Correction to: Nitric Oxide Participates in the Brain Ischemic Tolerance Induced by Intermittent Hypobaric Hypoxia in the Hippocampal CA1 Subfield in Rats.

The order of corresponding author was inadvertently published. Hence, the first and the second corresponding authors should be Min Zhang (hebmuzhangmin@163.com) and Jing-Ge Zhang (zhangjg001@163.com).

Nitric Oxide Participates in the Brain Ischemic Tolerance Induced by Intermittent Hypobaric Hypoxia in the Hippocampal CA1 Subfield in Rats.

Previous studies have shown that intermittent hypobaric hypoxia (IH) preconditioning protected neurons survival from brain ischemia. However, the mechanism remains to be elucidated. The present study explored the role of nitric oxide (NO) in the process by measuring the expression of NO synthase (NOS) and NO levels. Male Wistar rats (100) were randomly assigned into four groups: sham group, IH + sham group, ischemia group and IH + ischemia group. Rats for IH preconditioning were exposed to hypobaric hypoxia mimicking 5000 m high-altitude (PB = 404 mmHg, PO2 = 84 mmHg) 6 h/day, once daily for 28 days. Global brain ischemia was established by four-vessel occlusion that has been created by Pulsinelli. Rats were sacrificed at 7th day after the ischemia for neuropathological evaluation by thionin stain. In addition, the expression of neuronal NOS (nNOS), inducible NOS (iNOS), and NO content in the hippocampal CA1 subfield were measured at 2nd day and 7th day after the ischemia. Results revealed that global brain ischemia engendered delayed neuronal death (DND), both nNOS and iNOS expression up-regulated, and NO content increased in the hippocampal CA1 subfield. IH preconditioning reduced neuronal injury induced by the ischemia, and prevented the up-regulation of NOS expression and NO production. In addition, L-NAME + ischemia group was designed to detect whether depressing NO production could alleviate the DND. Pre-administration of L-NAME alleviated DND induced by the ischemia. These results suggest that IH preconditioning plays a protective role by inhibiting the over expression of NOS and NO content after brain ischemia.

Enhanced vasorelaxation effect of endogenous anandamide on thoracic aorta in renal vascular hypertension rats.

Emerging evidence has indicated that anandamide (AEA) is able to stimulate vasorelaxation in both spontaneously hypertensive rats (SHRs) and L-NAME-induced hypertensive rats. Yet it remains unknown whether AEA modulates vasomotion of the aorta in renovascular hypertensive (RVH) rats. The aim of present study is to explore the effect of AEA on the relaxation of thoracic aortas in two-kidney one-clip (2K1C)-induced RVH rats. It is demonstrated that AEA stimulates a pronounced relaxation in the aortas of 2K1C rats compared with sham rats. The enhanced relaxation caused by AEA in aortas from 2K1C rats was diminished in the presence of the cannabinoid receptor-1 (CB1 ) antagonist AM251 and the CB2 receptor antagonist AM630. Likewise, the vasodilation action of AEA was blocked in L-NAME-treated or endothelium-denuded aortas. The Western blot results revealed that the expression of CB1 and CB2 receptors was increased in the 2K1C rat aortas compared with sham rats. The phosphorylation of endothelial nitric oxide synthase (p-eNOS) at the activation site Ser1177 was enhanced in AEA-treated rings from 2K1C rats in both time-dependent and dose-dependent manners. The augmented p-eNOS expression was inhibited by the co-treatment with AM251 or AM630. Taken together, the present study demonstrated that AEA enhanced endothelium-dependent aortic relaxation through activation of both CB1 and CB2 receptors and P-eNOS/NO pathway in 2K1C rats.

The growth of oleaginous Rhodotorula glutinis in an airlift bioreactor on crude glycerol through a non-sterile fermentation process.

While the use of oleaginous Rhodotorula glutinis as a feedstock for biodiesel production is an attractive idea, as it can avoid the pollutions associated with over-consumption of fossil fuels. Nevertheless, the related costs, including the energy required for sterilization, remain a barrier to commercialization. This study thus used a low-pH non-sterile medium, instead of a completely sterilized one, to grow R. glutinis in a 5-L airlift bioreactor. The results show that R. glutinis can grow well at a low pH level of 4.0 and without sterilization of the medium, producing a final biomass of 11.7 g/L. Nevertheless, such a low pH will lead to fewer total lipids accumulation, and so a two-stage process of pH control in a non-sterile batch was proposed. Even this two-stage pH operation was also able to produce a similar final biomass of 11.7 g/L. However, the batch with two-stage pH control had a far higher lipid content of 55 ± 4% as compared to that of 21 ± 3% in the batch grown at pH 4.0. This study shows the potential of the proposed non-sterile process with two-stage pH control applied to the growth of R. glutinis to enhance the total lipid accumulation.

