Efeitos farmacológicos do extrato aquoso de Solidago chilensis Meyen em camundongos / Pharmacological effect of aqueous extract from Solidago chilensis Meyen on mice

Solidago chilensis Meyen (Asteraceae) é uma espécie nativa da América do Sul (Brasil) encontrada principalmente na região Sul do Brasil onde é conhecida popularmente como arnica-do-mato. Na medicina popular, ela é utilizada como diurética, cicatrizante, e anti-inflamatória. No presente trabalho, os efeitos farmacológicos do extrato aquoso das raízes de S. chilensis foram avaliados em modelos experimentais in vivo de atividade tipo-antidepressiva, antiinflamatória, antinociceptiva, e locomotora. O extrato (25, 100 e 250 mg kg-1) foi administrado por via oral 30 min antes dos experimentos comportamentais. Os resultados mostram que, nas doses utilizadas, o extrato aquoso de S. chilensis não apresentou atividade tipo-antidepressiva apesar de induzir efeitos analgésico e antiinflamatório significativos. Uma redução da atividade locomotora foi observada com a maior dose (250 mg kg-1) administrada, sugerindo efeito sobre o sistema nervoso central. Em conclusão, os resultados estão de acordo com a literatura acerca dos efeitos analgésicos e antiinflamatórios da planta, sugerindo também uma atividade do extrato de S. chilensis sobre o sistema nervoso central. Essas observações, porém, não excluem um possível efeito relaxante muscular periférico do extrato.

Solidago chilensis Meyen (Asteraceae) is a species native to South America (Brazil), found especially in the south region of Brazil, where it is commonly known as "arnica-do-mato". In folk medicine, it has been used as diuretic, healing and anti-inûammatory. In the present study, the pharmacological effects of aqueous extracts from roots of S. chilensis were assessed in vivo in experimental models for antidepressant, anti-inflammatory and locomotor-type activity. The extract (25, 50 and 250 mg kg-1) was administered by the oral route 30 minutes prior to behavioral tests. Results indicate that, at the employed levels, aqueous extract from S. chilensis did not show antidepressant-type activity although it induced significant analgesic and anti-inflammatory effects. A reduction in the locomotor activity was noted at the highest administered level (250 mg kg-1), suggesting an effect on the central nervous system. In conclusion, results agree with the literature about analgesic and anti-inflammatory effects of this plant, also suggesting an activity of S. chilensis extract on the central nervous system. These remarks, however, do not exclude a possible peripheral muscular relaxing effect of the extract.

Lessons from tumor and immunocompetent cells. The quantitative engagement of ligand-receptor interactions modulates stop-and-go behavior as well as proliferation

The four main cell functions, proliferation, apoptosis, differentiation and migration, are tightly regulated by external signals that initiate intracellular signal transduction pathways and determine the cellular behaviour. The concentration and composition of such external signals are at least important for the decision of cells as to which function has to be executed. Interleukin-8 is a well known inducing signal for neutrophil granulocyte migration, while the epidermal growth factor is an inducing signal for breast carcinoma cell migration. Depending on the concentrations of interleukin-8, the neutrophil granulocytes are capable of migration. However, at high concentration of interleukin-8 the migratory activity of each single cell is reduced, indicating that high concentrations of the chemokine inhibit migration and promote the performance of other cell functions. Concerning breast carcinoma cells, the epidermal growth factor is not only an inducer of migration but also an inhibitor of proliferation. These two examples provide evidence for a dose dependent action of external signals for several cell functions in parallel. This versatility of the effects of one ligand might be based on several intracellular signal transduction pathways that are turned on. For the dose-dependent differences of the effect of interleukin-8 we propose a two wheel model of an inositolphosphate-mediated, ATP-independent release of calcium from intracellular stores and a cyclic AMP-mediated, ATP-dependent uptake of calcium into the endoplasmatic reticulum.