Children's Eating Attitudes Test: revised factor structure for adolescent girls.

UNLABELLED: The Eating Attitude Test (EAT) and its language-simplified version for children (ChEAT) have been popular instruments for the assessment of eating attitudes among children, adolescents and young adult females. OBJECTIVE: Data collected from female adolescents using the ChEAT were analyzed to compare five previously proposed measurement models as well as a new model. METHOD: Confirmatory factor analysis (CFA) was used to directly compare models in terms of their goodness-of-fit indices and to determine which model best fits the overall data (N=737) as well as data from the youngest and oldest girls (N=200 each). RESULTS: A newly proposed 14-item, 5-factor model provided the best fit to the overall data as well as data analyzed separately for the youngest and oldest girls. Furthermore, each of the newly proposed factor scores varied somewhat independently as a function of grade level, with body image concerns increasing most dramatically from grades 5 through 8. This newly proposed model is based on factors previously suggested by others, but not previously combined into a single measurement model. DISCUSSION: Implications of the results for future research involving adolescent girls are discussed, especially research on developmental changes in eating attitudes and behaviors that may constitute risk factors for subsequent eating disorders.

Naloxone inhibits intermale aggression in isolated mice.

Aggression and thermal pain thresholds were measured in separate groups of isolated male mice following 0.2-5.0 mg/kg SC injections of the opiate antagonist naloxone. The drug inhibited aggressive behaviors dose-dependently, but had no effect on pain. These results suggest that endogenous opioid systems may be activated during repeated intermale aggressive encounters.

Heterogeneous distribution and upregulation of mu, delta and kappa opioid receptors in the amygdala.

Levels of mu, delta and kappa opioid receptors in 4 subnuclei of the rat amygdala were determined by quantitative autoradiography following chronic treatment with naloxone or saline. A different distribution of each receptor subtype was observed, with mu binding greatest in the lateral nucleus (La), delta greatest in the basolateral (Bl), and kappa greatest in the medial (Me). Levels of all 3 receptors were very low in the central nucleus. Receptor upregulation following chronic naloxone treatment was also anatomically heterogeneous. Increases in mu receptors were statistically significant in the Me, Bl and La, while increases in delta and kappa receptors were significant only in the Bl.

Neuropeptide Y attenuates satiety: evidence from a detailed analysis of patterns ingestion.

Centrally injected neuropeptide Y (NPY) is a potent stimulant of ingestive behavior capable of augmenting both food and fluid intake in fully satiated animals. To gain further insight into NPY's mechanism of action, we recorded patterns of licking behavior in rats drinking sweetened condensed milk solutions immediately after lateral ventricular injection of NPY (10 micrograms) or vehicle. In a separate study, we examined licking patterns after 23 h food deprivation (FD) that produced approximately the same total intake as NPY. Consistent with previous reports, we found NPY stimulated intake by increasing total ingestion time and total volume consumed during a 1-h test. Although NPY increased the number of bouts of licking and shortened pauses between bouts, it also decreased mean bout size, bout duration and within-bout lick rate (local rate). It had no significant effect on start latency or lick efficiency (licks/ml). Further analyses revealed that NPY attenuated satiety (reduced slope of lick-rate functions with session time) but had no significant effect on the beginning lick rate, a measure related to orosensory excitation. In contrast to NPY, FD increased both the beginning lick rate and individual bout size without changing either the mean number of bouts or the pause between bouts. In general, NPY stimulated an intermittent pattern of licking and delayed satiation whereas FD increased the initial rate of licking and the size of individual bouts without changing the basic licking pattern. The increase in initial lick rate suggests that FD, unlike NPY, enhances orosensory stimulation. These data compliment previous results showing that NPY increases the motivation to eat.(ABSTRACT TRUNCATED AT 250 WORDS)

Neurotensin-induced hypothermia prevents hippocampal neuronal damage and increased locomotor activity in ischemic gerbils.

