Avaliação da toxicidade pré-natal: estudo de teratogenicidade do inseticida piriproxifeno em ratos Wistar / Prenatal toxicity assessment: teratogenicity study of the insecticide pyriproxyfen in Wistar rats

Este estudo investigou a toxicidade pré-natal do inseticida piriproxifeno em ratos Wistar, de forma a detectar possíveis alterações no desenvolvimento fetal da progênie exposta durante o período organogênico. Três doses de piriproxifeno (100, 300 e 500mg.kg-1) foram administradas por via oral às progenitoras, do sexto ao 15º dia de gestação. Os fetos foram submetidos à técnica de diafanização modificada descrita por Taylor e Van Dyke, para avaliação de malformações e alterações esqueléticas. Os resultados não demonstraram a ocorrência de toxicidade materna sistêmica ou alterações nos índices reprodutivos avaliados. Malformações ou alterações teratogênicas não foram detectadas, no entanto alterações esqueléticas sugestivas de retardo no desenvolvimento foram observadas especialmente nas doses mais altas testadas (300mg.kg-1 e 500mg.kg-1). Considerando-se a situação complexa de risco para a saúde humana, mostra-se importante a execução de investigações adicionais, de modo a contribuir para a adequada avaliação de risco do piriproxifeno em água potável.(AU)

This study investigated the prenatal toxicity of the insecticide pyriproxyfen in Wistar rats to detect the possible changes in the fetal development of the progeny exposed during the organogenic period. Three doses of pyriproxyfen (100, 300, and 500mg.kg-1) were administered orally to the progenitors, from day 6 to 15 of gestation. The fetuses were processed using the Taylor and Van Dyke modified diaphanization technique to evaluate malformations and skeletal changes. The results did not demonstrate the occurrence of systemic maternal toxicity or changes in the reproductive indexes evaluated. Malformations or teratogenic changes were not detected, however, skeletal changes suggestive of developmental delay were observed, especially in the highest doses tested (300 mg.kg-1 and 500 mg.kg-1). Owing to the potentially complex situation regarding its risk to human health, it is important that further studies be performed to contribute to the risk assessment of the addition of pyriproxyfen in drinking water.(AU)

Systemic absortion and adverse effects of topical ocular use of ketorolac tromethamine and sodium diclofenac in New Zealand rabbits for 90 days / Absorção sistêmica e efeitos adversos do uso tópico ocular por 90 dias de cetorolaco de trometamina e diclofenacode sódio em coelhos da raça Nova Zelândia

The effect of the systemic absorption of 0.1% diclofenac sodium (DS) eyedrop was compared to that of 0.5% ketorolac tromethamine (KT) in female New Zealand white rabbits treated on both eyes three times a day for 90 days. The rabbits were divided in three groups of six animals (n= 18): KT group, DS group, and control (Co) group, in which saline (0.9% NaCl) solution was instilled. Water and food consumption were measured daily, clinical examination was performed weekly, and blood samples were collected every 30 days for laboratory examination. The plasma was analyzed for the presence of KT and DS by solid-phase extraction (SPE) associated with mass spectrometry (MS). Systemic absorption of these drugs was confirmed by SPE-MS, allowing their separation and identification in the plasma. At the end of the treatment, the animals were euthanized and necropsied, and no macroscopic or microscopic changes were found. This observation confirmed the laboratory results, which were within normal reference standards for the species. According to the results obtained, it can be concluded that treatment with eyedrops containing KT and DS for 90 days in healthy rabbits does not cause adverse systemic effects.(AU)