The role of glutamate transporter-1a in the induction of brain ischemic tolerance in rats.

This study was undertaken to determine the role of glutamate transporter-1a (GLT-1a), one of the splice variants of glutamate transporter-1, in the induction of brain ischemic tolerance by cerebral ischemic preconditioning (CIP). We used a rat global cerebral ischemic model and assessed changes by neuropathological evaluation, Western blot analysis, immunohistochemistry, real-time PCR, in vivo brain microdialysis, and high performance liquid chromatography. We found that CIP induced a significant upregulation of GLT-1a expression in the CA1 hippocampus in a time course corresponding to that of neuroprotection of CIP against brain ischemia. Severe brain ischemia for 8 min induced delayed downregulation of GLT-1a, an obvious increase in glutamate concentration and delayed neuronal death of the pyramidal neurons in the CA1 hippocampus. When the animals were pretreated with CIP before the severe ischemia, the above changes normally induced by the severe ischemia were effectively prevented. Importantly, such a preventive effect of CIP on these changes was significantly inhibited by intracerebroventricular administration of GLT-1a antisense oligodeoxynucleotides, which have been proven to specifically inhibit the expression of GLT-1a protein and mRNA, and had no effect on the expression of GLT-1b. In addition, the concentration of aspartate was also elevated after severe brain ischemic insult. However, CIP had no effect on the elevated aspartate concentrations. These results indicate that GLT-1a participated in the brain ischemic tolerance induced by CIP in rats.

Facilitation of chronic intermittent hypobaric hypoxia on carotid sinus baroreflex in anesthetized rats.

Our previous study showed that chronic intermittent hypobaric hypoxia (CIHH) could prevent decreases in systemic arterial blood pressure (SABP) during acute hypoxia. However, the mechanism was not clear. The purpose of the present study was to observe whether the carotid sinus baroreflex (CSB) was involved in the antagonizing effect of CIHH on SABP decrease induced by acute hypoxia and to explore the underlying mechanism using perfusion technique in rat isolated carotid sinus area. After 14-day and 28-day CIHH exposure, the CSB in rats was enhanced markedly, manifesting as increases in PS and RD, and decreases in TP and SP. This facilitation of CSB was partly abolished by Glibenclamide (Gli, 10 µM), a K ATP channel blocker, but was not influenced by L-NAME (100 µM), a nitric oxide synthase (NOS) inhibitor. The results of the study suggested that CIHH facilitated CSB through opening the K ATP channels in carotid sinus of anesthetic rats and might be one of mechanisms of CIHH keeping SABP homeostasis during acute hypoxia.

[Effects of exogenous hydrogen sulfide on pulmonary hypertension in rabbits with endotoxic shock].

Objective: To investigate the effects of exogenous hydrogen sulfide (H2S) on pulmonary vascular reactivity induced by endotoxic shock (ES) in rabbits. Methods: In this experiment, the model of endotoxic shock (ES) was induced by injection of lipopolysaccharides (LPS) to New Zealand big eared white rabbit through jugular vein (8 mg/0.8 ml/kg), the intervention was performed by H2S donor(sodium hydrosulfide, NaHS) which was injected intraperitoneally (28 µmol/kg) 15 min in advance. New Zealand rabbits were randomly divided into 4 groups(n=8):control group, LPS group, LPS+NaHS group and NaHS group. The changes of mean arterial pressure (MAP) and mean pulmonary arterial pressure (MPAP) were detected. The tension of pulmonary artery ring (PARs) was detected byin vitro vascular ring technique. The ultrastructure of pulmonary artery wall and pulmonary artery endothelial cells were observed by light microscope and scanning electron microscope. Results: ①MAP was decreased while MPAP was increased in rabbits after LPS injection, and ES animal model was established successfully. Compared with LPS group, mPAP of rabbit in LPS+NaHS group was decreased significantly (all P＜0.05). ②Compared with normal control group, pulmonary artery of rabbits in LPS group had an increased contractile response to phenylephrine (PE) and a decreased relaxation response to acetylcholine (ACh) (both P＜0.01); Compared with LPS group, pulmonary artery of rabbits in LPS+NaHS group had a decreased contractile response to PE and an increased relaxation response to ACh (both P＜0.05). ③Under light microscope, the structure of vascular endothelial cells was continuous in the normal control group, the elastic fibers were intact in the subcutaneous layer, and the smooth muscle layer was arranged neatly. LPS can shed some of the pulmonary artery endothelial cells, break the subcutaneous elastic fibers, and disorder the smooth muscle layer structure. Compared with LPS group, the injury of pulmonary artery wall in LPS+NaHS group was ameliorated. The morphology of pulmonary artery wall was normal in NaHS group. It is showed that some endothelial cells of pulmonary artery were missing in LPS group by Scanning electron microscopy. The morphology of pulmonary artery endothelial cells in LPS+NaHS group was similar to that in the control group: slightly widened intercellular space was observed, and no cell exfoliation was observed. Conclusion: These results suggest that exogenous H2S can protect pulmonary artery endothelial cells and regulate the reactivity changes of pulmonary artery during ES, which may be one of the mechanisms reducing PAH in ES rabbits.

