartner ◽  
Irwin M. Arias
Keyword(s):  
Guinea Pigs ◽  
Wistar Rats ◽  
Newborn Rats ◽  
Adult Liver ◽  
Adult Rats ◽  
Pig Liver ◽  
Liver Slices ◽  
Rat Liver Cells ◽  
Old Rats ◽  
Guinea Pig Liver

o-Aminophenol (OAP) glucuronide formation by liver slices from fetal and newborn Wistar rats up to 70 hr old is equivalent to or greater than OAP glucuronide formation by liver slices from adult rats. OAP glucuronide formation by homogenates of liver from 3-day-old rats, and slices or homogenates of liver from 3-day-old guinea pigs is substantially less than that observed in comparable preparations of adult liver. These observations suggest that glucuronidation is deficient in newborn guinea pigs but not in newborn rats. Although the mechanisms responsible for these differences are unknown, the possibility is discussed that disruption of rat liver cells reduces glucuronide formation by activation of an inhibitor.

Development of gastrointestinal surface. VIII. Lectin identification of carbohydrate differences

1987 ◽  
Vol 252 (5) ◽  
pp. G685-G691 ◽  
Author(s):  
K. Y. Pang ◽  
J. L. Bresson ◽  
W. A. Walker
Keyword(s):  
Binding Sites ◽  
Binding Capacity ◽  
Newborn Rats ◽  
Age Dependence ◽  
Newborn Rat ◽  
Con A ◽  
Adult Rats ◽  
Ulex Europaeus ◽  
Adult Rat ◽  
Old Rats

Binding of microvillus membranes (MVM) from newborn and adult rats by concanavalin A (Con A), Ulex europaeus (UEA I), Dolichos bifluorus (DBA), and Triticum vulgaris (WGA) was examined to determine the availability of carbohydrate-containing sites for these lectins on the intestinal surface during development. Consistent patterns of differences in the reaction of MVM with these lectins were found. Con A and UEA had much higher reactivities to MVM of adult than newborn rats. 125I-labeled-UEA gel overlay experiments revealed the abundance of UEA-binding sites in MVM of adult rat in contrast to the two binding sites in MVM of a newborn rat. DBA bound only to MVM of the adults, and very few binding sites were found in immature MVM. In contrast to these lectins, WGA binding was much higher in MVM of the newborns and decreased with maturation. Additional experiments on the age dependence of UEA and DBA reactivities revealed that the most striking changes occur in animals from 2 to 4 wk of age. In MVM from 2-wk-old rats, there were only 13.9% and less than 0.2% of the adult binding capacities for UEA and DBA, respectively. By the time the animals were 4 wk old, the binding capacity for UEA had attained close to the level of the adults, whereas for DBA it reached 71.3% of the adult value. These results provide definite evidence of changes in the intestinal surface during perinatal development.

Intestinal uptake and transport of proteins in the adult rat

1978 ◽  
Vol 203 (1151) ◽  
pp. 177-189 ◽  
Keyword(s):  
Protein Transport ◽  
The Body ◽  
Neonatal Rat ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
Intestinal Uptake ◽  
Adult Rats ◽  
Adult Rat ◽  
Old Rats ◽  
Bovine Immunoglobulin

The transport of immunoglobulin and ferritin across the intestinal mucosa of adult rats provides an excellent model for transcellular protein transport study. Intestinal uptake and transcellular transport have been extensively studied in the neonatal rat, but not to such an extent in the adult rat. The transport of 125 I labelled bovine immunoglobulin G and ferritin was studied in 100 days old rats using intestinally administered proteins. Antigen was estimated in the tissues by reacting extracts against specific immune antiserum prepared in rats, and visualization studies were carried out by fluorescence microscopy and direct deposition autoradiography at electron microscopic level. From these studies, it can be seen that these proteins are taken up by the intestinal cells and transported, antigenically intact, across the barriers to the body organs.

scholarly journals ONTOGENETIC ASPECTS OF CHANGING LYSOZYME ACTIVITY AFTER ACUTE SOMATIC PAIN

2014 ◽  
Vol 69 (11-12) ◽  
pp. 17-23
Author(s):  
V. G. Ovsyannikov ◽  
A. E. Boichenko ◽  
M. V. Blikyan ◽  
V. V. Alekseev ◽  
N. S. Alekseeva ◽  
...  
Keyword(s):  
Single Phase ◽  
Lysozyme Activity ◽  
Phase Reaction ◽  
Newborn Rats ◽  
Adult Rats ◽  
Somatic Pain ◽  
Eye Opening ◽  
Old Rats ◽  
The Common ◽  
Intact Rats