Comparou-se o efeito da absorção sistêmica do colírio de diclofenaco de sódio 0,1% (DS) em relação ao de cetorolaco de trometamina 0,5% (CT) em coelhas da raça Nova Zelândia, tratadas nos dois olhos, três vezes ao dia, por 90 dias. As coelhas foram separadas em três grupos de seis animais (n=18): grupo CT, grupo DS e grupo controle (Co), no qual foi instilada solução fisiológica (NaCl 0,9%). Os consumos de água e ração foram mensurados diariamente, os exames clínicos foram realizados semanalmente e o sangue foi coletado a cada 30 dias para realização de exames laboratoriais. O plasma foi analisado para detectar a presença de CT e DS por extração em fase sólida (SPE) associada à espectrometria de massas (MS). A absorção sistêmica desses fármacos foi confirmada por SPE-MS, permitindo sua separação e identificação no plasma. Ao final do tratamento, os animais foram eutanasiados e necropsiados, e não foram encontradas alterações macroscópicas ou microscópicas. Essa observação confirmou os resultados laboratoriais, que estavam dentro dos padrões de referência para a espécie. De acordo com os resultados obtidos, pode-se concluir que o tratamento com colírio contendo KT e DS, por 90 dias, em coelhos saudáveis, não causa efeitos adversos sistêmicos.(AU)

Estenose ureteral após cistectomia radical associada à ureterostomia cutânea abdominal: relato de caso / Ureteral stricture after radical cystectomy and cutaneous abdominal ureterostomy: case report

O presente trabalho tem como objetivo relatar a realização de cistectomia total associada à ureterostomia abdominal, uma técnica ainda pouco descrita na veterinária, bem como descrever as complicações pós-operatórias observadas. Um canino da raça Akita, macho, 11 anos, castrado, foi atendido com histórico de prostração, hiporexia, disúria, hematúria e incontinência urinária havia aproximadamente 10 dias. No exame clínico, foi observada leve algia abdominal; demais parâmetros estavam dentro da normalidade. Os exames complementares de imagem revelaram presença de massa envolvendo grande parte da vesícula urinária. O paciente foi submetido à cirurgia de cistectomia total associada à implantação cutânea abdominal dos ureteres, e o exame histopatológico chegou ao diagnóstico de carcinoma de células de transicionais (CCT) infiltrativo não papilar. No pós-operatório, o paciente desenvolveu dermatite urêmica leve no local de inserção dos ureteres e estenose ureteral em região distal, de maneira que reintervenções cirúrgicas foram necessárias para a correção. Além disso, observaram-se pielonefrite e hidronefrose secundárias ao quadro obstrutivo. Devido às complicações pós-operatórias, a tutora optou pela eutanásia do cão. Dessa maneira, conclui-se que a estenose ureteral e a pielonefrite são possíveis complicações da técnica de cistectomia associada à implantação abdominal dos ureteres.(AU)

This study aims to report the technique of total cystectomy associated with abdominal ureterostomy, a technique -little described in veterinary medicine, as well as to describe the postoperative complications observed. A male Akita canine, 11 years old, castrated, was attended with a history of prostration, hyporexia, dysuria, hematuria, and urinary incontinence for approximately ten days. The clinical examination revealed mild abdominal pain and other parameters within the normal range. Complementary imaging studies revealed the presence of mass involving a large part of the urinary bladder. The patient underwent total cystectomy surgery associated with abdominal cutaneous implantation of the ureters and histopathological examination led to a diagnosis of non-papillary infiltrative transitional cell carcinoma. In the postoperative period, the patient developed mild uremic dermatitis at the insertion site of the ureters and ureteral stenosis in the distal region, so that surgical reinterventions were necessary for correction. In addition, pyelonephritis and hydronephrosis secondary to the obstructive condition were observed. Due to the postoperative complications, the tutor chose to euthanize the dog. Thus, it is concluded that ureteral stenosis and pyelonephritis are possible complications of the cystectomy technique associated with abdominal implantation of the ureters.(AU)

Egg production evaluation of laying hens by multivariate analysis / Avaliação da produção de ovos de poedeiras por análise multivariada

