Avaliação da toxicidade aguda do extrato das cascas de Pithecellobium cochliocarpum (Gomez) Macbr / Evaluation of acute toxicity of the Pithecellobium cochliocarpum (Gomez) Macbr bark extract

O uso popular, e mesmo o tradicional, não são suficientes para validar as plantas medicinais como medicamentos eficazes e seguros. Para melhor entendimento, é necessário avaliar a relação risco/benefício de seu uso, por meio de estudos toxicológicos. O objetivo desta pesquisa foi estimar a toxicidade aguda do extrato etanólico das cascas secas de Pithecellobium cochliocarpum (Gomez) Macbr através da obtenção da dose letal (DL50) em roedores, e da Concentração letal (CL50) frente à Artemia salina Leach. Foram realizados experimentos por via oral e intraperitoneal utilizando camundongos fêmeas albinos Swiss (Mus musculus) (n=6). Por via oral foram administradas 3 doses (1.000, 3.000 e 5.000 mg Kg-1) e por via entraperitoneal, 5 doses (155, 160, 176, 345,6 e 414,72 Kg-1). Os sinais comportamentais foram avaliados durante uma hora após a administração do extrato, ficando em observação até 48 horas. O número de óbitos foi quantificado para posterior cálculo da DL50. A administração por via intraperitoneal foi realizada em intervalo de 5 minutos para cada animal. Nos ensaios de toxicidade por via oral a solução foi introduzida por via intragástrica através de cânula metálica acoplada a seringa (gavagem) no mesmo intervalo de tempo utilizado pela via intraperitoneal. Os animais do grupo de administração oral apresentaram algumas reações, porém não letais até a dose de 5.000 mg Kg-1. A DL50 para a via intraperitoneal foi 257, 49 mg Kg-1 (muito tóxico, grau 4) (Schuartsman, 1980). A CL50 (543,5 µg Kg-1) demonstrou ser tóxica frente à A. salina. Conclui-se que sob condições agudas de exposição, o extrato do Pithecellobium cochliocarpum é um agente tóxico, devendo ser considerado como tal, dependendo da dose administrada ou absorvida, do etempo e frequência de exposição e das vias de administração.

The popular use, and even the traditional one, is not enough to validate medicinal plants as effective and safe medicines. For a better understanding, it is necessary to assess the risk / benefit ratio of their use through toxicological studies. The aim of this work was to evaluate the acute toxicity of Pithecellobium cochliocarpum (Gomez) Macbr dried bark ethanolic extract through its lethal dose (LD50), in mice, and lethal concentration (LC50) in relation to Artemia salina Leach. Experiments were performed by oral and intraperitoneal route using female Swiss albino mice (Mus musculus) (n = 6). The first three doses were given orally (1,000, 3,000 and 5,000 mg kg-1) and the last five doses were given intraperitoneally (155, 160, 176, 345.6 and 414.72 Kg-1). The behavioral signs were evaluated one hour after administration of the extract, being observed up to 48 hours. The number of deaths was quantified for subsequent calculation of LD50. The intraperitoneal administration was carried out at an interval of 5 minutes for each animal. For the oral toxicity test, the solution was introduced in the digestive system of the animals through a metal cannula coupled to a syringe (gavage) at the same time interval used for the intraperitoneal route. The animals from the oral group presented some reactions, but they were not lethal up to the dose of 5.000 mg kg-1. The LD50 for the intraperitoneal group was 257.49 mg kg-1 (very toxic, grade 4) (Schuartsman, 1980). The LC50 (543.5 mg kg-1) was toxic to A. salina. We can conclude that, under acute conditions of exposure, the Pithecellobium cochliocarpum extract is a poisonous agent and should be considered as such depending on the administered or absorbed dose, the time and frequency of exposure, and the administration routes.

A morphometric and molecular study of Anastrepha pickeli Lima (Diptera: Tephritidae)

This study investigated the level of morphometric and genetic variability among populations of Anastrepha pickeli Lima from several localities in Brazil, one locality in Bolivia and one in Paraguay. Traditional and geometric morphometric analyses were used, as well as sequencing of a fragment of the cytochrome oxidase gene (COI). Six variables were measured from the aculeus for traditional morphometric analysis and 14 landmarks from the right wing were used for geometric analysis, using 10 specimes/population. The aculeus tip length, aculeus width at the end of the cloaca opening, and the serrate part length contributed with 62.7 percent for grouping. According to the results from traditional morphometry, there was no significant difference, but the multivariate tests showed that the canonical variables were statistically significant, indicating a difference in the wing conformation among populations. Molecular phylogenetic analysis indicated that the populations clustered into three clades and revealed a high level of genetic variation within A. pickeli populations from various geographic regions. Anastrepha pickeli populations differed among them according to the methods used in this study, showing incongruence among the methods used.

Morphometric Analysis of Populations of Centris aenea Lepeletier (Hymenoptera: Apidae) from Northeastern Brazil

Centris aenea Lepeletier is a solitary bee that has raised interest in management to pollinate crops, such as acerola, Malpighia emarginata. This study investigated the level of morphometric variability among populations of C. aenea from Northeastern Brazil. Traditional and geometric morphometric analyses were used. Head length, leg length, wing length, and wing shape were measured in samples (5-10 females) from eight localities. We did not find statistically significant differences among the populations (P > 0.01). The partial wing warps were similar in the populations and indicated that the bees were not morphometrically different. Our results suggest that C. aenea shows low population morphometric variability and highlight the need for further investigations on population variation in this species, preferably including populations sampled at the extremes of their geographic distribution. Significant insight into the population variation of C. aenea will probably require the use of molecular markers to allow a comparative approach between morphometric variability and genetic variability.

