1
|
Li L, Wang MY, Jiang HB, Guo CR, Zhu XD, Yao XQ, Zeng WW, Zhao Y, Chi LK. Bisphenol A induces testicular oxidative stress in mice leading to ferroptosis. Asian J Androl 2022; 25:375-381. [PMID: 36153926 DOI: 10.4103/aja202266] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Bisphenol A is a common environmental factor and endocrine disruptor that exerts a negative impact on male reproductive ability. By exploring bisphenol A-induced testicular cell death using the Institute of Cancer Research (ICR) mouse model, we found that a ferroptosis phenomenon may exist. Mice were divided into six groups and administered different doses of bisphenol A via intragastric gavage once daily for 45 consecutive days. Serum was then collected to determine the levels of superoxide dismutase and malondialdehyde. Epididymal sperm was also collected for semen analysis, and testicular tissue was collected for ferritin content determination, electron microscope observation of mitochondrial morphology, immunohistochemistry, real-time quantitative polymerase chain reaction, and western blot analysis. Exposure to bisphenol A was found to decrease sperm quality and cause oxidative damage, iron accumulation, and mitochondrial damage in the testes of mice. In addition, bisphenol A was confirmed to affect the expression of the ferroptosis-related genes, glutathione peroxidase 4 (GPX4), ferritin heavy chain 1 (FTH1), cyclooxygenase 2 (COX2), and acyl-CoA synthetase 4 (ACSL4) in mouse testicular tissues. Accordingly, we speculate that bisphenol A induces oxidative stress, which leads to the ferroptosis of testicular cells. Overall, the inhibition of ferroptosis may be a potential strategy to reduce male reproductive toxicity caused by bisphenol A.
Collapse
Affiliation(s)
- Li Li
- Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Min-Yan Wang
- Department of Pathology, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Hua-Bo Jiang
- Shanghai Key Laboratory of Maternal Fetal Medicine, Department of Fetal Medicine and Prenatal Diagnosis Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai 201203, China
| | - Chun-Rong Guo
- Teaching Experimental Center, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Xian-Dan Zhu
- Laboratory Animal Center, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Xia-Qin Yao
- Department of Obstetrics, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai 201203, China
| | - Wei-Wei Zeng
- Department of Gynecology, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Yuan Zhao
- Laboratory Animal Center, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Ling-Kan Chi
- Reproductive Medicine Center, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| |
Collapse
|
2
|
Liang WJ, Wu DQ, Lyu ZJ, Hu WX, Wang JJ, Zheng JB, Yan Q, Wu WL, Cai GF, Yao XQ, Li Y. [Application of indocyanine green fluorescence proctoscope in rectal cancer surgery]. Zhonghua Wei Chang Wai Ke Za Zhi 2020; 23:1104-1105. [PMID: 33212561 DOI: 10.3760/cma.j.cn.441530-20191030-00466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
3
|
Lyu ZJ, Liang WJ, Wu DQ, Hu WX, Wang JJ, Zheng JB, Yan Q, Wu WL, Cai GF, Yao XQ, Li Y. [Safety and feasibility of indocyanine green injection through accessory incision in laparoscopic right hemicolectomy]. Zhonghua Wei Chang Wai Ke Za Zhi 2020; 23:791-794. [PMID: 32810952 DOI: 10.3760/cma.j.cn.441530-20190715-00274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Objective: To explore the safety and feasibility of indocyanine green (ICG) injection through accessory incision in laparoscopic right hemicolectomy. Methods: A descriptive case series study was carried out. Clinicopathological data of 29 patients with colon cancer undergoing right hemicolectomy at Department of General Surgery, Guangdong Provincial People's Hospital were retrospectively analyzed. All the patients received ICG injection through accessory incision at the beginning of operation. Results: Among 29 patients, 13 were male and 16 were female with a mean age of (60.8±7.7) years and mean body mass index of (24.3±2.8) kg/m(2); 3 were stage I, 19 were stage II, 7 were stage III. Pericolic, intermediate and main lymph nodes could be detected under near infrared fluorescence imaging (NIRFI) in all the cases. No.6 lymph nodes were observed in 3 cases, while no lymph nodes around superior mesenteric vein (SMV) were found. The average number of fluorescent lymph node was 14.2±6.1. The average developing time of fluorescence was (36.2±3.7) minutes. The average number of harvested lymph nodes was 22.4±8.2. There was no extravasation of imaging agent during the operation, and there were no intraoperative complications such as allergies, massive abdominal bleeding, peripheral organ damage, etc. Operative time was (113.1±10.7) minutes, blood loss during operation was (22.4±3.9) ml, ambulatory time was (1.2±0.4) days, time to the first flatus was (1.7±0.7) days, time to the first fluid diet was (0.7±0.4) days, and postoperative hospital stay was (5.8±1.5) days. No operation-associated complications such as anastomotic bleeding, anastomotic leakage, peritoneal bleeding, peritoneal infection, incision infection occurred after operation. Conclusion: ICG injection through accessory incision in laparoscopic right hemicolectomy is safe and feasible.
