Search PubMed⌕ Search

Biomedical subjects

E L Abel

Publications and source records attributed to E L Abel.

At least 19 recordsLinked to original sources
PubMed1992

Response to alarm substance in different rat strains.

Two studies were conducted. In the first study, four strains of male rats--Long-Evans (LE), Sprague-Dawley (SD), Wistar, Fisher 344--were immersed in fresh water or water soiled by a rat of the same strain which presumably contains an alarm substance. LE rats were less immobile than SD, Wistar, and Fisher rats in fresh water. All strains were significantly less immobile in soiled water; however, relative to immobility times in fresh water, the decrease in immobility in soiled water was greatest for SD rats and least for Wistar rats. A second study tested SD and Wistar rats in water soiled by animals of the same strain compared to water soiled by animals of the other strain. This study indicated that Wistar rats produce less alarm substance or less potent substance and are also less reactive to it than SD rats. The results of these two studies indicate that some strains are more affected by alarm substance than others and the differential response is due both to decreased production/potency and reaction to the substance.

Animals↗
PubMed1992

Effects of chronic forced swimming and exposure to alarm substance: physiological and behavioral consequences.

Rats tested for 7 consecutive days in the forced swim test in fresh water were more immobile than those tested in soiled water on all days. Animals in both water conditions increased their immobility times slightly over days, but animals tested in soiled water, which presumably contained an alarm substance, never attained the immobility times of those tested in fresh water. When animals were switched between fresh and soiled water, they behaved exactly like animals in the water condition to which they were switched. Prior inescapable forced swimming in either water condition affected subsequent escape in a Morris water maze, but more so for animals tested only in fresh water. A second study corroborated the escape results. Serum corticosterone and relative adrenal weights were increased as a result of forced swimming but escape performance differences could not be attributed to differences in the stress-provoking consequences of the two water conditions.

Animals↗
PubMed1992

Maudsley reactive and nonreactive rats in the forced swim test: comparison in fresh water and soiled water.

Maudsley reactive (MR) and nonreactive (MNRA) and Sprague-Dawley (SD) male rats were tested for their immobility response in the forced swim test when the water was fresh or soiled by a rat of the same or other strain. For all strains, rats tested in soiled water were less immobile than rats in fresh water. The three strains did not differ as producers of soiling substance, but did differ in their response to it. The MR strain was least responsive, whereas the MNRA and SD did not differ from one another. These results support a previous study suggesting that MR rats are more immobile than MNRA rats in the forced swim test. The interpretation of these findings regarding the use of the Maudsley rat strains as an animal model for studying anxiety and/or depression is discussed.

Animals↗
PubMed1992

Alarm substance induces convulsions in imipramine-treated rats.

Male rats were injected with imipramine (0-30 mg/kg) and subsequently tested in the forced-swim test in either fresh water or water soiled by other rats, which presumably contains an alarm substance. Imipramine did not affect the behavior of rats in fresh water. More than half the animals given the combination of imipramine (30 mg/kg) and stress from alarm substance had clonic convulsions. Adrenalectomy did not affect this relationship. This is the first study demonstrating the potential of an alarm substance for inducing convulsions.

Adrenal Glands↗
PubMed1992

Animal models of prenatal alcohol exposure.

Since the first reports of fetal alcohol syndrome (FAS), thousands of studies have examined the effects of antenatal alcohol exposure in humans and in animal models. Research with animal models has led to discoveries which would be difficult if not impossible in human subjects. Most importantly, these models have resulted in valuable insights into the actions of alcohol on various parts of the developing embryo and have helped researchers come closer to identifying the mechanisms of its teratogenic action. Both the direct and indirect biological effects of alcohol exposure in utero appear to work in conjunction with other concurrent and predisposing factors such as genotype, nutritional status, pattern of exposure and use of other drugs such as nicotine and cocaine. At present animal research indicates a multifactorial mechanism of the teratogenicity of alcohol resulting from nutrient deficiencies, fetal hypoxia and alterations in enzyme activities and cell function important in cell division and membrane integrity. This review examines how animal models are used to clarify issues associated with alcohol-related birth defects and to shed light on the underlying mechanisms.

Abnormalities, Drug-Induced↗
PubMed1992

Audiogenic seizure susceptibility and auditory brainstem responses in rats prenatally exposed to alcohol.

Rats prenatally exposed to alcohol (0%, 17.5%, or 35% ethanol-derived calories) were tested for audiogenic seizure susceptibility on one of postnatal days 18 to 23, then retested 5 days later. Prenatal alcohol exposure did not influence audiogenic seizure susceptibility or severity. There was, however, a significant increase in seizure incidence on the retest day for all groups, suggesting a priming effect. Auditory brainstem response (ABR) data suggested that prenatal alcohol exposure and acoustic trauma (i.e., exposure to an alarm bell used for eliciting audiogenic seizures) induced measurable sensorineural hearing loss, and that the combined exposure to alcohol and acoustic trauma interacted additively to produce greater hearing loss than either alone.

