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Biomedical subjects

B J Rolls

Publications and source records attributed to B J Rolls.

At least 109 records · Page 6Linked to original sources
PubMed1982

How sensory properties of foods affect human feeding behavior.

The sensory properties of food which can lead to a decrease in the pleasantness of that food after it is eaten, and to enhanced food intake if that property of the food is changed by successive presentation of different foods, were investigated. After eating chocolates of one color the pleasantness of the taste of the eaten color declined more than of the non-eaten colors, although these chocolates differed only in appearance. The presentation of a variety of colors of chocolates, either simultaneously or successively, did not affect food intake compared with consumption of the subject's favorite color. Changes in the shape of food (which affects both appearance and mouth feel) were introduced by offering subjects three successive courses consisting of different shapes of pasta. Changes in shape led to a specific decrease in the pleasantness of the shape eaten and to a significant enhancement (14%) of food intake when three shapes were offered compared with intake of the subject's favorite shape. Changes in just the flavor of food (i.e., cream cheese sandwiches flavored with salt, or with the non-nutritive flavoring agents lemon and saccharin, or curry) led to a significant enhancement (15%) of food intake when all three flavors were presented successively compared with intake of the favorite. The experiments elucidate some of the properties of food which are involved in sensory specific satiety, and which determine the amount of food eaten.

Adolescent↗
PubMed1982

Physiological mechanisms for thirst in the nonhuman primate.

The relationship between body fluid deficits and drinking has been investigated in a nonhuman primate. Intravenous sodium chloride infusions (0.93-3.25 M) given to rhesus monkeys caused drinking correlated with increases in plasma osmolality and sodium concentrations. Sucrose infusions (0.3 M in 0.15 M NaCl) also caused drinking while equiosmolal urea infusions did not. It was found that the drinking threshold corresponded to a 2.3% increase in plasma osmolality. Water deprivation for 24 h caused significant cellular dehydration, as indicated by a 5.8% elevation in plasma osmolality that exceeded the threshold for thirst, and a significant hypovolemia as indicated by elevated plasma protein and hematocrit values. Intravenous water preloads decreased plasma osmolality and produced a dose-related decrease in subsequent drinking. Infusions that restored plasma osmolality to predeprivation values, reduced intake by 85%. Intravenous isotonic saline preloads which abolished the hypovolemia did not have a consistent effect and reduced mean water intakes by only 3.2%. Thus in the rhesus monkey, cellular dehydration is an effective stimulus for thirst, and it is the primary determinant of drinking after water deprivation, used as an example of a natural thirst stimulus. In contrast to findings in nonprimates, the extracellular deficit contributes very little to drinking after water deprivation.

Animals↗
PubMed1980

Impaired lipogenesis in mammary glands of lactating rats fed on a cafeteria diet. Reversal of inhibition of glucose metabolism in vitro by insulin.

In lactating rats fed on a cafeteria diet (chow plus palatable high-energy foods) the decreased glucose uptake and lipogenesis in vitro in acini correlated with the depressed mammary-gland lipogenesis in vivo. Insulin in vitro restored the rate of glucose uptake and its conversion to lipid to values approaching those for acini from rats fed on the chow diet alone.

Animals↗
PubMed1980

Drinking in the rhesus monkey: peripheral factors.

Rhesus monkeys prepared with chronic cannulae implanted in the stomach and duodenum were water deprived for 22.5 hr. With both cannulae closed, a mean of 137 ml was drunk within a 60-min period. When ingested water drained freely from an open gastric cannula, continuous drinking far in excess (878 ml mean intake) of normal occurred. Sham drinking also exceeded (634 ml mean intake) normal when ingested water drained through an open duodenal cannula. This pattern of continuous sham drinking indicates that oropharyngeal stimulation is not sufficient alone, or together with the passage of water through the stomach and the initial part of the duodenum, to terminate drinking. Duodenal infusions of water (25-100 ml) slowed or stopped gastric sham drinking in a dose-dependent fashion, but equivalent infusions of isotonic saline were without effect. Thus, pre- or postabsorptive signals at or beyond the level of the intestine distal to the site of the duodenal cannula are probably important for the termination of drinking in the rhesus monkey.

Animals↗
PubMed1980

Drinking in rhesus monkeys: role of presystemic and systemic factors in control of drinking.

The effect of 24-hr water deprivation and subsequent drinking on systemic fluid balance was determined in rhesus monkeys prepared with indwelling cardiac catheters. Significant intracellular and extracellular depletions, as indicated by increased plasma sodium concentrations, osmolality, and plasma protein concentrations, resulted from the deprivation. An early attenuation in rehydrational drinking rate (2--4 min) was not associated with changes in systemic fluid balance, which suggests presystemic influences on behavior at this time. When drinking terminated (10 min), however, plasma dilution was significant. In experiments in which monkeys were sham drinking (open gastric cannula), water but not isotonic saline infusions, given through an intestinal cannula, reduced drinking rate and produced significant plasma dilution. Intravenous water infusions reduced drinking to only a comparable extent despite more rapid and substantial plasma dilution. Thus, systemic absorption does not account entirely for the effect of intestinal water infusions on drinking. It is concluded that stimulation of mechanisms both presystemically (within the intestine or the hepatic portal circulation) and systemically is important in the control and termination of rehydrational drinking in this species.