Rictor maintains endothelial integrity under shear stress.

Background: Endothelial injury induced by low shear stress (LSS) is an initiating factor in the pathogenesis of various cardiovascular diseases, including atherosclerosis, hypertension, and thrombotic diseases. Low shear stress activates the mammalian target of rapamycin complex 2 (mTORC2) signaling pathway. Rictor, the main constituent protein of mTORC2, is involved in vascular development. However, the impact of conditional Rictor ablation on endothelial homeostasis, especially on endothelial-specific markers, such as vascular endothelial-cadherin (VE-cadherin) and von Willebrand factor (VWF), under blood flow stimulation is unclear. Objective: We aimed to investigate whether endothelial Rictor is involved in maintaining vascular endothelial integrity and the potential role of Rictor in atheroprone blood flow-mediated endothelial injury. Methods and results: Immunofluorescence staining showed that endothelial Rictor was successfully knocked out in a mouse model. Scanning electron microscopy (EM) detection revealed disruption of the endothelial monolayer in the thoracic aorta of Rictor-deficient mice. Furthermore, scanning electron microscopy and transmission electron microscopy showed that Rictor deletion disrupted endothelial integrity and expanded cell junctions in the left common carotid artery region. In vitro, low shear stress disrupted actin filament polarity and the promoted the translocation of vascular endothelial-cadherin, the key component of adherens junctions (AJs) in human umbilical vein endothelial cells. After Rictor downregulation by small interfering RNA, the translocation of vascular endothelial-cadherin and stress fibers increased. Rictor knockdown inhibited low shear stress-induced von Willebrand factor upregulation, and downregulation of vascular endothelial-cadherin decreased low shear stress-induced von Willebrand factor expression. These results suggest that vascular endothelial-cadherin/von Willebrand factor is a possible mechanism mediated by Rictor in the pathological process of low shear stress-induced endothelial injury. Conclusion: Rictor is a key protein that regulates endothelial integrity under vascular physiological homeostasis, and Rictor mediates low shear stress-induced endothelial injury by regulating adherens junctions and von Willebrand factor.

Left atrial diameter and atrial fibrillation, but not elevated NT-proBNP, predict the development of pulmonary hypertension in patients with HFpEF.

BACKGROUND: The determinants of pulmonary hypertension (PH) due to heart failure with preserved ejection fraction (HFpEF) have been poorly investigated in patients with cardiovascular diseases (CVD). METHODS: From July 1 2017 to March 31 2019, a total of 149 consecutive HFpEF patients hospitalized with CVD were enrolled in this prospective cross-sectional study. A systolic pulmonary artery pressure (PASP) > 35 mmHg estimated by echocardiography was defined as PH-HFpEF. Logistic regression was performed to establish predictors of PH in HFpEF patients. RESULTS: Overall, the mean age of participants was 72 ± 11 years, and 74 (49.7%) patients were females. A total of 59 (39.6%) patients were diagnosed with PH-HFpEF by echocardiography. The left atrial diameter (LAD) was related to the ratio of the transmitral flow velocities/mitral annulus tissue velocities in early diastole (E/E') and the left ventricular diameter in systole (LVDs). N-Terminal pro B-type natriuretic peptide (NT-proBNP) was not found to be associated with LAD and impaired diastolic or systolic function of the left ventricle. Multivariable logistic regression showed that atrial fibrillation (AF) increased the risk of PH-HFpEF incidence 3.46-fold with a 95% confidence interval (CI) of 1.44-8.32, P = 0.005. Meanwhile, LAD ≥ 45 mm resulted in a 3.43-fold increased risk, 95% CI: 1.51-7.75, P = 0.003. However, the significance levels of NT-proBNP, age and LVEF were underpowered in the regression model. Two variables, AF and LAD ≥ 45 mm, predicted the PH-HFpEF incidence (C-statistic = 0.773, 95% CI: 0.695-0.852, P < 0.001). CONCLUSIONS: Two parameters associated with electrical and anatomical remodelling of the left atrium were related to the incidence of PH in HFpEF patients with CVD.

