Sevoflurane And Isoflurane Regulate Vascular Smooth Muscle Contraction By PI3K-C2?/Rho Kinase

Introduction:Vascular tension is regulated by both internal and external mechanisms.Inhalation anesthetics can directly affect vascular smooth muscle and endothelial cells in various vascular beds,affect vascular resistance,and lead to changes in organ blood flow.In vascular smooth muscle cell(VSMC),K+channel plays an important role in maintaining vascular tension.Activation of K+ channels can mediate vasodilation induced by various endogenous mediators and metabolic activity changes.The mechanism of KCl-stimulated vascular smooth muscle(VSM)contraction may involve Ca2+-dependent and Ca2+sensitization pathways.Membrane depolarization by KCl increases Ca2+influx via voltage-dependent Ca2+channel receptors on VSMCs,leading to an increase in cytosolic free Ca2+([Ca2+]i).This increase in[Ca2+]i activates Ca2+-calmodulin-dependent myosin light chain kinase(MLCK),resulting in myosin light chain(MLC)phosphorylation and vascular contraction.In addition to the Ca2+-dependent pathway,the Ca2+-induced Ca2+sensitization pathway may also regulate myosin light chain phosphatase(MLCP)through modulation of Class II phosphoinositide 3-kinase ? subunit(PI3K-C2?)and Rho kinase activity,which results in vascular contraction.Phosphoinositide 3-kinases(PI3Ks)are a ubiquitously expressed enzyme family that phosphorylates membrane inositol lipids and exert diverse biological activities.There are eight PI3K subtypes in mammals.According to their structure,distribution,activation mechanism and function,PI3K can be divided into three types:?,? and ?.Class ? PI3K can be further divided into class IA and class IB according to different types of coupling receptors and regulatory activators.PI3Ks are involved in glucose transport,insulin secretion,cell migration,platelet activation and endothelial cell remodeling in vivo.Class ? PI3K is divided into PI3K-C2?,PI3K-C2?,and PI3K-C2?,each of which contains a C2 domain.Studies have shown that PI3K-C2?and PI3K-C2P participate in Rho activation and Rho kinase dependent MLCP inhibition,and enhance MLC phosphorylation and vascular smooth muscle contraction in VSM.Class ? exists in yeast and is composed of Vps34 protein(phosphoinositide 3-kinase vacuolating protein classification 34),which regulates autophagy mainly by producing phosphatidylinositol 3-phosphate.VSM is known to express multiple PI3Ks,including the class ? enzymes p110? and p110?,and Class ?PI3K-C2? and C2?.PI3Ks have been proved to be closely related to diabetes mellitus(DM)and its complications,and they are the key molecules of glucose homeostasis.The importance of PI3Ks in diabetic patients is not only limited to the regulation of glucose metabolism,but also closely related to the target organ damage caused by DM,such as blood vessels,heart and brain.Studies have confirmed that DM can reduce the activity of PI3K in the central nervous system.Up regulation of PI3K Signal in the brain can reverse the pathological consequences of DM,while PI3K inhibitor can restore the damage related to DM.Rho kinases(Rock)play an important role in VSMC contraction.Activation of Rho/Rock in vivo can change the sensitivity of Ca2+,phosphorylate myosin phosphatase target subunit 1(MYPT1),and inhibit MLCP induced vasoconstriction.In vivo,Angiotensin ?(Ang ?),thrombin and hyperglycemia in endothelial cells or smooth muscle cells can trigger the activation of Rock.Recent studies have shown that the activity of Rock in circulating leukocytes of DM patients is significantly increased.Inhibition of Rock activity may play an additional role in the prevention and treatment of DM.PI3K/Akt signaling pathway widely exists in cells.Akt is the downstream effector molecule of PI3K,which can activate and regulate many kinase targets,and plays an important role in maintaining cell survival and inhibiting apoptosis.PI3K/Akt pathway is a key regulator of vascular tension under physiological and pathophysiological conditions.It participates in the typical functions of endothelial cells,such as regulating vascular smooth muscle tension and angiogenesis.Previous studies have shown that sevoflurane(SEVO)and isoflurane(ISO)can provide protection against ischemia-reperfusion injury through PI3K/Akt pathway.It has been confirmed that the main vasoconstrictors of PI3K/Akt are Ang ? and endothelin-1(ET-1).PI3K/Akt