Evaluation of Taste Aversion Learning Procedure for the Generalization of Aversion Using Palatable Foods / Evaluación del procedimiento aprendizaje aversivo gustativo para la generalización de la aversión con dos alimentos palatables

Abstract An experiment to evaluate the effectiveness of the taste aversion conditioning paradigm in the generalization of aversion with palatable foods was performed. Ten experimentally naive females Wistar rats and three types of foods were used: a) standard purina rodent chow, b) vanilla flavor cookies and c) chocolate-flavored cookies. Subjects were divided into two groups, five subjects per group. Using the taste aversion conditioning paradigm protocol, subjects were exposed to the types of food keeping an intake record. The experiment demonstrated that rats can acquire an aversion to palatable foods accompanied by a tendency to generalize, when using elements that share characteristics such as nutritional content and texture. In addition, the intake of a food that does not share the characteristics of texture, taste, smell and energy content with the one used for conditioning was not been affected. These findings indicate that the aversion generalization seems to depend on the properties of the food used.

Resumen Se evaluó experimentalmente la efectividad del paradigma de aprendizaje aversivo gustativo en la generalización de la aversión utilizando alimentos palatables. Se utilizaron diez ratas Wistar hembras experimentalmente ingenuas y tres tipos de alimentos: a) purina comida estándar para roedores, b) galletas con sabor a vainilla y c) galletas con sabor a chocolate. Los sujetos fueron divididos en dos grupos, cinco sujetos en cada uno. Usando el paradigma de condicionamiento de aversión al sabor, los sujetos fueron expuestos a los tipos de alimentos manteniendo un registro de ingesta. El experimento demostró que las ratas pueden adquirir una aversión a los alimentos palatables acompañados por una tendencia a generalizarse, cuando se utilizan elementos que comparten características como el contenido nutricional y la textura. Además, la ingesta de un alimento que no comparte características como la textura, sabor, olor y contenido energético como el utilizado para el condicionamiento no se vio afectada. Estos hallazgos demuestran que la generalización de la aversión parece depender de las propiedades de los alimentos utilizados.

Changes in appetite, taste, smell, and food aversion in post-bariatric patients and their relations with surgery time, weight loss and regain.

PURPOSE: We aimed to study the occurrence of long-term changes in appetite, taste, smell perceptions, and food aversion in patients following bariatric surgery. Additionally, we compared two surgery types, excess weight loss, rate of weight regain, and time since surgery. METHODS: This cross-sectional study included 146 post-bariatric patients who were without regular medical follow-up (126 post-Roux-en-Y gastric bypass [RYGB] and 20 post-sleeve gastrectomy [SG]), aged 42 ± 8 years, BMI of 32.6 ± 6.3 kg/m2, with excess weight loss of 87.5 ± 20.2%, rate of weight regain (RWR) of 15.4 [3.9-30.9]% and time since surgery of 5.0 ± 4.0 years. They answered a questionnaire about sensory and food perceptions at their first medical appointment at our unit. RESULTS: Changes in appetite (76%), taste (48.6%), and an increased sensation for sweet taste (60.2%) frequently occurred in our sample. Sensory and food aversion perceptions, taste changes to specific foods, and loss level of taste and smell were similar between RYGB and SG. No differences between patients with or without changes in appetite, taste, smell, and food aversion perceptions concerning excess weight loss were observed. The RWR in post-RYGB was lower in those with changes in taste and smell (P = 0.05). Sensory changes were noted in those with shorter time since surgery for both surgeries (P ≤ 0.05). CONCLUSION: Changes in appetite and taste occurred frequently in our patients even in the long term. Post-RYGB patients with lower RWR had more changes in taste and smell while a shorter time since surgery showed more frequent changes in appetite, taste, and smell. LEVEL OF EVIDENCE: Level V, cross-sectional study. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov (NCT04193384).

Sour aversion in frontotemporal dementia: a case report and review on physiologic-anatomic mechanisms.

Frontotemporal dementia (FTD) is a common cause of early-onset dementia characterized by behavioral and personality changes, as well as, altered eating habits. FTD is associated with complex changes in neural networks of gustatory processing which may be responsible for eating abnormalities. Here, we present a 66-years-old lady suffered from behavioral variant of FTD with an interesting symptom of food aversion, typically sour foods.

