First record of geophagy in Jungle Babbler (Turdoides striata) prior to egg-laying: an instinct for calcium supplement.

Geophagy has been documented in different animal taxa including Aves and particularly in Passeriformes. However, no geophagic activity has been reported in the genus Turdoides of the family Leiothrichidae belonging to the passerine order. Studies reveal the behaviour of geophagy to be aiding in nutrient supplementation, toxin neutralisation, cytoprotection, gut pH stabilisation and parasite liberation. Here, we provide a record of geophagy in Jungle Babbler Turdoides striata in a peri-urban area of Berhampur city in India. Although this species, being insectivorous, was thought to be feeding on insects, nevertheless, close observations confirmed the activity to be a case of geophagy, which was followed up by nest-building, egg-laying and hatching. The soil samples from the geophagic sites (Ca = 2415 mg/kg) contained 130% more Ca than that of the non-geophagic sites (Ca = 1050 mg/kg). The biochemical requirement of calcium throughout the reproductive phase of Turdoides sp. may corroborate the soil consumption instinct, which was also extrapolated from the reproductive success observed, because the demand for calcium in birds remains high during the egg-laying time. Although the possible explanations for geophagy, reported for the first time in this species, were oriented specifically towards Ca supplement, the present findings provide impetus for furthering research in this domain.

Geophagy in large-headed capuchin monkeys (Sapajus apella macrocephalus) in the Reserva Nacional Tambopata, Peru.

Many primate species have been observed descending to the forest floor to intentionally consume soil (geophagy) at licks. The practice of geophagy is assumed to provide health benefits, such as mineral supplementation and/or gastrointestinal tract protection. We collected data on geophagy events through the use of camera traps at Tambopata National Reserve in southeastern Peru. Two geophagy sites were monitored for 42 months, during which time we observed repeated geophagy events by a group of large-headed capuchin monkeys (Sapajus apella macrocephalus). To the best of our knowledge, this is the first report of its kind for the species. Geophagy was rare, with only 13 events recorded over the study period. All but one event took place during the dry season, and 85% of events took place in the late afternoon between 1600 and 1800 hours. The monkeys were observed consuming soil both in situ and ex situ, and displayed heightened vigilance behavior during geophagy events. Although the small sample size makes it difficult to draw clear conclusions as to the drivers of this behavior, the seasonal timing of the events and the high percentage of clay in the consumed soils suggest that these events are linked to the detoxification of secondary plant compounds in the monkeys' diet.

Effectors of Pregorexia and Emesis among Pregnant Women: A Pilot Study.

During pregnancy, women tend to improve their lifestyle habits and refine their dietary intake. Quite often, however, these dietary improvements take an unhealthy turn, with orthorexia nervosa (ON) practices being apparent. The aim of the present pilot cross-sectional study was to assess the prevalence of ON tendencies and the incidence of pica and record diet practices in a sample of pregnant women. A total of 157 pregnant women were recruited through private practice gynecologists during the first months of 2021. Nutrition-related practices were recorded, orthorexic tendencies were assessed using the translated and culturally adapted Greek version of the ORTO-15 questionnaire, pica practices were evaluated with a binary question and nausea and emesis during pregnancy (NVP) was evaluated using the translated modified Pregnancy-Unique Quantification of Emesis and Nausea (mPUQE). Only two women reported pica tendencies, with ice and snow being the consumed items. The majority (61.1%) of women reported improving their diet since conception was achieved. Folic acid and iron oral nutrient supplements (ONS) were reportedly consumed by the majority of participants (87.9% and 72.6%, respectively) and 9.6% reported using herbal medicine products. The ORTO-15 score was reduced with tertiary education attainment, ART conception, being in the third trimester of pregnancy, consumption of folic acid and MV supplements and was only increased among women who were at their first pregnancy. The majority of participants experienced severe NVP and the remaining experienced moderate NVP. NVP was associated with lower hemoglobin levels, lack of supplementary iron intake, avoidance of gluten-containing foods, as well as with increased gestational weight gain. The results highlight the need to screen pregnant women for disturbed eating behaviors and nutrition-related problems, in order to ensure a healthy pregnancy outcome.

Effects of Rikkunshi-To, a Japanese kampo medicine, on donepezil-induced gastrointestinal side effects in mice.