pathway leads to vasoconstriction through the regulation of L-type Ca2+channel and the activation of Rho kinase and phosphodiesterase 5(PDE5).Studies have shown that inhibition of PI3K signaling pathway is a potential anti hypertension and vascular protection therapy.Currently,SEVO and ISO are commonly used volatile anesthetics,which usually produce concentration dependent myocardial suppression and vasodilation,resulting in hypotension.This is mainly caused by the decrease of cardiac output and systemic vascular resistance(SVR)by Ca2+influx and sarcoplasmic reticulum Ca2+concentration changes.But high concentrations of inhaled anesthetics can also lead to some complications,such as increased blood pressure.The possible mechanisms include the direct effect of intracellular signal transduction on VSM,but the exact mechanism is still unclear.We previously demonstrated that SEVO inhibited GTP? S-stimulated Rho-Rho kinase-mediated vasoconstriction in isolated rat aortic VSM.We also revealed that SEVO attenuated Angiotensin ?(Ang ?)-induced vasoconstriction by reducing PKC phosphorylation without affecting[Ca2+]i in VSM.We recently demonstrated that SEVO inhibited MLC,the PKC potentiated inhibitory protein CPI-17,and myosin phosphatase target subunit 1/Thr853(MYPT1/Thr853)phosphorylation in response to Ang ?.ISO also inhibited MLC phosphorylation in response to Ang ?,which was associated with a decrease in MYPT1/Thr853,but not in CPI-17 phosphorylation.Neither SEVO nor ISO affected Ang ?-induced phosphorylation of MYPT1/Thr696.Studies have shown that SEVO at clinical concentration can significantly inhibit the response of non-diabetic rats to norepinephrine(NE),but has no effect on DM rats.Clinical studies have confirmed that the foot skin temperature of non-diabetic patients induced by isoflurane or sevoflurane anesthesia is higher than that of diabetic patients,suggesting that the thermoregulation controlled by sympathetic nervous system is impaired in diabetic patients.These findings suggest a change in the responsiveness of diabetic vessels to volatile anesthetics.The difference of vascular reactivity to volatile anesthetics in diabetes mellitus and its mechanism have not been determined,especially in the elderly with severe vascular disease.At present,little is known about the effect of SEVO and ISO on Ca2+induced Ca2+sensitization in regulating VSM contraction.This study is divided into three parts.In the first part,we studied the effects of inhaled anesthetics on the contraction of aortic smooth muscle in normal rats by regulating the activities of PI3K subunit and Rho kinase.In the second part,we studied the effects of inhaled anesthetics on the contraction of aortic smooth muscle in diabetic rats,and the specific effects of age and DM on the vasodilation of inhaled anesthetics.The aorta is an elastic reservoir vessel.and the resistance vessel is the main determinant of peripheral vascular resistance Therefore,in the third part,the greater omental artery in patients with gastric cancer was selected to investigate the effect of inhaled anesthetics on the contraction of greater omental artery vascular smooth muscle by regulating the activity of PI3K subunit and Rho kinase.This study will provide more theoretical basis for clinical rational use of inhalation anesthetics,and help to improve the prognosis of patients.Part One:Sevoflurane and isoflurane regulate rat aortic smooth muscle contraction by PI3K-C2?/Rho kinaseObjective:Class ? phosphoinositide 3-kinase ?-isoform(PI3K-C2?)is involved in regulating KCl-induced vascular smooth muscle contraction.The current study was to investigate the effects of sevoflurane(SEVO)and isoflurane(ISO)on KCl-elicited PI3K-C2? mediated vasoconstriction in rat aortic smooth muscle.Methods:1.Vascular smooth muscle tissue preparation.Male Wistar rats(250-350 g)were anesthetized with halothane and euthanasia was performed by bleeding from the common carotid artery.Dissect the descending aorta carefully,remove the attached fat and connective tissue,and cut into 3-4 mm long arterial rings.Use stainless steel needle to gently rub the inner surface to remove the endothelial cells.The arterial ring is vertically installed between two hooks,and the upper hook is connected to the lever of the isometric force sensor.2.Isometric force measurement.KCl(60 mM)was used to culture the aortic rings and observe their overall