Either Cochinchinenin A Or Cochinchinenin B Could Slightly Increase Intracellular Ca²⁺ Concentration In Rat Dorsal Root Ganglion Neurons

Traditional Chinese medicine（TCM）clinical applications have several thousandyears of history, but the use of modern medicine method of TCM research mechanismbegan in the1920s. Through the study of Chinese medicine pharmacology, not onlycan very good validation of TCM theory, but also to deepen and developingtraditional Chinese medicine efficacy, make it more reasonable safe clinicalapplications have very important significance. Dragon’s blood is one of thewell-known TCM used in different areas of the world. It has astringent effect and hasbeen used as a hemostatic and antidiarrhetic drug. We used confocal laser scanningmicroscopy in combination with Ca²⁺sensitive fluorescent dyes to study the changesof intracellular free calcium concentration ([Ca²⁺]i) in cultured rat dorsal root ganglia（DRG） neurons caused by cochinchinenin A （CA） and cochinchinenin B （CB）, twoactive components of “Dragon’s blood”. The result demonstrated that CA or CB innormal external cell solution could evoke the slow elevation of [Ca²⁺]ivia a dosedependent manner. However, the elevation of [Ca²⁺]icaused by CA or CB in calciumfree solution was much smaller than that in the normal external cell solution,suggesting that the changes of [Ca²⁺]iwas mainly due to the Ca²⁺stores releasewhich were relied on a little bit of extracellular calcium influx. Comparing to [Ca²⁺]ichanges after CB treatment, CA had stronger effect than that of CB.In addition, there were only small size of neurons （19-29μm）[Ca²⁺]igot slow rise after adding cochinchinenin A （CA） and cochinchinenin B （CB）, at thesame time, the capsaicin receptor transient receptor potential vanilloid1（TRPV1） channels expressed in small neurons. After the TRPV1channels are blocked with Capsazepine （CPZ, antagonist of TRPV1channel）, CA or CB can stillinduce the elevation of [Ca²⁺]i,The results showed that the changes of [Ca²⁺]iwas mainly due to the Ca²⁺storesrelease which were relied on a little bit of extracellular calcium influx., and CA hasstronger effect than CB. Moreover, compared to the transients induced by capsaicin,the CA and CB-induced [Ca²⁺]irise is much slower and more stable. These resultsindicate that the capability of CA and CB of inducing the [Ca²⁺]irise is solid andunique.