Biomedical subjects

E Hård

Publications and source records attributed to E Hård.

40 records · Page 3Linked to original sources

PubMedDate not supplied

Effects of ibotenic acid lesions of the ventral striatum and the medial prefrontal cortex on ethanol consumption in the rat.

The purpose of this study was to to assess the effect on ethanol drinking of ibotenic acid lesions in the medial prefrontal cortex and the ventral striatum of female rats with continuous access to water and a 6% ethanol solution. Ibotenic acid infusions in the prefrontal cortex did not affect ethanol intake at any time, but a significant increase in water intake was observed on the third postoperative week. Ventral striatal lesions significantly increased ethanol intake during the first 2 postoperative weeks. On the third week consumption was not significantly different from vehicle-infused controls. Apparently, then, severe excitoxic injury to the ventral striatum is compatible with normal, or increased, intake of ethanol; in contrast, similar lesions reduce the intake of other drugs of abuse such as psychostimulants and opioids.

Alcohol Drinking↗

PubMedDate not supplied

Amphetamine-induced hyperactivity: differences between rats with high or low preference for alcohol.

This study determined the relationship between ethanol intake and spontaneous and amphetamine-induced locomotor activity. Locomotion was studied in high-preferring (HP; > 70% of total fluid intake consumed as alcohol) and low-preferring (LP; < 20% of total fluid intake consumed as alcohol) male Wistar rats with free access to water and a 6% (v/v) ethanol solution for 3 weeks. Following an alcohol-free 3-week period, the animals were tested for spontaneous motor activity for 1 h. One week later, locomotion was recorded in the same activity boxes following a subcutaneous injection with d-amphetamine sulfate (1 mg/kg). For determination of plasma levels of corticosterone, blood samples were taken immediately after each of the two tests for locomotor activity. There was no difference between HP and LP rats with regard to spontaneous locomotor activity. Neither were there any differences in plasma levels of corticosterone between the groups. Amphetamine stimulated locomotion in both HP and LP rats, but to a significantly greater extent in HP animals. Both groups had higher blood levels of corticosterone after the amphetamine test than after the drug-free test, but the corticosterone increase was significantly larger in the HP than in the LP rats. These data indicate that the same neural substrate (e.g., the mesocorticolimbic dopamine system) may mediate important aspects of both ethanol drinking and amphetamine responsiveness. Individual differences in the properties of this substrate may account for the finding that ethanol drinking and amphetamine responsiveness covary. A possible explanation for this association may be that prior consumption of ethanol sensitizes the neural substrate responsible for amphetamine-induced hyperactivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Drinking↗

PubMedDate not supplied

Sexual orientation in male rats prenatally exposed to ethanol.

Previous studies have shown that prenatal ethanol exposure causes feminization of the male offspring, as evidenced by display of female sexual response (lordosis), when mounted by a stud male. In the present study we examined whether or not the feminization induced by prenatal ethanol exposure also affected a different aspect of sexually motivated behavior, namely, the approach towards a receptive female normally displayed by male rats. The testing apparatus consisted of an open-field arena with two small boxes in which were placed the stimulus animals, in one box a male rat, in the other a receptive female. The partition between the stimulus and the experimental animals consisted of a metal net allowing both animals to see and smell each other without actual physical contact. The tendency to approach the receptive female or the male was assessed by the proportion of the observation period the experimental male spent near the receptive female or the male rat, respectively. The experiment was performed on the adult male offspring of mothers consuming a liquid diet containing 5% ethanol, giving rise to a daily ethanol intake of about 14 g/kg. One group of control mothers was given a liquid diet without alcohol but isocaloric with the alcohol-containing diet. Another control group had free access to water and lab chow. The results showed that male offspring of both control groups devoted 29% of the observation period near the receptive female as compared to 13% near the male. The ethanol-exposed males on the other hand devoted as much time, 20%, to the male as to the receptive female.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMedDate not supplied

Effects of early weaning and social isolation on subsequent alcohol intake in rats.

The present study investigated the influence of early weaning and separation from mother and littermates on voluntary ethanol intake and general activity during prepuberal age, and adult age corticosterone levels. On day 16 after birth the male offspring of a litter were divided in three groups, each subjected to a different rearing condition: 1)early weaned and isolated from its littermates; 2) early weaned but growing up together with two littermates; 3) staying with mother and two littermates. On day 25 the animals were tested for general activity including assessment of fearfulness. From day 30 all animals were given a free choice between water and ethanol solution. The ethanol concentration was increased by 2% during each of the following weeks until 10% was reached during the 5th week. Ten days later, after cessation of alcohol testing, blood samples were taken from the tail for assessment of plasma levels corticosterone. The isolated, early weaning pups displayed higher activity levels than both normally reared pups and group-living, early weaning pups. The quotient peripheral locomotion/total locomotion was lower for the isolated pups compared with the other groups, suggesting less fearfulness in the early weaned, isolated pups. For 2%, 4%, and 6% ethanol solutions the normal-reared rats consumed more ethanol and displayed higher ethanol preference than either of the early weaned groups of animals. No group differences were observed either at 8% or 10% ethanol solutions. Levels of plasma corticosterone in adult age in the early weaned rats were slightly reduced, not reaching statistical significance, compared to the normally weaned animals.

Aging↗