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PubMed2006

Feeding behavior, diet, and the functional consequences of jaw form in orangutans, with implications for the evolution of Pongo.

Orangutans are amongst the most craniometrically variable of the extant great apes, yet there has been no attempt to explicitly link this morphological variation with observed differences in behavioral ecology. This study explores the relationship between feeding behavior, diet, and mandibular morphology in orangutans. All orangutans prefer ripe, pulpy fruit when available. However, some populations of Bornean orangutans (Pongo pygmaeus morio and P. p. wurmbii) rely more heavily on bark and relatively tough vegetation during periods of low fruit yield than do Sumatran orangutans (Pongo abelii). I tested the hypothesis that Bornean orangutans exhibit structural features of the mandible that provide greater load resistance abilities to masticatory and incisal forces. Compared to P. abelii, P. p. morio exhibits greater load resistance abilities as reflected in a relatively deeper mandibular corpus, deeper and wider mandibular symphysis, and relatively greater condylar area. P. p. wurmbii exhibits most of these same morphologies, and in all comparisons is either comparable in jaw proportions to P. p. morio, or intermediate between P. p. morio and P. abelii. These data indicate that P. p. morio and P. p. wurmbii are better suited to resisting large and/or frequent jaw loads than P. abelii. Using these results, I evaluated mandibular morphology in P. p. pygmaeus, a Bornean orangutan population whose behavioral ecology is poorly known. Pongo p. pygmaeus generally exhibits relatively greater load resistance capabilities than P. abelii, but less than P. p. morio. These results suggest that P. p. pygmaeus may consume greater amounts of tougher and/or more obdurate foods than P. abelii, and that consumption of such foods may intensify amongst Bornean orangutan populations. Finally, data from this study are used to evaluate variation in craniomandibular morphology in Khoratpithecus piriyai, possibly the earliest relative of Pongo from the late Miocene of Thailand, and the late Pleistocene Hoa Binh subfossil orangutan recovered from Vietnam. With the exception of a relatively thicker M(3) mandibular corpus, K. piriyai has jaw proportions that would be expected for an extant orangutan of comparable jaw size. Likewise, the Hoa Binh subfossil does not differ in skull proportions from extant Pongo, independent of the effects of increase in jaw size. These results indicate that differences in skull and mandibular proportions between these fossil and subfossil orangutans and extant Pongo are allometric. Furthermore, the ability of K. piriyai to resist jaw loads appears to have been comparable to that of extant orangutans. However, the similarity in jaw proportions between P. abelii and K. piriyai suggest the latter may have been dietarily more similar to Sumatran orangutans.

Animals↗

PubMed1999

Orexins and orexin receptors: implication in feeding behavior.

Orexin-A and -B are initially identified as endogenous ligands for an orphan G protein coupled receptor. Since the discovery of orexins, investigations of their functions have been guided by their distribution in the lateral hypothalamic area, which has been implicated in feeding behavior. In fact, when administered intracerebroventricularly in early light phase, orexin-A stimulated food consumption. Orexin mRNA is up-regulated by fasting, suggesting their expression is regulated by animal's nutritional status. The orexin neurons project widely in the brain, and thus the physiological role of orexins is likely to be complex. Orexin neurons in the lateral hypothalamic area was shown to receive terminal appositions from NPY-, AgRP-, and a-MSH-IR fibers. The innervation of orexin neurons by peptidergic fibers corresponding to leptin-responsive cell types that reside in the arcuate nucleus may have a role in linking peripheral metabolic cues to autonomic regulatory sites and the cerebral cortical mantle, providing a neuroanatomic basis for regulation of feeding behavior. The wide distribution of orexin-immunoreactive fibers in the brain has also suggested their additional roles. Actually, orexins have been reported to have roles in regulating drinking behavior, neuroendocrine function and the sleep-wake cycle.

Amino Acid Sequence↗

PubMedDate not supplied

Gastrin in the mechanisms of genetic determination of feeding behavior in rabbits.