GDF15 Induces an Aversive Visceral Malaise State that Drives Anorexia and Weight Loss.

The anorectic and weight-suppressive effects of growth differentiation factor-15 (GDF15) are attracting considerable attention for treating obesity. Current experiments in rats investigate whether GDF15 induces an aversive visceral malaise-based state that mediates its acute anorectic effect and, through aversion conditioning, exerts longer-term anorexia. Visceral malaise, conditioned affective food responses (taste reactivity), gastric emptying (GE), food intake, and body weight are evaluated after acute and chronic systemic dosing of GDF15 or long-acting Fc-GDF15. Pica, a marker of visceral malaise, is present at all anorectic GDF15 doses. Moreover, malaise induced by GDF15 does not decline over time, suggesting the lack of an improved tolerance after prolonged exposure. One association between GDF15 and novel food conditions a disgust/aversive response that persists beyond GDF15 acute action. Delayed GE is not a requirement for GDF15-induced anorexia. Clinical studies are required to evaluate whether GDF15's aversive-state-based anorexia will be contraindicated as an obesity treatment.

Food aversion and poor weight gain in food protein-induced enterocolitis syndrome: A retrospective study.

BACKGROUND: Food protein-induced enterocolitis syndrome (FPIES) is a form of non-IgE-mediated gastrointestinal food allergy. Insufficient data exist in regard to gastrointestinal history and outcome, particularly comorbidity, family history, food aversion, and poor body weight gain. OBJECTIVE: We sought to identify the gastrointestinal outcomes and related risk factors in FPIES. METHODS: We analyzed the clinical features and gastrointestinal outcomes of patients with FPIES retrospectively at 4 hospitals in Boston. RESULTS: Two hundred three patients with FPIES were identified, including 180 only with acute FPIES, 8 with chronic FPIES, and 15 with both. Oat (34.5%), rice (29.6%), and cow's milk (19.2%) were the most common food triggers. The prevalence rates of personal history with allergic proctocolitis (23.2%) and family history with inflammatory bowel diseases (9.4%) and celiac disease (7.3%) were higher than those in the general population. Compared with patients with FPIES with 1 or 2 food triggers, the risk of developing food aversion increased in cases triggered by 3 or more foods (adjusted odds ratio, 3.07; 95% CI, 1.38-6.82; P = .006). The risk of poor body weight gain increased in FPIES triggered by cow's milk (adjusted odds ratio, 3.41; 95% CI, 1.21-9.63; P = .02) and banana (adjusted odds ratio, 7.63; 95% CI, 2.10-27.80; P = .002). CONCLUSIONS: Gastrointestinal comorbidities and family history were common in patients with FPIES. Patients with FPIES with 3 or more triggers were at risk of food aversion. Patients with FPIES with cow's milk and banana as triggers were at risk of poor body weight gain.

Selection of new chemicals to be used in conditioned aversion for non-lethal predation control.

Globally, native predators and scavengers are threatened through the incidence of illegal poisoning due to increasing human-wildlife conflicts. The use of conditioned taste aversion (CTA) may mitigate such conflicts. CTA is a robust learning paradigm that occurs when animals associate a food with a discomfort induced by a chemical, thereby avoiding that food in subsequent encounters. We reviewed the potential of 167 chemical compounds to be used in CTA, considering effects, margin of safety, accessibility, and detectability. After the review, 15 compounds fulfilled the required characteristics, but only five (thiabendazole, thiram, levamisole, fluconazole and fluralaner) were finally selected to be tested in CTA assays with dogs. Of the tested compounds, thiabendazole, thiram and levamisole caused target food rejection by dogs and reduced the time spent eating during post-conditioning. However, despite being microencapsulated, levamisole appeared to be detectable by dogs, whereas thiram and thiabendazole were not. Fluconazole and fluralaner did not produce any CTA effect. Thiabendazole, thiram and levamisole can therefore induce CTA, and thus are potential candidates as aversive compounds for wildlife management. Thiram is an undetectable, relatively safe and accessible compound that can induce CTA in canids, and opens new possibilities to develop methods of non-lethal predation control.

Perampanel-induced, new-onset food aversion in a 29-year-old female with medically refractory frontal lobe epilepsy.