This study aimed to verify the existence of differences between hens from the Barred Plymouth Rock (PRB) breed and White Plymouth Rock (PRW) breed by multivariate analysis of weekly egg production and cumulative during the years of 1998 and 2010, from the Laboratório de Avicultura (LAVIC) of the Departamento de Zootecnia at the Universidade Federal de Santa Maria (UFSM). For the analysis of the univariate and multivariate variance, the experimental design was completely randomized with two treatments (breed) and 299 repetitions of the PRW breed and 350 of the PRB breed. The parameters analyzed were the weekly productions of eggs per bird from the 21st to the 50th week of age (P21, P22, ..., P50) and production of eggs accumulated being from the 21st to the 25th (PA1), 21st to the 30th (PA2), 21st to the 35th (PA3), 21st to the 40th (PA4), 21st to the 45th (PA5) and 21st to 50th (PA6). Analyzes of univariate and multivariate variance were conducted and the comparison of means were made by "T" Student and Wilks respectively (P < 0, 05). Based on the results, an analysis of the principal components was performed with parameters PA1, PA2, PA4, PA5 and PA6. With the average egg production per family accumulated, a cluster analysis using Euclidean distance and single linkage method (nearest neighbors) was performed. The first two principal components meet the total variation in egg production accumulated from the 21st to 25th, 21st to 30th, 21st to 40th, 21st to 45th and 21st to 50th weeks of age. Most of the phenotypic variation of the layers can be explained by the production of eggs accumulated from the 21st until the 40th week of age, and this variable is highly correlated with total egg production. Families from the PRW and PRB breed form seven distinct groups, but homogeneous by the similarity between them. This allows direct crossings between different groups, in the pursuit for heterosis.(AU)

Objetivou-se verificar a existência de divergência entre poedeiras das raças Plymouth Rock Barrada (PRB) e Plymouth Rock Branca (PRW) por meio da análise multivariada da produção de ovos semanal e acumulada dos anos de 1998 e 2010, do Laboratório de Avicultura (Lavic) do Departamento de Zootecnia da Universidade Federal de Santa Maria (UFSM). Para as análises de variância uni e multivariada, o delineamento experimental foi inteiramente ao acaso, com dois tratamentos (raças) e 299 repetições da raça PRW e 350 da raça PRB. Os parâmetros analisados foram a produção de ovos semanal por ave da 21ª à 50ª semana de idade (P21, P22,..., P50) e a produção de ovos acumulada, sendo da 21ª à 25ª (PA1), 21ª à 30ª (PA2), 21ª à 35ª (PA3), 21ª à 40ª (PA4), 21ª à 45ª (PA5) e 21ª à 50ª (PA6). Realizaram-se as análises de variância uni e multivariada, e a comparação de médias foi feita pelos testes "T" de Student e de Wilks, respectivamente (P<0,05). Com base nos resultados, foi realizada a análise de componentes principais, com os parâmetros PA1, PA2, PA4, PA5 e PA6. E, com as médias de produção de ovos acumulada por família, foi realizada a análise de agrupamento por meio da distância euclidiana e pelo método de encadeamento único (vizinhos mais próximos). Os dois primeiros componentes principais reúnem a variação total da produção de ovos acumulada da 21ª à 25ª, 21ª à 30ª, 21ª à 40ª, 21ª à 45ª e 21ªá 50ª semanas de idade. A maior parte da variação fenotípica das poedeiras pode ser explicada pela produção de ovos acumulada da 21ª até a 40ª semana de idade, e essa variável tem alta correlação com a produção de ovos total. As famílias da raça PRW e da raça PRB formam sete grupos distintos, mas homogêneos, pela similaridade existente entre elas, o que permite direcionar cruzamentos entre os diferentes grupos, em busca da heterose.(AU)

Acute effects of resistance exercise and intermittent intense aerobic exercise on blood cell count and oxidative stress in trained middle-aged women