Spreading of a dominant motivation to the molecular intracellular mechanisms of genetic memory was studied. Blockage of protein synthesis in the nervous system selectively abolishes food motivation in rabbits during stimulation of the lateral hypothalamus but exerts no noticeable effect on avoidance responses during stimulation of the ventromedial hypothalamus. During protein synthesis blockage, food motivation returns to normal upon pentagastrin intracerebroventricular (i.c.v.) injection. Intracerebroventricular administration of antigastrin immunoglobulin inhibits feeding reaction to lateral hypothalamic stimulation but not avoidance response to ventromedial hypothalamic stimulation. It was concluded that feeding motivation translates into feeding behavior in the following stages: motivational excitation, gene activation, mRNA synthesis, formation of a gastrin-like peptide, and expression of feeding behavior.

Animals↗

PubMed2000

Brain regulation of feeding behavior and food intake in fish.

In mammals, the orexigenic and anorexigenic neuronal systems are morphologically and functionally connected, forming an interconnected network in the hypothalamus to govern food intake and body weight. However, there are relatively few studies on the brain control of feeding behavior in fish. Recent studies using mammalian neuropeptides or fish homologs of mammalian neuropeptides indicate that brain orexigenic signal molecules include neuropeptide Y, orexins, galanin and beta-endorphin, whereas brain anorexigenic signal molecules include cholecystokinin, bombesin, corticotropin-releasing factor, cocaine- and amphetamine-regulated transcript, and serotonin. Tachykinins may also have an anorectic action in fish. The brain hypothalamic area is associated with regulation of food intake, while sites outside the hypothalamus are also involved in this function. There is correlation between short-term changes in serum growth hormone levels and feeding behavior, although possible mechanisms integrating these functions remain to be defined.

Animals↗

PubMed1995

Gustatory control of feeding behavior in goldfish.

The present study tests the effects of gustatory quality on feeding behaviors exhibited by goldfish. Goldfish were trained to feed on gelatin pellets, then tested with pellets containing potentially aversive taste stimuli (quinine or caffeine), or mixtures of aversive and appetitive components (amino acids or food). Goldfish feeding includes: initial intake of food particles, a sorting phase consisting of rinsing and backwashing, and a final phase terminating in either rejection or ingestion. Pellets flavored with quinine or caffeine were rejected at concentrations above 10(-5) and 10(-3) M, respectively. Pellets containing a mixture of quinine and ground food or quinine and either L-alanine or L-proline were ingested more frequently than pellets flavored only with quinine. These pellets with mixed chemical components also produced extended sorting behaviors, including prolonged periods of rinsing and backwashing. The prolonged sorting of quinine-food mixtures enabled the animals to separate mechanically the food from the gelatin matrix. These results show that goldfish use chemical cues to drive the intraoral sorting and rejection/ingestion behaviors.

Amino Acids↗

PubMed1998

Evidence that hemolymph glucose in Aplysia californica is regulated but does not affect feeding behavior.

Hemolymph glucose increased following a meal of a commercially available dried seaweed (laver) in Aplysia californica (Aplysia). Glucose injected into the hemocoel did not affect meal size, bite latencies, swallowing rate, or 24-hr food intake. The authors found that injection of a homogenate of nerves containing a putative Aplysia insulin-like substance decreased hemolymph glucose. The nerve homogenate, however, did not affect feeding behavior. Injection of 2-deoxy-D-glucose was found to increase hemolymph glucose, an indication of gluco-privation, but instead of increasing feeding it either had no effect or, at high doses, debilitated animals and interfered with feeding. These studies suggest that glucose may be physiologically regulated in Aplysia, but it does not appear to play a role in the control of feeding behavior.

Analysis of Variance↗

PubMedDate not supplied

Chemical plasticity of visual cortical neurons in integrative organization of feeding behavior in cats.

