Effects of ephedrine on expression of Nogo-A and synaptophysin in neonatal rats following hypoxic-ischemic brain damage

BACKGROUND： Central nervous system axons regenerate poorly following neonatal hypoxic-ischemic brain damage （HIBD）, partly due to inhibitors, such as Nogo-A. Very few studies have addressed the regulation of Nogo-A in neonatal rats following HIBD. However, numerous studies have shown that ephedrine accelerates neuronal remodeling and promotes recovery of neural function in neonatal rats following HIBD. OBJECTIVE： To investigate the effects of ephedrine on expression of Nogo-A and synaptophysin in brain tissues of neonatal rats following HIBD. DESIGN, TIME AND SETTING： A completely randomized, controlled study was performed at the Immunohistochemistry Laboratory of the Research Institute of Pediatrics, Children＇s Hospital of Chongqing Medical University from August 2008 to March 2009. MATERIALS： Ephedrine hydrochloride （Chifeng Pharmaceutical Group, China）, rabbit anti-Nogo-A polyclonal antibody （Abcam, UK）, and rabbit anti-synaptophysin polyclonal antibody （Lab Vision, USA） were used in this study. METHODS： A total of 96 healthy, neonatal, Sprague Dawley rats were randomly assigned to three groups （n = 32）： sham operation, HIBD, and ephedrine. The HIBD model was established by permanent occlusion of the left common carotid artery, followed by 2 hours of hypoxia （8% oxygen and 92% nitrogen）. In the sham operation group, the left common carotid artery was exposed, but was not ligated or subjected to hypoxia. Rats in the ephedrine group were intraperitoneally injected with ephedrine immediately following HIBD, with 1.5 mg/kg each time. Rats in the sham operation and HIBD groups were injected with an equal volume of saline. All neonatal rats were treated once daily for 7 days. MAIN OUTCOME MEASURES： Histopathological damage to the cortex and hippocampus was determined by hematoxylin-eosin staining. Expression of Nogo-A and synaptophysin was detected using immunohistochemical staining. RESULTS： Neuronal degeneration and edema were observed in the hypoxJc-Jschemic cortex and hippocampus by hematoxylin-eosin staining. Compared with the sham operation group, the levels of Nogo-A significantly increased in the HIBD group at various time points （P 〈 0.01）. Nogo-A expression was significantly reduced in the ephedrine group compared with the HIBD group （P 〈 0.01）. Synaptophysin expression was significantly decreased in the hypoxic-ischemJc cortex, compared with the sham operation group （P 〈 0.01）. Synaptophysin levels were significantly increased in the ephedrine group, compared with the HIBD group （P 〈 0.01）. CONCLUSION： Altered Nogo-A expression was associated with inversely altered synaptophysin expression. The use of ephedrine normalized expression levels of Nogo-A and synaptophysin following HIBD.

Surface Confined Ionic Liquid——A New Stationary Phase for the Separation of Ephedrines in High-performance Liquid Chromatography

In this article, a new and effective stationary phase based on ionic liquid modified silica is first reported and used for the separation of ephedrines in high-performance liquid chromatography (HPLC). The separation results indicate the high efficiency and reproducibility of the stationary phase. The electrostatic interaction, ion-exchange interaction between the solutes and the stationary phase are considered to attribute the effective separation. Moreover, the free silanols on the surface of the silica are effectively masked by the immobilized ionic liquid, a result of which is to decrease the non-specific absorption.

Crystal Structure and Thermodynamic Study of Ephedrine Hydrochloride C_(10)H_(16)NOCl(s)

The crystal structure of ephedrine hydrochloride was determined by means of X-ray crystallography. The crystal system of the compound is monoclinic, and the space group is P21. Unit cell parameters are a=0.7308（6） nm, b=0.6124（5） nm, and c= 1.2618（11） nm; β=90°, β= 102°, and γ =90°; Z=2. Low-temperature heat capacities of the title compound were measured with an improved precision automated adiabatic calorimeter over a temperature range from 77 K to 396 K. A polynomial equation of the heat capacities as a function of temperature in the temperature region was fitted by the least-squares. Based on the fitted polynomial equation, the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at the intervals of 5 K.

