Human & experimental toxicology
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The present study aims to investigate the influence of electrical stimulation of periaqueductal gray (PAG) following peripheral nerve injury and its modulation by naloxone and N-methyl-D-aspartate (NMDA). Chronic neuropathic pain was induced by chronic constriction injury of the sciatic nerve, and subsequently a cannula was implanted in the PAG area for the purpose of electrical stimulation and intra-PAG drug administration. ⋯ Electrical stimulation of PAG was also observed to demonstrate decreased pain response on hot-plate test, and this effect was reversed by the administration of naloxone, NMDA, and their combination, when injected into the PAG area. These findings suggest that apart from the opioid receptors, probably NMDA receptors also have a role to play in stimulation-produced analgesia.
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The inhibitory effect of vernolide-A (C(21)H(28)O(7)) on lung metastasis induced by B16F-10 melanoma cells was studied using C57BL/6 mice. Vernolide-A was administered in three different modalities such as simultaneously with tumor, prophylactic to tumor and after tumor development. Maximum inhibition in the metastasis was observed when vernolide-A was administered simultaneously with tumor. ⋯ Vernolide-A treatment also inhibited the migration of B16F-10 melanoma cells across a polycarbonate filter in vitro. Vernolide-A could inhibit MMP-2 and MMP-9 protein expression in gelatin zymographic analysis of B16F-10 cells. (3)H-thymidine proliferation assay showed that vernolide-A could inhibit the proliferation of B16F-10 melanoma cells in vitro. These results indicate that vernolide-A could inhibit the metastatic progression of B16F-10 melanoma cells in mice.