Pharmacological suppression of eating behavior in relation to diencephalic noradrenergic receptors

The effect of the anorexigenic agents fenfluramine and dexamphetamine was studied on the eating behavior elicited by unilateral injections of noradrenaline in the perifornical area of the rat brain. Both agents were able to inhibit the eating response.Bilateral injections of the α-adrenergic receptor blocker phentolamine were performed into the perifornical area and the effect on eating behavior of rats under three different deprivation conditions was studied. Depression of eating behavior by phentolamine was most pronounced in the group of undeprived rats that were given mealworms as highly appetizing food and absent in the group of rats who were deprived of food for 24 hours. These results are discussed in relation to the role of the noradrenergic system in the regulation of food intake.     

A mathematical model of the food-consumer system I. A case without food replenishment

A simple mathematical model was proposed to describe the dynamics of a food-consumer system. The model was based on the Logistic Theory and consisted of Eqs. (4), (5) and (6). The model was divided into the following three cases for further analyss; i) without food supply except at the initial time, ii) with continuous food supply at a constant rate, and iii) with food supply at varying rates. Only the first model was dealth with in this paper. The assumptions of the model 1 are that a definite amount of food is given only once at the initial time and only the feeding by animals is responsible for the decrease of food, and that the rate of decrease is proportional to the amount of animals. It is also assumed that the growth of animal population is represented by the logistic curve, and that the upper limit of the population is proportional to the amount of food at that time. For simplicity the parameters of basic differential equations are assumed to be constant throughout the time course. Analytical solutions of this non-linear model were given by Eqs. (8), (9), (10) and (11). The properties of time course of the food amount and consumer population were discussed from the mathematical and biological points of view. The method of the estimation of the three constants λ,b, and c from the experimental data was also suggested. Since we had no available data for animal populations, we applied the model, regarding reserve substance as x and new plant body as y, to the data of the initial growth of Azuki bean plant in the dark. This model is very simple, but it may be useful for analyzing the behavior of food-consumer system. And it may give some clue to the analysis of the more complex systems.     

布氏田鼠合作贮食行为及其影响因素

合作贮食是社会性动物应对食物匮乏的重要对策,但其内在的生态学机制尚未阐明。本文以布氏田鼠为研究对象,根据亲缘关系划分为亲缘组和非亲缘组。在人工实验箱中录像统计不同组别合作贮食行为占用时间的差异,探究亲缘关系对合作贮食行为的影响,并利用相关性分析探究亲缘组个体对贮食的贡献—收益关系以及与贮食行为相关的个体特征因素。结果表明,在组间水平上,与非亲缘组相比,亲缘组的布氏田鼠表现更多的合作贮食。在亲缘组个体水平上,不同个体对贮食的参与度和贡献度存在很大差异。个体对合作贮食的付出与其取食的收益呈显著负相关关系,并且个体合作贮食贡献越大,其睾丸指数和睾酮含量降低越显著。研究结果说明,亲缘关系的存在有利于布氏田鼠的合作贮食,但合作贮食贡献大的个体,其繁殖受到了抑制。     

Search mechanism of a stream grazer in patchy environments: the role of food abundance

Summary The search behavior of the grazing stream insect Baetis tricaudatus (Ephemeroptera: Baetidae) was examined in field and laboratory experiments. Regardless of food abundance in experimental habitats, nymphs spent significantly more time in food patches than predicted if they had moved randomly with respect to patches. A significant reduction in movement rate within patches relative to movement rate between patches largely accounted for these results. The movement pattern within patches was highly systematic and in agreement with predictions of optimal foraging theory since food was uniformly distributed within patches. Between-patch search movements were affected by food abundance in the most recently grazed patch. Search intensity after departure from a patch was positively related to food abundance in the patch while movement rate after patch departure was inversely related to patch food level. These effects produced between-patch movement patterns that were suboptimal in the experimental habitats because they resulted in revisitation of previously depleted patches. However, differences between experimental and natural habitats in the spatial occurrence of patch types suggest that Baetis between-patch search behavior may be adaptive in natural habitats.     

