The differential sensitivity of the hypothalamic-hypophysial-ovarian axis to 5-hydroxytryptophan alters the secretion of estradiol.

Serotonin [5-hydroxytryptamine (5-HT)] modulates ovarian function. The precursor of 5-HT, 5-hydroxytryptophan (5-HTP), has been used to treat depression. However, the effects of 5-HTP on ovarian and reproductive physiology remain unknown. In this research, we analysed the impact of 5-HTP on the monoaminergic system and its interactions with the reproductive axis and ovarian estradiol secretion when administered by distinct routes. Female rats 30 days of age were injected with 5-HTP i.p. (100 mg/kg), into the ovarian bursa (1.5 µg/40 µL) or into the median raphe nucleus (20 µg/2.5 µL) and were killed 60 or 120 min after injection. As controls, we used rats of the same age injected with vehicle (0.9% NaCl). Monoamine, gonadotrophin and steroid ovarian hormone concentrations were measured. The injection of 5-HTP either i.p. or directly into the ovarian bursa increased the concentrations of 5-HT and the metabolite 5-hydroxyindole-3-acetic acid in the ovary. For both routes of administration, the serum concentration of estradiol increased. After i.p. injection of 5-HTP, the concentrations of luteinizing hormone were decreased and follicle-stimulating hormone increased after 120 min. Micro-injection of 5-HTP into the median raphe nucleus increased the concentrations of 5-HT in the anterior hypothalamus and dopamine in the medial hypothalamus after 120 min. Our results suggest that the administration of 5-HTP either i.p. or directly into the ovarian bursa enhances ovarian estradiol secretion.

p-Chloroamphetamine decreases serotonin and induces apoptosis in granulosa cells and follicular atresia in prepubertal female rats.

Amphetamine derivatives negatively impact serotonin (5-HT) production, which triggers apoptosis in different tissues, depending on the receptor they bind. 5-HT in the ovary stimulates estradiol secretion, a survival factor of granulosa cells. The effect of amphetamine derivatives on the serotonergic system of the ovary and follicular development is unknown. Therefore, in this study, we investigated the effects of p-chloroamphetamine (pCA), derived from amphetamines, on estradiol production, follicular development, apoptosis of granulosa cells, and serotonin 5-HT7 receptor (R5-HT7) expression. Female rats (30 days old) were injected with 10 mg/kg of pCA intraperitoneally and were euthanized 48 or 120 h after treatment. The concentration of 5-HT in the hypothalamus decreased at 48 and 120 h after treatment and in the ovary at 120 h. The serum concentration of estradiol decreased at all times studied. Follicular atresia, TUNEL-positive (apoptotic) granulosa cells and Bax expression were elevated by pCA, but none of these effects was associated with R5-HT7 expression. These results suggest that pCA induces the dysregulation of the serotonergic system in the hypothalamus and the ovary, negatively impacting estradiol production and follicular development.

Dorsal and medial raphe nuclei participate differentially in reproductive functions of the male rat.

BACKGROUND: Innervation of the hypothalamus and median eminence arise from the dorsal and medial raphe nuclei (DRN and MRN, respectively). The hypothalamus regulates the secretion of gonadotropins, which in turn regulate the reproductive function of males and females. However, it is not known the role of raphe nuclei in male reproductive function. Our goal was to investigate the role of the DRN and MRN in the regulation of the testicular function and secretion of gonadotropins in prepubertal rats. METHODS: Dihydroxytryptamine (5,6-DHT) in ascorbic acid was used to chemically lesion the DRN or MRN. Rats were treated at 30 days-of-age and sacrificed at 45 or 65 days-of-age. Sham-treated controls were injected with ascorbic acid only. Negative controls were untreated rats. The damage induced by the 5,6-DHT was monitored in coronal serial sections of DRN and MRN; only the animals in which lesion of the DRN or MRN was detected were included in this study. As output parameters, we measured the concentrations of noradrenaline (NA), dopamine (DA) and serotonin (5-HT) in the anterior (AH) and medial (MH) hypothalamus by high performance liquid chromatography (HPLC); whereas, circulating concentrations of gonadotropins and sexual steroids were measured by radioimmunoassay. Seminiferous epithelium and sperm quality were also evaluated. RESULTS: Lesion of DRN or MRN does not induced changes in concentrations of LH, progesterone, and testosterone. Compared with the control group, the sham or lesion of the DRN or MRN did not modify noradrenaline or dopamine concentrations in the AH and MH at 45 or 65 days of age. Meanwhile, serotonin concentrations decreased significantly in lesioned rats. Lesion of DRN induced significantly lower concentrations of FSH regardless of age; similar lesion in the MRN had no impact on FSH levels. Sperm concentration and motility were significantly decreased in the same animals. The lesion of the MRN does not induced changes in the seminiferous epithelium or gonadotropin levels. Our results suggest that raphe nuclei regulate differentially the male reproductive functions. CONCLUSIONS: The DRN but not the MRN regulates the secretion of gonadotropins and testicular function.

