[Silent pulmonary shadows].

An elderly woman with a 1-year history of pulmonary shadows was admitted because of intermittent cough and sputum production for 2 months. Chest computed tomography (CT) scans showed bilateral consolidations and ground-glass opacities, with areas of low attenuation inside consolidative opacities on the mediastinal window. Previous history of radiotherapy for nasopharyngeal carcinoma and long-term use of a compound menthol nasal drops provided were important clues to the diagnosis. CT scan-guided needle lung biopsy and bronchoalveolar lavage were performed, and lipid-laden macrophages were confirmed in both bronchoalveolar lavage and lung tissue. Final diagnosis of exogenous lipoid pneumonia was made on the basis of her risk factors for aspiration, history of oil exposure, and classic radiological and histopathological features. Symptoms improved after discontinuation of causative exposure. It is important for clinicians to raise awareness of exogenous lipoid pneumonia and other aspiration lung diseases.

[Marked improvement in rheumatoid lung nodules after treatment with tocilizumab combined with glucocorticoids and leflunomide: a case report and literature review].

Rheumatoid arthritis (RA), a chronic autoimmune disorder, is characterized by erosive inflammation of bone and cartilage, leading to progressive joint destruction. Pulmonary involvement occurs in approximately 60% of RA patients, manifests most commonly as interstitial lung disease and, less commonly, as rheumatoid lung nodules. Here, we report a 50-year-old woman, non-smoker, with recurrent cough and sputum of 7 years' duration, accompanied by a chest CT showing multiple cavitary nodules in both lungs. She had been treated empirically at several medical centers and was finally diagnosed with rheumatoid lung nodules. Marked improvement in rheumatoid lung nodules was observed after treatment with tocilizumab in combination with glucocorticoids and leflunomide. The aim of this study was to improve clinicians' understanding of rheumatoid lung nodules by analyzing the clinical features, diagnosis, and treatment of this case, and reviewing the relevant medical literature.

[Expression of MSI1 and HER2 in mammary Paget's disease and their correlation with clinicopathological features and prognosis].

Objective: To investigate the expression of MSI1 and HER2 in mammary Paget's disease, and the correlation between the expression levels of MSI1 and HER2 and the clinicopathologic characteristics and prognosis of the patients. Methods: Clinical data and paraffin-embedded specimens of 34 pairs of mammary Paget's disease and underlying breast cancer were collected at the Department of Pathology, Affiliated Lianyungang Oriental Hospital of Xuzhou Medical University from March 2011 to December 2019. Immunohistochemistry was used to detect the expression of MSI1 and HER2 in mammary Paget's disease and the accompanying breast cancer, and to analyze the correlation between the expression levels of MSI1 and HER2 and their clinicopathologic features, as well as their influence on prognosis. Results: In mammary Paget's disease, the positive rate of MSI1 was 91.2% (31/34) and the positive rate of HER2 was 88.2% (30/34); the expression of MSI1 and HER2 was positively correlated (P=0.001, r=0.530). The expression of MSI1 was positively correlated with menopausal status (r=0.372, P=0.030) and lymph node metastasis (r=0.450, P=0.008). HER2 expression was positively correlated with menopausal status (r=0.436, P=0.010), and negatively correlated with ER expression (r=-0.365, P=0.034). The co-expression of MSI1 and HER2 was positively correlated with age (r=0.347, P=0.044) and menopausal status (r=0.496, P=0.003), and negatively correlated with ER expression (r=-0.461, P=0.006). Conclusions: MSI1 and HER2 are highly expressed in mammary Paget's disease and their expression levels are positively correlated. The correlation analysis between clinicopathological features and prognosis suggests that both of them may be involved in the occurrence and development of mammary Paget's disease and are potential therapeutic targets for mammary Paget's disease.

[COL11A1 regulates PI3K/Akt/GSK-3ß pathway and promotes human lung adenocarcinoma primary cell migration and invasion].