contractile reactivity.To examine the effect of anesthetics on KCl-induced contraction,six aortic rings from each individual rat(n=7)were randomly exposed to 0,1,2,and 3 minimum alveolar concentration(MAC)of each anesthetic,1 mM LY294002(PI3K inhibitor),or 1 ?M Y27632(Rho kinase inhibitor)for 15 min before the addition of KCl.The KCl induced tension was measured using the isometric contraction force method,and Isometric force development in response to KCl was expressed as a percentage relative to that induced by KCl.The isometric changes of SEVO,ISO,LY294002 and Y27632 on KCl Induced Contraction of rat descending aortic smooth muscle were expressed as a percentage of the maximum isometric force relative to KCl induced contraction,and the effects of the studied compounds on the same arterial ring were evaluated.3.Phosphorylation of MYPT1,CPI-17,and MLC.An endothelial strip(about 3.5cm long)was taken from the descending aorta of each rat.For measurement of MYPT1,CPI-17,and MLC phos-phorylation,the endothelium-denuded strips(approximately 3.5 cm)were bathed in oxygenated KBS and were equilibrated for 60 min before the start of the experiment.Aortic strips from different animals were incubated with 0(control),60 mM KCl,1 MAC SEVO,2 MAC SEVO,1 mM LY294002,and 1 ?M Y27632,or 0(control),60 mM KCl,1 MAC ISO or 2 MAC ISO,1 mM LY294002,and 1 ?M Y27632 for 15 min without KCl or 5 min in the presence of KCl.MYPT1/Thr853,MYPT1/Thr696,CPI-17/Thr38 and MLC phosphorylation were determined by Western blotting after quickly frozen with liquid nitrogen.Western blotting analysis was used to determine the phosphorylation degree of MYPT1,CPI-17 and MLC.After treatment with kinase antibody,the density of immunoreactive band was detected by chemiluminescence and were assessed with image analysis software.The ratios of phosphorylated to total CPI-17,MLC,and MYPT1 were used as an indicator of activation of each enzyme and expressed as the percentage relative to the baseline control level(referred to as 100%).4.Membrane translocation of PI3K and Rho kinase(Rock ?).To measure the dose effect of SEVO,ISO,and kinase inhibition on KCl-stimulated membrane translocation of PI3K or Rock ?,some aortas were treated with either 1.7%SEVO,3.5%SEVO,1.2%ISO,2.3%ISO,1 mM LY294002,or 1 ?M Y27632 for 15 min before exposure to KCl,and then treatment with KCl for 5 minutes.The activity of PI3K and Rho kinase(Rock ?)was measured by Western blotting.The density of the immunoreactive band was detected by chemiluminescence method after the treatment with kinase antibody,and evaluated by image analysis software.The contents of PI3K-p85?,PI3K-C2? and Rock ? are expressed as a percentage of the total value(i.e.,membrane fraction plus cytosolic fraction).Results:1.Vascular smooth muscle tissue preparation.KCl induced rapid contraction and reached a maximum level approximately 5 min after,which was sustained for more than 30 min in rat aortic rings.SEVO and ISO attenuated KCl-induced contraction in a concentration-dependent manner,and the contraction was also suppressed by LY294002(1 mM)and Y27632(1 ?M).There was no statistical difference between SEVO and ISO when comparing equipotent concentrations.2.Phosphorylation of MYPT1,CPI-17,and MLC.Determination of phosphorylation degree of MYPT1,CPI-17 and MLC.Consistent with the change in isometric force measurements,the phosphorylation of MLC induced by KCl increased rapidly and reached the maximum level after 5 min of KCl exposure.SEVO and ISO also inhibited MLC phosphorylation in a concentration-dependent manner in response to KCl,and the contraction was also suppressed by LY294002(1 mM)and Y27632(1?M).Both SEVO and ISO inhibited the phosphorylation MYPT1/Thr853 in response to KCl in a concentration-dependent manner.Neither SEVO nor ISO affected the increase in the phosphorylation of MYPT1/Thr696 and CPI-17/Thr38 in response to KCl.3.Membrane translocation of PI3K and Rho kinase(Rock ?).SEVO and ISO inhibited membrane translocation of PI3K-C2? and Rock ?,but not PI3K-p85 in response to KCl in a concentration-dependent manner in rat aortas.LY294002(1 mM)inhibited KCl-induced PI3K-p85 and PI3K-C2? membrane translocation in response to KCl(P<0.05,P<0.01,respectively).In addition to Y27632(1 ?M),LY294002(1mM)also inhibited KCl-induced MLC phosphorylation and Rock ? membrane translocation in rat aortic smooth muscle(P<0.01)Conclusions:1.SEVO and