An Experimental Study On The Effect Of Mahuang Lianqiao Chixiaodou Decoction On Ca²⁺ In Spinal Dorsal Horn Neurons Of Rat Models With Itch Based On The Synergistic Effect Of 5-HT1a-GRPR

Objective:Itching is one of the health problems that seriously affects the quality of human life.Mahuang Lianqiao Chixiaodou Decoction has been clinically proven to have a clear therapeutic effect on itching,but the existing data cannot fully clarify its mechanism of action.The previous research of the research group showed that Mahuang Lianqiao Chixiaodou Decoction can inhibit mast cell degranulation and improve allergic inflammation.Further research found that Mahuang Lianqiao Chixiaodou Decoction can interfere with type ? allergic reaction through the PAR2-TRPV1 pathway to reduce or even relieve bile Silting itching.Recent studies have found that5-HT is one of the substances that cause cholestatic pruritus.5-HT1 a receptor is a key receptor for activating GRP-related pruritus.It can activate 5-HT1 a and GRPR at the same time,greatly reducing the itchiness.Threshold,and thus itching.The GRP / GRPR signaling pathway is a specific signaling pathway for pruritus.GRPR binds to G protein-coupled receptors,activates PLC,increases intracellular IP3,causes intracellular Ca2+release and extracellular Ca2+influx,and increases intracellular freeness The concentration of Ca2+activates protein kinase C isozymes,causing increased activity of PKC and MAPK,and finally exerts a biological effect.In this project,the effects of Mahuang Lianqiao Chixiaodou Decoction on 5-HT1 a receptor and GRPR,the intracellular calcium concentration of spinal dorsal horn neurons in rats,and the mechanism of antipruritic are discussed to lay the foundation for further research.Method:Taking SD rats as the research object,they were randomly divided into a blank group,a model group,a low,medium and high dose group of Mahuang Lianqiao Chixiaodou Tang.The rat model of itching was established with 5-HT.One day after the model was completed,the rats in the drug intervention group were fed with4.3g·kg-1,8.6g·kg-1,17.2g·kg-1ephedra forsythia chixiaodou soup After 14 days of treatment,the blank group and the model group were treated with equal volume of normal saline.The rats were observed and recorded on the day of modeling,the 7th day of treatment,and the number of scratches on the 14 th day of treatment.After the treatment was completed,the drug-containing serum of spinal dorsal horn ganglion and Mahuang Lianqiao Chixiaodou Decoction were taken,and the expression levels of 5-HT1 a and GRPR at the spinal dorsal horn neurons were detected by immunoblotting and immunohistochemistry;high performance liquid chromatography was used-The mass spectrometry method was used to detect the concentration of ephedrine in the drug-containing serum of the rats in the drug intervention group;the calcium ion imaging method was used to detect the intracellular calcium ion concentration in the spinal dorsal horn ganglion.Result: 1.Mahuang Lianqiao Chixiaodou Decoction can relieve the itching sensation in model rats;compared with the blank group,the scratching behavior of the model group and the drug intervention group is significantly enhanced,there is a significant difference(P <0.01).After 14 days of treatment,compared with the rats in the model group,the scratching behavior of the rats in the drug intervention group was significantly reduced,and there was a significant difference(P <0.05),and the high-dose group was better than the low-dose group in the treatment effect(P <0.05).2.Mahuang Lianqiao Chixiaodou Decoction can inhibit the activation of 5-HT1 a and GRPR;by immunoblotting and immunohistochemistry,it was found that compared with the model group rats,5-HT1 a in spinal dorsal horn neurons of the drug intervention group And the content of GRPR decreased significantly.3.The presence of ephedrine in the drug-containing serum of rats in the drug intervention group.4.Mahuang Lianqiao Chixiaodou Decoction-containing serum can reduce intracellular free calcium ion concentration in spinal dorsal horn neurons;detected by calcium ion imaging technique;compared with model group rats,in drug intervention group rats spinal dorsal horn neurons The calcium ion concentration was significantly reduced(P <0.01).Conclusion:1.Using 5-HT to make itching model is successful;2.After treatment with Mahuang Lianqiao Chixiaodou Decoction,the number of spontaneous scratches in itching model rats was significantly reduced,suggesting that Mahuang Lianqiao Chixiaodou Decoction has a certain anti-itch effect on 5-HT-induced itch,and 5-HT-induced itch may be Related to wind,humidity and heat evil;3.In the 5-HT itching model,Mahuang Lianqiao Chixiaodou Decoction may reduce the intracellular calcium ion concentration by inhibiting the synergistic effect of 5-HT1a-GRPR,thereby achieving the anti-itch effect.