Animals↗
PubMed1991

Maternal and paternal alcohol use: effects on the immune system of the offspring.

There is no single mechanism which can account for such a complex biological phenomenon as immune regulation, nor is it clear how alcohol teratogenicity exerts its multiple adversive effects, including lasting immune deficits. Much of the research aimed at unravelling effects of pre- or early postnatal alcohol exposure on the organism's defense mechanisms and long-term health risks has been phenomenological. A better understanding of mechanisms which underlie alcohol effects on immune competency will require integrated studies of the neuro-immune-endocrine networks.

Adult↗
PubMed1991

Alarm substance emitted by rats in the forced-swim test is a low volatile pheromone.

A series of studies was conducted to determine if the alarm substance produced by rats in the forced-swim test satisfies criteria for pheromones: well-defined behavioral effect, species specificity, minimal influence of experience and control for nonspecific arousal. The alarm substance satisfied these criteria. Additional studies involving activity testing in the presence of the alarm pheromone and preference/avoidance for odors emanating from cylinders containing the pheromone indicated it has very low volatility.

Animal Communication↗
PubMed1991

Gradient of alarm substance in the forced swimming test.

Three studies were conducted with rats to study the effects of a proposed alarm substance released during the forced swimming test. In the first study, rats were retested in water previously swum in but which had been subsequently diluted to varying degrees. When water was diluted by more than 25% the proposed alarm substance could no longer be detected. In the second study, rats were retested at various times after initial testing. This study showed that the alarm substance was still active by eight days after it had been initially released. The final study tested animals to see if the alarm substance could be depleted by repeated testing. Testing animals for more than an hour did not result in depletion of the alarm substance. These three studies suggest that the proposed alarm substance secreted by rats during the forced swimming test has considerable biological significance.

Animals↗
PubMed1991

Behavior and corticosteroid response of Maudsley reactive and nonreactive rats in the open field and forced swimming test.

Maudsley reactive (MR) and nonreactive (MNRA) male rats were tested in the open field and in the forced swimming test. MR rats defecated more and were less active than MNRA rats in the open field. MR rats also defecated more, but were more immobile in the forced swim test. The two strains did not differ significantly in basal corticosteroid levels or corticosteroid levels in response to either test. These results suggest that the increased defecation rates exhibited by MR rats in various tests are not indicative of a general increase in "emotionality" or stress level.

Animals↗
PubMed1991

A revised conservative estimate of the incidence of FAS and its economic impact.

We have conducted a new analysis of the incidence of fetal alcohol syndrome (FAS) and its economic impact based on prospectively gathered data of consecutive pregnancies. This more conservative analysis reflects our concern over possible inclusion of "false positives" in our previous estimate and now puts the overall rate in the western world at 0.33 cases per 1000. The estimate among whites is 0.29 per 1000 compared with 0.48 per 1000 for blacks. We did not include estimates for native Americans owing to the absence of prospectively gathered data on FAS for this group. Retrospective studies suggest larger disparities. Both prospective and retrospective studies may be influenced by examiner bias especially for minorities since minorities are often evaluated against standards derived from whites. Based on our estimates and the number of black and white children born each year, we estimate that about 1200 children are born with FAS each year in the United States. This is a probable lower limit based on considerations of ascertainment and absence of relevant information for other minorities such as native Americans. In calculating economic costs, we have now adjusted our estimates to take into account costs that would be incurred whether cases were FAS or not, and also have now included estimated costs for anomalies in FAS cases not considered in previous estimates. Based on these considerations, we now estimate the incremented annual cost of treating this disorder at $74.6 million. About three-quarters of this economic burden is associated with care of FAS cases with mental retardation.(ABSTRACT TRUNCATED AT 250 WORDS)

Costs and Cost Analysis↗
PubMed1991

Alcohol consumption does not affect fathers but does affect their offspring in the forced swimming test.

Male rats that had consumed alcohol for seven months did not differ significantly from controls in their immobility response in the forced swimming test. In contrast to this observation, the offspring of these males exhibited a significant dose-related decrease in immobility. These results suggest that while alcohol's effects may not be observable in males consuming it, this does not necessarily mean that it has no important biological effects on these males. However, these effects may not be appreciated until their offspring are examined.

Animals↗
PubMed1991

A revised estimate of the economic impact of fetal alcohol syndrome.

