Material basis for inhibition of dragon's blood on capsaicin-induced TRPV1 receptor currents in rat dorsal root ganglion neurons.

The effects of dragon's blood and its components cochinchinenin A, cochinchinenin B, loureirin B as well as various combinations of the three components on capsaicin-induced TRPV1 receptor currents were studied in acutely dissociated DRG neurons using both voltage and current whole-cell patch clamp technique. The results indicated that dragon's blood and its three components concentration-dependently reduce the peak amplitudes of capsaicin-induced TRPV1 receptor currents. There was no significant difference between the effects of dragon's blood and the combination wherein the three components were present in respective mass fractions in dragon's blood. The respective concentrations of the three components used alone were all higher than the total concentration of three components used in combination when the percentage inhibition of the peak amplitude was 50%. The proportion of three components was adjusted and the total concentration reduced, the resulting combination still inhibit the currents with a lower IC50 value, and inhibit capsaicin-induced membrane depolarization on current clamp. The combination of three components not only increase the capsaicin IC50 value, but also reduce the capsaicin maximal response. These result suggested that analgesic effect of dragon's blood may be partly explained on the basis of silencing pain signaling pathways caused by the inhibition of dragon's blood on capsaicin-induced TRPV1 receptor currents in DRG neurons and could be due to the synergistic effect of the three components. Antagonism of the capsaicin response by the combination of three components is not competitive. The analgesic effect of dragon's blood was also confirmed using animal models.

Chemical constituents with free-radical-scavenging activities from the stem of Microcos paniculata.

The free-radical-scavenging activities of various solvent extracts of Microcos paniculata were evaluated through in vitro model systems, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and Co (II) EDTA-induced luminol chemiluminescence by flow injection. In all three of these systems the ethyl acetate (EtOAc) extract showed the highest free-radical-scavenging activity compared with the other three (n-BuOH, water and petroleum ether) extracts. Free-radical-scavenging assay-guided chromatographic separation of the EtOAc extract, using a normal-phase and reverse-phase silica gel column chromatography yielded five compounds: a new triterpene named methyl 3beta-O-p-hydroxy-E-cinnamoyloxy-2alpha,23-dihydroxyolean-12-en-28-oate (1), whose spectral data are presented for the first time, together with four known compounds, epicatechin (2), 3-trans-feruloyl maslinic acid (3), maslinic acid (4) and sucrose (5). All of the compounds were isolated from Microcos paniculata for the first time. The compounds were identified by spectroscopic methods. Among them, compound 2 displayed significant free-radical-scavenging activity which is similar to that of standard antioxidant ascorbic acid (V(C)) and therefore may be a promising natural antioxidant.

Two new triterpenoids from Lycopodium obscurum L.

Two new onoceranoid triterpenoids, (3 alpha,8 beta,14 alpha,21 beta)-26,27-dinoronocerane-3,8,14,21-tetrol (1) and 26-nor-8 beta-hydroxy-alpha-onocerin (2), were isolated from Lycopodium obscurum L. Their structures were elucidated on the basis of spectroscopic analyses.

Inhibitory effect of cochinchinenin B on capsaicin-activated responses in rat dorsal root ganglion neurons.

Vanilloid receptor 1 (VR1) is a noxious receptor and a novel target for pain therapy. Cochinchinenin B (6-hydroxy-7-methoxy-3-(4'-hydroxybenzyl) chromone; CB) is one of the small-molecular components from the flavonoids of Dragon's Blood, a well-known herbal medicine to treat various types of pain. Using whole-cell patch clamp technique, we found that capsaicin (CAP)-activated currents (ICAP) was inhibited by CB with an IC50 of 0.92 mM in acutely isolated rat dorsal root ganglion (DRG) neurons. The inhibition was reversible and not competitive. We also found that the inhibition was neither voltage- nor agonist-dependent. The bind site was on the extracellular part of the channel since intracellular application of CB did not alter the inhibition effect on ICAP. In addition, CB inhibited CAP-evoked depolarization under current-clamp condition. Our findings indicate that CB may be a candidate in developing new analgesic drugs targeting the VR1 receptor.

[Dried meats and the provisions of poisonous dried meat recorded in Er nian lü ling (Statutes of the second year) on Han bamboo slips unearthed in Zhangjiashan].

It was a common social phenomenon to process, to store and to consume dried meat in the Qin and Han Dynasties. But some dried meat was poisonous, which did much harm to people's health and even influenced the social stability at that time. A provision of poisonous dried meat in Statutes of the Second Year is the earliest statutes in ancient China on preventing and dealing with food poisoning now discovered. For the purpose of maintaining the social stability in early Han Dynasty, they stipulated the principles and methods of disposing the dried meat, and established the penalty standard for the breach of the dried meat disposing regulations, which has great significance in medical history and legislative history.

Effect of Salvia miltiorrhiza injection on hyperpolarization-activated current channels in dorsal root ganglion neurons of rats.

AIM: To explore the modulation of Salvia miltiorrhiza on hyperpolarization-activated current (Ih) channels in dorsal root ganglion (DRG) neurons of rats and identify the mechanism of Salvia miltiorrhiza in alleviating pain and inhibiting calcium overload. Methods The effect of Salvia miltiorrhiza injection on Ih channels in DRG neurons of rats were examined by using whole-cell patch clamp technique. Results The experimental results showed that the amplitude of Ih evoked by -150 mV was (-1.06 +/- 0.18) nA. The Ih could be fitted well into the single kinetics and the time constant of activation, pi was clearly voltage-dependent with tau = (322.14 +/- 28.81) ms at -100 mV, decreasing to tau = (62.51 +/- 9.78) ms at -150 mV. The reversal potential of Ih was (-35.03 +/- 1.12) mV measured from tail currents. But no significant differences were found between the DRG neurons in the absence and presence of Salvia miltiorrhiza injection (10%, 25%, 50%) in the current amplitude, the time constant of activation and the reversal potential. The only difference between the DRG neurons in the absence and presence of Salvia miltiorrhiza injection was the half-activation potential of Ih. In control recordings the half-activation potential was (-106.07 +/- 3.59) mV. By comparison, the half-activation potentials changed to (-111.59 +/- 3.79) mV (n=31 neurons, P < 0.05), (-119.37 +/- 4.96) mV (n=31 neurons, P < 0.05) and (-121.23 +/- 3.86) mV (n=31 neurons, P < 0.05) in the presence of 10%, 25%, 50% Salvia miltiorrhiza injection, respectively. CONCLUSION: Only the half-activation potential of Ih in the arthritic and neuropathic rat models shifted in the depolarizing direction, which increased the electrophysiological activity of Ih and made it related to peripheral hyperalgesia. The selective inhibition of Salvia miltiorrhiza on the electrophysiological activity of Ih may be one of the mechanisms underlying its analgesic effects.

[Study on the pharmacological mechanism of analgesic effect of injection stauntoniae].

OBJECTIVE: To study the effects of Injection Stauntoniae (IS) on voltage-gated sodium currents in dorsal root ganglion neurons and analyze its pharmacological mechanism of blocking the nerve conduction and anal gesic action. METHODS: Whole-cell patch-clamp recordings were performed in acutely isolated rat dorsal root ganglion neurons and the effects of 10% , 25% and 50 % IS on voltage-gated sodium currents were observed. RESULTS: IS inhibited the peak sodium currents in dorsal root ganglion neurons in a dose-dependent way and affected the activation and inactivation process of the channels. CONCLUSION: The analgesic effect of IS was presumably caused by modulation of voltage-gated sodium channels in primary sensory neurons besides structure destruction of myelin sheath and axon membrane.