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The review provides information on the effect of dietary fibers on the production of key gastrointestinal hormonal peptides that affect eating behavior and the formation of feelings of hunger and satiety. The mechanisms of action of dietary fiber on the production of appetite-regulating peptides are discussed. Modulation of gastrointestinal hormonal peptide secretion by dietary fibers is involved in the regulation of the balance of energy, appetite, and body weight. The aim of the research was to expand the understanding about the effects of dietary fiber on the secretion of major gastrointestinal hormonal peptides involved in appetite control, the formation of feelings of hunger, satiety and satiation. Results . Gastrointestinal hormones, as physiological regulators of food intake, play an essential role in the formation of feelings of hunger, satiety and satiation, helping to reduce appetite and maintain normal body weight. Various dietary fibers, depending on the physic-chemical properties, the amount and duration of the consumption period, can have a modulating effect on the secretion of the hunger hormone ghrelin and the hormones of satiety: leptin and intestinal peptides (glucagon-like peptide-1, cholecystokinin and YY peptide). Conclusion . Dietary fiber influence on processes of energy intake, food ingestion and nutrient absorption in gastrointestinal tract, enhance neuroendocrine responses, modulate release of appetite-regulating hormones involved in energy balance and regulation of feelings of hunger and satiety. The possibility to promote a favorable profile of the endogenic gastrointestinal hormones by inclusion of dietary fiber in food ration both in the form of the natural food and additionally as dietary supplements is of interest as one from strategies of over appetite control and normal body weight maintenance., Competing Interests: The authors declare no overt and potential conflict of interest related to the publication of this article., (Copyright© GEOTAR-Media Publishing Group.)

The study is carried out the 1st-, 3rd-, 5th-, 7th, and 10th-day old free moving or loosely fixed rat pups (P1-10). In satiated and submitted to the 24-h starvation rat pups, parameters of spontaneous periodical motor activity (SPMA) and the blood glucose content were studied. The total glucose level in hungry rat pups was, on average, 1.5-2.5 times lower than in satiated animals. Administration of glucose to hungry rat pups increased 6-11 times its concentration in blood as compared with the animals not obtaining glucose. The glucose administration to the satiated rat pups led to a rise of its level in blood from 2 to 5 times as compared with intact animals, which was 2-3 times less than in the case of hungry animals. Analysis of pattern of motor activity recorded under conditions of the glucose deficit caused by the 24-h starvation of rat pups did not reveal significant changes of ratio of rhythmical components. Introduction of glucose to hungry and to the lesser degree to satiated rat pups led to potentiation of the minute rhythm of activity in all age groups. An exception was the first day after birth when the glucose administration to satiated rat pups promoted an enhancement of the decasecond rhythm and a decrease of the total level of motor activity. Comparison of ontogenetic dynamics of the SPMA parameters and the glucose content in blood of hungry rat pups revealed the clearly expressed regularity absent in the satiated animals: the glucose level in blood was higher during activity than in the state of rest. The performed study has shown that intensity, duration, and, to a degree, pattern of SPMA in the newborn rat pups depend on the level of satiety, and can be significantly changed in the artificially produced hypo- or hyperglycemia. The existing ontogenetic fluctuations in the character of reaction at performance of the glucose tolerance test can be connected both with morphofunctional maturation of the motor system and with immaturity of various chains of carbohydrate metabolism.

We studied the specific features of ultrasonic vocalization of Wistar rats in various motivational and emotional states. No significant changes were found in ultrasonic vocalization of rats during experimental food motivation and after the satisfaction of food requirements. The state of thirst and satisfaction of water requirements in animals were associated with an increase in the mean frequency of ultrasound and dominance of ultrasonic waves of a higher frequency. The formation of a negative emotional state in rats after immobilization with simultaneous electrocutaneous stimulation was accompanied by a decrease in the total duration of ultrasonic vocalization and shift in the power spectrum of ultrasound towards the dominant frequencies of 20-30, 40-50, and 80-90 kHz. During the post-stress period, the maximum power of ultrasonic waves approached the baseline (30-40 kHz). Our results indicate that the formation of various motivational and emotional states in rats is characterized by specific patterns of ultrasonic vocalization. Therefore, the parameters of ultrasonic vocalization can serve as an objective criteria for the subjective state of a living organism.

In chronic experiences on 5 rabbits subjected to airmentary deprivation, impulse activity of the chewing muscles before and after the food was given to them was studied. It has been established, that flashes of bruxism nonoperiodically arise in rabbits in conditions of hunger and satiation and are shown in electric activity of masseter and mylohyoideus muscles in the form of burst type phase impulse activity of MU. Bruxism in conditions of hunger and satiation reflects in the same type way in structure of the time organization of impulse activity of the chewing muscles in the form of bimodal distributions of interpulse intervals and monomodal distributions of periods of the burst type rhythmic of action potentials. The alimentary motivation exerts inhibitory modulating influence on frequency of phase discharge activity of chewing center motoneurons in medulla oblongata and frequency of generation of the action potentials' bursts by the chewing muscles participating in bruxism. Impulse activity of chewing muscles during bruxism and food intake behaviour has the same-type character. Bruxism arises due to reorganization of the impulse activity of chewing center motoneurons innervating masseter and mylohyoideus muscles. There is no basis to suppose the presence of the special center of bruxism in medulla oblongata.Bruxism in rabbits an be considered as natural model of the first type bruxism in man.

The character of impulsation of single neurons in the lateral hypothalamic and amygdalar central nucleus of rabbits recorded in bilateral derivations during quiet wakefulness, after 24-h food deprivation, and after satiation was studied by plotting autocorrelation histograms and by counting the mean frequency of discharges. During the transition from hunger to satiation, the character of impulsation of neurons in hypothalamus and amygdala changed in different ways: (1) a greater number of hypothalamic than amygdalar neurons changed their mean discharge frequency (85 versus 56%, respectively); (2) in hunger, the number of hypothalamic neurons with delta-frequency oscillations decreased as compared to quiet wakefulness and satiation, and in the amyglala the number of neurons with beta2-frequency oscillations increased; (3) in hunger, the number of hypothalamic neurons with bursting and periodic discharges decreased and the number of amygdalar neurons with equiprobabilistic discharges increased. During state alternation (according to the autocorrelation histograms) the strongest changes in the character of neuronal discharges took place in the left hypothalamus and left amygdala. The maximum differences in neuronal impulsation between the left and right hypothalamus were observed in the state of hunger and between the left and right amygdala, after satiation.

The behavioral effect of electrical stimulation of the lateral hypothalamus with a current of equal parameters in chronic experiments on dogs depended on the signal significance of the surroundings. Stimulation of the lateral hypothalamus against the background of a defensive situational reflex in dogs which were in an experimental situation for the first time, far from evoking orientation to food and the act of feeding, enhanced the background fear reaction. After transformation of the defensive signal significance of the situation into an alimentary one, stimulation of the lateral hypothalamus began to activate the alimentary instrumental reflex and the act of feeding. However, at first the former was manifested irregularly. Combinations of stimulation of the lateral hypothalamus and achievement of the alimentary instrumental reflex with subsequent reinforcement stabilized and enhanced the alimentary instrumental reflex to the stimulation of the lateral hypothalamus.

A study was made of the temporal characteristics of motor reactions in cats and dogs to an instantaneous change in the shape of a photic signal. The latency value is an individual characteristic of the animal; it undergoes only slight fluctuations on different experimental days. No influence has been found of the intersignal interval magnitude (8--70 sec) on the duration of latencies. Longer experiment (about 300 signals in three hours) leads to longer latencies and their greater variability.