The P.K. Anokhin conception of organization of systemic behavior was used to study the discharge activity and chemical plasticity of cortical neurons in a goal-directed behavior. Chemical sensitivity of neurons in the visual cortex of instrumentally conditioned cats was studied during successive stages of food procuring and consuming. The results showed that definite stages of this integrated behavioral act are characterized by differences in the chemical sensitivity of visual neurons to neurotransmitters. The largest number of neurons resistant to neurotransmitters was found among cells that did not respond at successive stages of goal-directed behavior. The iontophoretic delivery of cycloheximide and lyzilvasopressine altered the discharge activity of individual cortical neurons at different stages of stereotyped instrumental conditioned acts. This suggests that the integrative organization of the feeding behavior is determined by chemical plasticity of the brain's visual cortical neurons and is dependent upon the processes of protein synthesis. According to the functional system theory (Anokhin, 1974) each brain neuron is included, by various degrees of freedom, in the stages of systemic organization that underlie the goal-directed behavior. Thanks to the plastic reorganization of brain units, each stage is directed toward the achievement of useful adaptive results for the organism during interaction with different environmental factors (Adrianov, 1993; Fadeev, 1988). It may be proposed that the reorganization of discharges of brain neurons that occurs at different stages of activity is due to changes in their chemical capacities. In concordance with such a hypothesis, the purpose of the present investigation was to study the chemical sensitivity of single visual cortical neurons to neurotransmitters at different stages of systemic organization of feeding behavior. The influence of protein synthesis inhibitors on the sensitivity of cortical neurons was also investigated.

Acetylcholine↗

PubMed2006

The evolutionary basis for the feeding behavior of domestic dogs (Canis familiaris) and cats (Felis catus).

The dentition, sense of taste and meal patterning of domestic dogs and cats can be interpreted in terms of their descent from members of the order Carnivora. The dog is typical of its genus, Canis, in its relatively unspecialized dentition, and a taste system that is rather insensitive to salt. The preference of many dogs for large infrequent meals reflects the competitive feeding behavior of its pack-hunting ancestor, the wolf Canis lupus. However, its long history of domestication, possibly 100,000 years, has resulted in great intraspecific diversity of conformation and behavior, including feeding. Morphologically and physiologically domestic cats are highly specialized carnivores, as indicated by their dentition, nutritional requirements, and sense of taste, which is insensitive to both salt and sugars. Their preference for several small meals each day reflects a daily pattern of multiple kills of small prey items in their ancestor, the solitary territorial predator Felis silvestris. Although in the wild much of their food selection behavior must focus on what to hunt, rather than what to eat, cats do modify their food preferences based on experience. For example, the "monotony effect" reduces the perceived palatability of foods that have recently formed a large proportion of the diet, in favor of foods with contrasting sensory characteristics, thereby tending to compensate for any incipient nutritional deficiencies. Food preferences in kittens during weaning are strongly influenced by those of their mother, but can change considerably during at least the first year of life.

Animals↗

PubMed2002

Regulation of feeding behavior, gastric emptying, and sympathetic nerve activity to interscapular brown adipose tissue by galanin and enterostatin: the involvement of vagal-central nervous system interactions.

Galanin and enterostatin, which are distributed in both the central nervous system and the gastrointestinal tract, regulate the feeding behavior. In the first set of experiments, we investigated the effects of galanin and enterostatin, injected into the third ventricle, on food intake, gastric emptying, and the sympathetic activity of nerves innervating interscapular brown adipose tissue in rats. Galanin dose-dependently increased the intake of a high-fat diet after overnight starvation, but it did not affect low-fat diet intake. In contrast, enterostatin suppressed the intake of the high-fat diet, while intake of the low-fat diet was not affected. Galanin significantly and dose-dependently suppressed gastric emptying rate. However, gastric emptying showed no response to enterostatin. Galanin produced a dose-dependent suppression of sympathetic firing rate. In rats fed a high-fat diet, the injection of enterostatin showed a dose-dependent increase in firing rate. In contrast, animals fed a chow diet showed almost no response. In the second set of experiments, we investigated the role of the hepatic vagus nerve in modulating the peripheral response to enterostatin in rats. Intraperitoneal (i.p.) enterostatin reduced the intake of a high-fat diet. Immunohistochemical identification indicated that the Fos protein was present in the nucleus tractus solitarius, and parabrachial, paraventricular, and supraoptic nuclei after IP enterostatin. These responses to i.p. enterostatin were blocked by hepatic vagotomy. These results suggest that galanin and enterostatin coordinate to regulate feeding behavior, gastric emptying, and sympathetic activity to interscapular brown adipose tissue via central and peripheral sites of action, one of which was the interaction which was found to exist through the vagal system.

Adipose Tissue, Brown↗

PubMed2002

Orexin-mediated feeding behavior involves both leptin-sensitive and -insensitive pathways.