Acute effects of restraint, shock and training in the elevated t-maze on noradrenaline and serotonin systems of the prefrontal cortex / Efectos agudos de la restricción, choque y entrenamiento en el laberinto elevado en T en los sistemas de noradrenalina y serotonina en la corteza prefrontal / Efeitos agudos da restrição, choque e treinamento no labirinto elevado em T nos sistemas de noradrenalina e serotonina no córtex pré-frontal

The prefrontal cortex (PFC) participates in cognitive functions and stress regulation. Noradrenaline (NA) and serotonin (5-HT) levels in some regions of the central nervous system are modified by acute stress. The effects depend on the type of stressor and the time elapsed between the presence of the stressor and the assessment. The aims of the present study were to assess the acute effect of different stressors on NA and 5-HT activities in the PFC and its relation with corticosterone levels. Independent groups of male Wistar rats (250-280 g) were submitted to restraint, footshock or training in the elevated T-maze (ETMT). The animals were sacrificed immediately (T0) or one hour (T1) after stress exposure. An untreated group sacrificed concurrently with treated animals was included as control. Samples of the PFC were dissected and the concentration of NA, 5-HT and their metabolites were measured by HPLC. Corticosterone levels were measured in serum. None of the treatments modified NA levels in the PFC. Animals exposed to footshock or ETMT showed significantly higher concentrations of 5-HT at T0. Restraint and footshock treatments were associated with higher corticosterone levels at T0 and T1 after the respective treatment. Taken together the results show that in the PFC, the noradrenergic and serotonergic systems, and the corticosterone levels respond in different ways to different stressors.

La corteza prefrontal (CPF) participa en las funciones cognitivas y la regulación del estrés. Las concentraciones de noradrenalina (NA) y serotonina (5-HT) en algunas regiones en el sistema nervioso central son modificadas por el estrés agudo. El efecto depende del estresor y del tiempo que transcurra entre el estresor y la evaluación. El objetivo del presente estudio fue evaluar el efecto agudo de diferentes estresores en la actividad de la NA y 5-HT en la CPF y su relación con los niveles de corticosterona. Grupos independientes de ratas (250-270 g) fueron sometidos a restricción, choque o entrenamiento en el laberinto elevado en T (ELET). Los animales fueron sacrificados inmediatamente (T0) o una hora (T1) después de la exposición al estrés. Un grupo no tratado, sacrificado al mismo tiempo que los animales tratados, se incluyó como control. Las muestras de la CPF fueron disecadas y la concentración de NA, 5-HT y sus metabolitos fue detectada por la técnica de HPLC. Las concentraciones de corticosterona fueron medidas en el suero. Ninguno de los tratamientos modificó las concentraciones de NA en la CPF. Al T0 los animales expuestos a choque o al ELET mostraron concentraciones de 5-HT significativamente mayores que el control. Los tratamientos de restricción y choque estuvieron asociados con altas concentraciones de corticosterona al T0 y a T1 después del tratamiento respectivo. En conjunto, los resultados mostraron que en la CPF los sistemas noradrenérgico y serotonérgico y la concentración de corticosterona responden en forma diferente a los distintos estresores.

O córtex pré-frontal (CPF) participa nas funções cognitivas e na regulação do estresse. As concentrações de noradrenalina (NA) e serotonina (5-HT) em algumas regiões do sistema nervoso central são modificadas pelo estresse agudo. O efeito depende do estressor e do tempo que transcorra entre o estressor e a avaliação. O objetivo do presente estudo foi avaliar o efeito agudo de diferentes estressores na atividade da NA e 5-HT no PFC e sua relação com os níveis de corticosterona. Grupos independentes de ratos (250-270 g) foram submetidos a restrição, choque ou treinamento no labirinto elevado em T (ELET). Os animais foram sacrificados imediatamente (T0) ou uma hora (T1) depois da exposição ao estresse. Um grupo não tratado, sacrificado ao mesmo tempo que os animais tratados, incluiu-se como controle. As mostras do PFC foram dissecadas e a concentração de NA, 5-HT e seus metabolitos foi detectada pela técnica de HPLC. As concentrações de corticosterona foram medidas no soro. Nenhum dos tratamentos modificou as concentrações de NA no PFC. Em T0 os animais expostos a choque o ao ELET mostraram concentrações de 5-HT significativamente maiores que o controle. Os tratamentos de restrição e choque estiveram associados com altas concentrações de corticosterona em T0 e em T1 depois do tratamento respectivo. Em conjunto, os resultados mostraram que no PFC os sistemas noradrenérgico e serotonérgico e a concentração de corticosterona respondem de maneira diferente aos diferentes estressores.

