Slow rise of intracellular Ca(2+) concentration in rat primary sensory neurons triggered by loureirin B.

In the present study, the intracellular free calcium concentration ([Ca(2+)](i)) in acutely isolated rat dorsal root ganglia (DRG) neurons modulated by loureirin B, an active component of "dragon's blood" which is a kind of Chinese herbal medicine, was determined by the means of Fura-2 based microfluorimetry. It was found that loureirin B could evoke the elevation of [Ca(2+)](i) in a dose-dependent manner. However, the elevation of [Ca(2+)](i) evoked in the calcium free solution was much smaller than that in the standard external cell solution, suggesting that most change of [Ca(2+)](i) was generated by the influx of extracellular Ca(2+), not by the activities of intracellular organelles like Ca(2+) stores and mitochondria.

Electrophysiological characterization of BmK I, an alpha-like scorpion toxin, on rNav1.5 expressed in HEK293t cells.

A recent study described the pharmacological properties of BmK I, an alpha-like toxin from the Chinese scorpion Buthus martensi Karsch, on the cardiac sodium channel (hH1) expressed in Xenopus oocytes. Considering that alpha-like toxins are unique in their inability to bind to rat synaptosomes despite a high toxicity by intravenous injection, the present study investigated the pharmacological properties of BmK I on rNav1.5 expressed in a mammalian HEK293t cell line.