Behavioral evidence for cholecystokinin-opiate interactions in neonatal rats

1988 ◽  
Vol 255 (6) ◽  
pp. R901-R907 ◽  
Author(s):  
A. Weller ◽  
E. M. Blass
Keyword(s):  
Dose Range ◽  
Neonatal Rats ◽  
Behavioral Measures ◽  
Distress Vocalization ◽  
Rat Pups ◽  
Within Subjects ◽  
Old Rats ◽  
Behavioral Evidence ◽  
Opioid Systems ◽  
Mediated Reduction

In adult mammals, cholecystokinin (CCK)-opiate interactions are complex and task dependent. Specifically, CCK antagonizes opiate effects in some cases, yet acts similarly to opiate agonists in others. The present study used behavioral measures to determine how CCK interacts with opiates in neonatal rats. CCK, at doses of 1 microgram/kg and higher, markedly reduced isolation-induced distress vocalization in rat pups. Moreover, CCK selectively prevented naltrexone antagonism of opiate-mediated reduction in distress vocalization in 3- and 11-day-old rats. Yet CCK did not affect opiate-induced analgesia, as measured by the hot-plate paw-lift response. Thus CCK either did not interact with opiates or did so agonistically, with the same (low) dose range, and within subjects. These findings suggest independence of stress and pain systems in neonatal rats and demonstrate a functional interaction between CCK and opioid systems.

Evoked Olfactory Responses in Neonatal Rats

1985 ◽  
Vol 61 (3_suppl) ◽  
pp. 1023-1029
Author(s):  
Estelle H. Gregory
Keyword(s):  
Olfactory Bulb ◽  
Electrical Activity ◽  
Evoked Potentials ◽  
Spontaneous Activity ◽  
Background Level ◽  
Neonatal Rats ◽  
Physiological Basis ◽  
Olfactory Responses ◽  
Rat Pups ◽  
Behavioral Evidence

Although there is behavioral evidence that rat pups respond to odors, the physiological basis of the response is unclear. In the present study, eight different odors were presented to 44 anesthetized rat pups between the ages of 0 and 20 days, and recordings of electrical activity were made from the olfactory bulb. The major finding was that, contrary to earlier neurophysiological findings, even on the first day of life—when spontaneous electrical activity is minimal—evoked potentials, in the form of synchronized waveforms two to four times the amplitude of the background level of spontaneous activity, can be recorded to a variety of odor stimuli.

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.

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.

Ontogeny of pepsin secretory response to secretagogues in isolated rat gastric glands

1986 ◽  
Vol 250 (2) ◽  
pp. G200-G204 ◽  
Author(s):  
J. Yahav ◽  
P. C. Lee ◽  
E. Lebenthal
Keyword(s):  
Term Neonate ◽  
Ionophore A23187 ◽  
Newborn Rats ◽  
Dibutyryl Camp ◽  
Gastric Glands ◽  
Cholecystokinin Octapeptide ◽  
Rat Pups ◽  
Isolated Gastric Glands ◽  
Old Rats ◽  
Isolated Rat

By use of isolated gastric glands from rats at various ages, we demonstrated that full-term neonate and 1-day-old rats showed no response to cholecystokinin octapeptide (CCK-OP), carbachol, or Ca2+ ionophore. The same glands, however, were responsive to dibutyryl cAMP. A mature response was not found until the pups were 2 days old. Injection of hydrocortisone into newborn rats led to an increase in pepsinogen concentrations in gastric glands and also an increased responsiveness to CCK-OP, carbachol, and Ca2+ ionophore A23187 24 h after administration. Hydrocortisone thus caused precocious maturation of both pepsinogen accumulation and pepsinogen secretory responsiveness of gastric glands in rat pups.

scholarly journals Strong Effort Manipulations Reduce Response Caution: A Preregistered Reinvention of the Ego-Depletion Paradigm