The aim of this study was to compare the effect of an intermittent intense aerobic exercise session and a resistance exercise session on blood cell counts and oxidative stress parameters in middle-aged women. Thirty-four women were selected and divided into three groups: RE group (performing 60 min of resistance exercises, N = 12), spinning group (performing 60 min of spinning, N = 12), and control group (not exercising regularly, N = 10). In both exercise groups, lymphocytes and monocytes decreased after 1-h recuperation (post-exercise) compared to immediately after exercise (P < 0.05). Immediately after exercise, in both exercised groups, a significant increase in TBARS (from 16.5 ± 2 to 25 ± 2 for the spinning group and from 18.6 ± 1 to 28.2 ± 3 nmol MDA/mL serum for the RE group) and protein carbonyl (from 1.0 ± 0.3 to 1.6 ± 0.2 for the spinning group and from 0.9 ± 0.2 to 1.5 ± 0.2 nmol/mg protein for the RE group) was observed (P < 0.05). A decrease in antioxidant activities (non-protein sulfhydryl, superoxide dismutase, catalase) was also demonstrated with a negative correlation between damage markers and antioxidant body defenses (P < 0.05). These results indicate that an acute bout of intermittent or anaerobic exercise induces immune suppression and increases the production of reactive oxygen species, causing oxidative stress in middle-aged and trained women. Furthermore, we demonstrated that trained women show improved antioxidant capacity and lower oxidative damage than sedentary ones, demonstrating the benefits of chronic regular physical activity.

Salmonella typhimurium em linfonodos mesentéricos de ovinos ao abate / Presence of Salmonella typhimurium in ovine mesenteric lymph nodes at slaughter

O rebanho de ovinos no Brasil está estimado em mais de 16 milhões de cabeças. Embora o consumo da carne desta espécie ainda seja pequeno, comparado ao de outros países, o consumo de carne, inclusive ovina, tem sido associado às doenças transmitidas por alimentos, em especial a salmonelose. No presente estudo, investigou-se a ocorrência de salmonelas em linfonodos mesentéricos e conteúdo intestinal de 175 ovinos ao abate. "Pools" constituído por cinco amostras de contéudo fecal ou 5 amostras de linfonodos de 25 g foram pre-enriquecidos em 250 mL de água peptonada tamponada e incubados a 37° C por 18-24 horas. Uma alíquota de 0,1 mL do préenriquecimento foi transferida para 9,9 mL de caldo de enriquecimento Rappaport-Vassiliadis e 1,0 mL do pré-enriquecimento foi transferido para 10 mL de caldo tetrationato Muller-Kaufmann, incubados a 42° C for 24h. 10 µL do caldo de enriquecimento foi semeado superfície de placas de ágar BPLS e ágar XLT4 incubadas a 37º C for 24-48h. Colônias suspeitas de salmonela foram testadas por provas bioquímicas e serologicas. Os testes bioquímicos utilizados para identificação de Salmonella foram TSI (triple sugar iron àgar), LIA (lysine iron àgar) e ágar ureia. Sorotipagem foi realizada no Laboratório de Enterobactérias do Instituto Osvaldo Cruz. Isolou-se Salmonella Tiphymurium de um pool de linfonodos mesentéricos, provenientes de cinco animais. O fato de se observar a ocorrência de salmonela em ovino portador sadio alerta para necessidade de monitorar este micro-organismo também nesta espécie, especialmente quando destinada ao abate, com vistas à produção de alimentos seguros.

