Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto

About: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto is a based out in . It is known for research contribution in the topics: Population & Genus. The organization has 2143 authors who have published 3674 publications receiving 71071 citations. The organization is also known as: FFCLRP & FFCLRP-USP.

Ion-motive ATPases and active, transbranchial NaCl uptake in the red freshwater crab, Dilocarcinus pagei (Decapoda, Trichodactylidae).

Abstract: SUMMARY The present investigation examined the microanatomy and mRNA expression and activity of ion-motive ATPases, in anterior and posterior gills of a South American, true freshwater crab, Dilocarcinus pagei . Like diadromous crabs, the anterior gills of this hololimnetic trichodactylid exhibit a highly attenuated (2–5 μm), symmetrical epithelium on both lamellar surfaces. In sharp contrast, the posterior gill lamellar epithelia are markedly asymmetrical. Their proximal side consists of thick (18–20μ m) cells, displaying features typical of a transporting epithelium, while the distal epithelium is thin (3–10 μm) and formed entirely by apical pillar cell flanges. Both anterior and posterior gills express Na + /K + - and V-ATPases. Phylogenetic analysis of partial cDNA sequences for the Na + /K + -ATPase α-subunit and V-ATPase B-subunit among various crab species confirmed the previous classification and grouping of D. pagei based on morphological criteria. Semi-quantitative RT-PCR clearly showed that mRNA for both ion pump subunits is more intensely expressed in posterior gills. Na + /K + -ATPase activity in the posterior gills was nearly fourfold that of anterior gills, while V-ATPase and F-ATPase activities did not differ. A negative short-circuit current ( I sc ) was measured using the distal side of split, posterior gill lamellae, mounted in a modified Ussing chamber and perfused symmetrically with identical hemolymph-like salines. Although hemolymph-side ouabain did not affect this current, concanamycin significantly reduced I sc without altering preparation conductance, suggesting V-ATPase-driven Cl – absorption on the distal side of the posterior gill lamellae, as known to occur in diadromous crabs adapted to freshwater. These findings suggest that active Na + uptake predominates across the thick proximal epithelium, and Cl – uptake across the thin, distal epithelium of the posterior gill lamellae.

Dopamine D2 receptor mechanisms in the expression of conditioned fear.

Abstract: The increase in the startle reflex in the presence of a stimulus that has been previously paired to foot shock is taken as an index of anxiety and named fear potentiated startle (FPS). Freezing behavior, defined as a cessation of all observable movements except those associated with respiration, has also been used as an index of fear in rats. Recently, a growing body of evidence has suggested that dopaminergic mechanisms are significant for different aspects of affective memory, namely its formation, expression or retrieval. However, the results of studies that have directly examined the ability of the dopaminergic system to influence fear have been inconsistent. This work is aimed at examining the involvement of D1 and D2 receptors in the acquisition and expression of conditioned fear using the fear potentiated startle test and the freezing behavior. We evaluated the effects of systemic administration of the D1 antagonist SCH 23390, the D1 agonist SKF 38393, the D2 antagonist sulpiride and the D2 agonist quinpirole before and after conditioning on FPS and freezing as indices of fear memory. The motor activity of the animals was also evaluated in an open field test. Injections of SCH 23390, SKF 38393, sulpiride and quinpirole before conditioning sessions did not produce any significant effect on FPS, but SCH 23390 decreased freezing. Injections of SCH 23390, SKF 38393 and sulpiride before testing session did not produce any significant effect on FPS or freezing. Quinpirole caused significant reduction in FPS and freezing when injected before testing. Drugs' actions were not due to nonspecific impairments in the ability to respond to the CS because the identical drug treatments had no effect in an open field test. Our findings indicate that DA mechanisms mediated by D2 receptors are mainly involved in the expression rather than in the acquisition of fear.

Angiogenic properties of natural rubber latex biomembranes and the serum fraction of Hevea brasiliensis

Abstract: The angiogenic properties of natural rubber were evaluated in this work. We have used the chick chorioallantoic membrane assay (CAM) as a model to investigate the influence of the heating on biological activity in rubber membranes and in non rubber fraction as well. Results showed that natural rubber membranes can induce vascularization. It was observed that angiogenesis activity was maximum when membranes were heated in temperatures between 65oC and 85oC, considering a range from 55oC to 105oC. The same behavior was observed for non rubber fraction and it indicates that this serum fraction may be responsible for angiogenesis. When infrared spectroscopy was performed in the cast films of non rubber fraction samples, as a function of heating, no structural changes was observed. The results obtained shown that natural rubber latex films produced by casting induce the vessel growth in the CAM and it can be considered as a potential biomaterial.