Brain research
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The effect of 17beta-estradiol on the secondary damage following spinal cord injury (SCI) was examined in male rats subjected to moderate compression. Two doses of 17beta-estradiol (0.1 or 4 mg/kg) were injected i.p. immediately after spinal cord compression. Functional outcome was observed during 4 weeks following injury with two different tests. ⋯ These results suggest that 17beta-estradiol protects the spinal cord by stimulating early cytokines release and astroglial responses. These stimulations may prevent the area of damage from expanding and inflammatory cells to spread in the surrounding tissue during the critical first week following SCI. Although transient, these effects improved the locomotor recovery that was sustained over 4 weeks after injury.
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Bilobalide, a constituent of Ginkgo biloba, has neuroprotective properties. Its mechanism of action is unknown but it was recently found to interact with neuronal transmission mediated by glutamate, gamma-aminobutyric acid (GABA) and glycine. The goal of this study was to test the interaction of bilobalide with glycine in assays of neuroprotection. ⋯ In this model, glycine release was induced by ischemia, an effect that was strongly reduced by bilobalide. We conclude that bilobalide does not interact with glycine receptors in neurochemical assays but it significantly reduces the release of glycine under ischemic conditions. This effect likely contributes to bilobalide's neuroprotective effects in assays of excitotoxicity and ischemia.
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Vanilloid receptor 1 (VR1) is a noxious receptor and a novel target for pain therapy. Cochinchinenin B (6-hydroxy-7-methoxy-3-(4'-hydroxybenzyl) chromone; CB) is one of the small-molecular components from the flavonoids of Dragon's Blood, a well-known herbal medicine to treat various types of pain. Using whole-cell patch clamp technique, we found that capsaicin (CAP)-activated currents (ICAP) was inhibited by CB with an IC50 of 0.92 mM in acutely isolated rat dorsal root ganglion (DRG) neurons. ⋯ The bind site was on the extracellular part of the channel since intracellular application of CB did not alter the inhibition effect on ICAP. In addition, CB inhibited CAP-evoked depolarization under current-clamp condition. Our findings indicate that CB may be a candidate in developing new analgesic drugs targeting the VR1 receptor.
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Comparative Study
Exacerbated mechanical allodynia in rats with depression-like behavior.
Although a clinical connection between pain and depression has long been recognized, how these two conditions interact remains unclear. Here we report that both mechanical allodynia and depression-like behavior were significantly exacerbated after peripheral nerve injury in Wistar-Kyoto (WKY) rats, a genetic variation of Wistar rats with demonstrable depression-like behavior. ⋯ Moreover, there was a lower plasma melatonin concentration and a lower melatonin receptor expression in the anterior cingular cortex in WKY rats than in Wistar rats. These results suggest that there exists a reciprocal relationship between mechanical allodynia and depression-like behavior and the melatoninergic system in the anterior cingular cortex might play an important role in the interaction between pain and depression.