ISO can inhibit the contraction of aorta by inhibiting the activities of PI3K-C2a and Rho kinase and the phosphorylation of MLC in normal aortic smooth muscle.2.PI3K inhibitor LY294002 can inhibit vasoconstriction by inhibiting MLC phosphorylation and PI3K activity.3.The inhibition mechanism of volatile anesthetics is mediated by KCl/PI3K-C2a/Rho kinase/MYPT1/MLC pathway.Significance:SEVO and ISO can inhibit the contraction of aortic smooth muscle by regulating the activities of PI3K-C2a and Rho kinase.Clinical concentration of inhaled anesthetics combined with PI3K inhibitor can enhance vasodilation.This study provides some clinical guidance for the circulation management of inhalation anesthetics in patients who use PI3K inhibitors for anti-cancer treatment.Part Two:Sevoflurane and isoflurane regulate the contraction of diabetic vascular smooth muscle by PI3K/Rho kinaseObjective:To study the effects of SEVO and ISO on KCl-induced vasoconstriction in aged type 2 diabetes mellitus rats.Methods:1.Experimental animals.Aged male OLETF rats(65-70 weeks old),age-matched non-diabetic LETO rats and young Wistar rats(6-8 weeks old)were selected as the research objects.OLETF rat is a spontaneous T2DM animal model,which has the characteristics of congenital polydipsia,mild obesity,delayed hyperglycemia,hyperinsulinemia,hypertriglyceridemia and hypercholesterolemia,and is similar to the pathophysiological process of human T2DM.2.Oral glucose tolerance test.In order to verify the quality of the model,oral glucose tolerance test(OGTT)was performed before the experiment.After fasting for 8-14 h,fasting blood glucose was measured.Then glucose(2 g/kg)was given by gavage,and the blood glucose was measured at 30,60,90 and 120 min.Rats in each group were used in the follow-up experiment after meeting the standard.3.Preparation of vascular smooth muscle.Three groups of rats were anesthetized by intraperitoneal injection of pentobarbital sodium(40 mg/kg),and then euthanized by Bloodletting from common carotid artery.The descending aorta was dissected carefully and cut into 3-4 mm long rings.The inner surface was rubbed gently with stainless steel needle to remove endothelial cells.The arterial ring is vertically installed between two hooks,and the upper hook is connected to the lever of the equidistant force sensor.4.Isometric force measurement.Isometric force sensor was used to measure the contractile tension of aorta induced by KCl(60 mM).After the rings were induced by KCl,the rings were randomly exposed to SEVO or ISO(0,1,2,3 MAC),10 ?M LY294002 and 1 ?M Y27632 for 15 min.SEVO and ISO are introduced into the gas mixture through a calibrated vaporizer at a fresh flow rate of 2 L/min.The concentration of SEVO in KBS solution is monitored and adjusted by gas chromatography.The isometric force of SEVO,ISO,LY294002 and Y27632 on KCl-induced contraction of rat arterial smooth muscle was expressed as a percentage of the maximum isometric force induced by KCl.Results:1.Changes of glucose tolerance curve.The OGTT curve showed that the postprandial blood glucose of aged OLETF rats was significantly higher than that of LETO rats and young Wistar rats of the same age in the control group(P<0.01),and reached the highest value in 30 min.The peak of blood glucose in LETO rats and Wistar rats was less than 10 mmol/L,but the peak time was different.The peak of blood glucose in aged LETO rats was 30 min after meal,and that in young Wistar rats was 60 min after meal.2.The effect of KCl on the contraction of aortic smooth muscle in three groups.KCl induced rapid and continuous contraction of aortic smooth muscle in three groups.Compared with LETO group and Wistar group,the contraction of aorta in OLETF group was more obvious(P<0.01),but there was no significant difference between LETO group and Wistar group.3.Effects of SEVO and ISO on KCl-induced contraction of aortic smooth muscle in three groups.SEVO had more significant inhibitory effect on KCl induced vascular responses in young Wistar rats than ISO,and 2 MAC and 3 MAC SEVO had significant differences compared with ISO(P<0.05).The inhibitory effect of ISO was more significant than that of SEVO,and OLETF group was more significant than LETO group.1 MAC SEVO had the strongest inhibitory effect in young Wistar rats(P<0.05).3 MAC SEVO had the strongest inhibitory effect in OLETF group,which was significantly different from