Orexin-A and -B are neuropeptides that are implicated in the regulation of vigilance states and energy homeostasis. Orexins are specifically produced by neurons located within the lateral hypothalamic area (LHA), a region implicated in the regulation of feeding behavior. Here, we examined the functional interactions between orexins and anorectic factors [leptin, alpha-melanocyte-stimulating hormone (alpha-MSH) and glucagon-like peptide-1 (GLP-1)] in rats. Intracerebroventricular injection of orexin-A (10 nmol) potently augmented food intake in rats. Neuropeptide Y (NPY) (0.3 nmol) and galanin (3 nmol) also induced a transient increase in food intake. Both NPY- and galanin-induced feeding behaviors were completely inhibited by preadministration of leptin (3 microg), while the same or a higher dose (10 microg) of leptin only partially inhibited orexin-A or -B-induced increase of food intake. Preadministration of anorectic peptides (alpha-MSH and GLP-1), which are shown to be regulated by leptin, abolished NPY-induced feeding; however, orexin-induced feeding was only partially inhibited by these anorectic peptides. These observations suggest that NPY- and galanin-induced increases of feeding involve a leptin-sensitive pathway, while orexin-induced feeding involves both leptin-sensitive and -insensitive pathways.

Animals↗

PubMed1998

Orexins and orexin receptors: a family of hypothalamic neuropeptides and G protein-coupled receptors that regulate feeding behavior.

The hypothalamus plays a central role in the integrated control of feeding and energy homeostasis. We have identified two novel neuropeptides, both derived from the same precursor by proteolytic processing, that bind and activate two closely related (previously) orphan G protein-coupled receptors. These peptides, termed orexin-A and -B, have no significant structural similarities to known families of regulatory peptides. prepro-orexin mRNA and immunoreactive orexin-A are localized in neurons within and around the lateral and posterior hypothalamus in the adult rat brain. When administered centrally to rats, these peptides stimulate food consumption. prepro-orexin mRNA level is up-regulated upon fasting, suggesting a physiological role for the peptides as mediators in the central feedback mechanism that regulates feeding behavior.

Animals↗

PubMed2002

Feeding behaviors and other motor development in healthy children (2-24 months).

OBJECTIVES: To monitor infant's gross, fine and oral motor development patterns related to feeding. DESIGN: An incomplete block design was used with 57 to 60 (sample = 98) mothers interviewed when their children were 2, 3, 4, 6, 8, 10, 12, 16 and 24 months (within +/- 5 days of birth date). Each mother had 5 to 6 interviews. SETTING: Selected developmental feeding behaviors were monitored using in-home interviews conducted by trained interviewers (n = 2). At each interview, mothers reported the child's age when behaviors first occurred, and anthropometric measurements were performed. SUBJECTS: Subjects were healthy white children who lived mostly in homes with educated two-parent families of upper socioeconomic status. RESULTS: Mean behavioral ages were within normal ranges reported in the literature, whereas individuals exhibited a wide diversity in reported ages. Examples of gross motor skills (age in months, +/- SD) included sitting without help (5.50+/-2.08) and crawling (8.00+/-1.55). Mean ages for self-feeding fine motor skills showed children reaching for a spoon when hungry (5.47+/-1.44), using fingers to rake food toward self (8.87+/-2.58) and using fingers to self-feed soft foods (13.52+/-2.83). Oral behaviors included children opening their mouth when food approached (4.46+/-1.37), eating food with tiny lumps (8.70+/-2.03) and chewing and swallowing firmer foods without choking (12.17+/-2.28). CONCLUSIONS: Mean ages for feeding behaviors occurred within expected age ranges associated with normal development. However, mothers reported that individual children exhibited a wide age range for achieving these behaviors. Our results should be considered in counseling mothers about infant feeding practices.

Aging↗

PubMed2002

Studies on modulation of feeding behavior by atypical antipsychotics in female mice.