The ovine flock in Brazil is estimated at over 16 million head. Despite that meat consumption of this species is still small when compared to other countries, general meat consumption, including mutton, has been associated to food borne diseases, especially salmonellosis. In the present study, the occurrence of salmonella in mesenteric lymph nodes and intestinal content of 175 ovines during slaughter was investigated. A pool of 5 feces samples or 5 lymph node samples of 25 grams was pre-enriched in 250 mL of buffered peptone water at 37° C for 18-24h. Following this, 0.1 mL of pre-enriched broth was transferred to 9.9 mL of Rappaport-Vassiliadis enrichment broth and 1.0 mL of pre-enriched broth was transferred to 10 mL of Muller-Kaufmann tetrationate broth, incubated at 42° C for 24h. Then, a 10 µL of the enrichment broth was spread on the surface of a BPLS and an XLT4 plate, both incubated at 37º C for 24-48h. Suspected Salmonella colonies were picked from the agar and tested with biochemical and serological methods. Biochemical testing was carried out for the identification of Salmonella, using the TSI (triple sugar iron agar), LIA (lysine iron agar) and urea agar tests. Serotyping was done at the Laboratory of Enterobactérias of the Instituto Osvaldo Cruz. Salmonella Tiphymurium was isolated from a pool of mesenteric lymph nodes from 5 animals. That Salmonella was observed in healthy carrier ovines points out the necessity of monitoring this microorganism in this species as well, especially when animals are destined to slaughter, so to assure safe food production.

Desenvolvimento pós-natal e potencial teratogênico da prole de ratos Wistar no estudo da toxicidade reprodutiva de duas preparações fitoterápicas contendo soja Glycine max (L) Merr / Neonatal development and teratogenic potential of Wistar rats offspring in the study of reproductive toxicity of two commercial phytotherapic preparations with soy Glycine max (L) Merr

Avaliou-se o efeito de duas preparações fitoterápicas comerciais que continham soja sobre o desenvolvimento geral e sexual da progênie de ratos Wistar e sobre o potencial teratogênico das preparações fitoterápicas durante um estudo de toxicidade reprodutiva. Para tanto, observaram-se, diariamente, as características de desenvolvimento dos filhotes e analisou-se o comportamento em campo aberto, e, para avaliar o potencial teratogênico, realizou-se diafanização dos fetos removidos por cesariana. Inferiu-se que o tratamento dos pais não comprometeu o desenvolvimento de sua progênie e também não determinou efeitos teratogênicos aos fetos de ratos Wistar.

The effect of two commercial phytotherapic preparations containing soy was evaluated on the general and sexual development of Wistar rats offspring and on the teratogenic potential during a reproductive toxicity study. For this, the offspring development characteristics were daily observed, and the behavior in open field was studied. To assess the teratogenic potential, diaphanization of the fetuses removed by caesarean section was done. It was concluded that the treatment of the parents did not compromise the development of their progeny and also did not determine the teratogenic effects in the fetuses.

Morphological study of the eggs and nymphs of Triatoma dimidiata (Latreille, 1811) observed by light and scanning electron microscopy (Hemiptera: Reduviidae: Triatominae)

Eggs and nymphs of Triatoma dimidiata were described using both light and scanning electron microscopy. The egg body and operculum have an exochorion formed by irregular juxtaposed polygonal cells; these cells are without sculpture and the majority of them are hexagonal in shape. The five instars of T. dimidiatacan be distinguished from each other by characteristics of the pre, meso and metanotum. The number of setiferous tubercles increases progressively among instars. The sulcus stridulatorium of 1st instar nymphs is amorphous, showing median parallel grooves; from the 2nd instar on the sulcus is, progressively, elongate, deep and posteriorly pointed with stretched parallel grooves. All instars have a trichobothrium on the apical 1/3 of segment II of the antenna. The opening of the Brindley's gland is on the mesopleura. Fifth instar nymphs have an apical ctenidium on the ventral surface of the fore tibia. Dorsal glabrous patches are found on the lateral 1/3 of abdomen. Bright oval patches are found on the ventral median line of the abdomen, from segment IV-VI; 1st instar nymphs lack these patches. Abdominal dorsal plates are present from the 1st-5th instars; the 1st instar also contains a rectangular plate in segment IX. From the 2nd instar on, variably-shaped plates are present on segments VII to IX. Morphometric data were also obtained and proved to be useful for distinguishing T. dimidiata instars.

