| Objection:Most local anesthetics produce anesthetic effect by the dispersion effect block sodium ion channels on the cell membrane. QX-314 is a derivative of lidocaine, QX-314 is not easy to penetrate the cell membrane, but after the TRPV1 channel through capsaicin-active QX 314 can enter into the nociceptor cells play a long-lasting analgesic effect and movement function is not affected by QX-314-OH[1]. QX-314-OH is a newly hydroxide compound of QX-314, bupivacaine is also an activator of TRPV1 channel. Experiments show that QX-314-OH and levobupivacaine co-administrate can produce analgesic effect. The objection of this article to study which channel and receptor involved in the anesthesia effect of QX-314-OH and levobupivacaine besides the TRPV1 channel.Method:The 15 mM QX-314-OH with 1 mM Levobupivacaine group was combined with the TRPV1 (transient receptor potential vanilliod 1) receptor antagonist(Capsazepine),TRPA1 (transient receptor potential channel Al) receptor antagonist(HC030031), HCN channel(hyperpolarization-activated cyclic nucleotide-gated) antagonist(ZD7288),HCN channel agonist(Forskolin), FAAH(fatry acid amide hydrolase) antagonist(URB937), CB1(Cannabinoid Receptor 1)antagonist(AM251) and CB2(Cannabinoid Receptor 2)antagonist(AM630) was given 30 min by intraperitoneal injection before sciatic nerve block, respectively.160 SD rats, half male and half female, were randomly divided into 20 groups,8 rats in each group.15 mM QX-314-OH group(n=8),1 mM levobupivacaine group(n=8),2 mM levobupivacaine group(n=8),3 mM levobupivacaine group(n=8) and 15 mM QX-314-OH with 1 mM levobupivacaine (QX with LB)group(n=8), 10mg/kg URB937 and 15 mM QX-314-OH group(n=8), 10mg/kg URB937 with 1 mM levobupivacaine group(n=8), 10mg/kg URB937 and 2 mM levobupivacaine group(n=8), 10mg/kg URB937 and 3 mM levobupivacaine group(n=8); 7.5mg/kg CPZ with (QX with LB) group(n=8),8mg/kgHC030031 with (QX with LB) group(n=8),3mg/kg Forskolin with (QX with LB) group(n=8),5mg/kg ZD7288 with (QX with LB) group(n=8),3mg/kg AM251 with (QX with LB) group(n=8), 10mg/kg AM251 with (QX with LB) group(n=8),3mg/kg AM630 with (QX with LB) group(n=8),3mg/kg URB937 with (QX with LB) group(n=8), lOmg/kg URB937 with (QX with LB)group(n:=8); 2ml/kg DMSO with (QX with LB)group(n=8) and 2ml/kg [TW80:ethanol H2O=1:3:16] with (QX with LB)group(n=8). The receptor agonist and antagonist were not required to be given in single use group before sciatic nerve block.1,2,3 mM Levobupivacaine,15 mM QX-314-OH,15 mM QX-314-OH with 1 mM Levobupivacaine were administrated through rats sciatic nerve block (SNB) model. After completed sciatic nerve block, observed the onset and block duration time of the sensory and motor function. The sensory and motor function are evaluated by paw withdraw latency of hot plate test and postural extensor test, respectively. Animals were euthanized at 1,3,7,14 days after drug administration and sciatic nerves harvested for histological analysis by HE staining and myelin staining.Result:1. Comparison of their basic value, the 15 mM QX-314-OH or 1 mM Levobupivacaine alone can not block the sensory and motor function of Rats, But co-administration of 15 mM QX-314-OH and 1 mM Levobupivacaine, the sensory and motor function were blocked and their duration time more longer than 15 mM QX-314-OH or 1 mM Levobupivacaine alone.2.Capsazepine with 15 mM QX-314-OH and 1 mM Levobupivacaine group was compared with 15 mM QX-314-OH and 1 mM Levobupivacaine group, the onset time of sensory and motor function block have no statistically significant, but the duration time of sensory and motor function was shortened, and it had statistical difference.HC030031 with 15 mM QX-314-OH and 1 mM Levobupivacaine group was compared with 15 mM QX-314-OH and 1 mM Levobupivacaine group, the onset time of sensory and motor function block have no statistically significant, but the duration time of sensory and motor function was shortened, and it had statistical difference.3. ZD7288 with 15 mM QX-314-OH and 1 mM Levobupivacaine group was compared with 15 mM QX-314-OH and 1 mM Levobupivacaine group, the onset time of sensory and motor function block have no statistically significant, but the duration time of sensory nerve block was extended, and it had statistical difference, but the duration time of motor nerve block was not obvious and has no statistical difference. Forskolin with 15 mM QX-314-OH and 1 mM Levobupivacaine group was compared with 15 mM QX-314-OH and 1 mM Levobupivacaine group, the onset time of sensory and motor function block have no statistically significant, but the duration time of sensory and motor function was shortened, and it had statistical difference.4. URB937 with 15 mM QX-314-OH and 1 mM Levobupivacaine group was compared with 15 mM QX-314-OH and 1 mM Levobupivacaine group, the onset time of sensory and motor function block have no statistically significant, but the duration time of sensory and motor function was extended, and it had statistical difference. URB937 with 15 mM QX-314-OH is also block the sensory and motor function compared with 15 mM QX-314-OH group, and the duration time of sensory and motor function was extended, it also had statistical difference. URB937 with different concentrations of levobupivacaine (1 mM,2 mM,3 mM) compared with the corresponding concentration of levobupivacaine, the sensory function block only 3 mM levobupivacaine was combined with URB937 have statistical significance and the motor function block only 2 mM levobupivacaine was combined withURB937 have statistical significance. AM251 or AM630 with 15 mM QX-314-OH and 1 mM Levobupivacaine, compared with 15 mM QX-314-OH and 1 mM Levobupivacaine, the onset time and duration time of sensory and motor function block was not changed and have no statistical difference.5. Observation by light microscope:No obvious nerve injure in any group, but at the 1 day, groups had varying degrees inflammatory cell infiltration in the sciatic, but fortunately no inflammatory cell infiltration at the 3,7,14 day.Conclusion:1. The low concentration (15 mM) QX-314-OH with low concentration (1 mM)levobupivacaine co-administration in sciatic nerve block model can obviously block the sensory and motor function, and produce the exact of anesthesia.2. TRPV1 and TRPA1 receptors are involved in the anesthetic effect of QX-314-OH and levobupivacaine, the antagonist of them make the block time of its sensory and motor function is shortened.3. HCN channel is one of channels of the effects of the co-administrated of QX-314-OH and levobupivacaine, the agonist of HCN channel reduce the duration time of the effects of QX-314-OH, the antagonist has the opposite effects.4. URB937 is the inhibitor of the enzyme fatty acid amide hydrolase (FAAH), it extend the duration time of sensory and motor function block time of the co-administrated of QX-314-OH and levobupivacaine that may be related to the anandamide (AEA) active the TRPV1 receptor; CB1 and CB2 receptor have no influence on the sensory and motor function of the co-administrated of QX-314-OH and Levobupivacaine.5.15 mM QX-314-OH administrated with 1mM levobupivacaine or QX-314-OH and levobupivacaine administrated with TRPV1 receptor blocker, TRPA1 receptor blocker, HCN channel antagonist and agonist, CB1 and CB2 receptor blocker can produce transient reversible inflammatory cell infiltration but no nerve injury to the sciatic nerve. |
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