Comparison of lever press and nose poke operants for acquiring the demand function for food intake and meal patterns in mice

Male obese and lean Zucker rats were adrenalectomized (ADX) or sham-operated at 10 wk of age. Approximately 16 wk later, patterns of food intake were monitored by computer-interfaced top loading balances. Data were collected from ADX rats before, during, and after access to a corticosterone-supplemented saline solution (20 micrograms/ml). Although total food intake during the precorticosterone treatment period was not different between ADX and sham controls, ADX resulted in attenuation of light cycle food intake, primarily via decreased meal frequency. With steroid replacement, light cycle meal frequency and food intake increased. Despite comparable self-administered dose (20.33 +/- 0.89 vs. 17.05 +/- 1.2 mg corticosterone/period, obese vs. lean), obese ADX rats were more responsive to steroid than were lean ADX rats. This increased responsiveness was reflected by a 30% increase in food intake and 60% increase in body weight gain of obese ADX rats during replacement. Lean ADX rats exhibited no change in total food intake or weight gain with replacement. Further, during corticosterone treatment, obese ADX rats increased meal frequency, total food intake, and consumption of large meals (greater than or equal to 4 g) during the dark cycle. Significant postprandial correlations were found only in obese ADX rats, both with and without replacement during the dark cycle. These results suggest adrenal glucocorticoids have a minimal effect on food intake and meal patterns in lean Zucker rats but significantly alter intake and meal patterns in obese rats.

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Diurnal food intake patterns of broiler chickens offered a choice of feed varying in protein content

Proceedings of the British Society of Animal Production (1972) ◽

10.1017/s0308229600021978 ◽

1992 ◽

Vol 1992 ◽

pp. 85-85 ◽

Cited By ~ 1

Author(s):

F. Shariatmadari ◽

J.M. Forbes

Keyword(s):

Food Intake ◽

Protein Content ◽

Protein Intake ◽

Broiler Chickens ◽

The Other ◽

Meal Patterns ◽

Low Protein ◽

Regulate Protein ◽

Intake Regulation ◽

Food Intake Patterns

The ability of broiler chickens to regulate protein intake when given a choice of high- and low-protein feeds has been demonstrated (Shariatmadari and Forbes, 1990). However, it is not know whether birds take several meals from one feed and then several from the other, or whether both feeds are taken in mixed meals. Therefore, to determine how protein intake regulation operates on a meal-to-meal basis, the meal patterns of broiler chickens were automatically recorded when they were offered two feeds of different protein content.

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Reducing effect of a Phaseolus vulgaris dry extract on operant self-administration of a chocolate-flavoured beverage in rats

British Journal Of Nutrition ◽

10.1017/s0007114510001017 ◽

2010 ◽

Vol 104 (5) ◽

pp. 624-628 ◽

Cited By ~ 15

Author(s):

Paola Maccioni ◽

Giancarlo Colombo ◽

Antonella Riva ◽

Paolo Morazzoni ◽

Ezio Bombardelli ◽

...

Keyword(s):

Body Weight ◽

Food Intake ◽

Phaseolus Vulgaris ◽

Lever Press ◽

Fixed Ratio ◽

Rodent Models ◽

Self Administration ◽

Dry Extract ◽

Reduce Body Weight ◽

Derivatives Of

Extracts from or derivatives of Phaseolus vulgaris beans reduce body weight and food intake, including highly palatable foods and fluids, in multiple rodent models of overeating and obesity. The present study was designed to assess whether a standardised P. vulgaris dry extract was effective in reducing also the operant self-administration of a chocolate-flavoured beverage. To this end, rats were initially trained to lever-press for a chocolate-flavoured beverage under a fixed ratio 10 schedule of reinforcement in daily 60 min sessions. Once lever-responding reached stable levels, the effect of a P. vulgaris dry extract on the number of lever-responses for the chocolate-flavoured beverage was determined. Pretreatment with 50, 200 and 500 mg (intragastric) P. vulgaris dry extract per kg produced an approximate 15, 35 and 40 % reduction, respectively, in lever-responding for the chocolate-flavoured beverage. These results indicate the capacity of a P. vulgaris preparation to reduce the reinforcing properties of a highly palatable fluid in rats.

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The Meal Patterns of the Oestrous Cycle and Their Motivational Significance

Quarterly Journal of Experimental Psychology ◽

10.1080/14640747408400438 ◽

1974 ◽

Vol 26 (3) ◽

pp. 489-494 ◽

Cited By ~ 49

Author(s):

R. F. Drewett

Keyword(s):

Food Intake ◽

Direct Effect ◽

Ovarian Hormones ◽

Oestrous Cycle ◽

Sexual Receptivity ◽

Reduce Food Intake ◽

Short Term ◽

Meal Patterns ◽

Nutritional Deprivation ◽

The Way

Food intake was monitored continuously throughout the oestrous cycle of the rat by operant methods. On the night of oestrus the size of meals eaten was reduced and the average intermeal interval was shorter; and even after meals of the same size, oestrous animals returned to eat again more quickly than dioestrous animals. These results suggest that the way in which ovarian oestrogens reduce food intake is by intensifying processes responsible for the short-term satiation of hunger without affecting the motivational processes responsible for its arousal. Signs of motivational arousal at oestrus could thus be the result of a self-imposed nutritional deprivation, rather than a direct effect of ovarian hormones on sexual receptivity.