Optimal compatible doses and effects of ephedrine and naloxone on neural plasticity in cerebral ischemia/reperfusion rats

BACKGROUND： Ephedrine promotes neural plasticity in rats following cerebral ischemia/reperfusion injury. Ephedrine has been combined with naloxone in some studies, and it has been confirmed that their combination has synergistic effects on increasing neural plasticity following cerebral ischemia/reperfusion injury. OBJECTIVE： To investigate the effects of ephedrine combined with various doses of naloxone on neural plasticity and to find an optimal dose of naloxone in rats after cerebral ischemia/reperfusion injury by analyzing growth associated protein-43 （GAP-43）, synaptophysin and β-endorphin expression in the hippocampal CA3 area. DESIGN, TIME AND SETTING： This immunohistochemical, randomized, controlled, animal experiment was performed at the Chongqing Research Institute of Pediatrics, China from September 2007 to June 2008. MATERIALS： Ephedrine hydrochloride injection and naloxone hydrochloride injection were respectively purchased from Shandong Lvliang Pharmaceutical Factory, China and Sichuan Jingwei Pharmaceutical Co., Ltd., China. A total of 192 healthy adult Sprague Dawley rats were used to establish models of left middle cerebral artery occlusion using the suture occlusion method. METHODS： At 2 hours following cerebral ischemia, the rats were intraperitoneally injected with 1.5 mg/kg/d ephedrine （ephedrine group）, with 0.1, 0.2, or 0.3 mg/kg/d naloxone （low, moderate and high doses of naloxone groups）, with 1.5 mg/kg/d ephedrine ＋ 0.1, 0.2, or 0.3 mg/kg/d naloxone （ephedrine ＋ low, moderate and high doses of naloxone groups）, and with 0.5 mL saline （model group）, respectively. MAIN OUTCOME MEASURES： GAP-43, synaptophysin and β -endorphin expression were detected in the hippocampal CA3 area using immunohistochemistry 1-4 weeks after surgery. Sensorimotor integration in rats was assessed using the beam walking test. RESULTS： GAP-43 and synaptophysin expression was greater in the ephedrine group, and in the ephedrine ＋ moderate and high doses of naloxone groups compared with the model group. GAP-43 and synaptophysin expression was greatest in the ephedrine ＋ high dose of naloxone group at 2 and 3 weeks alter surgery. β -endorphin expression was significantly lower in the ephedrine group, and in the ephedrine ＋ moderate and high doses of naloxone groups compared with the model group （P 〈 0.05）. β -endorphin expression was persistently low in the ephedrine ＋ high dose of naloxone group. At 1-3 weeks after surgery, the beam walking test score was significantly higher in the ephedrine group and ephedrine ＋ various doses of naloxone groups than in the model group （P 〈 0.05）. The score was higher in the ephedrine ＋ moderate and high doses of naloxone groups than in the ephedrine group （P 〈 0.05）. Moreover, the score was increased as the dose of naloxone increased in the ephedrine ＋ various doses of naloxone groups. CONCLUSION： Ephedrine promotes GAP-43 and synaptophysin expression, inhibits /3 -endorphin expression in the hippocampal CA3 area, and improves motor function in rats following cerebral ischemia/reperfusion injury. Naloxone does not have the above-mentioned effects. During combined treatment with ephedrine and naloxone, however, the above-described effects are enhanced with an increased dose of naloxone. The combination of ephedrine （1.5 mg/kg/d） and naloxone （0.3 mg/kg/d） can produce optimal therapeutic efficacy in treatment of cerebral ischemic injury.