Eficácia antitussígena de duas formulações fitoterápicas / Antitussive efficacy of two phytotherapics formulations

Avaliaram-se os efeitos antitussígenos-expectorantes de duas formulações fitoterápicas utilizando-se três modelos biológicos diferentes. Foram utilizados ratos Wistar no modelo da secreção das vias aéreas, cobaias no modelo de tosse induzido por ácido cítrico e codornas japonesas na determinação da velocidade de transporte mucociliar. Os animais foram distribuídos em grupos e tratados por via oral com as formulações, com doses equivalentes a 10 vezes a terapêutica recomendada, 9ml.kg-1. O grupo-controle negativo de cada espécie foi tratado com solução fisiológica, 10ml.kg-1. O grupo-controle positivo no modelo de tosse induzida pelo ácido cítrico foi tratado com morfina, 1mg.kg-1, por via subcutânea. No modelo em que foram utilizados ratos e codornas, o grupo-controle positivo recebeu erdosteína por via oral, 600mg.kg-1. Os resultados mostraram que as duas formulações fitoterápicas foram eficazes no reflexo da tosse em cobaias, causando 36,4 por cento e 27,3 por cento, respectivamente, de redução. Nos modelos de secreção das vias aéreas e determinação da velocidade de transporte mucociliar, ambas as formulações não apresentaram eficácia significativa.

The antitussive-expectorant effects of two phytotherapic formulations available in the Brazilian market were evaluated using three different biological models. Each phytotherapic formulation, with different composition, had the same batch number and fabrication date. The trade names of the phytotherapics were: Gripalplus Solução® and Melagrião®. Wistar rats were used in the airway secretion model, guinea pigs in the citric acid-induced cough model and japanese quails in the mucociliary transport rate determination. The animals (one group/formulation) were divided in the two phytotherapic groups and orally treated with the equivalent to ten told the therapeutic recommended dose, which was 9ml.kg-1. Animals of negative control group of each specie were orally treated with 10ml.kg-1 of saline. Positive guinea-pigs citric acid-induced cough model was subcutaneously treated with 1mg.kg-1 of morphine. In the rats airway secretion model and japanese quails mucociliary transport rate, a positive control orally received 600mg.kg-1 of erdosteine. The results showed that both phytotherapic formulations were able to inhibit the guinea pig cough reflex induced by citric acid, being 36.4 percent of reduction in the Gripalplus Solução® group and 27.3 percent in the Melagrião® group. The rats airway secretion and the mucociliary transport rate were not significantly affected by the two phytotherapic formulations.

Comparison of Pavlovian serial conditional discrimination in rats and hamsters in the same experimental situation

The present study compares behavioral changes between two distinct rodent groups, hamsters (Mesocricetus auratus) and Wistar rats, when submitted in the same homogeneous experimental situations to a serial conditional discrimination procedure which involves water deprivation and the processing of temporal variables. Both hamsters and rats acquired serial positive conditional discrimination as indicated by higher frequencies of magazine-oriented behavior during the tone followed by reinforcement (T+) and preceded by the feature stimulus light (L) and during the empty interval, than during the tone alone not followed by reinforcement (T-). Rats' frequencies of magazine-oriented behavior were high during T+ and T-, initially during training, and decreased during T- as the training progressed. However, the hamsters' frequencies of magazine-oriented behavior started very low and increased only during T+ as the training progressed. Comparison of the frequencies of magazine-oriented behavior during the empty interval in relation to the frequencies during the preceding L period showed that rats' frequencies remained very high and hamsters' frequencies increased during training. These results suggest that rats and hamsters have different behavioral strategies for the acquisition of a conditional discrimination. The results of the comparisons made in these experiments support the view of the importance of an ecological psychology approach to the understanding of complex learning in animals

Interleukin-5 and interleukin-10 are major cytokines in cerebrospinal fluid from patients with active neurocysticercosis