Hypothermia induced by surface cooling has shown to protect vulnerable regions of the brain during an ischemic insult. This study evaluated the neuroprotective efficacy of neurotensin, a potent hypothermic agent, using a 5-min carotid occlusion procedure in the gerbil. In Experiment 1, the dose-response and time course of neurotensin-induced hypothermia were evaluated (n = 5/dose). Central infusion of 10, 20, and 30 micrograms neurotensin were found to significantly decrease core body temperature of conscious gerbils within 30 min of administration. In Experiment 2, gerbils pretreated with 30 micrograms neurotensin were permitted to become hypothermic or were maintained at 37 degrees-38 degrees C (rectal) during ischemic insult. Other gerbils were pretreated with peptide vehicle prior to ischemic insult (at 37 degrees -38 degrees C) or underwent a sham procedure (n = 6/condition). At 24 h after surgery, gerbils were tested for increased locomotor activity in an open-field apparatus. Gerbils pretreated with peptide vehicle or neurotensin and maintained at 37 degrees-38 degrees C during ischemia had significantly higher activity levels compared to the other treated groups. In contrast, gerbils made hypothermic with neurotensin exhibited activity levels similar to sham gerbils. Histological assessment revealed that neurotensin-induced hypothermia protected the CA1 region from ischemic damage.

Naloxone suppresses intake of highly preferred saccharin solutions in food deprived and sated rats.

In repeated tests naloxone (1 mg/kg, sc) suppressed intake of a narrow range of highly preferred saccharin concentrations (0.1 and 1.0%) in nondeprived male rats but a wider range of concentrations (.001-1.0%) following 10 hr. food deprivation. In sated rats a low dose of morphine (0.1 mg/kg, sc) had no effect on intake of low concentrations of saccharin but significantly facilitated intake of the highest (10%) and least preferred concentration. These data support the hypothesis that endogenous opioids can modulate the affective quality of gustatory stimuli.

Endogenous opioids: naloxone disrupts learned performance in rats.

The effect of naloxone on learned performance reinforced by food was examined in 2 experiments. Male rats were trained to run down a short runway for 5 (45 mg) food pellets per trial and were then shifted either to 1 or 0 pellets. Following such an abrupt reinforcement shift, animals typically show an emotional disruption of performance (Crespi, 1942) referred to as "depression". We examined the postshift depression-effect in groups treated either with saline (SAL) or naloxone (NAL). In experiment 1 NAL groups received a single 10 mg/kg (s.c.) injection prior to each postshift session. When compared with SAL controls, NAL animals showed an exaggerated postshift depression-effect. Furthermore, a single (0.3 mg/kg, s.c.) injection of the enkephalin analog FK 33-824 (D-Ala2, MePhe4, Met-(0)5-o1) produced a dramatic recovery of performance. In the second experiment, these effects were replicated at a low NAL dose (1 mg/kg), which had no direct effect on motor performance. These findings suggest that opiate systems may modulate the incentive motivation that maintains learned performance.

Effects of bombesin on temporal patterns of ingestion in the rat.

Bombesin, an analog to gastrin releasing peptide, has previously been shown to inhibit food intake in the rat. In order to further characterize the effects of bombesin on ingestive behavior, the present study examined licking patterns of rats drinking sweetened condensed milk following bombesin (4 micrograms/kg, IP) or vehicle injection under two levels of food deprivation (0 and 24 h). Both bombesin treatment and satiety (reducing food deprivation from 24 to 0 h) significantly decreased total milk consumption during a 1-h test. Analysis of licking patterns suggested that bombesin and satiety operate by similar but not identical mechanisms. Deprivation reduction tended to decrease ingestion by reducing the rate of drinking and size of the first meal. Bombesin, by contrast, reduced the total duration of drinking and the number of meals taken, but had no effect on lick rate. Cumulative intake records suggested that bombesin reduces the volume threshold for termination of drinking such that intake continues at a normal rate below this threshold but ceases above it. This bombesin-imposed threshold for cessation of drinking was between about 5 and 7 ml for individual animals under both food-deprived and nondeprived testing conditions.

Effects of neuropeptide Y on ingestion of flavored solutions in nondeprived rats.

Recent evidence suggests that in addition to altering energy balance, neuropeptide Y (NPY) may stimulate ingestive behavior by modifying the orosensory quality of ingested substances. The present experiments investigated the effect of intracerebroventricular administration of NPY (5 micrograms/5 microliters) on ingestion of various flavored solutions in nondeprived rats. Experiment 1 examined the effects of NPY on ingestion of a range of concentrations of saline, sucrose, and saccharin solutions in single-bottle tests. Results indicated that NPY stimulates ingestion of both sucrose and saccharin solutions that are normally palatable. In Experiment 2, palatable sucrose solutions flavored with either orange or black cherry Kool-Aid for separate training groups were selectively associated with NPY injection during single-bottle training sessions. Subsequent two-bottle preference tests showed a significant shift in preference toward the flavor paired with NPY during training. The results of these experiments extend previous findings by showing that NPY can stimulate ingestion of sweet solutions regardless of caloric value and may potentiate sweet taste preference via an associative mechanism.