BACKGROUND: Perampanel is a selective, noncompetitive amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid glutamate receptor antagonist indicated for management of partial-onset and primary generalized seizures in epilepsy patients aged ≥12 years. PATIENT HISTORY: A 29-year-old, white female with significant history of medically refractory frontal lobe epilepsy, status post right frontal and temporal resections, was initiated on perampanel as an add-on therapy to phenytoin extended-release (330 mg/d) and clonazepam (2.5 mg/d). She previously failed several antiepileptic drugs because of inefficacy and/or intolerance. Perampanel was initiated at 2 mg/d and the dose was increased by 2 mg/d increments every 2 to 3 weeks. Following the first dose, nausea and drowsiness were reported but resolved the following day. Three days after titration to 6 mg/d, the patient developed complete food aversion and became more irritable and anxious while no seizure frequency improvement was noted. No change of sense of taste was reported. After reduction to 4 mg/d, adverse effects improved but did not completely resolve until 2 months following perampanel discontinuation. REVIEW OF LITERATURE: A PubMed search revealed no published literature or case reports of perampanel-induced food aversion or anorexia in a presence or absence of phenytoin and clonazepam. CONCLUSION: In this report, a temporal relationship was observed between perampanel dose-increase and the development of food aversion. Return to baseline appetite and eating habits following perampanel discontinuation strongly suggest perampanel involvement. At this time, the exact mechanism(s) behind food aversion associated with perampanel is/are unknown.

Gustatory Function of Pregnant and Nonpregnant Women in a Tertiary Health Institution.

Physiological changes in pregnancy may cause taste dysfunction. The aim of this study was to determine and compare gustatory function of pregnant women with nonpregnant women and also to investigate the effect of pregnancy on gustatory function. It was a case-control study of consecutive 70 healthy pregnant women (cases) and 70 healthy nonpregnant women (control). Participants scored their taste perception on a visual analogue scale (1-10) and their gustatory function was assessed using "taste strips" impregnated with graded concentration of sweet, sour, salty, and bitter taste substances applied on tongue surfaces. Subjective mean gustatory score, correct identification of taste in the strips and total taste strip (TTS) score were compared between both groups and analysis was done using appropriate statistics. The mean age of pregnant women (30.5 [3.9]) and controls (28.5 [6.6]) were comparable. Twenty-one (30%) pregnant women changed their diet in first trimester due to change in taste sensation. Almost all cases developed craving for spicy and salty foods and, aversions to fish, beans, and vegetables. There was a significant difference in the subjective rating of taste perception between the 2 groups ( P = .037). About 2.9% of pregnant women have hypogeusia. There was a significant difference between pregnant and nonpregnant women in sour taste ( P = .006; 2.90 [0.71] vs 3.92 [0.82]) and TTS ( P = .02; 27.50 [3.48] vs 29.21 [2.69]) scores, respectively. In conclusion, gustatory function was reduced in pregnancy compared to nonpregnant women and this led to dietary change in some pregnant women.

Intra Strain Variation of the Effects of Gram-Negative ESKAPE Pathogens on Intestinal Colonization, Host Viability, and Host Response in the Model Organism Caenorhabditis elegans.

In its native environment of rotting vegetation, the soil nematode Caenorhabditis elegans encounters a range of bacteria. This includes species from the ESKAPE group of pathogens that pose a clinical problem in acquired hospital infections. Here, we investigated three Gram-negative members of the ESKAPE group, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. Pathogenicity profiles as measured by time to kill adult C. elegans showed that P. aeruginosa was the most pathogenic, followed by K. pneumoniae, while C. elegans cultured on A. baumannii exhibited the same survival as those on the standard laboratory food source for C. elegans, Escherichia coli OP50. The pathogenicity was paralleled by a reduction in time that C. elegans resided on the bacterial lawn with the most pathogenic strains triggering an increase in the frequency of food-leaving. Previous reports indicate that gut colonization is a feature of pathogenicity, but we found that the most pathogenic strains were not associated with the highest level of colonization. Indeed, clearance of P. aeruginosa strains from the C. elegans gut was independent of bacterial pathogenicity. We show that this clearance is regulated by neuromodulation as C. elegans mutants in unc-31 and egl-3 have enhanced clearance of P. aeruginosa. Intriguingly this is also not linked to their pathogenicity. It is likely that there is a dynamic balance occurring in the C. elegans intestinal environment between maintaining a healthy, beneficial microbiota and removal of pathogenic bacteria.