ALDH2 rs671 polymorphism and the risk of heart failure with preserved ejection fraction (HFpEF) in patients with cardiovascular diseases.

Aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism is an established genetic risk of hypertension, diabetes, and coronary heart diseases in Asian population. Previous experimental data showed ALDH2 regulated inflammation, a potential mechanism of heart failure with preserved ejection fraction (HFpEF). However, clinically, the association between ALDH2 polymorphism and incidence of HFpEF remains unknown. In this prospective cross-sectional study, ALDH2 genotyping was performed in 613 consecutive patients enrolled with cardiovascular diseases (CVDs), including hypertension, coronary heart diseases, and/or diabetes mellitus, with normal left ventricular ejection fraction (LVEF). HFpEF was diagnosed according to symptoms and/or signs of dyspnea, fatigue or ankle swelling, N-terminal pro-B-Type natriuretic peptide (NT pro-BNP ≥ 280 pg/mL), LVEF ≥ 50%, and at least one additional criterion: left atrial enlargement (left atrial diameter > 40 mm), diastolic dysfunction (E/E' ≥ 13 or E'/A' < 1) or concurrently with atrial fibrillation. Finally, of 613 patients with CVD, 379 patients (61.8%) were assigned to the wild-type ALDH2*1/*1 group and 234 patients (38.2%) to the mutation-type ALDH2*2 group according to genotyping results. Sixty-nine patients (11.3%) were diagnosed with HFpEF. In ALDH2*2 group, the occurrence of HFpEF was higher (15.4% vs. 8.7%, p = 0.011) than that in ALDH2*1/*1 group. Leukocyte count, the indicator of systemic inflammation, was significantly higher (6.9 ± 2.4 × 109/L vs. 6.5 ± 1.9 × 109/L, p = 0.010) in ALDH2*2 group compared to ALDH2*1/*1 group. In conclusion, ALDH2*2 variant is associated with the risk of HFpEF in patients with CVD. Increased systemic inflammation probably involved in this disease process.

Risks of incident heart failure with preserved ejection fraction in Chinese patients hospitalized for cardiovascular diseases.

