OBJECTIVE To preliminarily investigate the antiasthmatic effect and mechanism of Ephedrae Herba-Armeniacae Semen Amarum herb pair on the respiratory center. METHODS Male SD rats were randomly divided into blank group， model group， dexamethasone group （positive control）， and Ephedrae Herba-Armeniacae Semen Amarum 2∶1， 1∶1 and 1∶2 groups. Rats in each group were administered different ratios of the herb pair decoction [all at 18 g （crude drug）/kg]， dexamethasone suspension （0.5 mg/kg）， or normal saline intragastrically twice daily for seven consecutive days. Forty minutes after the last administration， medicated cerebrospinal fluid was collected to determine the content of effective components entering the brain. One and a half hours after the last administration， the nucleus tractus solitarius （NTS） was located using a stereotaxic apparatus. Histamine phosphate （1 μL） was injected into the NTS region at a constant rate of 1 μL/min using a 10 μL microsyringe to induce excitation of the respiratory center in rats； the blank group was injected with normal saline. The contents of neurotransmitters [nerve growth factor （NGF）， substance P （SP）， norepinephrine （NA）， 5-hydroxytryptamine （5-HT） and acetylcholine （Ach）] in the medulla oblongata brain tissue were detected. The mRNA expressions of neurokinin-1 receptor （NK-1R）， p38 mitogen-activated protein kinase （MAPK）， and c-fos in the medulla oblongata， as well as the protein expressions of NK-1R， p38 MAPK， and c-fos in the NTS region， were determined. RESULTS The main active components of Ephedrae Herba-Armeniacae Semen Amarum herb pair entering the brain were ephedrine， pseudoephedrine， and methylephedrine. Compared with blank group， the contents of NGF， SP， NA， 5-HT and Ach， and the relative expression levels of NK-1R， p38 MAPK， and c-fos mRNA and protein were significantly increased in the model group （ P ＜0.01）. Compared with model group， Ephedrae Herba-Armeniacae Semen Amarum herb pair groups with different ratios significantly reduced the neurotransmitter contents and the relative expression levels of NK-1R， p38 MAPK， and c-fos mRNA and protein （ P ＜0.01）， with the 2∶1 Ephedrae Herba-Armeniacae Semen Amarum herb pair and 1∶1 mass ratios showing relatively better effects. CONCLUSIONS Ephedrae Herba alkaloids are the main active components in affecting the function of the respiratory center. The herb pair groups with a larger proportion of Ephedrae Herba exhibit stronger effects. Ephedrae Herba-Armeniacae Semen Amarum herb pair can reduce the excitability of the respiratory center by down-regulating the expression of the NK-1R/MAPK/c-fos pathway in the NTS and decreasing the abnormal release of neurotransmitters such as NGF and SP.

Objcetive To investigate the protective effects of the nitroxides R-1 on human liver cells exposed to ionizing radiation.Methods Human liver cells L-02 were cultured and irradiated with 60Co γ-rays at the doses of 0,1,2,4,and 8 Gy,in order to screen the proper irradiation dose.WR2721 at the terminal concentration of 4 mmol/L was used as positive control.L-02 cells irradiated with 4 Gy were added with R-1 at the terminal concentration of 0.25 μmol/L at 30 min before irradiation or immediately after irradiation.MIT method was used to screen the proper conditions for follow-up experiment 72 h later.L-02 cell culture fluid was added with R-1 at the concentrations of 0,0.125,0.25,0.5,and 1 μmol/L,respectively for 30 min before irradiation at the doses of 0,1,2,4,and 8 Gy to ealculate clone formation rate at 10 d post-irradiation.L-02 cells were cultured and divided into 4 groups:control group without any treatment.drug group pretreated by 0.25 μmol/L R-1 only,irradiation group,irradiated at 4 Gy only,and drug + irradiation group with combination of 0.25 μmol/L R-01 and 4 Gy irradiation.The inverted microscopy and Hoechst 33258 staining and flow eytometry were used to observe the apoptosis of the cells at 24,48,and 72 h later.Results Nitroxides R-1 did not inhibit the viability of L-02 cell when its concentration was less than 1 μmol/L and it inhibited the L-02 cell growth when the concentration wu higher than 2 μmoL/L.The A value and colony formation rate of different concentration of R-1 groups were all higher than those of the irradiation group,and the effect of the 0.25 μmol/L drug concentration group was the most significant.Consequently,the concentration 0.25 μmoL/L was selected for follow-up experiment.Compared with the irradiation group,the L-02 cells of the pretreatment group showed solid adherence, increased refraction,clear outline,less apoptotic and dead cells at 4 Gy post-irradiation.Conclusions Nitroxides R-1 can protect the human liver cells from 60Coγ-ray induced injury effectively.The mechanism of its protective effect may be the reduction of apoptosis.