A laboratory method for studying zooplankton swimming behaviors

A laboratory method is presented for studying zooplankton swimming behaviors such as phototaxis and photokinesis. The method attempts to standardize laboratory conditions and to minimize the effects of several phenomena which modify zooplankton behavior. The role of angular light distribution in zooplankton behavior is discussed, and an apparatus which simulates a natural underwater light environment is described. The procedure minimizes the fluctuations in zooplankton swimming speed and vertical distribution that are caused by large light stimuli, noise, food deprivation, endogenous rhythms, and other factors. The experimental animals were viewed remotely with the aid of a light amplifier and video camera. A mathematical equation and computer program for calculating three-dimensional swimming speeds of zooplankton from video recordings are described in detail.     

实验动物和食品安全

本文从食品安全、风险评估、食品毒理学、动物试验和实验动物5个方面对食品安全和实验动物的关系进行了阐述.     

食物丰度对宽鳍鱲的能量代谢、个性和集群行为的影响

水生生境中的食物资源经常变化,鱼类的能量代谢和行为随食物丰度改变的可塑性调节具有重要的进化和生态意义。为考察食物丰度对机体行为和代谢的影响,以雌性宽鳍鱲（Zacco Platypus）为实验对象,分别测定实验鱼在高、低食物丰度组4周喂养期前后的标准代谢率（Standard metabolic rate,SMR）、个性及集群行为。研究发现：（1）经4周喂养,高食物丰度组的体重和SMR上升,而低食物丰度组维持不变,喂养期结束时高食物丰度组的体重和SMR均显著大于低食物丰度组;（2）食物丰度对个性没有显著影响,但集群时,低食物丰度组活跃性较高,凝聚力较低;（3）高食物丰度下SMR保持稳定,低食物丰度下SMR不稳定。研究表明：宽鳍鱲的个性不受食物丰度影响;但食物丰度减少导致能量代谢下降、鱼群活跃性上升和凝聚力下降,可能与食物丰度较低时代谢的适应性下调和食物资源竞争加剧导致的觅食活动需求上升相关。     

Biological Conservation of a Prey–Predator System Incorporating Constant Prey Refuge Through Provision of Alternative Food to Predators: A Theoretical Study

We describe a prey–predator system incorporating constant prey refuge through provision of alternative food to predators. The proposed model deals with a problem of non-selective harvesting of a prey–predator system in which both the prey and the predator species obey logistic law of growth. The long-run sustainability of an exploited system is discussed through provision of alternative food to predators. We have analyzed the variability of the system in presence of constant prey refuge and examined the stabilizing effect on predator–prey system. The steady states of the system are derived and dynamical behavior of the system is extensively analyzed around steady states. The optimal harvesting policy is formulated and solved with the help of Pontryagin’s maximal principle. Our objective is to maximize the monetary social benefit through protecting the predator species from extinction, keeping the ecological balance. Results finally illustrated with the help of numerical examples.     

围栏条件下岩松鼠对核桃的贮藏

许多动物都能够贮藏食物以应对一定时期的食物短缺。岩松鼠是中国特有的一种啮齿动物,主要分布于华北山地和丘陵地区,对于其食物贮藏行为还了解不多。我们在北京东灵山地区建立了半自然围栏,在围栏一角设置一木质巢箱供其休息,在围栏中心设一食盘(给食处),就岩松鼠对核桃(已预先标记)的贮藏特征进行了观察。每只受试动物在实验开始前6 h断食,于13∶ 00 左右,随机选择1 只岩松鼠,将其放入围栏中适应2 ～ 3 h。随后,在给食处放置20 枚已标记的核桃。于第二天同一时间进入围栏,检查并记录岩松鼠对核桃的处理情况,将埋藏、取食和剩余的核桃全部移出,另置20 枚新的核桃,继续实验。第三天,重复上述检查和记录,将岩松鼠及被其处理的核桃全部移出,清理巢箱、整理围栏。随后放入第二只岩松鼠,重复上述实验过程,如遇恶劣气候,则实验顺延,直至实验结束。结果表明:岩松鼠兼具集中贮藏和分散贮藏两种食物贮藏方式,并且分散方式是其主要的食物贮藏方式;岩松鼠在围栏中选择一定的位置贮藏食物;文中还讨论了可能影响岩松鼠食物贮藏的因素。     

The study of sensory bases of the feeding behavior of the African catfish Clarias gariepinus (Clariidae,Siluriformes)