Donepezil, an acetylcholinesterase inhibitor, is associated with gastrointestinal symptoms, such as nausea, vomiting, and anorexia, which may affect adherence to continuous therapy. Since Rikkunshi-To, a Japanese herbal medicine, activates the ghrelin signaling pathway and promotes gastrointestinal function, it is administered to prevent gastrointestinal symptoms. We herein investigated whether donepezil-induced gastrointestinal side effects in mice are ameliorated by Rikkunshi-To and if its therapeutic efficacy is mediated by ghrelin. Since pica behavior, the ingestion of kaolin, correlates with nausea and vomiting in humans, donepezil was intraperitoneally administered with or without Rikkunshi-To daily to mice, and food and kaolin intakes were monitored. The effects of donepezil on intestinal motility and a ghrelin receptor antagonist on donepezil-induced pica behavior, anorexia, and changes in intestinal motility were examined in mice treated with Rikkunshi-To. Pica behavior and anorexia were significantly induced by donepezil and significantly inhibited by Rikkunshi-To. Intestinal motility was significantly suppressed by donepezil and promoted by Rikkunshi-To. Furthermore, the therapeutic effects of Rikkunshi-To were antagonized by the ghrelin receptor antagonist. The present results support the therapeutic efficacy of Rikkunshi-To against donepezil-induced gastrointestinal side effects.

Liujunanwei decoction attenuates cisplatin-induced nausea and vomiting in a Rat-Pica model partially mediated by modulating the gut micsrobiome.

Studies show that traditional Chinese medicine (TCM), such as Liujunanwei (LJAW) decoction, can play important roles in alleviating side effects of chemotherapy. The purpose of this study was to understand how LJAW can counter chemotherapy-induced emesis via alteration of gut microbiota. We evaluated the effect of LJAW on cisplatin (DDP)-induced nausea and vomiting using a rat-pica model. Rats react to emetic-producing stimuli with increased kaolin consumption, a phenomenon called pica. The rats were injected with cisplatin and then randomly assigned to the control (DDP), Ondansetron or LJAW. The intake of kaolin and chow diet as well as body weights were recorded every 24 hours. Fecal samples were collected prior to, after three and seven days of treatment. The expression of proteins was measured by western blot. The concentration of cytokines and serotonin was evaluated using ELISA assay kits. Kaolin consumption in rats induced by cisplatin was reduced by 16.5%, 22.5%, and 30.1% in the LJAW group compared to the DDP group at 24 hours, 48 hours and 72 hours, respectively (p>0.05). LJAW significantly increased the food intake of the rats (13.94 ± 4.73 g) during the first 24 hours as opposed to the DDP (9.23 ± 3.77 g) (p<0.05). 16S rRNA gene sequencing showed the abundance of Bacteroidetes increased in cisplatin treated rats. In addition, cisplatin injection caused an enrichment of Escherichia-Shigella and Enterococcus at the genus level. While, enrichment of Blautia and Lactobacillus was presented in LJAW treated rats. Serotonin decreased in LJAW treated intestine and medulla oblongata tissues. Further, the protein expression of tryptophan hydroxylase 1 (TPH1) a rate limiting enzyme of serotonin was inhibited in LJAW treated rat's jejunum compared with cisplatin only treated rats. In addition, LJAW downregulated chemotherapy induced elevated inflammation. The results of this study indicated that LJAW is capable of decreasing cisplatin-induced kaolin intake in rat-nausea model (pica), which might be mediated through gut microbiome-induced anti-inflammation and anti-serotonin synthesis functions.

Desiderosmia: a manifestation of iron deficiency in pregnancy.

A pregnant woman in her 20s presented with an excessive desire to smell a specific household cleaning product. She was found to have severe iron deficiency anaemia and her symptoms resolved following intravenous iron supplementation. She described symptoms of fatigue, shortness of breath and olfactory cravings. The specific scent could not be replicated with other smells and the woman had to significantly modify her lifestyle to accommodate the excessive desire. She had a similar experience during her prior pregnancy which resolved after the correction of severe iron deficiency anaemia. This unique symptom has been described as desiderosmia: iron deficiency manifesting as olfactory cravings. This underappreciated but useful symptom is defined as a separate entity to pica, as there is an absence of desire to ingest the product. Desiderosmia can harm mother and baby through inhalation of potentially harmful fumes; hence, women who describe this symptom should be assessed for iron deficiency anaemia.

Effect of niacin supplementation on nausea-like behaviour in an isoniazid-induced mouse model of pellagra.

