Modulation Of ChanSu And CBG On Sodium Channels Of Nervous System

At present, the pharmacological research of ChanSu is mainly focused on its anti-tumor, analgesic and cardiac effects in molecular pharmacology mechanism, but its channel pharmacology research is still blank. Sodium channels are involved in pain generation and transmission, regulation of harmful physiological incoming and pathological features are directly related to with neuron-specific voltage-gated sodium channels function modulation and expression and the distribution. Now the sodium channels have been an important target to study the molecular physiology of pain mechanisms to find new analgesics.Cell culture techniques and whole-cell patch-clamp technique were mainly used to study the the regulation of ChanSu on dynamic natures of sodium channels in peripheral nervous system and central nervous system. It revealed the possible pharmacology mechanism of sodium channels. In order to determine whether the CBG is an efficacy material of analgesic effect from ChanSu, the impact of CBG to DRG sodium channels were also investigated, which may be prepared for screening the ingredients as sodium channel blockers from ChanSu. The major findings are as follows:(1) Separated dorsal root ganglion neurons from SD rats, cultured for days for the patch clamp experiments. It showed ChanSu can concentration-dependent inhibit the sodium channel current peaks of DRG neuron membrane, delay the activation of sodium current; At the same time, ChanSu can increase the inactivation voltage, accelerate sodium channels' inactivation; ChanSu can also slow down the current state of recovery from inactivation. It can be reasoned that ChanSu may interfere the incoming pain information of DRG cells similar as the channel blocker.(2) The Hippocampus neurons from SD rat were isolated and cultured for about 7 days then used for the patch-clamp experiments. It revealed that ChanSu can activate sodium current peaks of hippocampus neurons, make the activation voltage left, but have no effect to the activation and inactivation of sodium channel current. It suggested that the central nervous system may not be a major target of analgesic effect.(3) Stably transfected HEK-293 cell lines which express the Nav1.2 a-subunit channels from rat were cultured for patch clamp experiments. It was found that the peak current can be activated by ChanSu; and the half-activation voltage V1/2 was decreased, the activation of sodium current was accelerated, but also the inactivation of Na1.2 channels was accelerated, No significant effect on recovery time was found. Compared with the central nervous system, The results showed that voltage-gated sodium channels in peripheral nervous system may probably be the pain drug targets.(4) Different concentrations of CBG can concentration-dependent inhibit the sodium channel current peak of DRG cell; High concentrations of CBG can also delay the activation of DRG sodium current; low concentrations (<14mg/L)of CBG have no significant changes on inactivation curves, but maximum drug concentration (14mg/L) can move the inactivation curves toward hyperpolarizing direction and accelerated the inactivation of sodium channels; CBG can also affect the recovery time of sodium channel from inactivation, slow down the recovery from inactivation.These results suggest that ChanSu has important effects to the voltage-gated sodium channels on dorsal root ganglion neurons. And CBG is one main component of ChanSu on analgesic aspect.