An experimental study of the role of vision and some other sensory systems in the feeding behavior of the African catfish Clarias gariepinus (SL 20–24 cm, weight 80–95 g) was performed. It was shown that catfish similarly efficiently detect pellets of artificial food in the light and in the dark; in the dark, they display a greater preference for liver pieces than for pellets of artificial food of the same size. Blue pellets were most attractive for fish; red pellets, less attractive; and green pellets were the least attractive. Color selectivity is exhibited by catfish in the light at various combinations of pellets of different colors delivered simultaneously, but is lost in total darkness. The data obtained indicate the polysensory basis of the feeding behavior of catfish. In the light, a well-developed visual reception provides not only for a successful search for food, but also for a selective choice of food items by color. The olfactory and taste properties of food are important regulators of feeding under various light conditions. Thus, C. gariepinus, like other euryphagous fish, lacks a profound sensory specialization in the feeding behavior. When environmental conditions change, the role of the leading sensory system may pass from one sense organ to another.     

Communication of food quality in captiveMacaca nemestrina and free-rangingAteles geoffroyi

While observational learning and social communication of feeding behavior have been demonstrated several times for edible foods, to date there has been no experimental evidence for learning to avoid distasteful or inedible foods by social cues in primates. A series of experiments on captive pigtail macaques (Macaca nemestrina) and free-ranging spider monkeys (Ateles geoffroyi) was performed to determine if members of these two species would avoid a food item that was rejected by a conspecific. The results indicated that, while individuals were capable of learning to avoid a distasteful food after personal experience, social cues were not sufficient to prevent other individuals from tasting the rejected foods or for discriminating between neutral and distasteful items. The results are discussed in terms of spacing patterns and visual access in the natural foraging situation.     

Dynamical behavior of two predators competing over a single prey

Dynamical behavior of a food web comprising two predators competing over a single prey has been investigated. The analysis of the food web model shows that the persistence is not possible for two competing predators sharing a single prey species in the cases when any one of the boundary prey–predator planes has a stable equilibrium point. The principle of competitive exclusion holds in such cases. However, numerical simulations exhibit persistence in the presence of periodic solutions in the boundary planes. The system exhibits quasi-periodic behavior in the positive octant. The co-existence in the form of a limit cycle is also possible in some cases.     

Dynamical behavior of two predators competing over a single prey

Dynamical behavior of a food web comprising two predators competing over a single prey has been investigated. The analysis of the food web model shows that the persistence is not possible for two competing predators sharing a single prey species in the cases when any one of the boundary prey–predator planes has a stable equilibrium point. The principle of competitive exclusion holds in such cases. However, numerical simulations exhibit persistence in the presence of periodic solutions in the boundary planes. The system exhibits quasi-periodic behavior in the positive octant. The co-existence in the form of a limit cycle is also possible in some cases.     

The melanocortin system during fasting

This paper sets out to review the implication of the melanocortin system in regulating feeding behavior and energy balance during short- and long-term food deprivation. It is discussed in relation to: (1) body fat exhaustion and the known enhanced drive for refeeding in late fasting and (2) peripheral hormonal status with emphasis on the effect of leptin administration on melanocortin gene expression according to fat store mobilization.     

Specification of cell morphology by endogenous determinants

We are studying the mechanisms by which cells elaborate their differentiated morphologies. Here we discuss one aspect of this issue: the specification of the detailed shape of individual cells. We describe an experimental system in which endogenous determinants of morphology are expressed. These determinants originally were detected in the morphological relationships between sister neuroblastoma cells. Approaches to analyzing these relationships are presented. The properties and behavior of the endogenous determinants have been partially characterized by further experiments, which are also described. The significance and the prospects for further analysis of our findings are discussed.     

Modeling of preparative reversed-phase HPLC of insulin

The adsorption isotherms of three recombinant proteins, human insulin, porcine insulin, and Lispro, were measured by frontal analysis on a YMC-ODS C18 column with an aqueous solution at 31% acetonitrile (0.1% TFA) as the mobile phase. The retention behavior of insulin, its related molecular structure, its conformation, and its aggregation in this phase system are discussed. The experimental isotherm data were fitted to the Langmuir, the Langmuir-Freundlich, and the Toth models. The results allow for a quantitative comparison of the saturation capacities, the equilibrium constants, and the exponents that represent the heterogeneity of the stationary phase obtained for the different insulin variants studied. The Toth model provided the best fit of the experimental data. The overloaded band profiles were calculated using the lumped pore diffusion and the equilibrium-dispersive model of chromatography. An excellent agreement between calculated and experimental profiles was demonstrated.     