Neurocysticercosis (NCC) is a common neurological disorder especially in developing countries, caused by infection of the brain with encysted larvae of the tapeworm Taenia solium. Seizures are a common finding associated with this disease. The objective of the present study was to evaluate the correlation between the levels of various cytokines present in the cerebrospinal fluid (CSF) of patients with NCC and the severity of the disease. The levels of the cytokines IL-1î, TNF-alpha, IL-5, IL-10 and IFN-gamma were determined in the CSF of 22 patients with active NCC, 13 patients with inactive NCC and 15 control subjects. CSF from patients with active NCC presented significantly higher IL-5 levels compared to control subjects. IL-5 and IL-10 levels in CSF from NCC patients with inflammatory CSF were significantly higher than those detected in non-inflammatory CSF. These results show a predominant Th2 lymphocyte activation in human NCC and also indicate the possible use of cytokines in the CSF as a marker for the differential diagnosis between inactive disease and the active form of NCC

Transient expression of an atypical D1-like dopamine receptor system during avian retina differentiation

Intact cultured retina cells from chick embryos at stage E9C5 (cultures initiated with retinae from 9-day old embryos followed by 5 days in culture), preincubated with 2 nM unlabelled SCH 23390 (R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride) for 20 to 60 min at 37 degrees Celsius and then washed 5 to 25 times (approximately 1.5 min/wash) with 2 ml SCH 23390 free medium, responded to dopamine with cAMP accumulation that corresponded to 30-50 per cent of the dopamine-promoted cAMP accumulation observed in untreated cells or in cells exposed to the inactive isomer of SCH 23390. Therefore, 50 to 70 per cent of the dopamine response of SCH 23390-pretreated cells was inhibited after extensive washings of the cultures. At E9C12 the fraction of the dopamine response that remained inhibited by SCH 23390 after the washings declined to 30 per cent of the control cultures or the cultures exposed to the SCH 23390 enantiomer. Cultures at stage E9C5 treated with SCH 23390 followed by extensive washings as above and then used for measuring the number of [3H]-SCH 23390 specific binding sites revealed that 60 per cent of the sites did not interact with the tritiated compound when compared to untreated cultures or to cultures preincubated with the inactive isomer of SCH 23390. When E9C12 cultures were subjected to the same experimental protocol less than 10 per cent of D1-like sites did not interact with [3H]-SCH 23390 after the cells had been exposed to the unlabelled compound. Dissociated cells prepared from intact retinae obtained from 12-13-day old embryos also displayed a subpopulation of D1-like sites that interacted irreversibly with SCH 23390 in a stereospecific way. These sites corresponded to 25 per cent of the total number of D1-like sites present in the retina at this developmental stage. In retina cells obtained from one-day old posthatched chicks these sites were no longer detected. These data show that cultured retina cells as well as cells obtained from retina developing in ovo display two populations of D1-like receptors. One interacts irreversibly with SCH 23390 and is present only in the undifferentiated tissue or in cells at the early stages of culture and the other has a lower affinity for SCH 23390 with which its interaction follows reversible kinetics. These sites are present throughout the differentiation stages studied.

Domoic acid induces neurotoxicity and ip3 mobilization in cultured cells of embryonic chick retina

Domoic acid (DOM), 1 to 50 µM, a glutamate agonist responsible for several neurological effects such as loss of memory and confusion, induced the death of cultured neurons of chick embryonic retina, in a concentration- and Ca2+ -dependent manner. This effect was blocked by 100 µM CNQX, a competitive antagonist of the non-NMDA receptor, but not by 10 µM MK-801, a non-competitive antagonist of the NMDA receptor. DOM also induced inositol triphosphate (ip3) accumulation 4 to 7 times above basal levels. This effect was also dependent on external Ca2+ and was entirely blocked by 100 µM CNQX, but not by 10 µM MK-801. These results suggest that DOM interaction with non-NMDA glutamate receptors mediates signal transduction with ip3 accumulation and cell death