Role of K+ channels in hypoxic pulmonary vasoconstriction in normal and chronic hypoxic rats

AIM:To investigate the role of K⁺ channels in the decreased hypoxic pulmonary vasoconstriction(HPV) in chronic hypoxic rats. METHODS:Blockers of three kinds of K⁺ channels, 4-AP(voltage dependent K⁺ channel blocker), TEA(Ca²⁺ activated K⁺ channel blocker), GLIB(ATP sensitive K⁺ channel blocker) were used in isolated perfused rat lungs to detect the role of K⁺ channels in HPV. RESULTS:In normal rats, 4-AP and TEA, but not GLIB, both elicited a significant increase in pulmonary artery baseline pressure, and also potentiated the acute hypoxic pulmonary vasoconstriction. In chronic hypoxic rats, the HPV is significantly decreased, while 4-AP, TEA, GLIB all elicited a significant but smaller increase in pulmonary artery baseline pressure. Additionally, all these three blockers potentiated the HPV stronger in chronic hypoxic rats than in control rats. CONCLUSION:The opening of Kv, K_Ca, K_ATP might modulate the hypoxic pulmonary vasoconstriction in isolated rat lungs, and the increase in this modulation by potassium channel in chronic hypoxic rats might play a role in its decrease in HPV.     

Protective effect of sodium selenite on human keratinocytes from ultraviolet-B irradiation

AIM: To investigate the protective effect of sodium selenite (Na₂SeO₃) on human keratinocytes under ultraviolet-B (UVB) irradiation. METHODS: The cultured HaCaT cells were divided into 4 groups: (1) normal control group; (2) Na₂SeO₃ group: pretreated with Na₂SeO₃ at doses of 10 nmol/L, 50 nmol/L, 100 nmol/L, 200 nmol/L and 1 μmol/L for 24 h; (3) UVB group: irradiated with UVB at doses of 300, 600 and 900 J/m² ; (4) Na₂SeO₃+UVB group: after pretreated with Na₂SeO₃ for 24 h, irradiated with UVB at doses of 300, 600 and 900 J/m² . The cell proliferation was detected by MTT assay. The apoptotic rates of HaCaT cells treated with UVB at dose of 300 J/m² were assessed by flow cytometry. RESULTS: Compared with normal control group, the cell proliferation activity in UVB group decreased significantly (P<0.05). The cell activity was inversely correlated with the irradiation intensity. No significant difference of the cell activity between Na₂SeO₃ group and normal control group was observed. The cell proliferation in Na₂SeO₃+UVB group was higher than that in UVB group significantly (P<0.05). Na₂SeO₃ at concentration of 100 nmol/L showed the strongest activity to promote cell proliferation. After 300 J/m² UVB irradiation, the apoptotic rate in Na₂SeO₃+UVB group decreased significantly (P<0.05) compared with UVB group. The inhibitory effect of Na₂SeO₃ at concentration of 100 nmol/L on apoptosis was the strongest.CONCLUSION: The damage of human keratinocytes by UVB irradiation is in a dose-dependent manner. The photoprotection performance of Na₂SeO₃ reduces the damage of human keratinocytes induced by UVB irradiation.     

不同无机盐离子对平菇菌丝体生长的影响

在基本培养基中添加不同浓度的K₂SO₄、MgSO₄、Na₂SO₄,研究了无机盐（阳离子）对平菇菌丝体生长的影响。结果表明:0.3%K₂SO₄、0.4%K₂SO₄、0.5%K₂SO₄和0.2%MgSO₄能显著地促进平菇菌丝的生长。     

The alteration of extracellular sodium and potassium ionic activities of hippocampal neurons in epileptiform rats kindled by coriaria lactone

AIM and METHODS: The sodium ion Na⁺ and potassium ion K⁺ selective microelectrodes were used to measure changes of ionic activity of extracellular sodium and potassium( [Na⁺]_o, [K⁺]_o) in hippocampus and hippocampal slice during epieptic seizure induced by intrahippocampal microinjection of coriaria lactone(CL) in rats and perfusing hippocampal slice with CL. RESULTS:30 s, 1min and 2min after injection of CL into hippocampus, the [Na⁺]_o decreased 27.7 mmol/L, 50.3 mmol/L, 57.8 mmol/L respectively and the [K⁺]_o increased 2.3 mmol/L, 2.4 mmol/L, 2.9 mmol/L respectively compared with control values(P＜0.01). The [K⁺]_o returned to the control level 3min after local application of CL, but the[Na⁺] _o was still lower than that of control group(P＜0.01). The [Na⁺]_o and the [K⁺]_o were measured also in hippocampal silces and results are similar to those of experiments in vivo. CONCLUSION: The influx of Na⁺and the flux of K⁺occurred during epileptiform discharges of hippocampal neurons induced by administration of CL.     