Opiate blockade inhibits saccharin intake and blocks normal preference acquisition.

Recent evidence indicates a close connection between oral sensory function and opioid effects on feeding. Not only is gustatory motivation influenced by opiate drugs but apparently gustatory stimuli can also activate central opiate receptor systems. In 3 experiments we studied the effect of opiate receptor blockade on drinking motivated by the sweet taste of saccharin. Experiment 1 established a dose-response function for inhibition of intake by naloxone (NAL) in short (60 min) 2-bottle tests. This experiment demonstrated the extreme sensitivity of nondeprived, nonstressed animals to NAL and estimated the MED50 at less than 0.1 mg/kg (SC), well below the threshold for effects due to illness or general motor disturbance. Experiment 2 further demonstrated that NAL's effectiveness depends on saccharin concentration. In particular, the lowest NAL dose studied was effective near the threshold for saccharin preference but not at higher concentrations. These data suggest that endogenous opioid systems may be activated by taste stimuli in a graded fashion. Finally, experiment 3 showed that the typical acquisition of preference for a moderate saccharin concentration can be effectively blocked by daily pre-test NAL injection. Together these experiments further demonstrate the close functional relationship between opioid systems and gustatory sensory systems.

Autoradiographic localization of kappa opiate receptors in CNS taste and feeding areas.

Recent evidence suggests that kappa opiate receptors may play a key role in the regulation of appetite. Such evidence implies that kappa receptors might be localized within specific brain areas known to regulate ingestive behaviors. On the basis of this implication we employed an in vitro film autoradiographic technique using 3H-ethylketocyclazozine as ligand to identify putative kappa receptors within CNS "taste" nuclei and surrounding areas. Coronal cryostat sections of rat brain were incubated with ligand in the presence of D-Ala2, D-Leu5-enkephalin (DADLE) and morphine, apposed to LKB Ultrofilm for 60 days, processed and kappa receptor densities evaluated with the aid of a hand held photometer and video image analyzer. Highest kappa receptor densities were found within various gustatory and feeding sites including the rostral pole of the nucleus of the solitary tract, parabrachial nuclei, ventral posterior and medial portions of the thalamus, medial hypothalamus, medial nuclei of the amygdala and bed nucleus of the stria terminalis. Various other midline and medial limbic areas also showed significant kappa densities.

Does binge eating play a role in the self-regulation of moods?

Self-reported emotional experiences and eating behaviors were studied in college students in an attempt to determine what types of emotional experiences precede and follow binge eating and how specific types of compensatory behaviors modify these experiences. First-year male and female students (N=390) were surveyed for depression, anxiety, health status, life satisfaction, and eating attitudes (EAT-26). Those reporting recurrent binge eating episodes were asked to describe their emotional feelings before and after bingeing and before and after compensatory activities. EAT-26 scores corresponding to scores previously reported for eating disordered patients were found in 9.7% of students. Binge eating was nearly twice as frequent among females (16.4%) as males (8.6%). Among females, positive relationships were found between specific EAT-26 factors scores and both anxiety and depression scores. The emotional antecedents and consequences of binge eating and of compensatory activities were compared in three sub-groups of individuals who reported recurrent bingeing with loss of self-control during binges. The three sub-groups consisted of individuals who reported, 1) bingeing without engaging in compensatory activities, 2) bingeing and compensating by means other than vomiting (fasting, exercising, or use of laxatives or diuretics), and 3) bingeing and compensating by vomiting. Regardless of the type of activity, those individuals who engaged in compensatory activities reported greater negative affect preceding binge episodes than those who did not compensate. In addition, contrary to expectations, negative affect did not decrease, but instead increased significantly, following binge episodes and decreased immediately before and after compensatory activities.

Opioid effects on intake of sweet solutions depend both on prior drug experience and on prior ingestive experience.