2019 ◽  
Author(s):  
Hause Lin ◽  
Blair Saunders ◽  
Malte Friese ◽  
Nathan J. Evans ◽  
Michael Inzlicht
Keyword(s):  
Drift Rate ◽  
Ego Depletion ◽  
Diffusion Modeling ◽  
Information Processing Speed ◽  
New Paradigm ◽  
High Demand ◽  
Behavioral Measures ◽  
Bayesian Analyses ◽  
Rate Information ◽  
Within Subjects

People feel tired or depleted after exerting mental effort. But even preregistered studies often fail to find effects of exerting effort on behavioral performance in the laboratory or elucidate the underlying psychology. We tested a new paradigm in four preregistered within-subjects studies (N = 686). An initial high-demand task reliably elicited very strong effort phenomenology compared with a low-demand task. Afterward, participants completed a Stroop task. We used drift-diffusion modeling to obtain the boundary (response caution) and drift-rate (information-processing speed) parameters. Bayesian analyses indicated that the high-demand manipulation reduced boundary but not drift rate. Increased effort sensations further predicted reduced boundary. However, our demand manipulation did not affect subsequent inhibition, as assessed with traditional Stroop behavioral measures and additional diffusion-model analyses for conflict tasks. Thus, effort exertion reduced response caution rather than inhibitory control, suggesting that after exerting effort, people disengage and become uninterested in exerting further effort.

Functional impairment of blood-brain barrier following pesticide exposure during early development in rats

1999 ◽  
Vol 18 (3) ◽  
pp. 174-179 ◽  
Author(s):  
Alka Gupta ◽  
Renu Agarwal ◽  
Girja S Shukla
Keyword(s):  
Blood Brain Barrier ◽  
Repeated Exposure ◽  
Neurological Dysfunction ◽  
Brain Barrier ◽  
Sodium Fluorescein ◽  
Rat Pups ◽  
Blood Brain ◽  
Brain Uptake Index ◽  
Old Rats ◽  
Bbb Permeability

1 The effect of certain pesticides on the functional integrity of the developing blood-brain barrier (BBB) was studied following single and repeated exposure, and after subsequent withdrawal in rats. 2 Ten-day-old rat pups exposed orally to quinalphos (QP, organophosphate), cypermethrin (CM, pyre-throid) and lindane (LD, organochlorine) at a dose of 1/50th of LD50, showed a significant increase in the brain uptake index (BUI) for a micromolecular tracer, sodium fluorescein (SF), by 97, 37 and 72%, respectively, after 2 h. Residual increases in the BUI were found even after 3 days of the single treatment of QP (28%) and LD (23%). 3 Repeated exposure for 8 days (postnatal days (PND) 10-17) with QP, CM and LD increased the BBB permeability by 130, 80 and 50%, respectively. Recovery from these changes was complete in QP and LD-treated animals after 13 days (PND 18-30) of withdrawal. However, CM showed persistent effects that were normalized only after 43 days (PND 18-60) of withdrawal. 4 A single dose reduced to 1/100th of LD50 also increased BUI in 10-day-old rat pups following QP (20%) and CM (28%) exposure at 2 h. 5 An age-dependent effect of these pesticides was evident from the study showing higher magnitude of BUI changes in 10-day-old rats as compared to that in 15- day-old rats. Furthermore, adult rats did not show any effect on BBB permeability even at a higher dose (1/25th of LD50) of these pesticides given alone or in combination with piperonyl butoxide (600 mg/kg, i.p.) for 3 consecutive days. 6 This study showed that developing BBB is highly vulnerable to single or repeated exposure of certain pesticides. The observed persistent effects during brain development even after withdrawal of the treatment may produce some neurological dysfunction at later life as well.