Participación de la corteza parietooccipital en el proceso de integración sensoriomotora: estudio electroencefalográfico / The role played by the parietooccipital cortex in the process of sensory-motor integration: An electroencephalographic study

Introducción. La planificación de acciones futuras tiene como aspecto fundamental la realización y el control de la tarea motora. Este comportamiento se da a través de la integración sensoriomotora. Objetivo. Explicar los mecanismos electrofisiológicos corticales (modificaciones en banda alfa) que intervienen en las acciones anticipatorias cuando los individuos tienen que coger un objeto en caída libre. Sujetos y métodos. La muestra estaba compuesta por 20 sujetos sanos de ambos sexos (11 hombres y 9 mujeres), con edades que oscilaban entre los 25 y 40 años (32,5 ± 7,5), sin enfermedades mentales ni físicas(anamnesis previa), diestros (inventario de Edimburgo) y que no tomaban ninguna sustancia psicoactiva o psicotrópica en el momento del estudio. El experimento consistió en una tarea de coger objetos en caída libre. Constaba de seis bloques con 15 pruebas, con una duración de 2 minutos y 30 segundos cada una de ellas, y con un minuto de intervalo entre los bloques.La captación de los datos a través de la electroencefalografía cuantitativa se produjo dos segundos antes y dos segundos después de la caída de la bola. Resultados. Se verificó una interacción de los factores momento y posición solamente para la corteza parietooccipital derecha, en la combinación de electrodos P4-O2. Conclusión. Estos hallazgos indican una importanteparticipación de la corteza parietooccipital derecha en el aumento de la expectativa y la celeridad en los procesos preparatorios de una tarea motora

Introduction. A fundamental aspect of planning future actions is the performance and control of motor tasks. This behaviour is done through sensory-motor integration.Aim. To explain the electrophysiological mechanisms in the cortex (modifications to the alpha band) that are involved in anticipatory actions when individuals have to catch a free-falling object.Subjects and methods. The sample was made up of 20 healthy subjects of both sexes (11 males and 9 females) with ages ranging between 25 and 40 years (32.5 ± 7.5) who were free of mental or physical diseases (previous medical history); the subjects were right-handed (Edinburgh Inventory) and were not taking any psychoactive or psychotropic substances at the time of the study. The experiment consisted in a task in which subjects had to catch freely falling objects. The experiment was made up of six blocks of 15 tests, each of which lasted 2 minutes and 30 seconds, with a break of one minute between blocks. Data were captured by means of a quantitative electroencephalogram two seconds before and two seconds after each ball was dropped. Results. An interaction of the factors moment and position was only observed for the right parietooccipitalcortex, in the combination of electrodes P4-O2. Conclusion. These findings suggest that the right parietooccipital cortex plays an important role in increasing expectation and swiftness in the processes of preparing for a motor task

Aprendizaje y memoria implícita: mecanismos y neuroplasticidad / Learning and implicit memory: mechanisms and neuroplasticity

El aprendizaje y la memoria son procesos complejos que hace más de un siglo que desafían a los investigadoresen su intento de esclarecer cuáles son los mecanismos básicos implicados. Objetivos. Revisar los mecanismoscelulares y moleculares básicos implicados en el proceso de retención de procedimientos, proporcionar una visión global de los mecanismos básicos implicados en el almacenamiento de información mediante teorías y modelos de la memoria, y discutir los diferentes tipos de memoria y el papel del cerebelo como modulador de la memoria de procedimientos. Desarrollo. Losresultados experimentales de las últimas décadas establecieron nuevas direcciones en la participación de los procesos bioquímicos y celulares relacionados con la consolidación de la información en el sistema nervioso. Conclusiones. Los circuitos neuronales implicados en la adquisición y consolidación de la memoria aún no se conocen del todo, ni tampoco la localizaciónde la memoria en el sistema nervioso. Numerosos factores intrínsecos y extrínsecos interfieren en estos procesos, como los mecanismos moleculares (potenciación y depresión a largo plazo) y celulares, que responden a la comunicación y transmisión entre las células nerviosas, y los factores que proceden del medio externo, capaces de propiciar, a través de las asociacionesde sucesos, la formación de nuevas memorias o de desviar al sujeto de su foco principal. La memoria no es un hechoúnico; se subdivide en declarativa y no declarativa, o, cuando se refiere al tiempo de duración, en memoria de corta y larga duración. Además, no se puede afirmar que la memoria constituya un proceso aislado, dada su relación con los mecanismos neuronales del aprendizaje

Learning and memory are complex processes that researchers have been attempting to unravel forover a century in order to gain a clear view of the underlying mechanisms. Aims. To review the basic cellular and molecular mechanisms involved in the process of procedural retention, to offer an overall view of the fundamental mechanisms involvedin storing information by means of theories and models of memory, and to discuss the different types of memory and the role played by the cerebellum as a modulator of procedural memory. Development. Experimental results from recent decades have opened up new areas of study regarding the participation of the biochemical and cellular processes related to the consolidationof information in the nervous system. Conclusions. The neuronal circuits involved in acquiring and consolidating memory are still not fully understood and the exact location of memory in the nervous system remains unknown. A number of intrinsic and extrinsic factors interfere in these processes, such as molecular (long-term potentiation and depression) and cellularmechanisms, which respond to communication and transmission between nerve cells. There are also factors that have their origin in the outside environment, which use the association of events to bring about the formation of new memories or may divert the subject from his or her main focus. Memory is not a singular occurrence; it is sub-divided into declarative and nondeclarative or, when talking about the time it lasts, into short and long-term memory. Moreover, given its relation with neuronal mechanisms of learning, memory cannot be said to constitute an isolated process