Separation of Ephedrines Using 1-Butyl-3-methylimidazolium-tetrafluoroborate Ionic Liquids as Eluent in High-performance Liquid Chromatography (HPLC)

A simple, effective HPLC method for separation of ephedrines was achieved by using 1-butyl-3-methylimidazolium-tetrafluoroborate ionic liquid solution (0.1% v/v) as eluent at pH 3.0. The involved mechanism may be due to that the imidazolium cations can effectively shield the silanol groups of alkylsilica surface, thereby decreasing band tailing and increasing the separation efficiency.

Comparison the effect of ephedrine and phenylephrine in treatment of hypotension after spinal anesthesia during cesarean section

Background and Objective: The effectiveness of ephedrine and/or phenylephrine, in treatment of hypotension secondary to spinal anesthesia for cesarean section and their effects on fetal/neonatal outcome were studied. Methods and Materials: Sixty healthy parturients were randomly assigned to two groups;group E (n = 33) received boluses 5 mg/ml increments ephedrine and group P (n = 27) received a boluses of phnylephrine 100 μg/ml increments for treatment of hypotension after spinal block during cesarean section. Changes in maternal blood pressure and heart rate, and incidence of nausea-vomiting, neonatal Apgar score at 1 and 5 minutes of delivery, and umbilical arterial blood gas values were recorded. Results: There were no differences in treatment of hypotension following sympathectomy after spinal block with two drugs. Neonatal outcome was similar in two groups. There were not significant differences in umbilical arterial values in two groups. Conclusion: Ephedrine and phenylephrine are both effective vasopressores for treatment of hypotension associated to spinal block during cesarean section without adverse effects on infants/neonates.

Volume Preload versus Ephedrine Infusion for Prevention of Hypotension Due to Spinal Anesthesia for Cesarean Section

Background: Spinal anesthesia is used for 95% of planned cesarean sections in the United States. It provides a fast and profound sensory and motor block. However, hypotension is a very common complication of spinal anesthesia during cesarean section, causing significant morbidity and mortality. It could be associated with severe nausea, vomiting and even unconsciousness and pulmonary aspiration in the mother and for the baby, hypoxia, acidosis, and neurological injuries may result. Methodology: Fifty patients were randomly allocated into two groups. Group I (F group) patients received preloading with 15 ml/kg Ringer lactate before induction of spinal anesthesia, and group II (E group) patients received IV ephedrine (5 mg in 1st minute after spinal anesthesia and 5 mg in the 2nd minute and 1 mg every minute after that for 15 minutes). Results: A statistically significant difference in the incidence of hypotension between group F (48%) and group E (24%) was seen, (p-value 0.03). Regarding side effects, the incidence of nausea and vomiting was higher in the group F (20%) when compared to group E (12%), (p-value 0.23). Conclusions: We concluded that IV infusion of ephedrine after induction of spinal anesthesia was more effective than crystalloid preloading in a prevention of hypotension in parturient undergoing cesarean section and did so without causing significant tachycardia.

Side effects of different doses of ephedrine in rats with cerebral ischemia/reperfusion injury

Ephedrine has a protective effect against cerebral ischemia,but its side effects limit its clinical application.Results from a previous study showed that 1.5 mg/kg per day ephedrine can promote motion recovery in rats following cerebral ischemia/reperfusion without significant side effects.In the present study,ephedrine at doses of 3.0,2.5 and 2.0 mg/kg was used to treat rats with cerebral ischemia/reperfusion and the effects of ephedrine on the heart,liver,kidney and cerebrum were observed.Results showed that the blood pressure of rats with cerebral ischemia/reperfusion injury following ephedrine treatment was lower than in rats that recovered naturally from cerebral ischemia/reperfusion,but the pressure decreased with increasing doses of ephedrine.In addition,serum aspartate transaminase,alkaline phosphatase and creatinine concentration in rats with cerebral ischemia/reperfusion injury following ephedrine treatment were greater than in rats that recovered naturally from cerebral ischemia/reperfusion.The concentrations of these enzymes were decreased with increasing doses of ephedrine.Ephedrine-treated rats displayed hyperemia,degeneration and edema in the cerebrum,liver,heart and kidney.Results demonstrated that ephedrine exhibited side effects on the cerebrum,heart,liver and kidney in rats following cerebral ischemia/reperfusion in a dose-dependent manner.