Effect of maternal sialoadenectomy on ontogenic response of rat gastric mucosa to luminal H+

1993 ◽  
Vol 265 (2) ◽  
pp. G354-G360 ◽  
Author(s):  
B. L. Tepperman ◽  
B. L. Vozzolo ◽  
B. D. Soper
Keyword(s):  
Gastric Mucosa ◽  
Neonatal Rat ◽  
Mucosal Permeability ◽  
Maternal Milk ◽  
Elution Pattern ◽  
Rat Pups ◽  
Rat Gastric Mucosa ◽  
Epidermal Growth ◽  
Old Rats ◽  
Chromatographic Elution

Epidermal growth factor (EGF) originating from salivary glands has been shown to affect the development and integrity of rodent gastrointestinal mucosa. Because newborn rats receive EGF from maternal milk, we have examined the effect of sialoadenectomy as a method of depleting EGF in milk on the resistance of neonatal rat mucosa to luminal H+. Rat dams were sialoadenectomized (SALX) or sham operated 5 days after parturition. Experiments were performed on newborns 10-22 days old. Mucosal permeability responses to intraluminal HCl (300 mM) were examined in terms of luminal appearances of Na+, K+, and protein and H+ loss. EGF levels in maternal milk were determined by immunoassay. In rat pups from control litters, luminal HCl resulted in an age-associated increase in cation and protein flux across the gastric mucosa. Luminal cation and protein fluxes observed in 10- to 18-day-old rat pups from SALX dams were not significantly different from similarly aged rats from control dams. However, in 19- to 22-day-old rats from SALX dams, the permeability responses to luminal HCl were exacerbated compared with similarly aged neonates from control dams. These responses were reduced by treatment with EGF. EGF levels in milk from sham-operated and SALX dams were not significantly different in the 10- to 16-day lactational period. However, in SALX dams EGF was significantly reduced at 19 and 22 days. Chromatographic elution pattern of milk EGF was dissimilar to the pattern exhibited by submandibular gland EGF.(ABSTRACT TRUNCATED AT 250 WORDS)

Ontogeny of epinephrine-induced anorexia in rats

1986 ◽  
Vol 250 (2) ◽  
pp. R313-R317
Author(s):  
A. M. Rodriguez-Zendejas ◽  
G. Chambert ◽  
M. C. Lora-Vilchis ◽  
A. N. Epstein ◽  
M. Russek
Keyword(s):  
Food Intake ◽  
Water Intake ◽  
Neonatal Rats ◽  
Adult Rats ◽  
Weanling Rats ◽  
Adrenergic Control ◽  
Food And Water Intake ◽  
Old Rats ◽  
Enriched Milk ◽  
Reduced Water

Intraperitoneal or intraportal epinephrine elicits a strong inhibition of food intake in adult rats and dogs but has no effect when injected intramuscularly or intrajugularly, in spite of production of larger hyperglycemia and cardiovascular changes. These facts suggest that the effect of epinephrine on feeding is elicited via the liver. Ontogeny of this adrenergic control of food intake was studied in newborn and weanling rats. Anorexic effect of intraperitoneal epinephrine was clearly observed in dam-deprived 3-day-old neonatal rats (youngest in which it was tested), both when they were offered enriched milk through an anterior oral cannula while they were isolated from their dam and when they were allowed to suckle from her. However, anorectic effect was less in neonatal rats (day 3-13) than in adults. Weanling rats, 21-26 days old, were as sensitive to intraperitoneal epinephrine as adults. In 3- to 4-day-old rats it also reduced water intake, but this effect disappeared by day 12 and was not observed in mildly water-deprived adults. Peripheral adrenergic control of intake appears very early in ontogeny of rats. First, it affects food and water intake equally, but by day 12 it affects only food intake. Increase in sensitivity to epinephrine after weaning is probably due to an increase in number of hepatocytic adrenergic receptors and/or increase in enzymes necessary for hepatic effects of epinephrine.