Biological pest control using cannibalistic predators and with provision of additional food: a theoretical study

Cannibalism is a conspecific lethal interaction, a typical phenomenon in many natural populations, which is used as a “life-boat strategy” to avoid circumstances leading to extinction. It is observed in many experimental studies that the cannibalistic nature of natural enemies deters the outcome of biological pest control programmes. One of the ways to deviate natural enemies from conspecific lethal interactions is to provide them with additional food. In this paper, using the theory of dynamical systems, we analyse the dynamics of a cannibalistic predator-prey system when predators are provided with additional food. A detailed mathematical analysis is carried out to study the permanence, stability and various bifurcations occurring in the system. The system analysis reveals several interesting phenomena. Depending on the choice of quality (characterised by the predator’s handling time towards additional food, and prey) and quantity of additional food, the system can exhibit multiple coexisting equilibria, leading to the emergence of a homoclinic loop. Further, it is observed that by varying the quality and quantity of additional food, one can not only limit and control the pest but also eradicate the predators. In the context of biological control programmes, the current theoretical study aids eco-managers in choosing the appropriate additional food that is to be supplied for enhancing the biocontrol efficiency of cannibalistic predators.     

Amphetamine anorexia in cats: the effect of encouraging to ingestive behavior

The effect of encouraging to ingestive behavior was examined in cats pretreated with amphetamine (AMPH) in a dose sufficient for evoking anorexia (2 mg/kg). AMPH evoked complete refusing of spontaneous food ingestion in all animals. However, the cats could eat in even frantic manner when they were encouraged to ingestive behavior by moving the bowl with food around the place where the animal was sitting in the experimental cage. This result reveals that so called "anorexic syndrome" does not consist simply in a loss of appetite. It may be temporarily suppressed by some additional external stimuli which enable to channel the animal's behavior to the ingestive one.     

Electric Cell-substrate Impedance Sensing for the Quantification of Endothelial Proliferation,Barrier Function,and Motility

Electric Cell-substrate Impedance Sensing (ECIS) is an in vitro impedance measuring system to quantify the behavior of cells within adherent cell layers. To this end, cells are grown in special culture chambers on top of opposing, circular gold electrodes. A constant small alternating current is applied between the electrodes and the potential across is measured. The insulating properties of the cell membrane create a resistance towards the electrical current flow resulting in an increased electrical potential between the electrodes. Measuring cellular impedance in this manner allows the automated study of cell attachment, growth, morphology, function, and motility. Although the ECIS measurement itself is straightforward and easy to learn, the underlying theory is complex and selection of the right settings and correct analysis and interpretation of the data is not self-evident. Yet, a clear protocol describing the individual steps from the experimental design to preparation, realization, and analysis of the experiment is not available. In this article the basic measurement principle as well as possible applications, experimental considerations, advantages and limitations of the ECIS system are discussed. A guide is provided for the study of cell attachment, spreading and proliferation; quantification of cell behavior in a confluent layer, with regard to barrier function, cell motility, quality of cell-cell and cell-substrate adhesions; and quantification of wound healing and cellular responses to vasoactive stimuli. Representative results are discussed based on human microvascular (MVEC) and human umbilical vein endothelial cells (HUVEC), but are applicable to all adherent growing cells.     

Opioids in the regulation of food intake and energy expenditure

This paper and the following four papers summarize a symposium on the role of opioids in regulation of feeding, body weight, and energy expenditure. The central sites of opioid action are discussed, as is opioid activity in invertebrates, large animals, and humans. This paper provides a historical review of developments in the field from the early concepts of an endogenous opioid system to the current understanding of multiple receptor types and their interaction in regulating ingestive behavior. Opioids from all three opioid families may stimulate food intake, and some evidence exists that opioids may stimulate energy expenditure. Eating and drinking behavior is very complex and involves a number of components. Our understanding of the role of opioids in this process is shallow, and future research must be designed carefully to evaluate individual components of ingestive behavior.