Niacin deficiency causes pellagra, the symptoms of which include dermatitis, diarrhoea and dementia. Investigating the mechanism underlying these phenotypes has been challenging due to the lack of an appropriate animal model. Here, we report a mouse model of pellagra-related nausea induced by feeding mice a low-niacin diet and administering isoniazid (INH), which is thought to induce pellagra. Mice fed a normal or low-niacin diet received INH (0·3 or 1·0 mg/mg per animal, twice daily, 5 d), and nausea was evaluated based on pica behaviour, which considered the rodent equivalent of the emetic reflex. Furthermore, the effect of therapeutic niacin administration on nausea was evaluated in this model. Urinary and hepatic metabolite levels were analysed by LC coupled with MS. INH-induced pica was observed in mice fed a low-niacin diet but not in those fed a normal diet. Levels of urinary metabolites, such as 1-methyl-2-pyridone-5-carboxamide, kynurenic acid and xanthurenic acid, were significantly reduced in the mice treated with INH compared with those that did not receive INH. Furthermore, niacin supplementation prevented pica and restored the levels of some metabolites in this mouse model. Our findings suggest that INH-related nausea is pellagra-like. We also believe that our newly established method for quantifying pica is a useful tool for investigating the mechanisms of pellagra-related nausea.

Pica: Treatment with Punica Granatum extract.

Pica is an eating disorder characterized by craving for nonfood items, such as dirt, clay, detergents, soap, stone, and paper. It occurs in children who start feeling the world with the oral cavity. The exact etiology of this disorder is still unknown; nonetheless, its treatment and prevalence vary according to patients' behavior and characteristics. We aim to present a case report of a patient with pica who was treated with Persian Traditional Medicine. This treatment was performed using four doses of 15 ml Punica granatum extract after every meal for 3 weeks while fasting before breakfast. The patient's appetite improve within 3 weeks, with remarkable improvement in pica symptoms. Punica granatum extract seems to be effective in controlling pica.

Forsythiae Fructus aqueous extract attenuates cisplatin-induced kaolin consumption (pica) by inhibiting NLRP3 inflammasome activation in rats.

The present study was conducted to evaluate the effect of Forsythiae Fructus aqueous extract (FAE) against cisplatin-induced emesis and to explore the antiemetic mechanism of FAE by focusing on NLRP3 inflammasome activation in a rat pica model. Our results showed that FAE significantly ameliorated cisplatin-induced acute and delayed pica in rats. Moreover, FAE improved the gastrointestinal histopathological injury and reduced the levels of serum ROS, IL-1ß, and IL-18 in cisplatin-treated rats. In addition, the expressions of NLRP3, ASC, caspase-1, and IL-1ß and the colocalization of the NLRP3 with ASC or caspase-1 in rat gastric antrum and ileum were also suppressed by FAE. Taken together, our findings indicate that FAE has a therapeutic effect against CINV, which may be related to its inhibition of the activation of NLRP3 inflammasome.

Selecting between iron-rich and clay-rich soils: a geophagy field experiment with black-and-white colobus monkeys in the Budongo Forest Reserve, Uganda.

Geophagy, the intentional consumption of soil, has been observed in humans and numerous other animal species. Geophagy has been posited to be adaptive, i.e., consumed soil protects against gastrointestinal distress and/or supplements micronutrients. We conducted a field experiment in the Budongo Forest, Uganda, to investigate geophagic behaviors, including soil preference, the quantity of soil eaten, and competition for access to preferred soils. We placed pairs of artificial tree stumps at two existing geophagy sites. One stump contained soil from the surrounding area, Sonso, that could supplement bioavailable iron. The other stump contained soil from a neighboring community, Waibira, that was richer in clay minerals, which could provide protection from plant secondary compounds. We monitored activity and engagement with the stumps for 10 days using camera traps. After 5 days, we reversed the type of soil that was in the stumps at both sites (i.e., a crossover design). Only Colobus guereza (black-and-white colobus monkeys) interacted with the stumps. These monkeys used visual and olfactory cues to select between the two soils and exclusively ate the clay-rich soil, consuming 9.67 kg of soil over 4.33 h. Our findings lend the greatest plausibility to the protection hypothesis. Additionally, monkeys competed for access to the stumps, and 13% of the videos captured aggression, including pushing, excluding, and chasing other individuals from the experimental stumps. Nine episodes of vigilance and flight behavior were also observed. Given that intentionally ingested soil is a valuable resource that may confer health benefits, geophagy sites should be conserved and protected.

RNA-Seq reveals inflammatory mechanisms of Xiao-Ban-Xia-Tang decoction to ameliorate cisplatin-induced emesis in a rat pica model.