SIMULTANEOUS DETERMINATION OF EPHEDRINE AND ITS ANALOGUES IN URINE BY CAPILLARY GAS CHROMATOGRAPHY

A method is developed for the simultaneous determination of ephedrine,pseudoephedrine, norephedrine, norpseudoephedrine and methylephedrine in urine on a capillary column using nitrogen-phosphorus detector.Diphenylamine is used as the internal standard.Calibration graphs are linear down to 1.30ug/ml urine.

Effect of ephedrine hydrochloride on regulation of body fluid metabolism and AQP1 and AQP2 in a rabbit model of mechanical ventilation

Objective:Ephedrine hydrochloride(EH)is a major component from Ephedra sinica STAPF,which is used as a traditional Chinese herbal medicine.This study was designed to investigate the effect of EH on water metabolism and further explore the relevant signaling pathway of body fluid regulation in“lung governing regulation of water passage”using a rabbit model of mechanical ventilation.The molecular mechanism of the EH effect in the kidney was also investigated.Methods:Rabbits were randomly divided into a control group,model group,EH group,and dexmedetomidine hydrochloride(DH)group.Urine volume was measured by the intubation method and pathologic changes in lung and renal tissue were measured by hematoxylin and eosin staining.Nitric oxide(NO)production in lung,serum,and kidney were analyzed using chemical methods.An ELISA was used to analyze angiotensin II(Ang II),antidiuretic hormone(ADH),prostaglandin E2(PGE2),atrial natriuretic peptide(ANP),and endothelin-1(ET-1)levels in the lung,serum,and kidney.Aquaporin-1(AQP1)and aquaporin-2(AQP2)mRNA and protein expression in the kidney was determined using qRT-PCR and immunohistochemistry.Results:EH significantly inhibited the decrease in the total urine volume in the third and fourth stages,and displayed significant regulatory effects on NO,Ang II,ADH,PGE2,ANP,and ET-1 in serum,lung,and renal tissues compared with the model group.In the kidney,AQP1 and AQP2 mRNA and protein expression in the EH group were remarkably downregulated compared with the model group.Conclusion:EH exerted a regulatory effect on water metabolism by diffusing the lung and increased urine volume in the rabbit model,which was consistent with the decrease in kidney AQP1 and AQP2 expression levels that led to an increase in urine volume.EH could assist with DH to exert a protective effect on the clinical application of mechanical ventilation.

THE STUDIES ON THE SEPARATION AND IDENTIFICATION OF EPHEDRINES IN URINE BY GC/MSD

The separation and identification of the ephedrines(cathine,norephe-drine,ephedrine,pseudoephedrine,methylephedrine and ethylephedrine)and their derivatives obtained from TFAA,MSTFA,MSTFA+MBTFA and MSTFA+Ethyl acetate deriva- tization were carried out by GC/MSD.

A Comparative Study of Uses of Ephedrine by Different Doses on Prevention of Hemodynamic Changes Accompanied with Induction of General Anesthesia through Propofol and Fentanyl without Adverse Effects

