Effect of sublethal exposure of Cartap on hypothalamo-neurosecretory system of the freshwater spotted murrel, Channa punctatus (Bloch).

In order to record the effect of carbamate pesticide on hypothalamus of Channa punctatus, fish were exposed to sublethal concentration (0.18 mg l(-1), 30% LC50 for 96 hr) of Cartap for 24, 48, 72 and 96 hr under static bioassay condition. Hypothalamo-neurosecretory complex of the murrel consisted mainly of nucleus preopticus (NPO), nucleus lateralis tuberis (NLT) and their axonal tracts. NPO is a paired structure situtated on either side of the third ventricle anterodorsal to the optic chiasma and looked inverted L-shape in the sagittal section. NPO is morphologically divisible into a dorsal pars magnocellularis (PMC) consisting of large neurons and ventral pars parvocellularis (PPC) formed of smaller neurosecretory cells. NLT cells are distributed in the infundibular floor adjacent to the pituitary stalk. Sublethal Cartap treatment induced an initial hypertrophy of the neurosecretory cells of NPO and NLT followed by loss of staining affinity as well as varying degrees of cytoplasmic vacuolization and necrosis. Herring bodies (HB) were also encountered in the neurohypophysis of the treated fishes.

Neuroendocrine regulation and pesticidal impact on freshwater crab, Barytelphusa guerini (H. Milne Edwards).

The extensive use of pesticides to control agricultural pests poses a serious threat to many non-target organisms of the aquatic environment such as the freshwater crab, B. guerini. The deleterious influence of the pesticide causes physiological, biochemical, histological and such other disorders in the animal exposed. In the present study impact of an organophosphate pesticide, monocrotophos and neuroendocrine regulation on the biochemical contents of hepatopancreas of B. guerini has been studied. Experimental studies revealed that glycogen and protein content decreased in normal crabs when exposed to sub lethal concentrations of monocrotophos, while lipid content was increased. In the ablated and pesticide exposed crabs glycogen, protein and lipid contents decreased. In case of ablated and exposed crabs when injected with eyestalk extract, glycogen and protein contents declined, whereas lipid content hiked. It was observed that glycogen, protein and lipid contents in eyestalk extract injected crabs were similar to those of normal exposed crabs. This indicates the vital role of eyestalk in the regulation of biochemical contents. Histological studies of the hepatopancreas indicate structural changes such as large number of vacuolated cells and phagocytes when exposed to the pesticide.

Usefulness of serotoninergic challenge with oral citalopram / Utilidade do desafio serotoninérgico com citalopram oral

OBJECTIVE: Challenge tests designed to evaluate serotoninergic pathways have widely used intravenous citalopram. Oral citalopram has also been used, but unsatisfactory results were obtained with a dose of 20 mg. The objective of this study was to determine whether a higher oral dose would reproduce similar to those described for intravenous administration. To that end, we evaluated cortisol, growth hormone and prolactin levels. METHOD: Eight healthy male volunteers were evaluated in a randomized crossover challenge test with 40 mg of oral citalopram or placebo. RESULTS: Cortisol levels increased at 2-4h after the oral citalopram intake, with a small amplitude peak occurring in two-thirds of the subjects. Levels of prolactin and growth hormone remained unchanged throughout the study. CONCLUSION: The use of oral citalopram might present an alternative in serotoninergic challenge tests, but higher doses are required.

OBJETIVO: Testes-desafio desenvolvidos para avaliar as vias serotoninérgicas utilizaram amplamente citalopram intravenoso. Citalopram oral também foi utilizado, mas obtiveram-se resultados insatisfatórios com uma dose de 20 mg. O objetivo deste estudo foi o de determinar se uma dose oral mais elevada poderia reproduzir resultados similares aos descritos para administração intravenosa. Com esta finalidade, avaliamos os níveis de cortisol, de hormônio do crescimento e de prolactina. MÉTODO: Oito voluntários do sexo masculino saudáveis foram avaliados em um teste-desafio cruzado, aleatorizado, com 40 mg de citalopram oral ou placebo. RESULTADOS: Os níveis de cortisol aumentaram após 2-4 horas da ingestão de citalopram oral, com um pequeno pico de amplitude ocorrendo em dois terços dos indivíduos. Os níveis de prolactina e de hormônio de crescimento permaneceram inalterados ao longo do estudo. CONCLUSÃO: O uso de citalopram oral poderia apresentar uma alternativa em testes-desafio serotoninérgicos, mas doses maiores são necessárias.

