Potent nonopioid antinociceptive activity of telocinobufagin in models of acute pain in mice.

INTRODUCTION: In recent decades, several researches have been conducted in search of new analgesics that do not present the side effects of opioids. In this context, animal venoms contain natural painkillers that have been used for the development of new analgesics. OBJECTIVE: The aims of this study were to evaluate the antinociceptive effects of telocinobufagin (TCB), a bufadienolide isolated from Rhinella jimi venom, in murine acute pain models, and to verify the participation of the opioid system in these effects. METHODS: TCB was purified from R. jimi venom by high-performance liquid chromatography, and its structure was confirmed by spectrometric techniques. TCB was administered intraperitoneally (i.p.) (0.062, 0.125, 0.25, 0.5, and 1 mg·kg-1) and orally (p.o.) (0.625, 1.125, 2.5, 5, and 10 mg·kg-1) in mice, which were then subjected to pain tests: acetic acid-induced writhing, formalin, tail-flick, and hot-plate. Involvement of the opioid system in TCB action was evaluated by naloxone i.p. injected (2.5 mg·kg-1) 20 minutes before TCB administration. In addition, the TCB action on the µ, δ, and κ opioid receptors was performed by radioligand binding assays. RESULTS: In all the tests used, TCB showed dose-dependent antinociceptive activity with more than 90% inhibition of the nociceptive responses at the doses of 1 mg·kg-1 (i.p.) and 10 mg·kg-1 (p.o.). Naloxone did not alter the effect of TCB. In addition, TCB did not act on the µ, δ, and κ opioid receptors. CONCLUSION: The results suggest that TCB may represent a novel potential nonopioid therapeutic analgesic for treatment of acute pains.

Multipotent stem cells from umbilical cord: cord is richer than blood!

The identification of mesenchymal stem cell (MSC) sources that are easily obtainable is of utmost importance. Several studies have shown that MSCs could be isolated from umbilical cord (UC) units. However, the presence of MSCs in umbilical cord blood (UCB) is controversial. A possible explanation for the low efficiency of MSCs from UCB is the use of different culture conditions by independent studies. Here, we compared the efficiency in obtaining MSCs from unrelated paired UCB and UC samples harvested from the same donors. Samples were processed simultaneously, under the same culture conditions. Although MSCs from blood were obtained from only 1 of the 10 samples, we were able to isolate large amounts of multipotent MSCs from all UC samples, which were able to originate different cell lineages. Since the routine procedure in UC banks has been to store the blood and discard other tissues, such as the cord and/or placenta, we believe our results are of immediate clinical value. Furthermore, the possibility of originating different cell lines from the UC of neonates born with genetic defects may provide new cellular research models for understanding human malformations and genetic disorders, as well as the possibility of testing the effects of different therapeutic drugs.

Bases genéticas da doença de Parkinson / Genetic basis of Parinson's disease

A doença de Parkinson (PD) é uma das enfermidades neurodegeneratívas mais comuns, afetando 1 por cento a 2por cento da população com idade acima de 65 anos. É caracterizada clinicamente por tremor de repouso, bradicínesia, rigidez, instabilidade postural e patolo- gicamente por perda de neurôníos da substância negra e presença de depósito protéico intracitopiasmático (corpos de Lewy). A identificação de vários genes ou loci responsá- veis por certas formas de DP tem permitido algumas explicações quanto à heterogeneídade genética da doença. As bases genéticas da DP têm permitido um enorme avanço na patogênese da doença. A terapia da DP inclui transplante de células fetaís e terapia gêníca e, em um futuro próximo, terapias neuroprotetoras efetivas que impedem a perda neuronal serão responsáveis pelo tratamento da DP.