Background: Propofol and fentanyl combination are common with general anesthesia. However, hypotension and bradycardia are common during induction of anesthetic. This study aimed to compare the response of different doses of ephedrine for attenuation of the hemodynamic changes after anesthetic induction without adverse effects. Materials and Methods: This was a randomized, double-blinded, case-controlled clinical trial. One hundred and twenty adult patients were allocated into one of the four groups: receiving IV saline, ephedrine 0.05 mg/kg, 0.1 mg/kg, or 0.2 mg/kg respectively. Induction of anesthesia was done with propofol 3 mg/kg and fentanyl 1 mg/kg. Alterations in systolic and diastolic blood pressures (SBP, DBP), mean arterial pressure (MAP), and heart rate (HR) were calculated every 1 min after induction, and 2, 3, 4 and 5 min. Then, intubation was made. Results: Baseline hemodynamic variables were comparable between groups. Patients received 0.1 mg/kg, and 0.2 mg/kg had less drop in blood pressure both systolic and diastolic, MAP, and HR with no significant rise in side effects. The numbers of patients with hypotension were significantly lower in the group receiving ephedrine 0.2 mg/kg compared to other groups (P-value 0.05). Use of IV ephedrine at a dose of 0.1 mg/kg was shown to be useful for reduction of hemodynamic changes but did not eliminate the risk of blood pressure drop. Ephedrine 0.2 mg/kg was better without causing any adverse effects. We can conclude that ephedrine 0.1 mg/kg was suitable for minimizing or decreasing changes in hemodynamic at propofol-fentanyl induction but ephedrine 0.2 mg/kg was better without causing more adverse effects.

Effects of ephedrine, phenylephrine and norepinephrine prevent hypotension after spinal anesthesia in cesarean section and comparison of effects on newborns

Objective: To compare the preventive effect of ephedrine, phenylephrine and norepinephrine on hypotension after lumbar anesthesia in cesarean section and their effects on newborns. Methods: 25 cesarean section women in our hospital from December 2016 to January 2018 were selected and divided into three groups according to different surgical medication, namely, ephedrine group (n=40), phenylephrine group (n=45) and norepinephrine group (n=40). Then the vital signs, neonatal blood gas analysis, neonatal Apgar score, adverse reactions of the three groups were compared. Results: The HR at T0~T3, and SBP and DBP at T0 and T1 had no difference among three groups (P>0.05). The HR, SBP and DBP at T3 ranking in a descending order was norepinephrine group, ephedrine group and phenylephrine group (P<0.05). The PCO2 and PO2 had no difference among three groups (P>0.05). The pH ranking in a descending order was norepinephrine group, ephedrine group and phenylephrine group (P<0.05). The SpO2 ranking in a descending order was phenylephrine group, ephedrine group and norepinephrine group (P<0.05). The Apgar score at birth in ephedrine group and norepinephrine group was significantly lower than that in phenylephrine group (P<0.05), while the Apgar score at post-birth 5 min and 10 min had no difference among three groups (P>0.05). The incidence of hypertension, gastrointestinal reaction, hyperhidrosis and palpitation in the phenylephrine group was significantly lower than that in the norepinephrine group (P<0.05). Conclusion: The phenylephrine and norepinephrine have no difference on the preventive effect of hypotension after spinal anesthesia in cesarean section, while safety of norepinephrine for puerpera and neonates is higher.

Management of Arterial Hypotension Induced by Spinal Anesthesia during Cesarean Section at the Parakou University Hospital in Benin in 2020: Ephedrine versus Noradrenaline

Background: Spinal anesthesia (SA) is a preferred anesthetic technique for childbirth through caesarean section. It causes a sympathetic block responsible for low blood pressure which can be prevented or treated with vasopressors. Aim: This research aims to compare the effect of Noradrenaline with that of Ephedrine in the management of arterial hypotension caused by SA during Caesarean act. Study method: It was a cross-sectional study with two comparative settings which took place at the Teaching hospital of Parakou from April 15th to August 15th 2020. It included all parturients who underwent a caesarian act and received spinal anesthesia. To prevent hypotension two groups were formed. The first group parturient received Noradrenaline (10 γ) as prophylactic and the second group received Ephedrine (10 mg) before anesthesia. The main evaluation criteria were the time before the hypotension occurs and, the secondary endpoint was the number of hypotension episode. The two groups were compared using the usual statistical tests. The study received the approval of the Local Ethical committee of University of Parakou. Results: Two hundred and four parturients were compiled with 102 in each group. The mean age was 28.37 ± 6.15 years with extremes of 16 and 45 years. The main indications for Caesarean section were respectively iterative Caesarean section (46.57%) for scheduled Caesarean section and acute fetal distress (15.69%) for emergency Caesarean section. The incidence of hypotension was 38.24%. The mean delay of occurrence of hypotension was significantly longer in adrenaline group (19.90 min) than ephedrine group (12.53 min) with P = 0.001. According to the secondary endpoint the number of episodes of hypotension, number of tachycardia, and the total doses of each vasopressor were significantly lower in adrenaline group than in the ephedrine group. Conclusion: The use of Noradrenaline according to the established protocol demonstrated its efficiency compared with Ephedrine in the management of hypotension after spinal anesthesia.