盐碱胁迫和干旱胁迫对紫苏种子萌发及幼苗生长的影响

通过研究盐碱胁迫和干旱胁迫对紫苏种子萌发及幼苗生长的影响,以期为抗性品种选育提供理论依据.采用培养皿滤纸培养法通过不同配比的NaCl、Na2SO4、NaHCO3和Na2CO3对紫苏种子进行盐碱胁迫模拟,不同浓度聚乙二醇和甘露醇进行干旱胁迫模拟,结果表明:紫苏种子的发芽率和发芽势均随盐胁迫和干旱胁迫程度增加而降低;3种盐...     

碳酸钠和碳酸氢钠对番茄壮苗和灰霉病的防治作用

以番茄品种L402幼苗为试材,研究外源喷施碳酸钠和碳酸氢钠对番茄生长和灰霉病的防治作用。结果表明:25mmol·L~(-1)和50 mmol·L~(-1)的碳酸钠与碳酸氢钠对番茄幼苗具有显著的壮苗作用;30～60 mmol·L~(-1)的碳酸钠和碳酸氢钠对灰霉菌菌丝生长具有不同程度的抑制作用,且抑制作用通常随着浓度的升高而加强;30～40 mmol·L~(-1)的碳酸钠和50～60mmol·L~(-1)的碳酸氢钠对番茄灰霉病具有良好的预防作用;50 mmol·L~(-1)的碳酸钠和50～60 mmol·L~(-1)的碳酸氢钠对番茄灰霉病具有良好的抑制作用。生产上可应用适宜浓度的碳酸钠和碳酸氢钠防治番茄灰霉病。     

Effects of hydrogen peroxide on sodium current in acutely isolated rat hippocampal CA1 neurons

AIM and METHODS: The effects of hydrogen peroxide on Na⁺ currents were studied in freshly dissociated rat hippocampal CA1 neurons using the whole-cell patch-clamp techinique. RESULTS: ①H₂O₂ caused a dose-dependent and voltage-dependent increase in the voltage-activated Na⁺ currents. The amplitudes of Na⁺ currents were increased (48.0±4.2)% and (88. 2±5. 1)% (n=10) by H₂O₂ at 10 μmol/L and 100 μmol/L, respectively. ②H₂O₂ (10 μmol/L) did not affect the activation process, but changed the inactivation process significantly. Before and after application of 10 μmol/L of H₂O₂, the half-inactivation voltage was (-64.58±1.22)mV and (-53.55±0.94)mV (n=10, P<0.01), but the slope factor was not changed. CONCLUSION: As a product of oxidation metabolism, H₂O₂ is related to some diseases in the central nervous system.     

The relationship between the activity of phospholipase A2 and chronic hypoxic pulmonary hypertension

AIM:To study the relationship between the activity of phospholipase A₂ (PLA₂) and chronic hypoxic pulmonary hypertension. METHODS:29 healthy SD rats were randomly divided into normal control group, chronic hypoxic group and hypoxia plus Polidatin (PD) group. The model of rat chronic hypoxic pulmonary hypertension was made by method of intermittent isobaric hypoxia for 21 days. The mean pulmonary arterial pressure (mPAP) was measured by inserting a microcatheter into the pulmonary artery. RESULTS:After exposing hypoxia for 21 days, the mPAP, R/L+S, the PLA₂ activity, TXB₂, MDA in plasma and lung homogenate increased significantly, while 6-k-PGF_1α, SOD decreased significantly. Pretreatment with PD could relieve the changes mentioned above.CONCLUSION:PLA₂ plays an important inducing role through its metabolic products and the interactional radicals in the formation of chronic hypoxic pulmonary hypertension.     

