Pablo E. Cruz-Casallas

Reproductive experience increases striatal and hypothalamic dopamine levels in pregnant rats

The effects of parity on the dopaminergic function of rats were studied. Striatal and hypothalamic levels of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), norepinephrine (NE), serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) as well as serum prolactin (PRL) levels of 7-days primigravid and multigravid rats were compared. Brains and trunk blood were collected from 1200-1400 h on day 7 of pregnancy and assayed for monoamines and their metabolites, and prolactin, respectively. Multigravid rats showed a significant increase in striatal and hypothalamic dopamine levels. A tendency to increase in striatal DOPAC levels was also observed in multigravid rats. Levels of other neuro-transmitters and metabolites were not statistically different. Haloperidol (1 mg/kg) treatment induced a significant increase in multigravid 5-HT striatal levels. There was no statistical difference among primigravid and multigravid serum PRL levels after either saline or haloperidol treatment. These data suggest that prior parity produces a shift in dopaminergic activity in multigravid rats.

Dual modulation of male sexual behavior in rats by central prolactin: relationship with in vivo striatal dopaminergic activity.

Prolactin (PRL) appears to be localized in several brain structures. Central, behaviorally meaningful, neural actions of this protein have been demonstrated in a large number of studies. The present report describes sexual behavioral and in vivo neurochemical data obtained from adult male rats injected intracerebroventricularly acutely (10 micrograms) or chronically (5 days; 10 micrograms/day) with ovine prolactin (oPRL). The extracellular striatal concentrations of dopamine and serotonin metabolites were estimated by HPLC measurements in microdialysis perfusates. A single (10 micrograms) administration of oPRL facilitated sexual activity and increased extracellular striatal DOPAC, HVA and 5HIAA levels, whereas five daily intracerebroventricular injections of oPRL, decreased the sexual behavior and reduced DOPAC and HVA striatal extracellular concentrations in response to a central oPRL injection. These results show that acute and chronic central oPRL treatments have stimulatory and inhibitory effects on male sexual behavior, respectively. In addition, the results suggest that striatal dopaminergic activity is increased and decreased by acute and 5-day central oPRL treatments. These data suggest that behavioral effects of PRL occur simultaneously with changes in striatal dopaminergic activity.

Reproductive experience modulates dopamine-related behavioral responses.

Reproductive experience (RE), i.e., mating, pregnancy, parturition and lactation, has long-term physiological effects. It reduces the basal levels of circulating prolactin in parous women, decreases the intensity of nocturnal and diurnal prolactin surges in multigravid rats during early pregnancy, as well as the hormonal and neurochemical responses to the dopamine receptor antagonists metoclopramide and haloperidol. In the present study, we evaluated the possible influences of RE on some dopaminergic-related behaviors: (1) acute responses to a new environment represented by an open-field arena plus injection stress; (2) modulation of behavior after a short-term withdrawal subsequent to 7 days amphetamine (AMPH) pretreatment; (3) stereotypy elicited by AMPH and apomorphine (APO); and (4) APO-induced hypothermia. In the 3-min open-field test, there was a decrease in locomotor activity as a function of RE. Behavioral depression was mild and AMPH pretreatment revealed RE alterations. APO-induced stereotyped behavior was slightly more intense in primiparous animals, although no significant differences were found in AMPH-induced stereotyped behavior. No differences were observed between intact and ovariectomized primiparous and nulliparous animals in APO-induced hypothermia. Our data suggest that RE modifies some DA-related behavioral responses. The physiological relevance of the phenomenon is discussed.

Reproductive experience reduces striatal dopaminergic responses in freely moving female rats

REPRODUCTIVE experience influences basal and pregnancy profiles of circulating prolactin levels in women and female rats, respectively. Endocrine responses to dopaminergic antagonists are modified by reproductive experience as well. Striatal extracellular dopamine metabolites were measured in vivo by HPLC-ED in perfusates obtained by microdialysis in non-anaesthetized, freely moving, intact and ovariectomized, nulliparous and primiparous rats. Data were collected for at least 7 h. This period always included the light-dark shift at 18:00 h. In a second experiment, microdialysis was performed in ovariectomized nulliparous and primiparous rats treated with haloperidol (1.0mg/kg s.c.). During the 1 h before and after the onset of the light-dark shift, HVA concentrations in the perfusates increased in nulliparous compared with primiparous rats. The haloperidol-induced increase in DOPAC and HVA was less intense in primiparous rats than that in nulliparous ovariectomized rats. These data revealed a different pattern of striatal dopaminergic anticipation and response to the shift in the light-dark cycle in nulliparous as compared with primiparous intact females. In addition, a distinct striatal dopaminergic response to haloperidol was observed in primiparous as compared to nulliparous ovariectomized rats. The results suggest that reproductive experience can modulate the activity of dopaminergic terminals in the striatum.