Exposure to ephedrine attenuates Th1/Th2 imbalance underlying OVA-induced asthma through airway epithelial cell-derived exo-somal lnc-TRPM2-AS

Although various anti-inflammatory medications,such as ephedrine,are employed to manage cough-variant asthma,their underlying mechanisms are yet to be fully understood.Recent studies suggest that exosomes derived from airway epithelial cells(AECs)contain components like messenger RNAs(mRNAs),micro-RNAs(miRNAs),and long noncoding RNA(lncRNA),which play roles in the occurrence and progression of airway inflammation.This study investigates the influence of AEC-derived exosomes on the efficacy of ephedrine in treating cough-variant asthma.We established a mouse model of asthma and measured airway resist-ance and serum inflammatory cell levels.Real-time polymerase chain reaction(RT-qPCR),Western blotting,and enzyme-linked im-munosorbent assay(ELISA)analyses were used to assess gene and protein expression levels.Exosomes were isolated and character-ized.RNA immunoprecipitation(RIP)and RNA pull-down assays were conducted to examine the interaction between hnRNPA2B1 and lnc-TRPM2-AS1.In the ovalbumin(OVA)-challenged mouse model,ephedrine treatment reduced inflammatory responses,air-way resistance,and Th1/Th2 cell imbalance.Exosomes from OVA-treated AECs showed elevated levels of lnc-TRPM2-AS1,which were diminished following ephedrine treatment.The exosomal lnc-TRPM2-AS1 mediated the Th1/Th2 imbalance in CD4^(+)T cells,with its packaging into exosomes being facilitated by hnRNPA2B1.This study unveils a novel mechanism by which ephedrine ameli-orates OVA-induced CD4^(+)T cell imbalance by suppressing AEC-derived exosomal lnc-TRPM2-AS1.These findings could provide a theoretical framework for using ephedrine in asthma treatment.

Ephedrine hydrochloride inhibits PGN-induced inflammatory responses by promoting IL-10 production and decreasing proinflammatory cytokine secretion via the PI3K/Akt/GSK3β pathway

Approaches for controlling inflammatory responses and reducing the mortality rate of septic patients remain clinically ineffective; new drugs need to be identified that can induce anti-inflammatory responses. Ephedrine hydrochloride （EH） is a compound that is widely used in cardiovascular diseases, especially to treat hypotension caused by either anesthesia or overdose of antihypertensive drugs. In this study, we reported that EH also plays an important role in the control of the inflammatory response. EH increased IL-IO and decreased proinflammatory cytokine （IL-6, tumor-necrosis factor （TNF）-a, IL-12 and IL-11~） expression in primary peritoneal macrophages and Raw264.7 cells treated with peptidoglycan （PGN）, a Gram-positive cell wall component. The anti-inflammatory role of EH was also demonstrated in an experimental mouse model of peritonitis induced by intraperitoneal PGN injection. The phosphatidylinositol 3-kinase （PI3K）/Akt pathway was found to be responsible for the EH-mediated increase in IL-IO production and decrease in IL-6 expression. Therefore, our results illustrated that EH can help maintain immune equilibrium and diminish host damage by balancing the production of pro- and anti-inflammatory cytokines after PGN challenge. EH may be a new potential anti-inflammatory drug that can be useful for treating severe invasive Gram-positive bacterial infection.