Animals↗
PubMed1980

Persistent obesity in rats following a period of consumption of a mixed, high energy diet.

1. Adult male hooded rats which were offered a mixed, high energy diet for 90 days were hyperphagic and became significantly obese compared to chow-fed control rats. Fasting plasma insulin and glucose levels were initially elevated in the experimental rats, but later in the 90 day period were similar to control levels. 2. When the high energy foods were withdrawn after 90 days and just chow was available, the obese rats maintained the elevated body weights. The obese rats were initially hypophagic, but chow intakes rapidly reached control levels. Plasma insulin and glucose levels were similar in both groups, suggesting that the persisting obesity may not be associated with altered insulin resistance. 3. Five weeks after withdrawal of the 'fattening' diet, half of the experimental rats were offered restricted access to chow for 27 days to reduce their weights to control levels. When the rats were again given free access to chow, they returned to the previously elevated weight. 4. Eighteen weeks after withdrawal of the 'fattening' diet, the experimental rats had significantly elevated body weights and fat stores. The elevated body weight was not simply due to increased growth because, although the experimental rats had slightly more lean body mass than the control rats, the increase in fat was not related to body size.

Animals↗
PubMed1980

Thirst following water deprivation in humans.

The effect of 24-h water deprivation and subsequent drinking on systemic fluid balance and subjective sensations has been determined in human beings. The deprivation caused significant intracellular and extracellular depletions, thirst, and a dry unpleasant tasting mouth. During rehydration, subjects drank 65% of their total intake within 2.5 min. The marked decrease in drinking rate thereafter, and the alleviation of thirst, occurred before plasma dilution had become significant. This attenuation of drinking was subjectively attributed to stomach fullness. Presystemic factors may therefore be important for drinking termination in humans. Within 20 min systemic deficits were removed, but intermittent drinking continued at a low rate, reportedly to alleviate unpleasant oral sensations, Following rehydration, the concentrated urine of hydropenia had disappeared. However, the excretion of solute-free water varied between subjects. Plasma renin activity was significantly elevated by water deprivation, while after rehydration this activity had decreased to levels not significantly different from predeprivation values.

Adult↗
PubMed1979

Bombesin suppresses feeding in rats.

Bombesin (BBS) is a tetradecapeptide originally isolated from amphibian skin1. BBS-like immunoactivity is widely distributed in mammalian gut2-5, and plasma levels have been shown to rise sharply following feeding (ref. 6 and V. Erspamer, personal communication). The physiological actions of BBS are unknown. We have previously shown that the classic gut hormone cholecystokinin (CCK) is a powerful and specific suppressor of food intake7-9. Although CCK and BBS lack common amino acid sequences, they have certain common actions on gut viscera10,11. We have now shown that BBS also suppresses food intake, and we compare its action with that of CCK.

Animals↗
PubMed1977

Role of angiotensin in thirst.

Angiotensin is a potent dipsogenic substance and causes elevated water intake in some pathological conditions but as yet no physiological role for angiotensin in normal thirst has been proven. If angiotensin is important in normal drinking, then it should contribute to the drinking which follows water deprivation. The rehydration of bilaterally nephrectomized rats, rats with bilateral ureteric ligation and control rats was compared after 21 hours of water deprivation. The total intake during the 6 hour rehydration was the same in the 3 groups despite the differences in the level of circulating angiotensin. Thus the renal renin-angiotensin system is not essential for deprivation-induced drinking. Another way to test any contribution to drinking by angiotensin is the administration of the competitive angiotensin inhibitor, saralasin acetate. In a control experiment saralasin acetate was found to block the dipsogenic effect of intravenous angiotensin. The infusion of saralasin acetate in a wide range of doses did not, however, affect the drinking following ligation of the inferior vena cava. Thus angiotensin is not essential for drinking following caval ligation. Two possible explanations for these results are that angiotensin is not normally involved in these types of thirst or that there is redundancy in the control of drinking with compensation for blocked mechanisms.

Angiotensin II↗
PubMed1977

Body fluid changes which influence drinking in the water deprived rat.

1. After overnight deprivation of water both the cellular and extracellular fluid volumes are significantly reduced in the rat. 2. In the rat with functional kidneys oral, intragastric or intravenous preloads of 10 ml. water reduce the total water intake after 1 hr by 64-69%. These preloads restore plasma osmolality to pre-deprivation levels but have little effect on plasma volume. 3. In the same rats if the plasma volume is restored with an oral, intragastric or intravenous preload of 10 ml. of an isotonic balanced salt solution which has little effect on osmolality, drinking is significantly reduced by 20-26%. The reduction of drinking correlated with the volume of the preload of balanced salt. 4. Plasma analysis shown that 1 hr after an oral preload of 10 ml. isotonic balanced salt solution, the extracellular fluid volume of the deprived rats is restored to pre-deprivation levels but osmolality is unchanged. Three hr after the balanced salt preload, extracellular fluid volume is still at pre-deprivation levels and there has been a slight decrease in osmolality due to excretion of salt. 5. In rats which had been nephrectomized or had the ureters ligated so there could be no renal modification of the preloads, the effects of the preloads of water and balanced salt are the same as in rats with intact kidneys. 6. The results indicate that after water deprivation in the rat, changes in both the cellular and extracellular fluid compartment are stimuli to drinking.

Animals↗