Effect of lappaconitine on neuropathic pain mediated by P2X3 receptor in rat dorsal root ganglion.

ATP facilitates initiation and transmission of the neuropathic pain at the dorsal root ganglion (DRG) level via the P2X receptors, especially the subtype P2X(3). Lappaconitine (LA) is an active principle isolated from Chinese herbal medicine and possesses analgesic effect. The aim of this study was to investigate the effect of LA on chronic constriction injury (CCI)-induced neuropathic pain mediated by P2X(3) receptor in the DRG neurons. In the presence of CCI and/or LA, the mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured and P2X(3) receptor expression in the DRG neurons was evaluated by immunohistochemistry and Western blotting. Following intrathecal administration of P2X(3) receptor oligonucleotide, the effect of LA on pain thresholds was assessed. Furthermore, the effect of LA on the P2X(3) receptor agonists ATP- and α,ß-meATP-induced inward currents (I(ATP) and I(α,ß-meATP)) in the acutely dissociated rat DRG neurons was investigated by whole cell patch-clamp. The results included: (1) There showed reduction of pain thresholds, enhancement of I(ATP) and I(α,ß-meATP) and up-regulation of P2X(3) receptor expression in rat DRG neurons when neuropathic pain occurred. (2) In the presence of LA, the decreased pain thresholds, the up-regulated P2X(3) receptor expression and the enhanced I(ATP) and I(α,ß-meATP) were reversible in the CCI rats. (3) The down-regulated P2X(3) receptor expression with pretreatment of P2X(3) receptor antisense oligonucleotide significantly attenuated the analgesic effect of LA. These results indicate that the analgesic effect of LA involves decrease of expression and sensitization of the P2X(3) receptors of the rat DRG neurons following CCI.

[Determination of arsenic and selenium in the industrial sulphur].

In this paper, the method of determining arsenic and selenium in the industrial sulphur sample has been studied. Carbon tetrachloride-boromine was used to dissolve the sulphur sample in classical methods, which is complex and harmful, and a little arsenic and selenium will be lost. In this paper, nitric acid and perchloric acid were used to dissolve the sulphur sample, which was simple, and scarcely arsenic and selenium were lost. Under the selected conditions, determination of arsenic and selenium can be determined simultaneously by HG-ICP-AES. The determination limits of arsenic and selenium are 0.6 ng.mL-1 and 0.7 ng.mL-1, respectively, the relatively standard deviations(RSD) (n = 8) are 2.1% for arsenic and 1.9% for selenium, respectively, and the recoveries are 99.6% for arsenic and 101% for selenium, respectively, which was a very satisfying result.