Interaction of PKCε with the CaR in hypoxic post-conditioning protects the cardiomyocytes in neonatal rat

AIM: To study the interaction of PKC_ε with the CaR in hypoxic post-conditioning for protecting the cardiomyocyte of neonatal rat. METHODS: The ventricular cardiomyocytes of Wistar neonatal rat (3-7 d after birth) were incubated for about 3-5 d, then randomly divided them into 7 groups: (1) Sham control group (N group); (2) Hypoxic/re-oxygenation group (H/Re group); (3) Hypoxic post-conditioning group (HPC group); (4) HPC+GdCl₃, NiCl₂, CdCl₂ group; (5) HPC+caffeine, GdCl₃, NiCl₂, CdCl₂ group; (6) HPC+PKC_ε inhibitor group (PKCI group); (7) HPC+PKCI+GdCl₃, NiCl₂, CdCl₂ group. The neonatal cells were incubated in the D-Hanks solution (pH=6.8) which was saturated with N₂ gas for 1 h at least and then re-incubated in the DMEM solution containing 20% new-born calf serum to establish a model of H/Re. The viability of cardiomyocytes was assayed by MTT, the activity of LDH and the content of MDA were determined, the expression of CaR and PKC_ε of the membrane in each group was analyzed by Western blotting, PKC_ε interaction with CaR in the membrane was detected by immunoprecipitation, and the concentration of intracellular calcium ([Ca²⁺]_i) was measured by laser confocal scanning microscope (LCSM), apoptotic cells were measured by TUNEL assay. RESULTS: The viability of cardiomyocytes in H/Re, GdCl₃ and PKCI groups was lower than that in N and HPC groups, while the activity of LDH and the content of MDA were significantly higher than those in N and HPC groups. Meanwhile, the quantitative expression of CaR in GdCl₃, caffeine and PKCI+GdCl₃ groups was higher than that in HPC and PKCI groups, and so were the [Ca²⁺]_i and the apoptosis index. The quantitative expression of PKCε in PKCI and PKCI+GdCl₃ groups was lower than that in H/Re, HPC, GdCl₃ and caffeine groups. Immunoprecipitation of cell membrane PKCε revealed the interaction of PKC_ε with CaR. CONCLUSION: In the cardiomyocytes of HPC, PKC_ε translocates to the membrane and interacts with CaR to reduce [Ca²⁺]_i, which protects the cardiomyocytes of neonatal rat during hypoxic/oxygenation.     

Role of potassium channels in the regulation of intracellular free Ca2+ concentration of pulmonary artery smooth muscle cells in rats

AIM: To investigate the role of potassium channels in the regulation of intracellular free calcium concentration ( [Ca²⁺]_i) of pulmonary artery smooth muscle cells (PASMCs) in rats. METHODS: The fluorescence Ca²⁺ indicator Fura-2/AM was used to observe [Ca²⁺]_i of rat PASMCs in normal and chronic hypoxic condition. The influences of potassium channels on PASMCs proliferation were assessed by MTT assay. RESULTS: 1. In normoxic condition, [Ca²⁺]_i was (156.91±8.60) nmol/L, and in hypoxic condition, [Ca²⁺]_i was (294.01±16.81) nmol/L. 2. In normoxic condition, the voltage-dependent K⁺-channel antagonist 4-aminopyridine (4AP), but not the Ca²⁺-activated K⁺-channel antagonist tetraethylammonium (TEA) and the ATP-sensitive K⁺-channel antagonist glibenclamide (Glib) increased [Ca²⁺]_i. 3. In hypoxic condition, 4AP and TEA caused the rise in [Ca²⁺]_i , but Glib had no effect on [Ca²⁺]_i. 4. MTT assay showed that 4AP increased the value of absorbing light degree (A value) in normoxic and hypoxic condition (0.582±0.062,0.873±0.043,respectively, P＜0.01), TEA increased A value only in hypoxic condition, and Glib had no effect on the proliferation of PASMCs. CONCLUSIONS: K_V plays an important role in the regulation of [Ca²⁺]_i and proliferation of PASMCs. K_Ca serves as distinct responsive roles in the regulation of proliferation of PASMCs in hypoxic condition. K_ATP has no effect on [Ca²⁺]_i and proliferation of PASMCs in normoxic and hypoxic conditions.     

Roles of PI3K/Akt and JAK2/STAT3 signaling pathways in protection of SO2 against limb ischemia/reperfusion-induced acute lung injury in rats