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Meal patterns and hypothalamic NPY expression during chronic social stress and recovery

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00820.2009 ◽

2010 ◽

Vol 299 (3) ◽

pp. R813-R822 ◽

Cited By ~ 34

Author(s):

Susan J. Melhorn ◽

Eric G. Krause ◽

Karen A. Scott ◽

Marie R. Mooney ◽

Jeffrey D. Johnson ◽

...

Keyword(s):

Food Intake ◽

Social Stress ◽

Recovery Period ◽

Ingestive Behavior ◽

Meal Size ◽

Male Rats ◽

Dominant Male ◽

Mrna Levels ◽

Meal Patterns ◽

Chronic Social Stress

In the present study, we examined meal patterns during and after exposure to the visible burrow system (VBS), a rodent model of chronic social stress, to determine how the microstructure of food intake relates to the metabolic consequences of social subordination. Male Long-Evans rats were housed in mixed-sex VBS colonies (4 male, 2 female) for 2 wk, during which time a dominance hierarchy formed [1 dominant male (DOM) and 3 subordinate males (SUB)], and then male rats were individually housed for a 3-wk recovery period. Controls were individually housed with females during the 2-wk VBS period and had no changes in ingestive behavior compared with a habituation period. During the hierarchy-formation phase of VBS housing, DOM and SUB had a reduced meal frequency, whereas SUB also had a reduced meal size. However, during the hierarchy-maintenance phase of VBS housing, DOM meal patterns did not differ from controls, whereas SUB continued to display a reduced food intake via less frequent meals. During recovery, DOM had comparable meal patterns to controls, whereas SUB had an increased meal size. Hypothalamic neuropeptide Y (NPY) mRNA levels were not different between these groups during the experimental period. Together, the results suggest that exposure to chronic social stress alters ingestive behavior both acutely and in the long term, which may influence the metabolic changes that accompany bouts of stress and recovery; however, these differences in meal patterns do not appear to be mediated by hypothalamic NPY.

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Food intake and meal patterns in rhesus monkeys: Significance of chronic hyperinsulinemia

Physiology & Behavior ◽

10.1016/0031-9384(90)90293-d ◽

1990 ◽

Vol 48 (4) ◽

pp. 519-522

Author(s):

Judy Hannah ◽

Barbara C Hansen

Keyword(s):

Food Intake ◽

Rhesus Monkeys ◽

Meal Patterns

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Salmon calcitonin reduces food intake through changes in meal sizes in male rhesus monkeys

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.90327.2008 ◽

2008 ◽

Vol 295 (1) ◽

pp. R76-R81 ◽

Cited By ~ 11

Author(s):

Nicholas T. Bello ◽

Matthew H. Kemm ◽

Timothy H. Moran

Keyword(s):

Food Intake ◽

Salmon Calcitonin ◽

Rhesus Monkeys ◽

Nonhuman Primates ◽

Dose Range ◽

Meal Size ◽

Meal Patterns ◽

Daily Food Intake ◽

Daily Food ◽

Male Rhesus

Amylinergic mechanisms are believed to be involved in the control of appetite. This study examined the effects of the amylin agonist, salmon calcitonin, on food intake and meal patterns in adult male rhesus monkeys. Fifteen minutes before the onset of their 6-h daily feeding period, monkeys received intramuscular injections of various doses of salmon calcitonin (0.032, 0.056, 0.1, 0.32, and 1 μg/kg) or saline. Salmon calcitonin dose dependently reduced total daily and hourly food intake, with significant decreases at the 0.1, 0.32, and 1 μg/kg doses. Daily food intake was reduced by ∼35%, 62%, and 96%, at these doses, respectively. An analysis of meal patterns revealed that size of the first meal was significantly reduced across the dose range of 0.056 to 1 μg/kg, while average meal size was reduced with the 0.32 and 1 μg/kg doses. Meal number was only affected at the 1 μg/kg dose. Repeated 5-day administration of the 0.1 μg/kg dose resulted in a reduction in daily food intake only on injection day 2, while significant reductions in food intake were observed on all five injection days with a 0.32 μg/kg dose. Daily food intake was also reduced for 1 day after the termination of the 5-day injections of the 0.32 μg/kg salmon calcitonin dose. These sustained reductions in intake were expressed through decreases in meal size. These data demonstrate that salmon calcitonin acutely and consistently decreases food intake mainly through reductions in meal sizes in nonhuman primates.

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Food intake and meal patterns of mice under various schedules of food reinforcement.

Appetite ◽

10.1016/j.appet.2007.03.169 ◽

2007 ◽

Vol 49 (1) ◽

pp. 324

Author(s):

N.E. Rowland ◽

M.A. Chaney ◽

C.H. Vaughan

Keyword(s):

Food Intake ◽

Food Reinforcement ◽

Meal Patterns

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