OBJECTIVES: Xiao-Ban-Xia-Tang decoction (XBXT), an antiemetic formula in traditional Chinese medicine, has been proved to be a potential treatment for chemotherapy-induced nausea and vomiting (CINV), but the underlying mechanisms are not adequately understood. This study aimed to investigate changes in the ileum transcriptome after cisplatin and XBXT treatment and to reveal whether the antiemetic mechanisms of XBXT are related to its anti-inflammatory effect. METHODS: The pica model was established by a single intraperitoneal injection of 6 mg/kg cisplatin in Wistar rats. Tissues from the gastric antrum and ileum were stained with hematoxylin-eosin to observe gastrointestinal tract pathological changes. Based on the differentially expressed genes (DEGs) which were altered by cisplatin and reversed by XBXT, the transcriptome data of rat ileum were analyzed by GO, KEGG, and PPI analyses. Several inflammatory DEGs were validated by RT-PCR. RESULTS: XBXT could reduce kaolin intake up to 72 h after modeling and alleviate the inflammatory damage of gastric antrum and ileum induced by cisplatin. According to the transcriptome profile, there were 75 DEGs down-regulated by cisplatin and up-regulated by XBXT and 343 DEGs up-regulated by cisplatin and down-regulated by XBXT. XBXT could blunt the overexpression of tryptophan hydroxylase 1 (the rate-limiting enzyme of serotonin synthesis) in ileum. Enrichment analysis showed that inhibiting overexpression of several conventional inflammation pathways and pro-inflammation cytokines were related to the antiemetic effectiveness of XBXT. CONCLUSIONS: This study implies that inhibiting inflammatory signaling pathways and synthesis of serotonin might be potential mechanisms of XBXT's antiemetic effect against CINV.

Cadmium and lead in geophagic clay consumed in Southern Nigeria: health risk from such traditional nutraceutical.

Geophagy is a cultural behavior, based on the recurrent intentional eating of clay soil, that is raising increasing concern as it implies multidimensional (space, time) potential risk of serious adverse health effects. This study investigated the level of toxic metals (Cd and Pb) in 20 Nigerian geophagic clays intended for both local consumption and distribution to the West Africa market. After sampling in 4 open markets in southern Nigeria (Akwa Ibom, Abia, Rivers, Imo), samples were subjected to digestion, ashing and analysis. The Pb levels in all samples exceeded the WHO/FAO maximum permissible limit of 0.1 mg kg-1 whereas 16% exceeded the Cd limit of 0.3 mg kg-1. The estimated daily intake of Pb for all samples ranged from 0.0032-0.0286 mg kgbw-1 day-1 to 0.0024-0.0215 mg kgbw-1 day-1 for children and adults, respectively. The estimated daily intakes for Cd ranged from bdl (below detection limit)-0.0010 mg kgbw-1 day-1 to bdl-0.0028 mg kgbw-1 day-1 for children and adults, respectively. In both cases, the WHO/FAO provisional Tolerable Weekly Intake is exceeded through the ingestion of these soils. Our results confirm health risks related to the geophagic practices, its role in exceeding health guidelines when considering aggregate exposure in the Nigerian scenario and body burden in developing organisms, young women, women at fertile age, and pregnant women. We discuss how geophagists consider clays as traditional nutraceuticals and how clarifying the nutraceutical role of geophagy could facilitate risk communication. Geophagic products are implicitly or explicitly marketed as dietary supplements, and as such they should be regulated (1) by labeling, and prohibition of scientifically unfounded health claims and (2) by safety standards before marketing. This is particularly critical when clays originate from countries living rapid, unplanned and uncontrolled development and dumped, like Nigeria.

A coin crisis: a case report of pica with minireview.

BACKGROUND: Pica is defined as a feeding and eating disorder where there is consumption of nonnutritive substances not consistent with cultural practices or social norms. Its aetiology is still unknown, as its prevalence and optimal treatment, which seem to vary with patients' characteristics and the specific behaviours involved. OBJECTIVES: The authors present a case report of pica treated with copper supplementation, with further diagnostic and treatment considerations. METHODS: Clinical records and interviews were used. A review was conducted using PubMed database. RESULTS: A 59-year-old patient, diagnosed with paranoid schizophrenia, presented with sideroblastic anaemia secondary to zinc-induced copper deficiency in the context of pica. These behaviours ceased with copper supplementation. After 2-year remission, the patient was discontinued on oral copper. One week after, pica behaviours reoccurred, with further remission with renewed copper treatment. Based on temporal relationship, we propose that there might be an association between copper supplementation and pica, not related to its plasma levels. CONCLUSIONS: As far as we know, this is the first case report in the literature with such a long-term follow-up of pica treatment. Our findings challenge the cause-effect relation between micronutrient deficiency and pica and prompts further research in the non-adaptive theories of this poorly understood clinical entity.