AIM: To investigate the role of PI3K/Akt and JAK2/STAT3 pathways in the protection of sulfur dioxide (SO₂) against limb ischemia/reperfusion (I/R)-induced acute lung injury (ALI) in rats. METHODS: ALI was induced by limb I/R in the SD rats. Na₂SO₃(0.54 mmol/kg, ip)/NaHSO₃ (0.18 mmol/kg, ip) as SO₂ donor was injected at 20 min before reperfusion. The inhibitors of JAK2/STAT3 and PI3K/Akt pathways, Stattic (3 mg/kg, iv) and LY294002(40 mg/kg, iv), respectively, were injected at 1 h before reperfusion. Peripheral blood and lung tissues were collected for determining the contents of the cytokines, the protein levels of the molecules related to the signaling pathways, apoptosis and histopathologic changes by ELISA, TUNEL and Western blot. RESULTS: Compared with control group, the content of MDA, the activity of MPO, lung coefficient, apoptotic index, cytokine expression, and the protein levels of p-Akt and p-STAT3 in I/R group all increased significantly, and administration of Na₂SO₃/NaHSO₃ attenuated the damage in the lung. Besides, the results of Western blot showed that the rat lung tissues expressed p-STAT3 protein and p-Akt protein. After I/R, the protein levels of p-STAT3 and p-Akt were increased. After using Na₂SO₃/NaHSO₃, p-Akt was increased, but p-STAT3 was decreased (P<0.05). CONCLUSION: Both JAK2/STAT3 and PI3K/Akt pathways are likely involved in the protective effect of SO₂ against limb I/R-induced ALI in rats. The activation of JAK2/STAT3 signaling pathway increases I/R injury. Reversely, the activation of PI3K/Akt signaling pathway reduces I/R injury. Besides, JAK2/STAT3 and PI3K/Akt signaling pathways may have crosstalk during I/R-induced ALI and JAK2/STAT3 pathway may have an impact on the P13K/Akt pathway.     

新书推荐：《分子克隆实验指南》（第三版）

AIM: To study the effect of panax notoginseng sponins (PNS) on L-type Ca²⁺ current in isolated right ventricle myocytes from chronic hypoxic rats. METHODS: Using whole cell patch clamp recording technique,we measured I_Ca-L in isolated right ventricle myocytes which were divided into three group:control group, chronic hy-poxic group and chronic hypoxic group with PNS(100 mg·kg^-1·d^-1). RESULTS: The result showed I_Ca-L of cells from chronic hypoxic group were significantly larger than the other two groups(P＜0.05). CONCLUSION: PNS decreases L-type Ca²⁺ current of the right ventricle myocytes from chronic hypoxic rats.     

Effect of sodium selenite on proliferation of endometrial cancer cells

AIM: To investigate the effect and mechanism of sodium selenite (Na₂SeO₃) on the proliferation of endometrial cancer cells. METHODS: Endometrial cancer Ishikawa cells and HEC-1A cells were treated with Na₂SeO₃. The effect of Na₂SeO₃ on cell proliferation was determined by MTT assay. The effects of Na₂SeO₃ on cell cycle distribution and apoptosis were tested by flow cytometric analysis. The expression of cyclin A was detected by Western blotting. RESULTS: Na₂SeO₃ inhibited the proliferation of Ishikawa cells and HEC-1A cells. For Ishikawa cells, IC₅₀ was 3.26 μmol/L, and for HEC-1A cells, IC₅₀ was 4.77 μmol/L. After treated with Na₂SeO₃, the cells in G₀/G₁ phase were reduced and the cells in S phase and G₂/M phase were increased. Na₂SeO₃ also increased the percentage of apoptosis cells. The result of Western blotting showed that the expression of cyclin A was increased. CONCLUSION: Na₂SeO₃ inhibits the proliferation of endometrial cancer Ishikawa cells and HEC-1A cells via up-regulating the expression of cyclin A, arresting cell cycle and inducing apoptosis.     

Role of prostaglandins,nitric oxide and potassium channel in the blunting of hypoxic pulmonary vasoconstriction in the high altitude adaptive animal

AIM: To investigate the possible role of prostaglandin, NO and potassium channel in the adaptive blunting of hypoxic pulmonary vasoconstriction (HPV) in high altitude animal (pika). METHODS: The effect of L-NAME, indomethacin and 4-AP on the response of isolated lung strips of pika and Wistar rats instead of pulmonary artery to acute hypoxia were studied. RESULTS: (1) After inhibition of prostaglandins by indomethacin, the percentage increase in hypoxic constriction in lung tissue strip of pikas was greater than that in Wistar rats , P＜0.05; (2) After inhibition of NO synthesis by L-NAME, the percentage increase in hypoxic constriction in lung tissue strip of pikas was greater than that in Wistar rats , P＜0.05; (3) After administration of 4-AP, there was no significant difference in the percentage decrease in hypoxic constriction of lung tissue strip between pika and Wistar rat. CONCLUSIONS: (1) Prostaglandins and NO might modulate HPV in either rat of pika; the closure of Voltage-gated K⁺ channels might mediate HPV in either rat or pika. (2) Prostaglandins and NO might play an important role in the blunting of HPV in pika, Voltage-gated K⁺ channels may play a minor role in the blunting of hypoxic pulmonary vasoconstriction in pika.     