Long-term outcome of peanut oral immunotherapy-Real-life experience.

BACKGROUND: Oral immunotherapy (OIT) is currently recommended as a treatment option for peanut-allergic patients. Data regarding its long-term compliance and efficacy in real life are required. METHODS: Peanut-allergic patients aged ≥4 years were enrolled in a single-center clinical OIT program. Buildup to 3000 mg peanut protein was performed. Patients reaching this dose before or after 12/2014 were instructed to consume 3000 or 1200 mg daily, respectively. Patients were followed ≥6 months after reaching maintenance and rechallenged to 3000 mg. RESULTS: Of the 145 patients studied, 113 (77.9%) were fully desensitized to 3000 mg and 133 (91.7%) were desensitized to ≥300 mg. 21/145 patients (14.5%) required adrenaline for home-dose reactions during buildup. Non-anaphylactic gastrointestinal symptoms, experienced by 9 patients (6.2%), reversed with dose reduction. Of the 111 patients available for analysis 6 months after reaching 3000 mg, 97 (87.4%) continued regular peanut consumption. Only 2/111 patients (1.8%) required adrenaline over the long-term (median, range; 18, 6-75 months) follow-up. Adherence to treatment was significantly higher in patients consuming 1200 mg (73/76, 96.1%) vs those consuming 3000 mg (24/35, 72.2%), (P = .001). A higher maintenance dosage and home adrenaline requirement during buildup predicted adherence cessation (OR 12.5, P = .001; and OR 7.8, P = .02, respectively). 63/64 patients (98.4%) consuming 1200 mg maintenance dose were successfully rechallenged to 3000 mg. CONCLUSIONS: This real-life experience demonstrates the efficacy of peanut OIT long-term. A lower maintenance dose minimized treatment cessation while maintaining desensitization. OIT should be performed in qualified centers given the prevalence of adverse reactions, particularly during buildup.

NMDA or 5-HT receptor antagonists impair memory reconsolidation and induce various types of amnesia.

Elucidation of amnesia mechanisms is one of the central problems in neuroscience with immense practical application. Previously, we found that conditioned food presentation combined with injection of a neurotransmitter receptor antagonist or protein synthesis inhibitor led to amnesia induction. In the present study, we investigated the time course and features of two amnesias: induced by impairment of memory reconsolidation using an NMDA glutamate receptor antagonist (MK-801) and a serotonin receptor antagonist (methiothepin, MET) on snails trained with food aversion conditioning. During the early period of amnesia (<10th day), the unpaired presentation of conditioned stimuli (CS) or unconditioned stimuli (US) in the same training context did not have an effect on both types of amnesia. Retraining an on 1st or 3rd day of amnesia induction facilitated memory formation, i.e. the number of CS + US pairings was lower than at initial training. On the 10th or 30th day after the MET/reminder, the number of CS + US pairings did not change between initial training and retraining. Retraining on the 10th or 30th day following the MK-801/reminder in the same or a new context of learning resulted in short, but not long-term, memory, and the number of CS + US pairings was higher than at the initial training. This type of amnesia was specific to the CS we used at initial training, since long-term memory for another kind of CS could be formed in the same snails. The attained results suggest that disruption of memory reconsolidation using antagonists of serotonin or NMDA glutamate receptors induced amnesias with different abilities to form long-term memory during the late period of development.

Aversiones alimentarias en adolescentes de la Secundaria Básica José Martí en municipio Cerro. 2015 / Food aversions of teenagers from the Junior High School Jose Marti in the municipality Cerro. 2015