BACKGROUND: Endogenous aldehyde damages DNA and potentiates an ageing phenotype. The aldehyde dehydrogenase 2 (ALDH2) rs671 polymorphism has a prevalence of 30%-50% in Asian populations. In this study, we aimed to analyze risk factors contributing to the development of heart failure with preserved ejection fraction (HFpEF) along with the genetic exposure in Chinese patients hospitalized with cardiovascular diseases (CVD). METHODS: From July 2017 to October 2018, a total of 770 consecutive Chinese patients with normal left ventricular ejection fractions (LVEF) and established CVD (hypertension, coronary heart diseases, or diabetes) were enrolled in this prospective cross-sectional study. HFpEF was defined by the presence of at least one of symptom (dyspnoea and fatigue) or sign (rales and ankle swelling) related to heart failure; N-terminal pro-B-Type natriuretic peptide (NT pro-BNP ≥ 280 pg/mL); LVEF ≥ 50%; and at least one criterion related to elevated ventricular filling pressure or diastolic dysfunction (left atrial diameter > 40 mm, E/E' ≥ 13, E'/A' < 1 or concurrent atrial fibrillation). Logistic regression was performed to yield adjusted odds ratios (ORs) for HFpEF incidence associated with traditional and/or genetic exposures. RESULTS: Finally, among 770 patients with CVD, 92 (11.9%) patients were classified into the HFpEF group according to the diagnostic criteria. The mean age of the participants was 67 ± 12 years, and 278 (36.1%) patients were females. A total of 303 (39.4%) patients were ALDH2*2 variant carriers. In the univariate analysis, eight exposures were found to be associated with HFpEF: atrial fibrillation, ALDH2*2 variants, hypertension, age, anaemia, smoking, alcohol consumption and sex. Multivariable logistic regression showed that 4 'A' variables (atrial fibrillation, ALDH2*2 variants, age and anaemia) were significantly associated with an increased risk of HFpEF. Atrial fibrillation was associated with a 3.8-fold increased HFpEF risk (95% CI: 2.21-6.61, P < 0.001), and the other three exposures associated with increased HFpEF risk were the ALDH2*2 variant (OR = 2.41, 95% CI: 1.49-3.87, P < 0.001), age (OR = 2.14, 95% CI: 1.27-3.60, P = 0.004), and anaemia (OR = 1.79, 95% CI: 1.05-3.03, P = 0.032). These four variables predicted HFpEF incidence in Chinese CVD patients (C-statistic = 0.745, 95% CI: 0.691-0.800, P < 0.001). CONCLUSIONS: 4 A traits (atrial fibrillation, ALDH2*2 variants, age and anaemia) were associated with an increased risk of HFpEF in Chinese CVD patients. Our results provide potential clues to the aetiology, pathophysiology and therapeutic targets of HFpEF.

Alternaria yunnanensis sp. nov., a New Alternaria Species Causing Foliage Spot of Rubber Tree in China.

A new species of Alternaria causing leaf spots on the rubber tree (Hevea brasiliensis) in Yunnan, China, was isolated, examined, and illustrated. Morphologically, it belongs to the section Porri of Alternaria, which produces relatively large conidia and a simple or branched, filamentous long beak. It is, however, characterized by conidiophores gradually enlarging near the apex into a clavate conidiogenous cell and long ellipsoid to obclavate, smooth-walled conidia with a long filamentous beak. Molecular phylogenetic analyses based on ITS rDNA, GAPDH, and TEF1-alpha sequences demonstrate that the phytopathogen falls in the clade of the section Porri, being most closely related to A. sidae, A. sennae, A. deseriticola, A. cyamopsidis, A. rostellata, A. nitrimali, A. crassa, and A. thunbergiae.

Microinjection of resveratrol into rostral ventrolateral medulla decreases sympathetic vasomotor tone through nitric oxide and intracellular Ca2+ in anesthetized male rats.

AIM: To define the effect of resveratrol (RES) on the central regulation of blood pressure (BP), heart rate (HR), and renal sympathetic nerve activity (RSNA). METHODS: RES was microinjected into the rostral ventrolateral medulla (RVLM), and BP, HR, and RSNA were recorded simultaneously in anesthetized rats. RESULTS: A microinjection of RES (20, 40, and 80 micromol/L, 0.2 microL) into the RVLM dose dependently decreased BP, HR, and RSNA. Pretreatment with an anti-estrogen tamoxifen (100 micromol/L, 0.2 microL) did not affect the effects of RES. Pretreatment with NG-nitro- L-arginine methyl ester (100 micromol/L, 0.2 microL), an inhibitor of nitric oxide (NO) synthase, could completely abolish the effect of RES. A prior microinjection of Bay K8644 (500 nmol/L, 0.2 microL), an agonist of calcium channels, could also abrogate the effect of RES. Prior administration of a potent inhibitor of tyrosine phosphatase, sodium orthovanadate (1 mmol/L, 0.2 microL), could partially attenuate the inhibitory effect of RES. CONCLUSION: The results suggest that a microinjection of RES into the RVLM inhibits BP, HR, and RSNA. The effects may be mediated by NO synthesis and a decrease in Ca2+ influx, in which protein tyrosine kinase is involved.

Hydrogen sulfide facilitates carotid sinus baroreceptor activity in anesthetized male rats.