Objective: To investigate the role and mechanism of COL11A1 in lung adenocarcinoma migration and invasion. Methods: Surgical pathological tissues of 4 patients with lung adenocarcinoma admitted to the Affiliated Hospital of Guizhou Medical University from September to November 2020 were used. Immunohistochemical methods were used to identify lung adenocarcinoma tissues, para-cancerous tissues and parallel transcriptome sequencing. Genetic prognostic analysis was conducted by TCGA and GTEx databases.The expression level of COL11A1 gene in lung adenocarcinoma and adjacent tissues was detected by Western blotting.The primary human lung adenocarcinoma cells cultured. The COL11A1 siRNA was transfected into primary human lung adenocarcinoma cells, then the transcriptome sequencing of differential genes was performed,and KEGG enrichment analysis of differential gene enrichment pathway was conducted. Protein expression and phosphorylation were detected by Western blot method. Cell migration was detected by scratch healing test. Cell proliferation was detected by CCK8 method and invasion ability was detected by Transwell method. Results: Ten differentially expressed genes were screened by transcription sequencing in lung adenocarcinoma. Prognostic analysis of single gene showed that COL11A1 gene expression level was correlated with survival rate (P<0.001). The expression of COL11A1 in lung adenocarcinoma was higher than that in adjacent tissues by Western blot (P<0.001). Transcriptome sequencing of COL11A1 siRNA transfection into primary human lung adenocarcinoma cells showed that differential genes were concentrated in PI3K-akt pathway. The expression of tumor suppressor gene PTEN in siRNA transfection group was significantly higher than that in control group and negative transfection group by Western blot. The expression of Aktp-Akt 473 p-Akt 308 p-PTENp-PDK1p-c-Rafp-GSK-3 ß was down-regulated (all P<0.05).Compared with the negative control group, the ability of migration, proliferation and invasion of primary human lung adenocarcinoma cells in siRNA transfection group decreased (all P<0.05). COL11A1 regulates PI3K/Akt/GSK-3 ß pathway to promote migration and invasion of primary human lung adenocarcinoma cells. Conclusion: COL11A1 regulates PI3K/Akt/GSK-3 ß pathway to promote migration and invasion of primary human lung adenocarcinoma cells.

[MiR-340 mediates the involvement of high mobility group box 1 in the pathogenesis of liver fibrosis].

Objective: To explore the pathogenic mechanism of the miR-340/high mobility group box 1 (HMGB1) axis in the formation of liver fibrosis. Methods: A rat liver fibrosis model was established by injecting CCl(4) intraperitoneally. miRNAs targeting and validating HMGB1 were selected with gene microarrays after screening the differentially expressed miRNAs in rats with normal and hepatic fibrosis. The effect of miRNA expressional changes on HMGB1 levels was detected by qPCR. Dual luciferase gene reporter assays (LUC) was used to verify the targeting relationship between miR-340 and HMGB1. The proliferative activity of the hepatic stellate cell line HSC-T6 was detected by thiazolyl blue tetrazolium bromide (MTT) assay after co-transfection of miRNA mimics and HMGB1 overexpression vector, and the expression of extracellular matrix (ECM) proteins type I collagen and α-smooth muscle actin (SMA) was detected by western blot. Statistical analysis was performed by analysis of variance and the LSD-t test. Results: Hematoxylin-eosin and Masson staining results showed that the rat model of liver fibrosis was successfully established. Gene microarray analysis and bioinformatics prediction had detected eight miRNAs possibly targeting HMGB1, and animal model validation had detected miR-340. qPCR detection results showed that miR-340 had inhibited the expression of HMGB1, and a luciferase complementation assay suggested that miR-340 had targeted HMGB1. Functional experiments results showed that HMGB1 overexpression had enhanced cell proliferation activity and the expression of type I collagen and α-SMA, while miR-340 mimics had not only inhibited cell proliferation activity and the expression of HMGB1, type I collagen, and α-SMA, but also partially reversed the promoting effect of HMGB1 on cell proliferation and ECM synthesis. Conclusion: miR-340 targets HMGB1 to inhibit the proliferation and ECM deposition in hepatic stellate cells and plays a protective role during the process of liver fibrosis.

[Clinical value of new coagulation biomarkers in pediatric sepsis].