Introducción: la adolescencia es considerada una etapa compleja no solo por los cambios que ocurren en el organismo desde todos los puntos de vista, sino por la complejidad que presupone el manejo psicológico de la misma, de esta forma también influye, lo relacionado con su hábitos alimenticios. Objetivo: describir el comportamiento de las aversiones alimentarias en 94 adolescentes, de la escuela Secundaria Básica "José Martí". Materiales y Métodos: se realizó un estudio descriptivo transversal, con 94 adolescentes de la escuela Secundaria Básica "José Martí" del municipio Cerro, que cursaban el 7mo grado, cuyas edades oscilaron de 11 a 15 años de edad, durante el período de septiembre a octubre del 2015. Resultados: los grupos de alimentos más detestados fueron los vegetales y las frutas. El pescado a pesar de su importancia nutricional fue el alimento más rechazado y el menos consumido. Las viandas, las legumbres, los cereales, las carnes blancas, el huevo y los lácteos fueron los grupos de alimentos por los que menos aversión mostraron. Continúa siendo un factor de riesgo para la población adolescente, la ingestión de dulces y azúcares por ser uno de los alimentos preferidos y de mayor consumo. Conclusiones: las aversiones alimentarias detectadas sitúan a este grupo atareo en una situación vulnerable desde el punto de vista nutricional, y ratifica que los alimentos con mayores valores nutricionales son los menos aborrecidos, a pesar de las consecuencias actuales y futuras que pueden generar en su salud, así como el incremento de la incidencia de enfermedades relacionadas con los hábitos dietéticos (AU).

Introduction: the adolescence is considered a complex stage not only because of the changes occurring in the organism from all the points of view, but also due to the complexness of its psychological management. Eating habits belong to this field. Objetive: to describe the behavior of food aversions in 94 teenagers of the Junior High School "José Martí." Materials and Methods: a cross-sectional, descriptive study was carried out during the period September-October 2015, with 97 7th-grade students of the Junior High school "José Martí", municipality Cerro, whose age ranged from 11 to 15 years. Results: the most detested food groups were vegetables and fruits. Fish, in spite of its nutritional importance, was the most rejected food and the less consumed one. Vegetables, legumes, cereals, white meats, eggs and dairy products are the food groups for which they showed less aversion. It is still a risk factor for the adolescent population the consumption of sweets and sugar because they are their preferable food and the ones they consume the most. Conclusions: the detected food aversions locate this age group in a vulnerable situation from the nutritional point of view, and ratifies foods with higher nutritional values are the less detested ones, in spite of the current and future consequences that could generate in their health, and also indicates the raise of the incidence of diseases related with dietary habits (AU).

Aversiones alimentarias en adolescentes de la Secundaria Básica José Martí en municipio Cerro. 2015 / Food aversions of teenagers from the Junior High School Jose Marti in the municipality Cerro. 2015

Introducción: la adolescencia es considerada una etapa compleja no solo por los cambios que ocurren en el organismo desde todos los puntos de vista, sino por la complejidad que presupone el manejo psicológico de la misma, de esta forma también influye, lo relacionado con su hábitos alimenticios. Objetivo: describir el comportamiento de las aversiones alimentarias en 94 adolescentes, de la escuela Secundaria Básica "José Martí". Materiales y Métodos: se realizó un estudio descriptivo transversal, con 94 adolescentes de la escuela Secundaria Básica "José Martí" del municipio Cerro, que cursaban el 7mo grado, cuyas edades oscilaron de 11 a 15 años de edad, durante el período de septiembre a octubre del 2015. Resultados: los grupos de alimentos más detestados fueron los vegetales y las frutas. El pescado a pesar de su importancia nutricional fue el alimento más rechazado y el menos consumido. Las viandas, las legumbres, los cereales, las carnes blancas, el huevo y los lácteos fueron los grupos de alimentos por los que menos aversión mostraron. Continúa siendo un factor de riesgo para la población adolescente, la ingestión de dulces y azúcares por ser uno de los alimentos preferidos y de mayor consumo. Conclusiones: las aversiones alimentarias detectadas sitúan a este grupo atareo en una situación vulnerable desde el punto de vista nutricional, y ratifica que los alimentos con mayores valores nutricionales son los menos aborrecidos, a pesar de las consecuencias actuales y futuras que pueden generar en su salud, así como el incremento de la incidencia de enfermedades relacionadas con los hábitos dietéticos (AU).