Dual Effects of Hyperprolactinemia on Carrageenan-Induced Inflammatory Paw Edema in Rats

Objectives: The effects of short-term 5-day and long-term 30-day hyperprolactinemia induced by domperidone (1.7 mg/kg/day, s.c.) or ectopic pituitary graft on the acute inflammatory response induced by carrageenan were evaluated in male rats. Both models of hyperprolactinemia effectively increased serum prolactin (PRL) levels. Methods: The volume in milliliters of inflammatory edema was measured by plethysmography 1, 2, 3, 4, 6, 8 and 24 h after carrageenan injection. The areas under the inflammatory time-response curves were compared. Additionally, the effects of hyperprolactinemia on body weight and serum corticosterone levels were evaluated. Results: In both domperidone-treated and pituitary graft-implanted animals, short-term 5-day hyperprolactinemia increased the inflammatory response, while long-term 30-day hyperprolactinemia had anti-inflammatory effects. Body weight was not affected by either short- or long-term hyperprolactinemia. Conclusion: These results show that PRL has biphasic effects on the carrageenan-induced inflammatory response.

Acute and Chronic Stress and the Inflammatory Response in Hyperprolactinemic Rats

Background/Aim: Prolactin (PRL), a hormone produced by the pituitary gland, has multiple physiological functions, including immunoregulation. PRL can also be secreted in response to stressful stimuli. During stress, PRL has been suggested to oppose the immunosuppressive effects of inflammatory mediators. Therefore, the aim of the present study was to analyze the effects of short- and long-term hyperprolactinemia on the inflammatory response in rats subjected to acute or chronic cold stress. Methods: Inflammatory edema was induced by carrageenan in male rats, and hyperprolactinemia was induced by injections of the dopamine receptor antagonist domperidone. The volume of inflammatory edema was measured by plethysmography after carrageenan injection. Additionally, the effects of hyperprolactinemia on body weight and serum corticosterone levels were evaluated. Results and Conclusion: Five days of domperidone-induced hyperprolactinemia increased the volume of inflammatory edema. No differences in serum corticosterone levels were observed between groups. No significant differences were found among 30 days domperidone-induced hyperprolactinemic animals subjected to acute stress and the inflammatory response observed in chronic hyperprolactinemic animals subjected to chronic stress. The results suggest that short-term hyperprolactinemia has pro-inflammatory effects. Because such an effect was not observed in long-term hyperprolactinemic animals, PRL-induced tolerance seems likely. We suggest that short-term hyperprolactinemia may act as a protective factor in rats subjected to acute stress. These data suggest that hyperprolactinemia and stress interact differentially according to the time period.