Objective: To evaluate the clinical value of new coagulation biomarkers including soluble thrombomodulin (sTM) and tissue plasminogen activator inhibitor complex (t-PAI·C) for the diagnosis and prognosis of sepsis in children. Methods: The prospective observational study enrolled 59 children who were diagnosed with sepsis including severe sepsis and septic shock in the Department of Pediatric Critical Care Medicine of Shanghai Children's Medical Center affiliated to the Medical College of Shanghai Jiao Tong University from June 2019 to June 2021. The sTM, t-PAI·C and conventional coagulation tests were detected on illness day one of sepsis. Twenty healthy children were selected as the control group, and the above parameters were detected on the day of inclusion. Children with sepsis were divided into survival group and non-survival group according to prognosis at discharge. Baseline comparisons between groups were performed using Mann-Whitney U test. Multivariate Logistic regression analysis was used to evaluate the risk factors for the diagnosis and prognosis of sepsis in children. Receiver operating characteristic (ROC) curve was conducted to evaluate the predictive values of above variables for the diagnosis and prognosis of sepsis in children. Results: The sepsis group included 59 patients (39 boys and 20 girls), aged 61(22, 136)months. There were 44 patients in the survival group and 15 patients in the non-survival group, respectively. The control group consisted of 20 boys, aged 107 (94,122) months. Patients in the sepsis group had higher sTM and t-PAI·C ((12 (9, 17)×103 vs. 9(8, 10)×103 TU/L, 10(6, 22) vs. 2 (1, 3) µg/L, Z=-2.15, -6.05, both P<0.05) compared with children in the control group. The t-PAI·C was superior to sTM for the diagnosis of sepsis. The areas under the curve (AUC) of t-PAI·C and sTM for the diagnosis of sepsis were 0.95 and 0.66, respectively, and the optimal cut-off value were 3 µg/L and 12×103 TU/L, respectively. Patients in the survival group had lower sTM (10 (8, 14)×103 vs. 17 (11, 36)×103 TU/L, Z=-2.73, P=0.006) than those in the non-survival group. Logistic regression analysis showed that sTM was a risk factor for death at discharge (OR=1.14, 95%CI 1.04-1.27, P=0.006). The AUC of sTM and t-PAI·C for predicting death at discharge were 0.74 and 0.62, respectively, and the optimal cut-off values were 13×103 TU/L and 6 µg/L, respectively. The AUC of sTM combined with platelet counts for predicting death at discharge was 0.89, which was superior to sTM and t-PAI·C. Conclusion: The sTM and t-PAI·C had clinical application values in diagnosing and predicting prognosis in pediatric sepsis.

[Prevalence and influencing factors of deciduous dental caries among preschool children in Qingdao city in 2019].

In 2019, the rate of primary tooth caries rate among 1 598 preschool children in Shinan District and Shibei District of Qingdao was 59.4%. The multivariate logistic regression model showed that compared with children ≤ 2 years old with history of iron deficiency anemia (IDA), suffering IDA, breastfeeding to 2 years old and no tooth melanin, children ≤ 2 years old without history of IDA, not suffering IDA, breastfeeding to less than 2 years old and heavy tooth melanin had a lower risk of primary tooth caries, with OR (95%CI) values about 0.328 (0.197-0.549), 0.354 (0.208-0.603), 0.636 (0.437-0.926) and 0.301 (0.143-0.635), respectively.

LncRNA ZFPM2-AS1 aggravates the malignant development of breast cancer via upregulating JMJD6.

OBJECTIVE: The purpose of this study was to explore the expression pattern of long non-coding RNA (lncRNA) ZFPM2-AS1 in breast cancer (BC) tissues, and its biological influence on clinical features and prognosis in BC patients. PATIENTS AND METHODS: ZFPM2-AS1 levels in 52 paired BC tissues and adjacent normal ones were detected. Then, the relationship between ZFPM2-AS1 level and clinical features in BC patients was analyzed. Regulatory effects of ZFPM2-AS1 on proliferative and migratory abilities in MCF-7 and SKBR3 cells were assessed. In addition, in vivo regulation of ZFPM2-AS1 in nude mice bearing BC was evaluated. Finally, the interaction between ZFPM2-AS1 and JMJD6 and the involvement of ZFPM2-AS1 in the development of BC were illustrated. RESULTS: The results showed that ZFPM2-AS1 was upregulated in BC tissues, and its high level was linked to advanced tumor stage, high rates of lymphatic metastasis, and distant metastasis, as well as poor prognosis in BC. The knockdown of ZFPM2-AS1 suppressed proliferative and migratory abilities in BC cells. In addition, JMJD6 was verified to be the downstream gene binding to ZFPM2-AS1, which was highly expressed in BC tissues and positively regulated by ZFPM2-AS1. In vivo knockdown of ZFPM2-AS1 in nude mice bearing BC showed a smaller tumor volume and lower tumor weight than controls. In addition, JMJD6 was downregulated in BC tumors extracted from mice with silenced ZFPM2-AS1. CONCLUSIONS: LncRNA ZFPM2-AS1 is upregulated in BC and linked to tumor stage, metastasis, and prognosis in BC patients. It aggravates the malignant development of BC via upregulating JMJD6.