Algunos conceptos actuales sobre digital y otras drogas usadas en el tratamiento de la insuficiencia cardiaca / Some current concepts on digitalis and other drugs used in the treatment of cardiac failure

Se revisan en forma muy resumida algunos conceptos actuales acerca del tratamiento de la insuficiencia cardíaca y del uso e indicaciones de los digitálicos. Al respecto, existen actualmente importantes controversias. La digital sigue siendo un medicamento plenamente vigente, cuyas principales indicaciones actuales se señalan. Se destaca que su utilidad en insuficientes cardíacos con ritmo sinusal es escasa. Se sugieren los siguientes esquemas terapéuticos: Insuficiencia cardíaca CF I: ¿diurético? CF II: diurético + digital o diurético + vasodilatodor CF III y IV: dirético + digital + vasodilatador

Respuesta de tres ejes neuroendocrinos en pacientes depresivos y esquizofrénicos / Response of 3 neuroendocrine axes in depressive and schizophrenic patients

Se evaluaron 19 pacientes esquizofrénicos, 17 con depresión mayor y 11 controles psiquiátricos con el test de estimulación con TRH, la prueba de supresión por dexametasona (PSD) y el test de estimulación con LHRH. Todos los pacientes cumplieron con criterios estrictos para considerar válidos los test y estuvieron sin medicación a lo menos durante 10 días. No se observaron diferencias significativas para la respuesta a LHRH ni al TRH entre los grupos. Sólo los resultados de la PSD difirieron significativamente en los depresivos (p<0,05). Noventa y cuatro por ciento de los depresivos tuvieron al menos una respuesta hormonalanormal, este porcentaje fue significativamentemayor que en los esquizofrénicos y controles (p<0,05). El test anormal más frecuente fue una respuesta exagerada a LHRH, pero no se encontraron diferencias entre los grupos. No se encontraron correlaciones significativas entre las respuestas anormales al TRH o en la PSD y la hormona folículo estimulante (FSH) o la hormona luteinizante (LH). En este estudio sólo el eje hipotálamo-hipófisis-adrenal evidencia una diferencia entre los grupos diagnósticos. Las anormalidades neuroendocrinas se observaron con mayor frecuencia entre los pacientes depresivos. Este trabajo muestra la existencia de disregulaciones neuroendocrinas, pero no sugiere especificidad diagnóstica o interdependencia entre los ejes

Effects of azadirachtin in Rhodnius prolixus: data and hypotheses

The effects of azadirachtin A, a tetranortriterpenoid from the neem tree Azadirachta indica J., on both development and interaction between Trypanosoma cruzi, the causative agent of Chagas' disease, and its vector Rhodnius prolixus were studied. Given through a blood meal, a dose-rsponse relationship of azadirachtin was established using antifeedant effect and ecdysis inhibition as effective parameters. A singlo dose of azadirachtin A was able to block the onset of mitosis in the epidermis and ecdysteroid titers in the hemnolymph, determined by radioimmuneassay, were too low for an induction of ecadysis. The survival of T. cruzi was also studied in R. prolixus treated with the drug. If the trypomastigotes were fed in presence of azadirachtin A the number of parasites drastically decreased. If the drug was applied after infection of the bug with T. cruzi, the parasite was still abolished from the gut. If the insect was pretreated with azadirachtin A before infection the same observation was obtained. A single dose of azadirachtin A was enough for a permanent resistance of the insect host against its reinfection with T. cruzi and for blocking the ecdysis for a long time. The effects of azadirachtin A on the hormonal balance of the host and growth inhibition of the parasite will be discussed on the basis of the present results.