LETO group and Wistar group(P<0.05).Different from SEVO,1 MAC,2 MAC and 3 MAC ISO had the weakest inhibitory effect on KCl-induced aortic vasoconstriction in young Wistar rats compared with OLETF group and LETO group(P<0.05).4.Effects of LY294002(10 ?M)and Y27632(1 ?M)on KCl-induced aortic vasoconstriction in three groups.LY294002 and Y27632 inhibited KCl-induced aortic vasoconstriction in three groups.There was no significant difference in the inhibition degree of LY294002 and Y27632 between Wistar group and LETO group(P>0.05).The aortic relaxation degree of OLETF group was significantly higher than that of LETO group and Wistar group(P<0.01).Conclusion:1.There was significant difference in the degree of KCl-induced isotonic contraction between diabetic and normal blood vessels.2.The effects of SEVO and ISO on aortic contraction of young and aged rats are significantly different.SEVO has more obvious inhibitory effect on young rats,especially at high concentration,while ISO has stronger inhibitory effect on aged rats.3.The response of volatile anesthetics to normal blood vessels and diabetic blood vessels was significantly different,suggesting that the activities of PI3K and Rho kinase in diabetic blood vessels were abnormal.4.PI3K inhibitor LY294002 and Rho kinase inhibitor LY294002 have stronger inhibitory effect on diabetic vascular contraction,which further indicates that the activity of PI3K and Rho kinase in diabetic vascular is abnormal.Significance:Objective to explore the specific response of inhaled anesthetics in regulating diabetic vasodilation,so as to provide theoretical basis for diabetic patients to reasonably choose anesthetics during perioperative period,realize the transformation from anesthesiology to perioperative medicine,and prevent the occurrence of acute cardiovascular and cerebrovascular events during perioperative period.Part Three:Sevoflurane regulate vascular smooth muscle contraction of greater omental artery by PI3K-C2?/Rho kinaseObjective:To study the effect of SEVO on KCl-induced contraction of greater omental artery smooth muscle by regulating PI3K-C2? and Rho kinase activity.Methods:1.Research object.Ten patients who underwent laparoscopic gastrectomy in our hospital were selected as the research object,and the omentum artery after gastrectomy was taken as the experimental material.2.Tissue preparation for in vitro studies.The omentum artery(about 7.0 cm in length and 0.5-1.0 mm in diameter)of 10 patients undergoing laparoscopic gastrectomy was taken as the experimental sample.Carefully dissect the greater omentum artery,remove the attached fat and connective tissue,and cut the prepared artery into 3-4 mm long arterial rings.The arterial ring is gently rubbed with a cotton swab or needle to mechanically remove endothelial cells to avoid endothelium-derived vasodilator-mediated changes.The arterial ring was pretreated with phenylephrine(10-5mol/L),and there was no diastolic response to bradykinin(10-6mol/L),indicating that the endothelial cells have been completely removed.The arterial ring is vertically installed between two hooks,and the upper hook is connected to the lever of the isometric force sensor.3.Isometric force measurement.The isometric force sensor measures the arterial vasoconstriction induced by KCl.A mixed gas of 95%(v/v)O2 and 5%(v/v)CO2 was introduced into the Krebs bicarbonate solution(KBS)at 37?(the flow rate of fresh gas was 2 L/min).The endothelial exfoliated omentum artery ring was equilibrated at a resting tension of 3 g for 60 min,and the culture medium was changed every 20 minutes.Subsequently,the arterial ring was cultured with KCl(60 mM),and its overall contractile reactivity was observed.Prior to adding KCl,the arterial ring was randomly exposed to SEVO(MAC values 0,1,2),10 ?M LY294002(PI3K inhibitor)and 1 ?M Y27632(Rho kinase inhibitor)for 15 min.SEVO is fed into the gas mixture with a fresh gas flow of 2 L/min through a calibrated vaporizer.The concentration of SEVO in the KBS solution is monitored and adjusted using gas chromatography.The changes in isometric force of SEVO,LY294002,and Y27632 on KCl-induced retinal artery smooth muscle contraction are expressed as a percentage of the maximum isometric force induced by KCl(60 mM),and the effects of the compounds studied on the same arterial ring are evaluated.4.Phosphorylation of MYPT1,CPI-17,and MLC.A strip of endothelial