A revised estimate of the national economic impact of fetal alcohol syndrome (FAS)-related abnormalities was conducted. The present evaluation included "corrections" for background rates of low birth weight, and costs normally incurred for housing and food regardless of whether an individual requires institutionalization or not. Additional anomalies were included along with hospital costs provided for in diagnostic-related groups. The current estimate for annual costs related to FAS is $249.7 million, which is about $80 million less than our previous estimate. This estimate is lower due to a slightly lower number of cases with low birth weight, a correction for costs that would otherwise have occurred, and exclusion of costs (about $75 million) for annual semi-independent support for individuals with IQs in the 70-85 range. Nonetheless, mental retardation accounts for almost 60% of the estimated total cost. A quarter of a billion dollars per year remains a high economic incremental cost by any reasonable standard and represents a benchmark against which costs of potential prevention strategies may be judged.

Cross-Sectional Studies↗
PubMed1990

Lack of lead effects on fetal development and offspring learning when combined with alcohol in the Long-Evans rat.

Two studies were conducted to evaluate the interactive effects of alcohol and lead during pregnancy in rats. Our purpose was to see if lead, as lead acetate, would influence the alcohol effect already known to exist. In the first study, pregnant Long-Evans rats received lead (as lead acetate), alcohol (20% w/v), or lead plus alcohol once a day on gestation days (GD) 10-20. On GD 20, when animals were sacrificed, mean blood alcohol levels were consistently higher for the lead-plus-alcohol-dosed groups compared to alcohol alone, but these two groups did not differ in maternal weight gain, percent resorptions, litter size, or fetal weight. Mean blood lead levels were not consistently higher in the lead-plus-alcohol groups compared to lead only, but the lead-plus-alcohol groups differed significantly from the lead-only groups at higher doses in the previously mentioned parameters. The lead-only groups did not differ from vehicle controls in any parameter in spite of blood lead levels as high as 300 micrograms/dl. In the second experiment, animals given a combination of alcohol and lead did not differ in activity, passive avoidance, or active avoidance learning compared to animals given alcohol or lead alone. Animals given lead only or the combination of lead plus alcohol had longer first trial latencies in the passive avoidance test. The data indicate that neither lead nor alcohol attenuates or potentiates each other's effects on reproduction or learning behavior in the Long-Evans rat even at high blood lead levels.

Animals↗
PubMed1990

Paternal alcohol exposure: paradoxical effect in mice and rats.

Male mice consumed liquid alcohol diets containing 25%, 10% or 0% ethanol-derived calories (EDC). Animals receiving the 10 and 0% EDC diets were pair fed to those consuming the 25% EDC diet. After 7 or 14 weeks of consumption, males were bred to non-treated females. Offspring were tested for swimming behavior at 75 days of age. Offspring sired by alcohol-consuming males were more immobile regardless of duration of paternal alcohol consumption or housing conditions (group or isolated). Imipramine (5, 15 mg/kg) reversed this effect such that after drug treatment, alcohol-sired offspring were less immobile than controls. Propranolol (1, 3 mg/kg) eliminated the group differences. Yohimbine (1, 10 mg/kg) significantly increased immobility in all groups but did not reverse the effects of paternal alcohol consumption. Metergoline (1 mg/kg) increased immobility in all groups but did not reverse the effects of paternal alcohol exposure. When rat offspring of alcohol-consuming fathers were tested, their swimming behavior was opposite to that of mice (i.e., rats were less immobile). However, as observed in mice, the effect was reversed by imipramine. These results extend the evidence for paternally mediated behavioral mutagenesis. They also indicate that the direction of induced changes are species dependent and that some of these effects, regardless of direction of change, are mediated by neurochemical changes sensitive to imipramine.

Animals↗
PubMed1990

Maternal age does not affect tetrahydrocannabinol's in utero actions in rats.

The potential contribution of maternal age to tetrahydrocannabinol's (THC) in utero effects in rats was studied. Pregnant animals were intubated with 25, 10 or 0 mg/kg of THC from gestation day six to parturition. Animals in the 10 and 0 mg/kg groups were pair fed to those given the 25 mg/kg dose. Each series of doses was administered to females three, four or six months of age. THC lowered maternal weight gain and weights of offspring at birth and at 21 days of age, but did not affect litter size, spontaneous alternation or passive avoidance learning in offspring. Increased maternal age was associated with smaller litter size and lower birth weight and weight at 21 days, but did not interact significantly with THC.

Animals↗
PubMed1990

Effects of low doses of alcohol on delta-9-tetrahydrocannabinol's effects in pregnant rats.

Pregnant rats were intubated with 50 mg/kg of delta-9-tetrahydrocannabinol (THC) or with THC plus alcohol to determine if a low dose of alcohol (1 g/kg) would significantly increase blood levels of THC. On the basis of this study, a second study was conducted in which pregnant rats were intubated with THC (50, 25 or 0 mg/kg) plus alcohol (2, 1 or 0 g/kg) from gestation day six to parturition. THC reduced birth weights but did not significantly affect litter size or passive avoidance learning. Alcohol did not have a significant effect on offspring birth weight nor did it interact with THC to affect offspring.

Animals↗