Patología comparada de neoplasias en carnívoros salvajes

Han sido observados diferentes tipos de neoplasias en distintas especies de animales, las cuales pueden agruparse segun el tejido de origen y su grado de malignidad. Pueden ser de origen epitelial, mesenquimal, de celulas redondas o de celulas productoras de pigmentos. De acuerdo con el grado de malignidad, se clasifican como benignas y malignas. Los carnivoros constituyen un orden perteneciente al reino animal, dentro del cual se encuentran varias familias. Segun la interaccion que tengan con el medio ambiente y la exposicion a agentes contaminantes, virus y situaciones estresantes, algunos individuos de ciertas familias pueden desarrollar un tipo de neoplasia. Tanto en felidos como canidos, se han encontrado mayor incidencia de neoplasias de tipo epitelial involucrando el sistema tegumentario; en pinnipedos el sistema mayormente afectado es el tracto reproductivo. Existen pocos reportes de neoplasias en procionidos y mustelidos, lo que puede sugerir una mayor resistencia genetica a la presentacion de neoplasias por parte de estas familias, o a una exposicion menor a cancerigenos. El proposito de esta revision es conocer las neoplasias mas frecuentes en especies salvajes, ya que estas sirven como centinelas del ecosistema y ayudan a determinar posibles contaminantes carcinogenicos en el ambiente. Conociendo el grado de similitud en la genesis y progresion tumoral en humanos, con relacion a la vida salvaje genera oportunidades de tratamiento y conservacion y pueden servir como centinelas efectivos para problemas de salud publica. Ademas, su importancia en favorecer y fortalecer mecanismos encaminados para la salud y conservacion de especies silvestres, ya que pueden ser mermadas considerablemente a causa de este tipo de enfermedades.espanolResumen Han sido observados diferentes tipos de neoplasias en distintas especies de animales, las cuales pueden agruparse segun el tejido de origen y su grado de malignidad. Pueden ser de origen epitelial, mesenquimal, de celulas redondas o de celulas productoras de pigmentos. De acuerdo con el grado de malignidad, se clasifican como benignas y malignas. Los carnivoros constituyen un orden perteneciente al reino animal, dentro del cual se encuentran varias familias. Segun la interaccion que tengan con el medio ambiente y la exposicion a agentes contaminantes, virus y situaciones estresantes, algunos individuos de ciertas familias pueden desarrollar un tipo de neoplasia. Tanto en felidos como canidos, se han encontrado mayor incidencia de neoplasias de tipo epitelial involucrando el sistema tegumentario; en pinnipedos el sistema mayormente afectado es el tracto reproductivo. Existen pocos reportes de neoplasias en procionidos y mustelidos, lo que puede sugerir una mayor resistencia genetica a la presentacion de neoplasias por parte de estas familias, o a una exposicion menor a cancerigenos. El proposito de esta revision es conocer las neoplasias mas frecuentes en especies salvajes, ya que estas sirven como centinelas del ecosistema y ayudan a determinar posibles contaminantes carcinogenicos en el ambiente. Conociendo el grado de similitud en la genesis y progresion tumoral en humanos, con relacion a la vida salvaje genera oportunidades de tratamiento y conservacion y pueden servir como centinelas efectivos para problemas de salud publica. Ademas, su importancia en favorecer y fortalecer mecanismos encaminados para la salud y conservacion de especies silvestres, ya que pueden ser mermadas considerablemente a causa de este tipo de enfermedades. portuguesResumo Tem sido observadas diferentes tipos de neoplasias en distintas especies de animais. As que se dividem segundo o tecido de origem e seu grau de malignidades. Podem ser de origem epitelial, mesenquimal, de celulas redondas e de celulas produtoras de pigmentos. De acordo ao grau de malignidade, classificam-se como benignas e malignas. Os carnivoros, constituem uma ordem pertencente ao reino animal, dentro do qual encontram-se varias familias. Segundo a interacao que tenham com o medio ambiente e a exposicao a agentes contaminantes, virus e situacoes estressantes, alguns individuos de certa familia podem desenvolver um tipo de neoplasia. Tanto em felidos e canideos, tem-se encontrado maior incidencia de neoplasias de tipo epitelial involucrando o sistema tegumentario; em pinipedos o sistema maiormente afetado e o trato reprodutivo. Existem poucos reportes de neoplasias em procionidos e mustelidos, o que pode dar sugestao de uma maior resistencia genetica a apresentacao de neoplasias por parte destes animais, ou a uma exposicao menor a cancerigenos. O proposito principal deste artigo, e conhecer as neoplasias em especies selvagens, ja que estas servem como sentinelas do ecossistema e ajudam a determinar possiveis contaminantes carcinogenicos no medio ambiente. Conhecendo o grau de similitude na genesis e progressao tumoral em humanos, com relacao a vida selvagem gera oportunidades de tratamento e conservacao. Podem server como sentinelas efetivas para problemas de saude publica. Alem disso, sua importância em favorecer e fortalecer mecanismos encaminhados para a saude e conservacao de especies silvestres, ja que podem ser mermadas consideravelmente a causa deste tipo de enfermedades. EnglishAbstract Different types of neoplasia have been observed in different species of animals. Neoplams are divided by the tissue of origin and its degree of malignancy. They may be of epithelial, mesenchymal origin, of round cells and of pigment-producing cells. According to the degree of malignancy, they are classified as benign and malignant. Carnivores constitute an order belonging to the animal kingdom, within which are several families. Depending on the interaction they have with the environment and exposure to pollutants, viruses and stressful situations, some individuals from a different family may develop a neoplasia. In both felids and canids, we have found a higher incidence of epithelial neoplams involving the integumentary system. In pinnipeds, the system most affected is the reproductive tract. There are few reports of neoplasms in procyonidae and mustelids, which may suggest a greater genetic resistance to the presentation of neoplams, or to a lesser carcinogenic exposure. The main purpose of this article is to identify the neoplasias in wild species, since these serve as sentinels of the ecosystem and help to determine possible carcinogenic pollutants in the environment. Knowing the degree of similarity in the genesis and tumor progression in humans, in relation to the wild life generates opportunities of treatment and conservation. They can serve as effective sentinels for public health problems. In addition, it is important in favoring and strengthening mechanisms directed to the health and conservation of wild species, since they can be reduced considerably because of this type of diseases.