The aim of this study was to examine the effects of different doses of typical antipsychotics, chlorpromazine (0.25-1 mg/kg) and haloperidol (0.25-1 mg/kg), and atypical antipsychotics, clozapine (0.5-2 mg/kg), olanzapine (0.25-1 mg/kg), risperidone (0.5-2 mg/kg), sulpiride (10-40 mg/kg) and dopamine D1 antagonist, SCH 23390 (0.25-1 mg/kg) on feeding behavior at different time intervals after acute administration. The study further investigated the central dopamine and serotonergic receptor involvement in clozapine-induced hyperphagia using SKF 38393, quinpirole and quipazine. Then, the authors also examined the effect of subchronic treatment for 21 days with fluoxetine on clozapine-induced hyperphagia and modulation of body weight and fat pad weights. The feeding behavior was assessed in nondeprived mice by presenting the palatable chow to different groups of mice in glass petri dishes and recording the food consumed at different time intervals. After acute administration, significant (P<.05) increase in food intake was observed at different time intervals with different doses of both typical and atypical antipsychotics. Further, clozapine-induced hyperphagia was significantly (P<.05) reversed after treatment with SKF 38393 (dopamine D1 agonist), quinpirole (dopamine D2 agonist) and quipazine (5-HT1B, 5-HT2 and 5-HT3 agonist). In subchronic study, treatment with fluoxetine (10 mg/kg) significantly (P<.05) antagonized the increase in body weight and food intake induced by clozapine (2 mg/kg). The current investigations underscore the reported increases in food intake and body weight gain observed with antipsychotics. The study further confirms the involvement of dopamine D1, D2 and serotonergic receptor involvement in clozapine-mediated hyperphagia. Further, the serotonergic agents may prove useful to counteract antipsychotic-induced obesity.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

PubMed2005

Corn grain endosperm type and brown midrib 3 corn silage: feeding behavior and milk yield of lactating cows.

Interactions of endosperm type of corn grain and the brown midrib 3 mutation (bm3) in corn silage on feeding behavior, productivity, energy balance, and plasma metabolites of lactating dairy cows were evaluated. Eight ruminally and duodenally cannulated cows (72 +/- 8 d in milk; mean +/- SD) were used in a duplicated 4 x 4 Latin square design experiment with a 2 x 2 factorial arrangement of treatments. Treatments were corn grain endosperm type (floury or vitreous), and corn silage type (bm3 or isogenic control). Diets contained 26% neutral detergent fiber (NDF) and 30% starch. Floury endosperm grain decreased dry matter intake (DMI) 1.9 kg/ d compared with vitreous grain when combined with control corn silage but did not affect DMI when combined with bm3 corn silage. This interaction of treatments occurred because of changes in meal size; floury endosperm grain decreased meal size in control silage diets but increased meal size in bm3 corn silage diets. Ruminal pool sizes reflected DMI differences among diets, suggesting that ruminal fill was not the primary limitation on intake. Brown midrib 3 corn silage reduced rumination time per day and number of rumination bouts per day. Floury endosperm grain decreased 3.5% fat-corrected milk by 1.2 kg/d when combined with control silage but increased 3.5% fat-corrected milk by 2.1 kg/d when combined with bm3 corn silage. Starch and fiber digestibility interact to affect feeding behavior and milk production and production response to bm3 corn silage depends on the grain source that is fed.

Animals↗

PubMed2005

Comparison of mammalian prolactin-releasing peptide and Carassius RFamide for feeding behavior and prolactin secretion in chicks.

Prolactin-releasing peptide (PrRP) was named for its originally reported effects as a prolactin (PRL) secretagogue in mammals. Carassius RFamide (C-RFa) is an orthologous PRL secretagogue in fishes and a gene encoding a 20-amino acid peptide of identical sequence is present in the chicken. These facts suggest that C-RFa is a putative chicken PrRP. However, no information is available for the physiological effects of C-RFa in chickens. Therefore, in the present study, we compared the effect of intracerebroventricular (ICV) injection of C-RFa and mammalian PrRP (mPrRP) on feeding behavior and plasma PRL, growth hormone (GH), and corticosterone (CORT) concentrations. ICV injection of C-RFa did not affect feeding behavior of chicks while mPrRP was stimulatory. The injection of C-RFa also did not significantly affect plasma PRL, GH, and CORT concentrations. In contrast, ICV injection of mPrRP exerted similar effects to those reported in mammals by increasing plasma CORT and decreasing GH concentrations. Additionally, the peptide induced an unexpected inhibitory effect on plasma PRL concentrations. Overall, these data suggest that an as yet unidentified peptide that shares some functional similarities with mPrRP is present in birds, but that the physiological role of the avian 20-amino acid C-RFa peptide remains to be determined.

Animals↗

PubMed2003

Hypothalamic malonyl-CoA as a mediator of feeding behavior.

