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Biomedical subjects

W P Bellingham

Publications and source records attributed to W P Bellingham.

12 recordsLinked to original sources

Sex differences in voluntary locomotor activity of food-restricted and ad libitum-fed rats. Implications for the maintenance of a body weight set-point.

1. Male and female Wistar-strain rats were studied under either ad libitum or 23-hour food restriction conditions both with and without access to a running wheel. 2. Daily measures were taken of body weight, food consumption and wheel revolutions. 3. It was observed that food restriction was associated with decreased food consumption and body weight but increased wheel revolutions. 4. Irrespective of feeding regime, females exhibited higher running rates than males.

Animals↗

Effect of alcohol content on beer consumption by rats.

Three brands of beer of varying alcohol content were presented to separate groups of male rats. The consumption data indicated, firstly, an inverse relationship between acceptability of the beer and its alcohol content. The data also indicated that the acceptability of full-strength beer could be augmented by prior exposure to low-alcohol and alcohol-free beer. The results are discussed with reference to orosensory- and inebriation-based models of alcohol consumption.

Alcohol Drinking↗

Ovarian hormone effects on activity, glucoregulation and thyroid hormones in the rat.

Ovarian hormonal influences on the range of physiological and behavioral variables which combine to affect overall energy balance are poorly delineated. In the present study 4 groups of virgin, female rats (intact, ovariectomized, ovariectomized with estrogen replacement and ovariectomized with estrogen plus progesterone) were allowed access to running wheels and activity; food intake and weight gain were measured initially under food restricted, then under ad lib conditions. Serum insulin, glucose, thyroxine (T4) and triiodothyronine (T3) were determined on trunk blood samples obtained at the end of the experiment. Ovariectomy resulted in an increased rate of weight gain through reduced activity and T3 but food intake was unchanged. Insulin levels were greatly reduced. Estrogen replacement restored activity to the intact group's level and normalized weight gain. Insulin and T3 were also raised to control levels but T4 was reduced as was serum glucose. Estrogen plus progesterone replacement reduced weight gain markedly and increased T3 with normal T4. Despite the lower body weight this group was hyperglycemic and hyperinsulinemic suggesting insulin resistance. The results have important implications for the glucoregulatory and energy balance perturbations of ovarian hormone fluctuations and focus particularly on progesterone.

Animals↗

Effects of scheduled food and water deprivation on food intake, water intake and body weight of cage-adapted and cage-naive rats.

The first experiment examined the effects of four food-deprivation schedules and four water-deprivation schedules on body weight, food intake and water intake of adult rats over ten days of deprivation and two days of recovery. During food deprivation, water intake was gradually reduced. During water deprivation, daily food intake was initially depressed but eventually returned to ad libitum levels. Consumption of restricted commodities increased over the deprivation phase. Experiment 2 showed that mutual deprivation of food and water are more apparent in rats not previously adapted to the test environment and the final experiment indicated that this was due to the inexperience of cage-naive rats in feeding under novel conditions. The results are evaluated in relation to the environmental factors that may play as great a role as physiological processes in regulating the feeding/drinking behaviour of laboratory rats.

Animals↗

Effect of guanethidine sympathectomy on intake and body weight of intact and LHA-lesioned rats.

The present study investigated the role of direct sympathetic nervous system innervation of the viscera in the reduced body weight levels maintained by animals bearing lesions of the lateral hypothalamic area (LHA). Adult, male rats with, and without, electrolytic lesions of the (LHA) were treated with guanethidine sulphate (25 mg/kg IP daily for 6 weeks) to produce destruction of the peripheral sympathetic nervous system. LHA-lesioned rats displayed the expected reduced body weight compared to intact rats. Sympathectomy in lesioned rats resulted in an identical pattern of effects to that seen in intact rats. Transitory reductions in intake were effected and weight was significantly depressed by one week of guanethidine treatment. However, weight had recovered to control levels in both intact and lesioned drug-treated groups by the end of the experiment. The reduced body weight level maintained by LHA-lesioned rats was not altered by guanethidine sympathectomy. The major conclusions are (1) the reduced body weights maintained following LHA lesions are not dependent upon an intact sympathetic nervous innervation of visceral organs, and (2) peripheral sympathectomy in intact adult rats has no chronic effects on either body weight or food and water intake.

Animals↗

Differential use of food and water cues in the formation of conditioned aversions by domestic chicks (Gallus gallus).

The differential use of cues in the formation of conditioned aversions to food and water by domestic chicks was examined. Aversions were more readily demonstrated to red food than to red water, and taste was found to be an adequate cue with water but not with food (Experiments 1-5). It is suggested that such asymmetry mitigates the usefulness of the concept of "belongingness" and can more profitably be viewed as a function of the particular response topographies adopted with respect to food and water. The sixth experiment demonstrated that aversions for colored water could be readily demonstrated when the response topography for drinking was manipulated to ensure the utility of visual cues in selecting fluids. These findings are discussed with respect to a general process approach to conditioned aversion learning.

Animals↗

Aversive properties of cycloheximide versus memory inhibition in chickens' formation of visually cued food aversions.

No memory inhibition for a conditioned aversion in chickens, produced by pairing a novel colored food and lithium chloride (LiCl), was found when cycloheximide (CXM) was injected intracerebrally (IC) two or six hr before feeding. Good conditioned aversions were found when CXM alone was injected IC following consumption of the novel food. No aversions were found when CXM alone was injected IC two hr before feeding. Possible reasons for apparent memory inhibition using CXM in some appetitive paradigms are discussed.

Animals↗