The modulation effects of BmK I, an alpha-like scorpion neurotoxin, on voltage-gated Na(+) currents in rat dorsal root ganglion neurons.
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| Abstract |
The present study investigated the effects of BmK I, a Na(+) channel receptor site 3 modulator purified from the Buthus martensi Karsch (BmK) venom, on the voltage-gated sodium currents in dorsal root ganglion (DRG) neurons. Whole-cell patch-clamping was used to record the tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) components of voltage-gated Na(+) currents in small DRG neurons. It was found that the inhibitory effect of BmK I on open-state inactivation of TTX-S Na(+) currents was stronger than that of TTX-R Na(+) currents. In addition, BmK I exhibited a selective enhancing effect on voltage-dependent activation of TTX-S currents, and an opposite effect on time-dependent activation of TTX-S and TTX-R Na(+) currents. The results suggested that the inhibitory effect of BmK I on open-state inactivation might contribute to the increase of peak TTX-S and TTX-R currents, and the enhancing effect of BmK I on time-dependent activation might also contribute to the increase of peak TTX-S currents. It was further suggested that a combined effect of BmK I including inhibiting the inactivation of TTX-S and TTX-R channels, accelerating activation and decreasing the activation threshold of TTX-S channels, might produce a hyperexcitability of small DRG neurons, and thus contribute to the BmK I-induced hyperalgesia.
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| Authors | Jin Chen, Zhi-Yong Tan, Rong Zhao, Xing-Hua Feng, Jian Shi, Yong-Hua Ji |
| Journal | Neuroscience letters (Neurosci Lett) Vol. 390 Issue 2 Pg. 66-71 (Dec 23 2005) ISSN: 0304-3940 [Print] Ireland |
| PMID | 16129561 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
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