[The role of EBUS-TBNA in the systematic evaluation of lymph node staging and resectability analysis in non-small cell lung cancer].

Objective: To evaluate the role of endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) in lymph node staging and resectability assessment of patients with non-small cell lung cancer (NSCLC). Methods: The clinical data of 154 patients with NSCLC who underwent EBUS-TBNA from March 2015 to December 2018 were collected. All accessible mediastinal and hilar lymph nodes were systematically explored and punctured using EBUS-TBNA. EBUS-TBNA and CT were used for preoperative staging and resectability evaluation. Results: The sensitivity, specificity and accuracy of EBUS-TBNA were 94.2%, 100.0% and 96.0%, respectively, while those of CT were 89.9%, 31.8% and 72.0%, respectively. The differences were statistically significant (P<0.05). The sensitivity, specificity and accuracy of EBUS-TBNA in lymph nodes with short diameter less than 15 mm were 92.4%, 100.0% and 96.0%, respectively, while those of CT were 80.7%, 34.8% and 60.1%, respectively, with statistical differences (P<0.05). The staging of 62 patients was changed, 27 cases were up-regulated and 35 cases were down-regulated. Among them, 32 cases had been changed to resectable. The evaluating resectability of EBUS-TBNA showed excellent consistency with that of pathological results (Kappa=0.95). The sensitivity and specificity were 100.0% and 97.2%, respectively. Conclusion: EBUS-TBNA can systemically evaluate the metastatic status of NSCLC patients and improve the accuracy of preoperative lymph node staging and resectability assessment.

p38 mitogen-activated protein kinase activation in amygdala mediates κ opioid receptor agonist U50,488H-induced conditioned place aversion.

κ opioid receptor agonists produce aversive effects in rodents, however the underlying mechanisms remain unclear. Activation of p38 mitogen-activated protein kinase (MAPK) has been discovered to play a critical role in the modulation of affective behaviors. The present study was undertaken to detect the possible involvement of p38 MAPK in the aversive effects induced by κ opioid receptor activation. We found that the κ opioid receptor agonist trans-(±)-3,4-Dichloro-N-methyl-N-[2-(1-pyrrolidinyl)-cyclohexyl]benzenacetamide methanesulfonate salt (U50,488H) produced significant place aversion in mice as measured by the conditioned place preference procedure, accompanied with significant p38 MAPK activation in the amygdala, but not in the nucleus accumbens and hippocampus. Stereotaxic microinjection of the p38 MAPK inhibitor 4-(4-fluorophenyl)-2-(4-methylsulfonylphenyl)-5-(4-pyridy-l)-1H-imidazole (SB203580) into amygdala significantly inhibited p38 MAPK activation and completely blocked the conditioned place aversion in mice. Thus, these results suggested that activation of p38 MAPK in the amygdala was required to mediate κ opioid receptor-induced aversive behavior.

Design and implementation of a 150 GHz single-channel millimeter wave interferometer on Joint TEXT tokamak.

A simple, single-channel millimeter-wave interferometer system has been designed, fabricated, and installed on the J-TEXT tokamak. For the plasma density anticipated on J-TEXT, a solid-state source operating at 150 GHz has been chosen to minimize errors due to both vibration along the beam path and refraction in the plasma. The new aspect of the interferometer design is to use a subharmonic mixer for detection with a frequency doubled 150 GHz source. It employs a single source which is bias-tuned and modulated with a sawtooth wave form up to 100 kHz in order to generate the intermediate frequency. The 12.5 GHz voltage-controlled oscillator is multiplied to 75 GHz before a final doubler raises it to 150 GHz. A portion of the 75 GHZ power is used for the local oscillator (LO) and is directly connected to the LO input of the subharmonic mixer. The phase is evaluated by a digital phase comparator using a software-based algorithm. Detection noise limits the minimum resolvable phase change with the interferometer to ±0.05 fringe, which corresponds to an averaged electron density change along the chord of ±1.1 × 10(17) m(-2). The maximum measurable electron density is expected to be ∼9 × 10(19) m(-3). A comparison of preliminary results from the millimeter wave interferometer with that from the far-infrared hydrogen cyanide laser (wavelength of 337 µm) interferometer shows good agreement during the pulse flat-top period. The millimeter wave interferometer system will be used as a part of the density feedback control system in the future.

Elevated homocysteine levels in levodopa-treated idiopathic Parkinson's disease: a meta-analysis.

