In 1995 the P2X 3 receptor was found to be expressed at high levels in nociceptive sensory neurones, consistent with earlier reports that ATP induced pain in humans and animals. At first it was thought that ATP was most likely to play a role in acute pain, following its release from damaged or stressed cells and since then a wide variety of experimental techniques and approaches have been used to study this possibility. Whilst it is clear that exogenous and endogenous ATP can indeed acutely stimulate sensory neurones, more recent reports using gene knockout and antisense oligonucleotide technologies, and a novel, selective P2X 3 antagonist, A-317491, all indicate that ATP and P2X 3 receptors are more likely to be involved in chronic pain conditions, particularly chronic inflammatory and neuropathic pain. These reports indicate that P2X 3 receptors on sensory nerves may be tonically activated by ATP released from nearby damaged or stressed cells, or perhaps from the sensory nerves themselves. This signal, when transmitted to the CNS, will be perceived consciously as chronic pain. In addition, it is now clear that several subtypes of P2Y receptor are also expressed in sensory neurones. Although their distribution and functions have not been as widely studied as P2X receptors, the effects that they mediate indicate that they might also be considered as therapeutic targets in the treatment of pain. Although our ability to treat persistent painful conditions, such as chronic inflammatory and neuropathic pain, has improved in recent years, these conditions are often resistant to currently available therapies, such as opioids or non-steroidal antiinflammatory drugs. This reflects a limited understanding of the underlying pathophysiology. It is now clear that the development and maintenance of chronic pain are mediated by multiple factors, but many of these factors, and the receptors and mechanisms through which they act, remain to be identified. Chronic pain is debilitating and can greatly decrease quality of life, not just due to the pain per se, but also because of the depression that can often ensue. Thus a greater understanding of the mechanisms that underlie chronic pain will help identify new targets for novel analgesics, which will be of great therapeutic benefit to many people.

The antioxidant activity of four species of the Malvaceae family (Sidastrum micranthum (A. St.-Hil.) Fryxell, Wissadula periplocifolia (L.) C. Presl, Sida rhombifolia (L.) E. H. L and Herissantia crispa L. (Brizicky)) were studied using the total phenolic content, DPPH radical scavenging activity and Trolox equivalent antioxidant capacity (TEAC) assays. The antioxidant activity of the crude extract, phases and two isolated flavonoids, kaempferol 3,7-di-O-α-L-rhamnopyranoside (lespedin) and kaempferol 3-O-β-D-(6''-E-p-coumaroil) glucopyranoside (tiliroside) was determined. The results showed that there is a strong correlation between total polyphenol contents and antioxidant activity of the crude extract of Sidastrum micranthum and Wissadula periplocifolia; however, this was not observed between Sida rhombifolia and Herissantia crispa. The ethyl acetate (EaF) phase showed the best antioxidant effect in the total phenolics, DPPH and TEAC assays, followed by the chloroform (CfF) phase, in most species tested. Lespedin, isolated from the EaF phase of W. periplocifolia and H. crispa may not be responsible for the antioxidant activity due to its low antioxidant activity (IC50: DPPH: 1,019.92 ± 68.99 mg/mL; TEAC: 52.70 ± 0.47 mg/mL); whereas tiliroside, isolated from W. periplocifolia, H. crispa and S. micrantum presented a low IC50 value (1.63 ± 0.86 mg/mL) compared to ascorbic acid in the TEAC assay.

Abstract:The Cactaceae family is composed by 124 genera and about 1438 species. Pilosocereus gounellei, popularly known in Brazil as xique-xique, is used in folk medicine to treat prostate inflammation, gastrointestinal and urinary diseases. The pioneering phytochemical study of P. gounellei was performed using column chromatography and HPLC, resulting in the isolation of 10 substances: pinostrobin (1), β-sitosterol (2), a mixture of sitosterol 3-O-β-D-glucopyranoside/stigmasterol 3-O-β-D-glucopyranoside (3a/3b), 13 2 -hydroxyphaeophytin a (4), phaeophytin a (5), a mixture of β-sitosterol and stigmasterol (6a/6b), kaempferol (7), quercetin (8), 7 I -ethoxy-trans-feruloyltyramine (mariannein, 9) and trans-feruloyl tyramine (10).Compound 9 is reported for the first time in the literature. The structural characterization of the compounds was performed by analyses of 1-D and 2-D NMR data. In addition, a phenolic and flavonol total content assay was carried out, and the anti-oxidant potential of P. gounellei was demonstrated.

Diplotropis ferruginea Benth. (Fabaceae) is a tree popularly known in Northeastern Brazil as “sucupira-preta”. In the present work, the isolation, identification and pharmacological activity of a furanoflavan-type flavonoid (2,3-trans-3,4-trans)-3,4,5,8-tetramethoxy-(6,7,2”,3”)-furanoflavan, which received the trivial name diplotropin is reported. The structure was determined by means of spectroscopic techniques, especially EIMS and 1D and 2D NMR. Diplotropin (10−8 −3 · 10−4 M) inhibited the phasic contractions induced by both acetylcholine (IC50 = 4.6±0.8 · 10−5 M) and histamine (IC50 = 2.3±1.1 · 10−5 M) in guinea-pig ileum. Diplotropin relaxed the ileum pre-contracted with KCl (EC50 = 3.9±1.1 · 10−6 M), acetylcholine (EC50 = 3.7±1.6 · 10−6 M) and histamine (EC50 = 4.4±1.4 · 10−5 M) in a concentration-dependent manner. As the maintenance of tonic contraction induced by these contractile agents involves Ca2+ influx through voltage-dependent Ca2+ channels, it is suggestive that this relaxation may be due to the blockade of Ca2+ influx through those channels. This hypothesis was confirmed by the observation that diplotropin antagonized (pD’2 = 4.83±0.37) CaCl2 induced contractions in Ca2+-free depolarizing medium (IC50 = 1.5±0.8 · 10−5 M).

A group of teachers from Northeast Brazil developed a model of membrane potentials and action potential and tested the hypothesis that using the peer-instruction model would provide a better performance for students in reading traditional texts and lectures. The results were obtained from 357 students from 20 different courses in 9 different undergraduate programs. All students attended two 100-min theoretical lecture and, at the end of the second lecture, were asked to answer a multiple-choice question (a pretest). In the following lecture, students were divided into three groups: control, text, and model. At the end of the lecture, everyone responded to a posttest. Student performance in the pretest did not differ significantly between groups. In the comparison between the pretest and the posttest, students in the model and text groups significantly improved their performance, but there was no improvement in the control group. In the posttest, the model group presented a better performance than the control group. In the evaluation of the strategies used, 46% of the students indicated that the text would be very useful to remind them about the subject in the future, whereas 80% of those who used the model indicated that it would be very useful or extremely useful. useful. Although it was not possible to support the hypothesis conclusively, the performance model group, at least in part, was due to the use of active methodologies that constitute a differential in the teaching-learning process.