芳酸偶氮吡唑啉酮及其麻黄碱盐的合成

近期报道了吡唑啉酮衍生物与稀土金属的络合作用。关于4-芳基偶氮吡唑啉酮与过渡金属络合的作用已有报道,但与稀土金属络合的文献不多。根据英国药典,麻黄碱与铜离子络合呈色而作为其鉴定方法,本文制备了麻黄碱类与芳酸偶氮吡唑啉酮形成的盐,以备研究它们的络合作用。在合成的5种吡唑啉酮衍生物中。

Studies of Active Ingredients in Cough Syrup by Capillary Zone Electrophoresis with Amperometric Detection

The present paper covers a simple, reliable and reproducible method, based on capillary zone electrophoresis(CZE) with amperometric detection(AD), for the separation and the determination of ephedrine hydrochloride, promethazine hydrochloride and codeine phosphate. Under the optimal conditions, the three analytes were base-line separated completely within 16 min. Good linear relationships between the peak heights and the concentrations of the three analytes were obtained with the correlation coefficients better than 0 9993. The method was directly applied to the determination of the active ingredients in pharmaceutical preparations and the assay results were satisfactory.

运动后鼻腔检查在招飞体检中的应用

招收飞行学员医学选拔中鼻科检查要求必须看清楚鼻腔结构,以明确在飞行环境中鼻腔结构是否影响鼻腔、鼻窦及咽鼓管的功能,做出受检对象是否适合飞行的结论.招飞体检中受时间的限制,需要短时间内做出结论,而自然状态下用前鼻镜检查方法多不能完全看清楚鼻腔完整结构,传统方法使用麻黄素收缩鼻腔黏膜进行检查.而麻黄素应用也存在一系列问题[1].

Comparison of two vasopressor protocols for preventing hypotension post-spinal anesthesia during cesarean section: a randomized controlled trial

Background:Norepinephrine infusion decreases hypotension after spinal anesthesia during cesarean section.This study aimed to compare the efficacy of norepinephrine infusion and ephedrine bolus against post-spinal hypotension in parturients.Methods:In this double-blinded,randomized controlled clinical trial,parturients scheduled for elective cesarean section were randomly allocated to receive norepinephrine infusion(0.05μg·kg^(-1)·min^(-1))just before spinal anesthesia continuing for 30 min or ephedrine bolus(0.15 mg/kg)just before spinal anesthesia.A rescue bolus(5μg norepinephrine for the norepinephrine group,and 5 mg ephedrine for the ephedrine group)was administered whenever hypotension occurred.Our primary outcome was the incidence of hypotension within 30 min of spinal anesthesia administration.Secondary outcomes included maternal and neonatal outcomes 30 min after spinal block,and neonatal cerebral oxygenation 10 min after birth.Results:In total,190 patients were enrolled;of these patients,177 were included in the final analysis.Fewer patients suffered hypotension in the norepinephrine group than in the ephedrine group(29.5%vs.44.9%,odds ratio[OR]:0.51,95%confidence interval[CI]:0.28-0.95,P=0.034).Moreover,the tachycardia frequency was lower in the norepinephrine group than in the ephedrine group(OR:0.22,95%CI:0.11-0.44,P<0.001),and patients suffered less nausea and vomiting(OR:0.28,95%CI:0.11-0.70,P=0.004).There was no difference in Apgar scores and umbilical arterial blood gas analysis between the two groups.However,neonatal cerebral regional saturations were significantly higher after birth in the norepinephrine group than in the ephedrine group(mean difference:2.0%,95%CI:0.55%-3.45%,P=0.008).Conclusion:In patients undergoing elective cesarean section with spinal anesthesia,norepinephrine infusion compared to ephedrine bolus resulted in less hypotension and tachycardia,and exhibited potential neonatal benefits.