Cytoplasmic control of DNA synthesis by myocardial nuclei

1980 ◽  
Vol 238 (1) ◽  
pp. H66-H72
Author(s):  
C. J. Limas
Keyword(s):  
Dna Synthesis ◽  
Dna Polymerases ◽  
Postnatal Growth ◽  
Neonatal Rats ◽  
Cytoplasmic Factor ◽  
Age Dependent ◽  
Rat Myocytes ◽  
Old Rats ◽  
Isolated Rat

In vitro DNA synthesis by isolated myocardial nuclei declines rapidly during postnatal growth. To study the mechanism(s) responsible for this decline, cytoplasmic extracts (CE) were prepared from isolated rat myocytes at different times after birth. CE from 2-day-old rats stimulated in vitro DNA synthesis by myocardial nuclei from adult (6 mo old) rats (55 +/- 6 pmol[3H]dTMP . mg DNA-1 . 15 min-1 vs. 32 +/- 4 pmol [3H]dTMP . mg DNA-1 . 15 min-1 in untreated controls, P less than 0.01). The ability of cytoplasmic extracts of stimulate DNA synthesis decreased with age, from 73 +/- 9% over controls at age 2 days to 18 +/- 6 at 28 days; adult myocytes were essentially ineffective. Pulse-chase experiments demonstrated that CE-directed DNA synthesis was replicative and discontinuous. CE stimulatory activity was heat-labile, nondialyzable, trypsin-sensitive, and distinct from DNA polymerases. The results indicate that a) adult myocyte nuclei can be induced to synthesize DNA by cytoplasmic extracts from neonatal rats, and b) that absence of regulatory cytoplasmic factor(s) may, in part, explain the age-dependent decline in myocardial DNA synthesis.

scholarly journals Comparative biological availability of manganese from extrinsically labelled milk diets using sucking rats as a model

1986 ◽  
Vol 55 (1) ◽  
pp. 49-58 ◽  
Author(s):  
M. Hassan Raghib. ◽  
Chan Wai-Yee ◽  
M. Owen Rennert
Keyword(s):  
Human Milk ◽  
Digestive Tract ◽  
Infant Formula ◽  
Bovine Milk ◽  
Neonatal Rats ◽  
Biological Availability ◽  
Gastric Intubation ◽  
Old Rats ◽  
Mn Concentrations

1. Very little is known about the biological availability of manganese from human milk and other infant milk diets. To determine the relative Mn availability, and to examine whether the age and the duration of previous fasting affect Mn absorption, sucking rats were given human milk, bovine milk and infant formula (regular Similac; Ross Laboratories, Columbus, OH) extrinsically labelled with 54Mn.2. Milk diets were given by gastric intubation and the radioactivity of the carcass, liver and digestive tract was measured 3 h after feeding.3. The concentration of endogenous Mn was lowest in human milk (7–10 μg/l) and highest in rat milk (140–165 μg/l). Increasing the non-radioactive total Mn concentrations of either human milk or bovine milk up to 150 μg/l did not affect the absorption of 54Mn by 10-d-old rats.4. No significant (P> 0.05) difference in 54Mn absorption was found among the three milk diets (human milk, bovine milk, infant formula) in 8- to 11-d-old rats. However, significantly more (P< 0.05) 54Mn was absorbed from human milk and infant formula than from bovine milk when 13-d-old rats were used.5. 54Mn radioactivity detected in carcasses of 8-, 9-, 10- and 11-d-old rats ranged from 25 to 27% of the dose from various milk diets. The activities of 54Mn in the carcasses of 13-d-old rats were 15, 11, and 16% of the dose from human milk, bovine milk and infant formula respectively.6. The trend of 54Mn incorporation into liver was similar to that of the carcass and over 60% of the absorbed 54Mn was incorporated into the liver regardless of the type of milk used.7. Absorption of 54Mn from extrinsically labelled rat milk using 9- or 10-d-old sucking rats was similar to its absorption from infant formula.8. The absorption of 54Mn from the three milk diets decreased with age of the neonatal rats and 54Mn absorption from human milk, bovine milk, infant formula as well as rat milk was affected similarly by duration of previous fasting.

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