Aim: to study impact of acute somatic pain on lysozyme activity of different ages rats: newborn, rats after eye opening, month of age rats, adult and old rats. Methods: Lysozyme activity determined before pain irritation and after 2, 30, 60, 120, 180 min using Dorofeychuk’s method in our modification. Pain effect was modeling by electrical stimulation. Results: activity of lysozyme was 0.434±0.01 units in intact newborn rats, it was higher than in adult rats — 0.260±0.01 units (p 0.001) and it was unchanged during the experiment. We found low lysozyme activity in ratsafter eye opening — 0.015±0.003 units and it was stable during the experiment. Month of age rats had diphasic reaction: lysozyme activity was 0.191±0.01 units in intact rats, it increased up to 0.378±0.01 units (p 0.001) in 2 min after painful irritation and it decreased up to 0.113±0.02 units (p 0.001) in 30 min. Lysozyme activity was 0.260±0.01 units. Single-phase reaction was determined after acute painful irritation: increase of lysozyme activity after acute somatic pain up to 0,450±0,014 units (p 0.001). Lysozyme activity was 0.246±0.02 units inblood plasma of old rats. It decreased up to 0.170±0.01 units (p 0.01) after painful irritation and it was 0.387±0.01 (p 0.001) in the end of the experiment. Conclusion: Response on pain irritation has differences in different groups. The common vector of response reaction after pain was the increase lysozyme activity in month of age rats, adult rats, rats after eye opening and old rats. Reaction of increasing lysozyme activity the most expressed in adult rats. The data are considered as a preventive readiness of lysozyme to answer on damage and infection.

scholarly journals Ventilatory and carotid body chemoreceptor responses to purinergic P2X receptor antagonists in newborn rats

2011 ◽  
Vol 110 (1) ◽  
pp. 83-94 ◽  
Author(s):  
Lalah M. Niane ◽  
David F. Donnelly ◽  
Vincent Joseph ◽  
Aida Bairam
Keyword(s):  
Carotid Body ◽  
Discharge Rate ◽  
Hypoxic Condition ◽  
P2x Receptor ◽  
Whole Body ◽  
Newborn Rats ◽  
Adult Rats ◽  
Before And After ◽  
Old Rats

Adenosine triphosphate, acting through purinergic P2X receptors, has been shown to stimulate ventilation and increase carotid body chemoreceptor activity in adult rats. However, its role during postnatal development of the ventilatory response to hypoxia is yet unknown. Using whole body plethysmography, we measured ventilation in normoxia and in moderate hypoxia (12% fraction of inspired O2, 20 min) before and after intraperitoneal injection of suramin (P2X2 and P2X3 receptor antagonist, 40 mg/kg) in 4-, 7-, 12-, and 21-day-old rats. Suramin reduced baseline breathing (∼20%) and the response to hypoxia (∼30%) in all rats, with a relatively constant effect across ages. We then tested the effect of the specific P2X3 antagonist, A-317491 (150 mg/kg), in rats aged 4, 7, and 21 days. As with suramin, A-317491 reduced baseline ventilation (∼55%) and the hypoxic response (∼40%) at all ages studied. Single-unit carotid body chemoreceptor activity was recorded in vitro in 4-, 7-, and 21-day-old rats. Suramin (100 μM) and A-317491 (10 μM) significantly depressed the sinus nerve chemosensory discharge rate (∼80%) in normoxia (Po2 ∼150 Torr) and hypoxia (Po2 ∼60 Torr), and this decrease was constant across ages. We conclude that, in newborn rats, P2X purinergic receptors are involved in the regulation of breathing under basal and hypoxic condition, and P2X3-containing receptors play a major role in carotid body function. However, these effects are not age dependent within the age range studied.

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.

THE ROLE OF THE MOTHER IN 131I METABOLISM OF SUCKING AND WEANLING RATS

1965 ◽  
Vol 43 (3) ◽  
pp. 431-436 ◽  
Author(s):  
M. Samel ◽  
A. Caputa
Keyword(s):  
Urinary Bladder ◽  
In Utero ◽  
The State ◽  
Newborn Rats ◽  
Weanling Rats ◽  
Immature Rats ◽  
Other Substances ◽  
Old Rats

In newborn rats the mother provokes the emptying of the urinary bladder by stimulating the perineum with her tongue. The possibility that mothers may thereby ingest the urine of their young has been studied by means of 131I on nine litters of rats aged 10 to 29 days. The results indicate that a considerable quantity of 131I administered intraperitoneally to 10- and 18-day-old rats, which were then reunited with their mothers for 4 hours, reappears in the organism of uninjected nurslings after passing through the organism of the mother. The amount of 131I transferred from injected rats into the bodies of isolated uninjected rats of the same litter decreased during the period of weaning. The observed recirculation of 131I between immature rats and their mothers in both directions may represent a saving mechanism which might include several other substances and would compensate for their loss via the milk, and suggests a new aspect of maternal–neonatal interrelationship which appears as a continuation of the state existing in utero.

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.

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