High umbilical cord blood lead levels and "calabar chalk" consumption amongst pregnant women in two hospitals in Cameroon.

INTRODUCTION: "Calabar chalk" is a lead-laden pica mostly consumed by pregnant women worldwide as a remedy for morning sickness. This clay material has been shown to have lead levels of up to 40mg per kilogram. Meanwhile blood lead levels, even at doses less than 10µg/dl will be toxic to humans and even worse-off to the fetus as it crosses the placenta. We, therefore, sort to determine the prevalence of "Calabar chalk" consumption amongst pregnant women and if it translates to higher umbilical cord blood lead levels. METHODS: We carried out a cross-sectional study by prospectively and consecutively enrolling 300 pregnant women from December 2014 through February 2015. A questionnaire was administered to ascertain "Calabar chalk" consumption. The levels of lead in the umbilical cord blood of 51 participants of each group of those who consumed and didn't consume "Calabar chalk" were measured by spectrometry and compared using the T-test (p<0.05). RESULTS: The prevalence of "Calabar chalk" consumption was 43.33%. This was mostly consumed during pregnancy only (46.34%), with higher rates observed amongst primigravidas. The mean umbilical blood lead levels amongst those who consumed and those who did not consume "Calabar chalk" was 39.19µg/dl and 25.33µg/dl respectively (P=0.111). CONCLUSION: The prevalence of "Calabar chalk" consumption was high in the pregnant women population. The overall umbilical cord blood lead levels were extremely high in both consumers and non-consumers. We recommend health education and chelation therapy to be considered.

Geophagy among East African Chimpanzees: consumed soils provide protection from plant secondary compounds and bioavailable iron.

Geophagy, the intentional consumption of earth materials, has been recorded in humans and other animals. It has been hypothesized that geophagy is an adaptive behavior, and that clay minerals commonly found in eaten soil can provide protection from toxins and/or supplement micronutrients. To test these hypotheses, we monitored chimpanzee geophagy using camera traps in four permanent sites at the Budongo Forest Reserve, Uganda, from October 2015-October 2016. We also collected plants, and soil chimpanzees were observed eating. We analyzed 10 plant and 45 soil samples to characterize geophagic behavior and geophagic soil and determine (1) whether micronutrients are available from the soil under physiological conditions and if iron is bioavailable, (2) the concentration of phenolic compounds in plants, and (3) if consumed soils are able to adsorb these phenolics. Chimpanzees ate soil and drank clay-infused water containing 1:1 and 2:1 clay minerals and > 30% sand. Under physiological conditions, the soils released calcium, iron, and magnesium. In vitro Caco-2 experiments found that five times more iron was bioavailable from three of four soil samples found at the base of trees. Plant samples contained approximately 60 µg/mg gallic acid equivalent. Soil from one site contained 10 times more 2:1 clay minerals, which were better at removing phenolics present in their diet. We suggest that geophagy may provide bioavailable iron and protection from phenolics, which have increased in plants over the last 20 years. In summary, geophagy within the Sonso community is multifunctional and may be an important self-medicative behavior.

Geophagy among a Cohort of Kenyan Women with Mixed HIV Status: A Longitudinal Analysis.

Geophagy, the craving and purposive consumption of earth, is commonly reported during pregnancy. To date, most studies of geophagy have been cross-sectional and have not assessed its relationship with HIV infection. Therefore, to concurrently examine proposed etiologies of geophagy, a cohort of 371 women with mixed HIV status from Nyanza region, Kenya were recruited in late pregnancy and interviewed about pica at nine time points, through 21 months postpartum. Nutritional status (hemoglobin concentration and food insecurity), physical health (HIV infection and gastrointestinal distress), and psychosocial health (depression and perceived stress) were also repeatedly assessed. Prevalence of geophagy was greatest during pregnancy and decreased significantly postpartum. In a two-level hierarchical linear model, a one-unit increase in average hemoglobin (g/dL) was associated with a 35% decrease in the odds of geophagy. The adjusted odds ratios (CI) of geophagy were 3.98 (2.99, 5.29), 2.54 (1.13, 5.69), and 1.68 (1.15, 2.44) times higher if a woman was pregnant, reported diarrhea in the prior 24 hours, or was HIV positive, respectively. The adjusted odds ratio of geophagy was 1.61 (1.06, 2.45) times higher if a woman reported geophagy during childhood. Our results lend greatest plausibility to the protection hypothesis (i.e., that geophagy occurs in response to compromised immunity and/or infection). Given the high prevalence of geophagy, clinicians should regularly screen for the behavior and measure inflammatory biomarkers before treating geophagy with iron supplements, which can exacerbate some infections.