Introduction: the adolescence is considered a complex stage not only because of the changes occurring in the organism from all the points of view, but also due to the complexness of its psychological management. Eating habits belong to this field. Objetive: to describe the behavior of food aversions in 94 teenagers of the Junior High School "José Martí." Materials and Methods: a cross-sectional, descriptive study was carried out during the period September-October 2015, with 97 7th-grade students of the Junior High school "José Martí", municipality Cerro, whose age ranged from 11 to 15 years. Results: the most detested food groups were vegetables and fruits. Fish, in spite of its nutritional importance, was the most rejected food and the less consumed one. Vegetables, legumes, cereals, white meats, eggs and dairy products are the food groups for which they showed less aversion. It is still a risk factor for the adolescent population the consumption of sweets and sugar because they are their preferable food and the ones they consume the most. Conclusions: the detected food aversions locate this age group in a vulnerable situation from the nutritional point of view, and ratifies foods with higher nutritional values are the less detested ones, in spite of the current and future consequences that could generate in their health, and also indicates the raise of the incidence of diseases related with dietary habits (AU).

Using long-term averted goats for selective grazing in olive groves.

Conditioned taste aversion (CTA) is a useful tool to modify animal feed preferences, allowing the implementation of selective grazing to control weeds in tree orchards without damaging the trees or affecting fruit production. LiCl is commonly used for inducing CTA. However, studies investigating the long-term persistence of CTA by LiCl in small ruminants are scarce. With this aim, we evaluated the efficiency of two LiCl doses (AV1 and AV2, 175 and 200 mg/kg BW, respectively) and a control (C, 0 mg/kg BW) for averting non-lactating dairy goats (n=15) to olive tree leaves. Aversion induction was reinforced on day 9 in those goats that consumed >10 g of olive leaves. Mid-term aversion effectiveness was assessed by five double-choice feeding tests (days 16, 24, 31, 38 and 53) of 30 min each, where 100 g of olive leaves were offered side-by-side with 390 g of Italian rye-grass (as-fed). Long-term aversion effectiveness was assessed in C, AV1 and AV2 goats by grazing for 30 min in paddocks with a simulated olive tree (days 59, 90, 121, 182 and 420). Moreover, C and AV2 goats were compared under on-field conditions (days 143, 211 and 363) in a commercial olive grove also for 30 min. The CTA proved to be established with a single LiCl dose in all goats and persisted for 4 and 55 days in AV1 and AV2 goats, respectively (P<0.001). However, 80% AV1 and 20% AV2 goats needed to be reinforced at day 9. When grazing under simulated olive tree and commercial olive grove conditions, the CTA goats, especially AV2 group, avoided the contact with the olive trees and minimally used a bipedal stance to feed leaves, than control goats. On average, time proportion spent consuming olive leaves and sprouts was much greater (P<0.05) for C (50.7±9.1%) than for AV1 (14.4±3.9%) and AV2 (3.1±0.9%). In conclusion, the 200 mg LiCl/kg BW dose was more effective than the 175 mg LiCl/kg BW dose for inducing an effective long-term CTA to olive tree leaves in goats.

The Neural Bases of Disgust for Cheese: An fMRI Study.

The study of food aversion in humans by the induction of illness is ethically unthinkable, and it is difficult to propose a type of food that is disgusting for everybody. However, although cheese is considered edible by most people, it can also be perceived as particularly disgusting to some individuals. As such, the perception of cheese constitutes a good model to study the cerebral processes of food disgust and aversion. In this study, we show that a higher percentage of people are disgusted by cheese than by other types of food. Functional magnetic resonance imaging then reveals that the internal and external globus pallidus and the substantia nigra belonging to the basal ganglia are more activated in participants who dislike or diswant to eat cheese (Anti) than in other participants who like to eat cheese, as revealed following stimulation with cheese odors and pictures. We suggest that the aforementioned basal ganglia structures commonly involved in reward are also involved in the aversive motivated behaviors. Our results further show that the ventral pallidum, a core structure of the reward circuit, is deactivated in Anti subjects stimulated by cheese in the wanting task, highlighting the suppression of motivation-related activation in subjects disgusted by cheese.

Effects of NO Donors and Inhibitors of NO Synthase and Guanylate Cyclase on the Acquisition of a Conditioned Defense Food Aversion Response in Edible Snails.