Impacto de una estrategia educativa en la medición de presión arterial por blanqueamiento en lactantes / Impact of an educational strategy in the measurement of blood pressure by whitening in infants

Introducción: Medir la presión arterial por la técnica de blanqueamiento demuestra utilidad y precisión en los pacientes recién nacidos y lactantes. La literatura reporta limitaciones en el conocimiento de la técnica de medición en forma adecuada. Objetivo: Medir el impacto de una estrategia educativa en el personal de enfermería de un servicio de lactantes, en la toma de presión arterial por la técnica de blanqueamiento. Metodología: Estudio cuasi-experimental en 20 enfermeras de un servicio de lactantes seleccionadas por muestreo no probabilístico por conveniencia. El estudio se dividió en tres etapas, la primera de sombra para conocer la forma en que las enfermeras medían la presión arterial por blanqueamiento utilizando una escala, en la segunda se aplicó una estrategia educativa haciendo énfasis en el número y secuencia de pasos para realizar la medición de la presión arterial y la tercera también fue un estudio de sombra, aplicando la escala en el mismo personal. Resultados: El 100% del personal no cumplió con el número y secuencia de pasos de la técnica de medición de la presión arterial por blanqueamiento, posterior a la estrategia educativa, de los 7 pasos necesarios para realizar la técnica, se corrigieran el segundo, séptimo y sexto paso, en este último con significancia estadística. Discusión: Con la estrategia educativa se concluyó que la omisión o modificación de pasos en la medición de la presión arterial por blanqueamiento conlleva a obtener determinaciones imprecisas, sin embargo no se observó cambio en la forma de medir la presión arterial, con este resultado se puede decir que la estrategia fue de bajo impacto y puede atribuirse a resistencia al cambio, por lo que es necesario implementar otras que desarrollen pensamiento crítico y actitud reflexiva en la práctica.

Introduction: Measuring blood pressure, by whitening technique, demonstrates usefulness and accuracy in newborn and infant patients. Medical literature reports limitations in the knowledge of the adequacy of measurement. Objective: To measure the impact of an educational strategy in nursing staff within an infant service regarding measurement of blood pressure by whitening technique. Methodology: Cuasi-experimental study in 20 nurses from an infant service, chose them by no randomized sampling, by convenience; 3 nurses were excluded, as they did not conclude the three phases of the process. The study was divided on 3 phases. The first one was a shadow study to know the way in which nurses measured blood pressure by whitening, using a scale. During the second one, an educational strategy was applied making emphasis in the number and sequence of steps to measure arterial blood pressure. The third phase of the study was, also, a shadow study applying the scale in the same staff. Results: 100% of staff did not comply with number and sequence of the technique to measure the blood pressure by whitening, thereafter to educational strategy. From 7 needed steps to do the technique, the second, seventh, and sixth steps were corrected; the last one with statistic significance. Discussion: With the educational strategy, it was concluded that either omission or modification of steps in the measurement of blood pressure by whitening, leads to obtain imprecise determinations; however, it was not observed any change in the way to measure blood pressure. With this result, it may be told that the educational strategy had a low impact y may be attributed to resistance of changing. For this reason, it is necessary to implement other strategies that develop critical thinking and reflexive attitude in the praxis.

Comparative effects of injecting 5,6-dihydroxytryptamine in the dorsal or medial raphe nuclei on rat puberty.

The role played by the serotoninergic system in the control of puberty onset and first ovulation in rats is studied in this paper by analyzing the effects of injecting the neurotoxin 5,6-dihydroxytryptamine (5,6-DHT) into the dorsal (DRN) or medial (MRN) raphe nucleus of 30-day-old female rats. Complete lesion to the DRN resulted in the blockade of ovulation and a decrease in both the number of ovarian follicles and the serum concentration of follicle stimulating hormone (FSH). This treatment was also found to be associated with an increase in serotoninergic activity in the anterior and medial hypothalami. A lesion to the central portion of the DRN resulted in a significant decrease in the concentration of progesterone in serum and in the number of ova shed by ovulating animals. The lesion to the lateral portion of the DRN did not have an apparent effect on ovulation rate, the number of ova shed, nor in hormone serum concentration. The injection of propranolol to rats with a lesion to the DRN restored ovulation in 73% of treated animals and returned serotoninergic activity in the anterior hypothalamus to levels similar to those of sham-operated animals. In turn, in the medial hypothalamus, the increase in serotoninergic activity was not modified. The results presented herein suggest that serotoninergic inputs to the anterior hypothalamus have a direct influence on gonadotropin secretion and first ovulation, while the noradrenergic innervation exerts an indirect influence.