Geophagy among nonhuman primates: A systematic review of current knowledge and suggestions for future directions.

OBJECTIVES: Geophagy, the intentional consumption of earth, is widely practiced among humans and other mammals, but its causes are not well understood. Given the growing number of reports of geophagy among nonhuman primates (NHP), we sought to (1) advance and codify our understanding of the patterns and functional and evolutionary significance of geophagy among NHP and (2) provide a research agenda for a more unified approach to its study. METHODS: We systematically reviewed all available literature on NHP geophagy, extracted available data on taxa, geography, climate, diet, sex, age-class, reproductive status, and the characteristics of the earth. We used these data to evaluate three major hypotheses about geophagy, that it is protective, provides mineral supplementation, and is nonadaptive. RESULTS: We identified 287 accounts of geophagy among 136 species, adding 79 new primate species to the list of those considered in prior reviews. Nineteen percent of species were in the suborder Strepsirrhini, while 81% were in the suborder Haplorrhini. There were reports of geophagy from 9 of the 17 families and 39 of the 76 genera currently recognized by the International Union for Conservation of Nature. DISCUSSION: The limited evidence suggests that geophagy is adaptive, and provides protection and mineral supplementation. We specify the behavioral, dietary, and soil data required to more rigorously investigate these hypotheses across representative species of all taxonomic groups, geographical regions, and dietary classification. Given the plausibility of geophagy for maintaining the health of both wild and captive populations, we urge further study and conservation of geophagy sites.

The role of the South African Medical Research Council in reducing lead exposure and preventing lead poisoning in South Africa.

Even at low levels in blood, lead has been associated with reduced IQ scores, behavioural problems, learning impediments, aggression and violent behaviour. Since the 1980s, the South African Medical Research Council (SAMRC) has been investigating the sources of exposure to lead in South Africa (SA), the groups at highest risk of lead poisoning and a selection of the myriad associated health and social consequences. SAMRC research evidence contributed to the phasng out of leaded petrol, restrictions on lead in paint and other interventions. Subsequently, childhood blood lead levels in SA declined significantly. More recent studies have revealed elevated risks of lead exposure in subsistence fishing and mining communities, users of arms and ammunition, those ingesting certain traditional medicines, and users of certain ceramicware and artisanal cooking pots. Lead-related cognitive damage costs the SA economy ~USD17.7 (ZAR261.3) billion annually, justifying further SAMRC investment in lead exposure research in the country.

Involvement of the Hypothalamic Glutamatergic System in the Development of Radiation-Induced Pica in Rats.

Since the peripheral serotoninergic pathway is involved in the development of radiation-induced nausea and vomiting, referred to as radiation sickness, serotonin 5-HT3 receptor antagonists are used as a preventive measure, although patients still suffer from these symptoms. Glutamate is known as the excitatory neurotransmitter and is involved in various autonomic symptoms. We investigated the effect of radiation on glutamate release in rats, as measured by in vivo brain microdialysis, and the effects of glutamate receptor antagonists on radiation-induced pica, which can be used as a behavioral assessment of radiation sickness in rats. A microdialysis probe was inserted into the hypothalamus of rats that received 4 Gy total-body irradiation (TBI) with or without pretreatment of 5-HT3 receptor antagonist (granisetron, 0.1 mg/kg, i.p.), and dialysates were collected for 3 h after TBI and subjected to HPLC assay of glutamate. In addition, rats were intracerebroventricularly injected with NMDA receptor antagonist (MK-801: 3 µg/rat) or AMPA receptor antagonist (CNQX: 1 µg/rat) before TBI, and radiation-induced pica was determined. An increase in glutamate release was observed within 1 h postirradiation. The increased glutamate release was suppressed by granisetron. We also found that CNQX, but not MK-801, effectively inhibited radiation-induced pica. These results indicate that the hypothalamic glutamatergic system contributes to radiation-induced pica through the AMPA receptors.