To assess the association between the elevation of plasma homocysteine (Hcy) level and long-term levodopa (L-dopa) therapy in idiopathic Parkinson's disease (PD). We performed a systematic literature review to recruit original studies published up to May 14, 2012. Studies enrolled should be controlled, with specific information of long-term L-dopa application and plasma Hcy in patients with PD. Effects were summarized using standardized mean differences (SMDs) or weighted mean differences (WMDs). Our search enrolled 22 eligible studies. Plasma Hcy levels were significantly higher in L-dopa-treated patients than those in healthy controls [SMD 0.97; 95% confidence interval (CI) 0.80-1.14, P < 0.001], L-dopa-naïve patients with PD (SMD 0.99; 95% CI 0.54-1.44, P < 0.001), and untreated patients (SMD 0.52; 95% CI 0.18-0.86, P < 0.01). However, its levels in untreated patients with PD were not significantly higher than in healthy controls (SMD 0.24; 95% CI -0.03 to 0.51, P > 0.05). Patients with PD treated with L-dopa plus catechol-O-methyltransferase inhibitor (COMT-I) showed lower plasma Hcy concentrations compared with L-dopa-treated patients (WMD 4.62; 95% CI 2.89-6.35, P < 0.001). L-dopa treatment is associated with the increase in plasma Hcy level in patients with PD. COMT-I may attenuate L-dopa-induced elevation of Hcy level.

Synthetic radiation-inducible promoters mediated HSV-TK/GCV gene therapy in the treatment of oral squamous cell carcinoma.

OBJECTIVE: To investigate the therapeutic effect of herpes simplex virus thymidine kinase (HSV-TK) gene mediated by synthetic radiation-inducible promoters in the treatment of oral squamous cell carcinoma (OSCC) in vitro and in vivo. METHODS: The plasmids pcDNA3.1(+)E6-HSV-TK were constructed, in which the HSV-TK genes were mediated by synthetic radiation-inducible promoters. The recombined plasmids were transfected into the Tca8113 cells and golden hamster buccal carcinoma, respectively. Low-dose radiotherapy was used to upregulate the HSV-TK genes expression. HSV-TK mRNA was assayed by RT-PCR. Apoptosis and proliferating cell nuclear antigen were detected respectively by in situ end-labeling and immunohistochemical method. RESULTS: Compared with control group, the comparative survival rate of Tca8113 cells in HSV-TK/GCV/IR group was markedly decreased and the golden hamster buccal carcinoma in HSV-TK/GCV/IR group was obviously suppressed. Up-regulation of HSV-TK gene expression was found in the Tca8113 cells and in the golden hamster buccal carcinoma resulting from exposure to low-dose irradiation. The apoptosis indexes in Tca8113 cells or golden hamster buccal carcinoma with irradiation were markedly higher than those without irradiation. At the same time, the proliferation indexes in Tca8113 cells or golden hamster buccal carcinoma with irradiation were markedly lower than those without irradiation. CONCLUSION: The results indicate that the synthetic radiation-inducible promoters can serve as a molecular switch to adjust the expression of HSV-TK gene in the treatment of OSCC, and low-dose induction radiation can significantly improve therapeutic efficiency.

Lack of effect of protein deprivation-induced intrauterine growth retardation on behavior and corticosterone and growth hormone secretion in adult male rats: a long-term follow-up study.

To further define the neuroendocrine consequences of intrauterine growth retardation (IUGR), we have used a rat model of maternal protein restriction throughout pregnancy to examine the pattern of corticosterone and GH secretion under basal conditions and in response to psychological stress in male offspring at 4, 9, and 18 months of age. The findings were correlated with studies of behavioral activity. Despite a consistent reduction in birth weight and failure of catch-up growth, there were no significant differences in GH secretory profiles between IUGR and control rats at any age. We were unable to demonstrate a difference in the number, amplitude, length, or area of corticosterone secretory pulses between control and IUGR animals; although again, there was a significant decrease with age. The mean peak plasma concentration of corticosterone in response to a noise stress also declined with age but was unaffected by IUGR. There were no consistent, statistically significant differences in behavioral responses between normal control and IUGR animals or between groups of animals at different ages. These results do not, therefore, support the presence of major functional abnormalities in either GH or corticosterone secretory responses in adult male rats subjected to IUGR.

[Production of u-PA with rCHO cell culture on porous microcarriers in serum-free growth medium].