Previous studies showed that i.p. administration of C75, a potent inhibitor of fatty acid synthase (FAS), blocked fasting-induced up-regulation of orexigenic neuropeptides and down-regulation of anorexigenic neuropeptides in the hypothalami of mice. As a result, food intake and body weight were drastically reduced. Here we provide evidence supporting the hypothesis that hypothalamic malonyl-CoA, a substrate of FAS, is an indicator of global energy status and mediates the feeding behavior of mice. We use a sensitive recycling assay to quantify malonyl-CoA to show that the hypothalamic malonyl-CoA level is low in fasted mice and rapidly (< or = 2 h) increases (approximately 5-fold) on refeeding. Intracerebroventricular (i.c.v.) administration of C75 to fasted mice rapidly (< or = 2 h) increased (by 4-fold) hypothalamic malonyl-CoA and blocked feeding when the mice were presented with food. Moreover, prior i.c.v. administration of an acetyl-CoA carboxylase inhibitor, 5-(tetradecyloxy)-2-furoic acid, rapidly (although only partially) prevented the C75-induced rise of hypothalamic malonyl-CoA and prevented the C75-induced decrease of food intake. These effects correlated closely with the rapid (< or = 2 h) and reciprocal effects of i.c.v. C75 on the expression of hypothalamic orexigenic (NPY and AgRP) and anorexigenic (proopiomelanocortin) neuropeptide mRNAs. Previous results showing that C75 administered i.c.v. rapidly activates hypothalamic neurons of the arcuate and paraventricular nuclei are consistent with the results reported in this paper. Together these findings suggest that level of hypothalamic malonyl-CoA, which depends on the relative activities of acetyl-CoA carboxylase and FAS, is an indicator of energy status and mediates feeding behavior.

4-Butyrolactone↗

PubMed1998

Inhibitory effect of serotonin on feeding behavior in goldfish: involvement of CRF.

The possible action of 5-HT on feeding behavior in goldfish has been studied. Food intake was significantly reduced by intracerebroventricular (ICV) injection of serotonin (5-HT, 10 microg) at 2 h postinjection. After peripheral (intraperitoneal) administration of 5-HT (1 and 10 microg/g bw), no significant modifications in food intake were detected. Thus, it can be concluded that there is a central anoretic action of 5-HT in teleost fish. Taking in mind the inhibitory effect of corticotropin releasing factor (CRF) on feeding in teleosts and the interactions between 5-HT and CRF described in mammals, we investigated the possible involvement of CRF as mediator of the 5-HT anoretic action in goldfish. The ICV pretreatment with alpha-Helical CRF[9-41](20 microg) partially blocked the inhibitory effect of 5-HT on food consumption in goldfish. These results show that CRF mediates, at least in part, the 5-HT-induced feeding inhibition in goldfish. On the other hand, the alterations in hypothalamic indoleamines content evoked by ICV treatments would suggest that the activation of CRF neurons by 5-HT appears to inhibit hypothalamic serotoninergic transmission, supporting the intermediate role of this neuropeptide in the central anoretic effect of 5-HT in goldfish.

Animals↗

PubMedDate not supplied

Feeding behavior of Aplysia: a model system for comparing cellular mechanisms of classical and operant conditioning.

Feeding behavior of Aplysia provides an excellent model system for analyzing and comparing mechanisms underlying appetitive classical conditioning and reward operant conditioning. Behavioral protocols have been developed for both forms of associative learning, both of which increase the occurrence of biting following training. Because the neural circuitry that mediates the behavior is well characterized and amenable to detailed cellular analyses, substantial progress has been made toward a comparative analysis of the cellular mechanisms underlying these two forms of associative learning. Both forms of associative learning use the same reinforcement pathway (the esophageal nerve, En) and the same reinforcement transmitter (dopamine, DA). In addition, at least one cellular locus of plasticity (cell B51) is modified by both forms of associative learning. However, the two forms of associative learning have opposite effects on B51. Classical conditioning decreases the excitability of B51, whereas operant conditioning increases the excitability of B51. Thus, the approach of using two forms of associative learning to modify a single behavior, which is mediated by an analytically tractable neural circuit, is revealing similarities and differences in the mechanisms that underlie classical and operant conditioning.

Adaptation, Physiological↗