Changes in endogenous nitric oxide and effects of inhaled nitric oxide on pulmonary artery hypertension in chronically hypoxic rats

AIM: To investigate the role of nitric oxide (NO)in the development of chronically hypoxic pulmonary artery hypertension (PAH) and the hemodynamic effects of inhaled NO on pulmonary circulation. METHODS: 67 male adult SD rats were randomly divided into 7 groups: (1) control (n=9);(2) chronically intermitent hypoxia (CIH, 6 h/d, 7 d/w) 1 week(n=7); (3) CIH 2 weeks (n=11); (4) CIH 3 weeks (n=11); (5) CIH 1 week+L-NAME (NO synthase inhibitor, 30 mg/kg, by gavage, n=10); (6)CIH 3 weeks+L-Arg (NO precursor, 10 mg/kg, by gavage, n=9); (7) CIH 3 weeks+inhaled NO (0.0004% for 20 min, n=10) to determine the mean pulmonary artery pressure (MPAP), weigh the right ventricle (R) and ventricular segment plus left ventricle (S+L), and calculate R/(S+L) (g/g) and R/Wt (Wt: body weight, g/kg). RESULTS: 1.MPAP increased compared with control when CIH 1 week, reaching the highest when CIH 2 weeks; R/(S+L) and R/Wt also increased notably when CIH 1 week (P＜0.01); 2. The level of plasma NO₂^-/NO₃^- elevated significantly when CIH 2 weeks, but fell when CIH 3 weeks; the content of plasma ET-1(endothelin-1) also increased significantly. The level of plasma ET-1 correlated with R/(S+L) and R/Wt, r=0.43 and 0.46, respectively, both P＜0.01; 3. The level of plasma NO₂^-/NO₃^- droped 33.2 % (P＜0.01) after treatment with L-NAME, with R/(S+L) increasing 15.2 % (P＜0.05); 4. L-Arg decreased the MPAP 17.8 %(P＜0.01). CONCLUSION: The endogenous NO release increases at early stage (1-2 weeks) of chronic hypoxia, but falls at the prolonged stage; the elevated level of plasma ET-1 possibly plays an important role in remodeling of chronically hypoxic pulmonary vessels and ventricle; inhaled NO significantly decreases the chronically hypoxic PAH.     

百合在NaHCO3胁迫下的生理响应机制

比较了耐盐碱的岷江百合（Lilium regale Wilson）和对盐碱敏感的东方百合‘索邦’（‘Sorbonne’）在不同浓度的碱性盐NaHCO₃胁迫下叶片的渗透调节物质、活性氧清除物质、离子调节物质（Na⁺、K⁺）及有机酸含量的变化,探讨百合耐盐碱的生理机制。研究发现,两种百合叶片中各种物质的变化趋势基本相似,但整体上岷江百合的各种物质含量或者活性均高于‘索邦’。随着NaHCO₃胁迫浓度的增加,两种百合叶片中的可溶性蛋白、脯氨酸含量增加,可溶性糖含量先升后降;SOD、GR的活性和AsA的含量先上升后下降,APX的活性和GSH的含量在低浓度胁迫时无明显变化,高浓度胁迫时显著下降;‘索邦’Na⁺主要积累在成熟叶和新生叶中,岷江百合则主要积累在茎和成熟叶中,且能维持根、成熟叶和新生叶中较高水平的K⁺/Na⁺值;岷江百合中的草酸、乳酸和乙酸含量都一直增加或高于对照,‘索邦’中的苹果酸和乙酸含量一直增加。与‘索邦’相比,岷江百合在低浓度NaHCO₃胁迫下提高SOD活性和AsA含量,高浓度NaHCO₃胁迫下增加可溶性蛋白的含量并保持可溶性糖的稳定性,是其耐盐碱性较强的原因之一。     

Demarcating specific ion (NaCl, Cl, Na) and osmotic effects in the response of two citrus rootstocks to salinity