exfoliation(approximately 3.5 cm in length)was taken from each patient's surgically removed omentum artery sample and immersed in an oxygenated KBS solution for 60 minutes.Omentum artery strips from different patients were cultured in 0(control),60 mM KCl,1 MAC-SEVO(1.7%),2 MAC-SEVO(3.4%),10 ?M LY294002,and 1?M Y27632.Incubate in the absence of KCl for 15 min,in the presence of KCl for 5 min,and then freeze quickly with liquid nitrogen.After centrifuging the homogenate,the degree of phosphorylation of MYPT1,CPI-17 and MLC was analyzed by Western blotting.After the experimental samples were treated with kinase antibody,the density of the immunoreactive band was detected by chemiluminescence method and evaluated by image analysis software.The ratio of phosphorylation to total CPI-17,MLC,and MYPT1 is used as an activation index for each enzyme and is expressed as a percentage relative to the baseline control level(referred to as 100%).5.Membrane translocation of PI3K and Rho kinase(Rock ?).The omentum artery strip from which the endothelial cells have been removed is selected,soaked in an organ bath containing 20 ml of KBS solution for 60 min,and the KBS solution is replaced every 20 min.The equilibrated arterial strips were then placed in 1 MAC-SEVO(1.7%),2 MAC-SEVO(3.4%),10 ?M LY294002 or 1 ?M Y27632 for 15 minutes.After treatment with KCl for 5 min,the samples were quickly frozen with liquid nitrogen.The activity of PI3K and Rho kinase(Rock ?)was measured using Western blotting.The experimental samples were treated with kinase antibody and then chemiluminescence method was used to detect the density of the immunoreactive band and evaluated with image analysis software.The contents of PI3K-p85?,PI3K-C2? and Rock ? are expressed as a percentage of the total value(i.e.,membrane fraction plus cytosolic fraction).Results:1.Isometric force measurement.Isometric force sensors measure KCl-induced arterial VSM contractile tension.The changes of isometric force of SEVO,LY294002 and Y27632 on KCl-induced retinal artery VSM contraction are expressed as a percentage of the maximum isometric force induced by KCl(60 mM).The measurement results show that SEVO attenuates KCl-induced contraction of human isolated omentum artery VSM in a concentration-dependent manner,and LY294002(10 ?M)and Y27632(1 ?M)can also inhibit it.2.Phosphorylation of MYPT1,CPI-17,and MLC.Western blotting analysis showed that KCl-induced MLC phosphorylation increased rapidly and reached a peak level after being exposed to KCl for about 5 min.SEVO inhibits MLC caused by KCl in a concentration-dependent manner.Chemiluminescence detection of immunoreactive bands and evaluation by image analysis software revealed that SEVO inhibited KCl-induced MYPT1/Thr853 phosphorylation in a concentration-dependent manner.Consistent with the results of animal experiments,SEVO does not affect the increase in phosphorylation of MYPT1/Thr696 and CPI-17/Thr38 caused by KCl;in addition,LY294002(10 ?M)and Y27632(1 ?M)can also inhibit KCl-induced MLC phosphorylation.3.Membrane translocation of PI3K and Rho kinase(Rock ?).Western blotting analysis showed that KCl could induce increased membrane transport of PI3K-C2?,PI3K-p85 and Rho kinase.Consistent with the results of animal experiments,SEVO inhibited KCl-induced PI3K-C2? and Rock ? membrane translocation in human aorta in a concentration-dependent manner,but did not inhibit PI3K-p85 response to KCl.Both LY294002(10 ?M)and Y27632(1?M)can inhibit KCl-induced PI3K-p85,PI3K-C2?,and Rock ? membrane translocation.Conclusion:1.As a resistance vessel,SEVO can inhibit vasoconstriction by regulating the activities of PI3K-C2? and Rho kinase in isolated human omental artery smooth muscle.2.Low concentration PI3K inhibitor LY294002(10 ?M)can effectively dilate blood vessels by inhibiting MLC phosphorylation and PI3K activity.3.The inhibitory effect of SEVO on KCl induced vasoconstriction is related to regulating the activity of PI3K-C2?/Rho kinase,the upstream activator of MLCP.Significance:SEVO can inhibit vasoconstriction by regulating the activities of PI3K-C2? and Rho kinase in isolated human omental artery smooth muscle.Inhalational anesthetics can inhibit both elastic reservoir vessels and resistance vessels.This study provides an important theoretical basis for the circulation management of volatile anesthetics in perioperative patients with PI3K inhibitors.