Two experiments investigated the effect of opioids on ingestion of sweet solutions in non-deprived rats. Experiment 1 replicated previous work from our laboratory showing virtually complete inhibition of sucrose and saccharin intake during 10 days of daily naloxone treatment. During recovery, prior naloxone experience significantly stimulated sucrose intake but had no effect on saccharin intake. In the absence of naloxone treatment, ingestive experience alone reduced naloxone's typical intake-suppressant effect. These findings suggest that drug experience and ingestive experience may interact to determine the intake-suppressant effect of naloxone. Experiment 2 examined the effects of opioid agonists on sucrose ingestion during 10 days of initial drug treatment and 5 days of recovery. A low dose of the kappa agonist U-50,488H significantly stimulated sucrose ingestion during the drug treatment period and this effect persisted for several days after treatment ended. Initial (non-significant) intake suppressant effects of the mu agonist morphine or a high dose of U-50,488H tended to decrease with repeated testing and did not reappear during recovery. These data suggest that in addition to immediate, direct effects on motivation, opioids may affect long-term changes in responsiveness to sweet tastes.

Vasomotor thresholds in the squirrel monkey: effects of central and peripheral temperature.

Six squirrel monkeys (Saimiri sciureus) participated in two ex,eriments examining how central (preoptic/anterior hypothalamic, Tpo) and peripheral (ambient, Ta, or mean skin, Tsk) temperatures influence peripheral vasomotion. In the first experiment, four monkeys with unilateral preoptic thermodes were exposed to a wide range of central (23 degrees C less than Tpo less than 44 degrees C) and peripheral (10 degrees C less than Ta less than 38 degrees C) temperatures. Results indicated that the skin of both tail and foot vasodilates at discrete but unique Ta thresholds (Tpo congruent to 39 degrees C) and that raising Tpo lowers these thresholds. In the second experiment, results from two monkeys implanted with bilateral thermodes surrounding the preoptic area replicated those of experiment 1. Subsequent tests with these two monkeys on the quantitative interaction between central and peripheral temperatures indicated that the dilation threshold is approximately a linear function of Tpo and Tsk. These effects are related to the interaction between central and peripheral inputs to the thermoregulatory system.

Unilateral nostril breathing influences lateralized cognitive performance.

Relative nostril efficiency (nasal cycle) is related to hemispheric EEG differences and performance on cognitive tasks. We investigated how unilateral forced nostril breathing influences spatial and verbal performance. Right-handed males and females performed both tasks under either left-nostril, right-nostril, or free-breathing conditions. Unilateral breathing affects performance differently in males and females. It influences male performance ipsilaterally on both tasks: Their spatial performance is better during right-nostril breathing, and their verbal performance is better during left-nostril breathing. Unilateral breathing influences female performance contralaterally, but only on the spatial task: Their spatial performance is better during left-nostril breathing. These differences within and between sexes may exist because unilateral nostril breathing differentially activates the two hemispheres and thereby facilitates performance, or because attempts of the brain to control the nasal cycle unilaterally interfere with performance.

Potential aversive compounds in leafy spurge for ruminants and rats.

Several wild and domestic ruminant species and horses apparently will not consume leafy spurge (Euphorbia esula) while grazing range and pasture lands. It has been demonstrated that leafy spurge can elicit conditioned food aversions in cattle and sheep, and the aversion-eliciting capacity of leafy spurge may account for why cattle seldom graze this nutritious plant and why sheep may not readily consume it at some locations. The identity of the aversive compound(s) in leafy spurge is unknown, but several different diterpenoid ingenol esters have been isolated from its tissues, and we suspect that one or more ingenol esters may be aversion-eliciting compounds in leafy spurge. The objectives of this study were to determine whether or not leafy spurge is aversive to laboratory rats and if a crude acetone extract of leafy spurge, presumably containing ingenol esters and other phytochemicals, could generate an aversive response in sheep and laboratory rats. An additional objective was to determine whether or not a particular ingenol monobenzoate, which may be similar to ingenol esters in leafy spurge, might also elicit an aversive response from rats. Rats exhibited food aversions associated with leafy spurge (P < 0.05). An acetone extract of leafy spurge induced conditioned food aversions in both sheep and rats (P < 0.01). The ingenol 3-monobenzoate also induced conditioned food aversions in rats (P < 0.01). Our interpretation of these data is that rats can be used as a model for cattle and sheep with respect to their aversion to leafy spurge ingestion. Additionally, we suggest that one or more ingenol esters may be aversion-inducing agents in leafy spurge. However, others may exist in leafy spurge that are also aversive or are the only or prime aversive chemicals.