The present work differentiates the effects of NaCl, Cl⁻, Na⁺ and concentrated macronutrients on two citrus species, sour orange (Citrus aurantium L) and Macrophylla (Citrus macrophylla Wester). Plants were grown in a base nutrient solution (0.07 MPa osmotic pressure) for 4 months before applying the treatments that consisted of isotonic solutions of 0.23 MPa osmotic pressure of Na⁺ (40 mM, without Cl⁻), Cl⁻ (40 mM, without Na⁺), NaCl (40 mM) and 3.5 times the concentration of macronutrients of the base solution. Plants were grown in the different treatment for 2 months before being examined for symptoms of toxicity. The two genotypes showed major differences in the extent of Cl⁻ and Na⁺ accumulation in leaves and in their ability to maintain the internal concentrations of essential nutrients in response to the different ionic compositions of the medium. Differences in mineral nutrient accumulation were observed among treatments in both rootstocks. It was concluded that growth response to the different treatments was primarily affected by an osmotic effect, although in Macrophylla, the ionic effects also seem to be present.     

Protective mechanism of metallothionein on cultivated rat cardiomyocytes in hypoxic preconditioning

AIM: Studying the mechanism of protective role of metallothionein(MT) in hypoxic preconditioning(HPC) of cultivated rat cardiomyocytes. METHODS:Using the model of hypoxia/reoxygenation of cultivated rat cardiomyocytes. Determining the contents of MT, malonyldialdehyde (MDA)-metabolism product of lipid peroxidation and the activities of Na⁺-K⁺ATPase, Ca²⁺-Mg²⁺ATPase of cardiomyocytes 24h after HPC, also determining the relevant changes after using MT antibody. RESULTS: After 24 h in HPC, the contents of MT and activities of Na⁺-K⁺ATPase, Ca²⁺-Mg²⁺ATPase were obviously higher than those in the control and hypoxia/reoxygenation(P＜0.05), and the contents of MDA were decreased remarkedly (P＜0.01). Then after using MT antibody, the activities of two enzyme were progressively decreased and the contents of MDA were significantly higher than those in the control and MT antibody-free groups(P＜0.01). CONCLUSION: HPC may induce excessive synthesis of MT, and MT can protect myocardial reoxygenation injury by eliminating lipid peroxidation and rising the activities of Na⁺-K⁺ATPase and Ca²⁺-Mg²⁺ATPase.     

Roles of ERK pathway and Panax notoginoside treatment in hypoxic hypercapnia pulmonary hypertension in rats

AIM: To investigate the roles of Panax notoginoside (PNS) and ERK1/2 signaling pathway in the pathological process of chronic hypoxic hypercapnia pulmonary hypertension in rats.METHODS: The animal model of chronic hypoxic hypercapnia pulmonary hypertension was set up in 72 male Sprague-Dawley rats and the animals were randomly divided into 6 groups: normal (N) group, hypoxic hypercapnia for 3-day (H_3d) group, hypoxic hypercapnia for 1-week (H_1w) group, hypoxic hypercapnia for 2-week (H_2w) group, hypoxic hypercapnia for 4-week (H_4w) group and PNS treatment (H_p) group.The rats in H_p group were injected with PNS (50 mg·kg^-1·d^-1, ip) before placing the animals into the hypoxic hypercapnia chamber.The rats in other groups were injected with normal saline (2 mL/kg, ip).The morphological changes of the pulmonary artery were observed under microscope with HE staining.Western blotting was used to detect the protein expression of p-ERK.The protein levels of p-ERK in the lung tissues and pulmonary blood vessels were determined by immunohistochemistry.RESULTS: The ratios of WA/TA in H_1w, H_2w, H_4w and H_p groups were higher than that in N group (P<0.05).The ratio of WA/TA in H_p group was obviously lower than that in H_4w group (P<0.05).The protein expression of p-ERK was barely positive in N group, but was up-regulated in the pulmonary tissues in all hypoxic rats.Compared with N group, the protein level of p-ERK was markedly up-regulated in H_3d group, reached its peak in H_2w group, and tended to decline in H_4w group (P<0.05).In pulmonary arterial tunica intima and tunica media, p-ERK protein was dramatically expressed in all hypoxic rats compared with the control animals (P<0.05).In the lung tissues, the protein level of p-ERK in H_p group was lower than that in H_4w group (P<0.05).In pulmonary arterial tunica intima and tunica media, the protein level of p-ERK in H_p group was lower by 84.86% than that in H_4w group (P<0.05).CONCLUSION: ERK1/2 as a signal transducer may play an important role in the development of hypoxia and hypercapnia induced pulmonary hypertension.PNS inhibits the expression of ERK1/2, thus attenuating the development of pulmonary hypertension and improving pulmonary vascular remodeling.