Fine-tuning of defensive behaviors in the dorsal periaqueductal gray by atypical neurotransmitters

This paper presents an up-to-date review of the evidence indicating that atypical neurotransmitters such as nitric oxide (NO) and endocannabinoids (eCBs) play an important role in the regulation of aversive responses in the periaqueductal gray (PAG). Among the results supporting this role, several studies have shown that inhibitors of neuronal NO synthase or cannabinoid receptor type 1 (CB1) receptor agonists cause clear anxiolytic responses when injected into this region. The nitrergic and eCB systems can regulate the activity of classical neurotransmitters such as glutamate and γ-aminobutyric acid (GABA) that control PAG activity. We propose that they exert a ‘fine-tuning’ regulatory control of defensive responses in this area. This control, however, is probably complex, which may explain the usually bell-shaped dose-response curves observed with drugs that act on NO- or CB1-mediated neurotransmission. Even if the mechanisms responsible for this complex interaction are still poorly understood, they are beginning to be recognized. For example, activation of transient receptor potential vanilloid type-1 channel (TRPV1) receptors by anandamide seems to counteract the anxiolytic effects induced by CB1 receptor activation caused by this compound. Further studies, however, are needed to identify other mechanisms responsible for this fine-tuning effect

Growth Evolution Of Self-textured Zno Films Deposited By Magnetron Sputtering At Low Temperatures

In this work, the evolution of the surface morphology of ZnO thin films deposited by reactive RF magnetron sputtering has been investigated using atomic force microscopy (AFM) and X-ray diffraction (XRD). All AFM images of the films were analyzed using scaling concepts. To study the growth evolution, different ZnO films with thicknesses of up to 1270nm were deposited at temperatures of 100 and 250°C. For the films grown at 100°C, AFM data show that the lateral length ξ evolves continuously while the temporal evolution of the root mean square roughness σ presents two distinct regimes. Early during the depositions, the morphology of the ZnO films is mainly characterized by granular structures. Beyond thickness of about 600nm, pyramid-like structures with {214} crystallographic facets start to develop. For the films grown at 250°C, however, only one growth regime was observed and for the thicker films, the surface morphology consisted of polygonal structures. For the films grown at 100°C, the growth exponents, β, and the exponent defining the evolution of the characteristic wavelength of the surface, p, were β 1 =0.70±0.02 and β 2 =0.26±0.2; and p =0.2±0.04. For the films grown at 250°C, the exponent values were β =0.78±0.02 and p =0.32±0.05. These values of the exponents indicate the occurrence of surface mechanisms, such as shadowing and surface diffusion, as well as facet stabilization at 100°C. For the films grown at 250°C, however, structural misorientation during growth also plays an important role

Plantas medicinais usadas nos distúrbios do trato gastrintestinal no povoado Colônia Treze, Lagarto, SE, Brasil Medicinal plants used for aliments of the gastro-intestinal tract at Colonia Treze village, Lagarto Municipality, Sergipe State, Brazil

Os modelos de desenvolvimento sócio-econômicos adotados pela sociedade humana refletem diferentes formas de relacionamento com a natureza, as quais no paradigma vigente têm levado à grande perda de recursos naturais. Na esfera dessa relação, a conservação e preservação da biodiversidade da flora medicinal torna-se fundamental, pela importância que as plantas medicinais assumem como potencial genético para o desenvolvimento de novas drogas, e como acesso primário à saúde para muitas comunidades. Utilizando a abordagem etnofarmacológica na pesquisa de plantas medicinais, este trabalho teve por objetivo estudar as plantas medicinais utilizadas popularmente contra distúrbios do trato gastrintestinal no povoado Colônia Treze em Lagarto, SE, comunidade que tem o uso popular das plantas medicinais inserido em sua cultura. Sua metodologia abrangeu trabalho de campo na comunidade, adotando o método etnográfico qualitativo rápido. A amostra foi composta por líderes da comunidade, usuários de plantas e praticantes da medicina popular. Baseando-se nas indicações populares sobre o uso das plantas medicinais, selecionaram-se oito plantas que foram submetidas aos experimentos farmacológicos. As plantas testadas no Modelo de Trânsito Intestinal não produziram alteração na motilidade. Já as submetidas ao Modelo de Indução de Lesão Gástrica aguda, mostraram-se efetivas na atividade antiulcerogênica. A partir destes resultados propõem-se estratégias de desenvolvimento local para esta comunidade, que aliem a conservação da flora medicinal à melhoria de sua qualidade de vida.<br>Models of socioeconomic development adopted by human societies reflect different ways of relating to Nature, which, given the present paradigm, have evolved towards great natural-resource loss. Within the sphere of this relationship, both the conservation and preservation of medicinal-plant biodiversity are fundamental because of the importance of medicinal plants as genetic potential for the development of new drugs, and as the primary access to health care for many communities. Using an ethnopharmacological approach in the study of medicinal plants, this work aimed to study the medicinal plants popularly used for gastro-intestinal tract ailments, at Colonia Treze village, in Lagarto/Sergipe, since this community is culturally attuned to the use of medicinal plants. Methodology consisted of field work within the community, adopting the ethnographic Rapid Assessment Procedure. The sample was composed of community leaders, plant users and practitioners of folk medicine. Based on their indications of medicinal-plant use, eight plants were selected and subject to pharmacological experimental tests. Plants tested by the Intestinal Transit Model did not provoke alterations in motility. However, those that underwent the Acute Gastric Lesion Induction Model proved to be effective in anti-ulcerogenic activity. Based on these results, strategies for local development at the community level are proposed, which will tie the conservation of medicinal flora to improvements in life quality