BACKGROUND: It has been reported that hydrogen sulfide (H(2)S) could relax vascular smooth muscle by direct activation of K(ATP) channels and hyperpolarization of the membrane potential. Recently, our study has shown that H(2)S facilitated carotid baroreflex. This study was conducted to investigate the effect of H(2)S on carotid baroreceptor activity (CBA). METHODS: The functional curve of carotid baroreceptor (FCCB) was constructed and the functional parameters of carotid baroreceptor were measured by recording sinus nerve afferent discharge in anesthetized male rats with perfused isolated carotid sinus. RESULTS: H(2)S (derived from NaHS) 25, 50 and 100 micromol/L facilitated CBA, which shifted FCCB to the left and upward. There was a marked increase in peak slope (PS) and peak integral value of carotid sinus nerve charge (PIV) in a concentration-dependent manner. Pretreatment with glibenclamide (20 micromol/L), a K(ATP) channel blocker, the above effects of H(2)S on CBA were abolished. Pretreatment with Bay K8644 (an agonist of calcium channels, 500 nmol/L) eliminated the role of H(2)S on CBA. An inhibitor of cystathionine gamma-lyase (CSE), DL-propargylglycine (PPG, 200 micromol/L) inhibited CBA in male rats and shifted FCCB to the right and downward. CONCLUSIONS: Our results suggest that exogenous H(2)S exerts a facilitatory role on isolated CBA through opening K(ATP) channels and further closing the calcium channels in vascular smooth muscle. Endogenous H(2)S may activate CBA in vivo.

Cepharanthine hydrochloride reverses P­glycoprotein-mediated multidrug resistance in human ovarian carcinoma A2780/Taxol cells by inhibiting the PI3K/Akt signaling pathway.

Ovarian cancer has the highest mortality rate among gynecologic malignant tumors. The major obstacle to treatment success is multidrug resistance (MDR) to chemotherapy drugs. Cepharanthine hydrochloride (CH), a natural alkaloid-derived compound, has shown MDR reversal potency in several tumor cell lines; however, the molecular mechanism is not entirely known. In the present study, we assessed whether CH sensitized malignant cells to chemotherapy drugs in ovarian cancer and explored the relevant mechanism. We found that CH reduced the IC50 value of paclitaxel and increased intracellular rhodamine-123 accumulation in human ovarian cancer A2780/Taxol cells in a concentration-dependent manner. Reverse transcription polymerase chain reaction and western blot assay demonstrated that CH inhibited MDR1 expression as indicated by reduced mRNA and protein levels in A2780/Taxol cells. In addition, the inhibitory effect was strengthened after CH was combined with the specific PI3K/Akt signaling pathway inhibitor LY294002. Furthermore, p­Akt expression decreased gradually with the concentration of CH (2, 4 and 8 µM). Taken together, these findings indicated that CH reversed P­glycoprotein-mediated MDR in A2780/Taxol cells by inhibiting the PI3K/Akt signaling pathway.

Cultivation of oleaginous Rhodotorula mucilaginosa in airlift bioreactor by using seawater.

The enormous water resource consumption is a concern to the scale-up fermentation process, especially for those cheap fermentation commodities, such as microbial oils as the feedstock for biodiesel production. The direct cultivation of oleaginous Rhodotorula mucilaginosa in a 5-L airlift bioreactor using seawater instead of pure water led to a slightly lower biomass being achieved, at 17.2 compared to 18.1 g/L, respectively. Nevertheless, a higher lipid content of 65 ± 5% was measured in the batch using seawater as compared to the pure water batch. Both the salinity and osmotic pressure decreased as the cultivation time increased in the seawater batch, and these effects may contribute to the high tolerance for salinity. No effects were observed for the seawater on the fatty acid profiles. The major components for both batches using seawater and pure water were C16:0 (palmitic acid), C18:1 (oleic acid) and C18:2 (linoleic acid), which together accounted for over 85% of total lipids. The results of this study indicated that seawater could be a suitable option for scaling up the growth of oleaginous R. mucilaginosa, especially from the perspective of water resource utilization.

[Designation and evaluation of antisense oligodeoxynucleotides targeted to glial glutamate transporter-1a].