A novel technique was developed to deal with apoptosis in large-scale animal cell culture. By means of replacing part of Cytopore porous microcarriers at regular intervals, a rCHO cell line, which produces urokinase-type plasminogen activitor(u-PA), was cultivated continuously with serum-free medium in a 30 L stirred tank for 91 days. The cell density was maintained at (1.3-2.6) x 10(7)/mL, and > 90% of cells was viable. In order to reduce the effect of cell density on cell growth and expression, a cyclic pressure oscillation was exerted on a 7.5 L reactor headspace to enhance cell expression at high cell density to a certain extent. During the 67 days of medium-replacement culture, the maximal cell density reached 2.64 x 10(7)/mL, and cell viability was always kept above 95% when combined with microcarrier-replacement. Compare to control culture, culture with cyclic pressure oscillation could enhance cell expression level and reduce the ratio of glucose metabolized anaerobically to produce lactate. With four-step purification process, about 80 g u-PA(approximately 90% scu-PA) was recovered from approximately 2100 liters supernatant which contained approximately 135 g u-PA.

Intra-uterine growth retardation results in increased cardiac arrhythmias and raised diastolic blood pressure in adult rats.

OBJECTIVES: Epidemiological evidence in humans suggests that intrauterine growth retardation is associated with an increased risk of hypertension and coronary heart disease in later life. To begin to understand the mechanisms involved, we developed and exploited a rat model of intrauterine growth retardation to assess predisposition to arrhythmias and resting blood pressure levels at defined ages from 4 to 18 months. METHODS: Isolated working heart experiments were carried out on rats that had been subjected to intrauterine growth retardation by prenatal protein deprivation and age-matched male Wistar controls to measure susceptibility to wall stress-induced arrhythmias. In addition, resting systolic and diastolic blood pressures were measured in conscious rats via an indwelling arterial catheter. RESULTS: Hearts from intrauterine growth retarded animals showed significantly more ventricular premature beats and more episodes of ventricular tachycardia at all ages examined (4, 9 and 18 months), and at 4 and 18 months, a reduction in coronary blood flow. Diastolic pressure was significantly raised by intrauterine growth retardation in both groups examined (4 and 9 months). CONCLUSIONS: Protein malnutrition during the intrauterine period results in profound intrauterine growth retardation that is associated with a raised diastolic blood pressure and an increased predisposition to cardiac arrhythmias in later life. These results are consistent with epidemiological observations made in human populations, and as similar pathophysiological changes may operate in both situations, intrauterine protein deprivation may be a useful model to help define some of the mechanisms involved.

In vitro formation by reverse dialysis of collagen gels containing highly oriented arrays of fibrils.

Acid extracts of rat tail tendon were subjected to reverse dialysis against 0.5% PEG at 4 degrees C in an attempt to induce liquid crystallization. After 48 h, gel and fibril formation were initiated by continuing dialysis at 20 degrees C against the same PEG solution adjusted to pH 7.4. The inclusion of calcium- or magnesium chloride (final concentration 0.3-33 mM) in the collagen solution before dialysis resulted in strongly birefringent gels that showed a progressive rotation of the slow axis of birefringence with increasing distance from the lateral margin of the gel. The gels contained fibers running predominantly in the plane of the flattened gel and crossing at angles of between 55 degrees and 90 degrees. We suggest that liquid crystallization is responsible for this phenomenon and that it might be possible to exploit this to produce materials for tissue engineering.

[Pressor effect of substance P applied to the pressor area of ventral surface of medulla oblongata and the underlying mechanism in rabbits].

Experiments were performed on urethane anesthetized and artificially ventilated rabbits. The results were as follows. Application of substance P (SP) to the pressor area of ventral surface of medulla oblongata (VSMp) elicited a dose-dependent increase in blood pressure (BP), but no significant change in heart rate. The pressor response of SP was blocked by pretreatment with SP receptor antagonist (DSP) in VSMp. Application of DSP alone to VSMp elicited a significant decrease in BP. The pressor response of SP was attenuated when VSMp was pretreated with phentolamine or prazosine, whereas pretreatment with yohimbin or propranolol was without effect. Application of SP to VSMp elicited an increase in renal sympathetic nerve discharge (RSND) in association with pressor response; both these responses were blocked by pretreatment with DSP in VSMp. Application of DSP alone to VSMp elicited a significant decrease in RSND and BP. The above results indicate that SP has a pressor effect in VSMp due to activation of SP receptor mediated by alpha 1-receptor. The pressor effect of SP may be mainly due to an increase of peripheral vascular resistance induced by the augmented sympathetic nerve activity. In summary, it appears that endogenous SP in VSMp plays an important role in maintaining sympathetic tone and BP level.