Efecto de la densidad de siembra sobre el peso corporal y sobrevivencia de larvas de bagre rayado (Pseudoplatystoma sp) en un sistema cerrado de circulación

In order to evaluate the effects of larval density rearing on body weight and survival of larvae of striped catfish (Pseudoplatystoma sp), was designed and built a closed recirculation system, which allowed maintaining stable physical and chemical variables of water throughout the experimental period. For this purpose, vitelline larvae were rearing in three densities: 10 (T1), 50 (T2) and 100 (T3) larvae per liter and monitored until 20 days post-hatch. They were evaluated four replicates per treatment, kept under photoperiod 0:24 (light: dark) and fed to apparent satiety with Artemia saline hatchlings, which were supplied divided into five portions a day: at 07:00, 09: 00, 14:00, 18:00 and 22:00 hours. The water quality characteristics observed during the test were: dissolved oxygen 5.7 ± 0.5 mg/L; temperature 26 ± 0.8 ° C; pH 7.6 ± 0.2; hardness 38.2 ± 5.2 mgCaCO3/L; alkalinity 26.5 ± 5.2 mg CaCO3 / L; NH3 0.05) were observed. Survival was higher in the density of 10 larvae/L, being statistically different between treatments (86.5 ± 1.9%, 54.7 ± 2.2% and 46.9 ± 3.1% for 10, 50 and 100 larvae/L, respectively, P<0.01). In conclusion, larval density inversely rearing affects body weight and survival of the larvae in this species.

Estudio retrospectivo de hallazgos histopatológicos en animales silvestres de vida libre y en cautiverio en Villavicencio, Colombia

O presente trabalho constitui um primeiro estudo retrospectivo dos achados histopatologicos em animais silvestres atendidos no Laboratorio de Histopatologia da Escola de Medicina Veterinaria da Universidade dos Llanos, Villavicencio (Colombia), entre 2004 e 2011. Foram analisados 43 casos, dos quais constaram infeccoes parasitarias, doencas malignas e reacoes necroticas e inflamatorias. Sessenta e dois por cento (n = 31) eram animais de vida livre e 28% (n = 12) de cativeiro. A maioria desses animais pertencia a classe dos mamiferos, que inclusive registrou a maior taxa anual (Chi-2, P < 0.01). As doencas infecciosas foram as mais frequentes, seguidas das doencas nao infecciosas e traumaticas. Em repteis e aves prevaleceram neoplasias (Chi-2, P < 0.01). Notou-se tambem que as doencas gastrointestinais foram achados patologicos mais comuns (27%), seguidas por lesoes no pulmao ou respiratorias (18.9%). O sistema digestivo foi principalmente afetado por doencas de origem infecciosa, bem como os sistemas respiratorio e cardiovascular, ao passo que a pele foi afetada por doencas neoplasicas e nao infecciosas e o sistema urinario por doencas neoplasicas (Chi-2, P < 0.05). Condicoes patologicas do sistema nervoso central e neoplasicas foram mais raras (10.8 e 8.0%, respectivamente). Entre as condicoes nao infecciosas, as mais comumente encontradas foram envenenamento e neoplasias mesenquimais.