Experiments on edible snails revealed that NO synthase blockade with a nonspecific neuronal NO synthase inhibitor L-NAME before defense food aversion conditioning is followed by a decrease in the rate of learning. Exogenous NO donors, sodium nitroprusside and dinitrosyl iron complex, were shown to improve learning. Chronic administration of a specific soluble guanylate cyclase inhibitor ODQ also increased the rate of learning. Our results indicate that NO has a modulatory effect on the formation of a conditioned response in this type of learning.

Transcription inhibitors prevent amnesia induced by NMDA antagonist-mediated impairment of memory reconsolidation.

Recent studies report that long-term memory retrieval can induce memory reconsolidation, and impairment of this reconsolidation might lead to amnesia. Previously, we found that reconsolidation of a conditioned food aversion memory could be disrupted by translation inhibitors for up to 3 h following a reconsolidation event, thus inducing amnesia. We examined the role of transcription processes in the induction of amnesia in the land snail, Helix lucorum. It received N-methyl-D-aspartate (NMDA) glutamate receptor antagonist and transcription inhibitor 2 days after learning in a neutral context environment; it was then transferred to the learning context followed by reminder with conditioned food stimulus. NMDA receptor blockade, followed by a reminder session, impaired reconsolidation of an aversive memory. Simultaneous administration of an NMDA receptor antagonist and a transcription inhibitor prior to reminder of an aversive event prevented amnesia induction. In contrast, when a transcription inhibitor alone was injected prior to a reminder session, the blockade had no effect on memory. We found that transcription inhibition 0-6 h after amnesia induction suppressed memory loss, but this suppression was lost when inhibitors were administered 9 h after amnesia. Thus, amnesia is likely dependent on transcription processes within a 9-h time window. We can hypothesize that amnesia induction initiates synthesis of specific mRNAs and proteins; furthermore, these events occur within specific time-dependent windows. Our findings could prove useful for the analysis of amnesia formation and for the development of possible ways to prevent memory loss associated with various diseases and injuries in animals and humans.

Improving Milk Intake in Milk-Averse Lactose Digesters and Maldigesters.

OBJECTIVE: To determine whether a 21-day milk-drinking intervention could reverse milk aversion. DESIGN: Participants consumed increasing amounts of cow's milk for 21 days. Milk and dairy consumption, aversion, and likeness were assessed pre- and post-intervention and at 3 and 6 months post-intervention. SETTING: A large Midwestern university. PARTICIPANTS: Twenty-seven milk-averse individuals completed the intervention, 26 completed the 3-month follow-up, and 24 completed the 6-month follow-up. MAIN OUTCOMES MEASURED: Participants self-reported milk and dairy consumption, aversion, and degree to which they liked milk. ANALYSIS: Analysis of variance determined between-subject effects. Independent samples t test determined the effect of time. Fisher exact test determined factors affecting milk consumption. RESULTS: Lactose digesters and maldigesters showed a significant decrease in overall symptom scores after the milk intervention, with no significant difference between groups. Independent of digestive status, subjects demonstrated a significant decrease in aversion, an increase in the amount to which they liked milk, and an increase in milk and overall calcium consumption at 3 and 6 months post-intervention. CONCLUSIONS AND IMPLICATIONS: The results suggest a reversal of milk avoidance and the possibility that milk avoiders can increase likeness and incorporate milk into their diet after exposure.

Avoidance of potentially harmful food cannot be socially transmitted between rats.

The social transmission of food preferences (STFP) is a behavioural task of olfactory memory, in which an observer rat learns safe food odours from a demonstrator rat, and shows preference for this odour in a subsequent choice test. However, previous studies have failed to detect the transmission of information about food of potential danger and food aversion using STFP test. In this study, we tested how demonstrators' health affects the exchange of odour information and whether observers can learn danger information from an unhealthy demonstrator. As expected, the observer rat formed an odour preference after interacting with a demonstrator rat that had just eaten food containing a new odour, however, odour preference rather than aversion was also formed after interacting with a demonstrator rat injected with LiCl (used to induce gastric malaise). Furthermore, anaesthetized demonstrator rats and half-anaesthetized demonstrator rats, which showed obvious motor deficits suggesting an unhealthy state, also socially transmitted food preferences to observers. These results suggest that the social transmission of food preferences task is independent of a demonstrators' health, and that information about dangerous foods cannot be transmitted using this behavioural task.