OBJECTIVE: The present study was undertaken to design antisense oligodeoxynucleotides (AS-ODNs) of glial glutamate transporter-la (GLT-1a) and to evaluate the effectiveness of the designed AS-ODNs on the expression of GLT-1a. METHODS: Five sequences of GLT-1a AS-ODNs were designed according to the C terminus specific sequences of GLT-1a mRNA using antisense design software of IDT Com- pany. Western blot analysis was used to evaluate the inhibition effects of the five GLT-1a AS-ODNs on the expression of GLT-la. RESULTS: The sequence of GLT-1a AS-ODNs with sequence of 5'-GGTTCTTCCTCAACACTGCA-3' could specifically inhibit the expression of GLT-1a in the hippocampal CA1 subfield of rats, while it had no effect on the expression of GLT-1b. This sequence showed similar inhibition on the expression of GLT-la in sham and ceftriaxone (Cef)-treated rats. It could also significantly inhibit the cerebral ischemic preconditioning (CIP)-induced up-regulation in the expression of GLT-1a. The magnitude of the inhibition in sham, Cef- or CIP-treated rats was similar by more than 60%. CONCLUSION: From the designed five sequences of GLT-1a AS-ODNs, we obtained an effective sequence which can specifically inhibit the expression of GLT-1a.

Cholecystokinin octapeptide inhibits carotid sinus baroreflex in anesthetized rats.

The purpose of this study was to determine the effect of cholecystokinin octapeptide (CCK-8) on carotid sinus baroreflex in 36 anesthetized male rats by isolated carotid sinus perfusion in vivo. The results obtained are as follows. (1) By perfusion with CCK-8 (0.1, 0.5, 1.0 micromol/L), the functional curve of baroreflex was shifted to the right and upward, with a decrease in peak slope (PS) (p<0.001) and a reflex decrease (RD) in mean arterial pressure, while the threshold pressure (TP) and saturation pressure (SP) were significantly increased. Among the functional parameters of carotid sinus baroreflex, the changes in RD, PS and TP were dose-dependent. (2) Pretreatment with proglumide (100 micromol/L), a nonselective CCK receptor antagonist, the inhibitory effect of CCK-8 (0.5 micromol/L) on the baroreflex was significantly attenuated. (3) Pretreatment with L-NAME (100 micromol/L), an inhibitor of nitric oxide (NO) synthase, did not affect the inhibitory action of CCK-8 (0.5 micromol/L). (4) Preperfusion with Bay K 8644 (500 nmol/L), an agonist of calcium channel, could attenuate the effect of CCK-8 (0.5 micromol/L). It is suggested that the inhibitory action of CCK-8 on the baroreflex may be mediated by the activation of its receptors in the carotid sinus baroreceptor, leading to an inhibition of stretch-sensitive channels and a decrease in Ca(2+) influx. However, NO released from the endothelium seems not to be involved in the mechanism of this effect.

Intrarenal artery injection of L-arginine inhibits spontaneous activity of renal afferent nerve fibers.

The purpose of this study was to determine the effect of intrarenal artery injection of L-arginine on multi- and single-unit spontaneous discharges of renal afferent nerve fibers in anesthetized rabbits. The results obtained are as follows: (1) intrarenal artery injection of L-arginine (0.05, 0.24, and 0.48 mmol/kg) decreased the renal afferent nerve activity (ARNA) in a dose-dependent manner with arterial pressure unchanged; (2) pretreatment with a nitric oxide synthase inhibitor L-NAME (N6-nitro-L-arginine methylester, 0.11 mmol/kg), completely abolished the effect of L-arginine; and (3) intrarenal artery injection of a nitric oxide donor SIN-1 (3-morpholinosydnonimine, 3.75 micromol/kg) also resulted in an inhibition of ARNA. The results suggest that intrarenal artery injection of NO precursor (L-arginine) and donor (SIN-1) can inhibit ARNA in anesthetized rabbits.

Injection of adenosine into the renal artery activates spontaneous activity of renal afferent nerve fibers.

The effects of injection of adenosine into the renal artery on multi- and single-unit spontaneous discharges of renal afferent nerve fibers were investigated in anesthetized rabbits. The results obtained are as follows: (1) injection of 50, 100, and 200 nmol/kg adenosine into the renal artery increased the renal afferent nerve activity (ARNA) in a dose-dependent manner with unchanged arterial pressure; (2) pretreatment with 8-cyclopenthl-1,3-dipropylxanthine (DPCPX, 160 nmol/kg), an adenosine A1 receptor antagonist, partly abolished the effect of adenosine; and (3) pretreatment with a nitric oxide synthase inhibitor N(omega)-nitro-L-arginine methylester (L-NAME, 0.1 mmol/kg) significantly enhanced the ARNA response to adenosine. The results suggest that injection of adenosine into the renal artery activates ARNA via adenosine receptors in anesthetized rabbits and that nitric oxide may be involved in regulating the activity of renal sensory nerve fibers as an inhibitory neurotransmitter.