Collapse
Affiliation(s)
- Z J Lyu
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - W J Liang
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - D Q Wu
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - W X Hu
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - J J Wang
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - J B Zheng
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - Q Yan
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - W L Wu
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - G F Cai
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - X Q Yao
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - Y Li
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| |
Collapse
|
4
|
Lyu ZJ, Liang WJ, Lin ZB, Zhang GR, Wu DQ, Luo YW, Yan Q, Cai GF, Yao XQ, Li Y. [Current practice patterns of preoperative bowel preparation in elective colorectal surgery: a nation-wide survey of Chinese surgeons]. Zhonghua Wei Chang Wai Ke Za Zhi 2020; 23:578-583. [PMID: 32521978 DOI: 10.3760/cma.j.cn.441530-20190611-00238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To understand the current practice of preoperative bowel preparation in elective colorectal surgery in China. Methods: A cross-sectional questionnaire survey was conducted through wechat. The content of the questionnaire survey included professional title of the participants, the hospital class, dietary preparation and protocol, oral laxatives and specific types, oral antibiotics, gastric intubation, and mechanical enema before elective colorectal surgery. A stratified analysis based on hospital class was conducted to understand their current practice of preoperative bowel preparation in elective colorectal surgery. Result: A total of 600 questionnaires were issued, and 516 (86.00%) questionnaires of participants from different hospitals, engaged in colorectal surgery or general surgeons were recovered, of which 366 were from tertiary hospitals (70.93%) and 150 from secondary hospitals (29.07%). For diet preparation, the proportions of right hemicolic, left hemicolic and rectal surgery were 81.59% (421/516), 84.88% (438/516) and 84.88% (438/516) respectively. The average time of preoperative dietary preparation was 2.03 days. The study showed that 85.85% (443/516) of surgeons chose oral laxatives for bowel preparation in all colorectal surgery, while only 4.26% (22/516) of surgeons did not choose oral laxatives. For mechanical enema, the proportions of right hemicolic, left hemicolic and rectal surgery were 19.19% (99/516), 30.04% (155/516) and 32.75% (169/516) respectively. Preoperative oral antibiotics was used by 34.69% (179/516) of the respondents. 94.38% (487/516) of participants were satisfied with bowel preparation, and 55.43% (286/516) of participants believed that preoperative bowel preparation was well tolerated. In terms of preoperative oral laxatives, there was no statistically significant difference between different levels of hospitals [secondary hospitals vs. tertiary hospitals: 90.00% (135/150) vs. 84.15% (308/366), χ(2)=2.995, P=0.084]. Compared with the tertiary hospitals, the surgeons in the secondary hospitals accounted for higher proportions in diet preparation [87.33% (131/150) vs. 76.78% (281/366), χ(2)=7.369, P=0.007], gastric intubation [54.00% (81/150) vs. 36.33% (133/366), χ(2)=13.672, P<0.001], preoperative oral antibiotics [58.67% (88/150) vs. 24.86% (91/366), χ(2)=12.259, P<0.001] and enema [28.67% (43/150) vs. 15.30% (56/366), χ(2)=53.661, P<0.001]. Conclusion: Although the preoperative bowel preparation practice in elective colorectal surgery for most of surgeons in China is basically the same as the current international protocol, the proportions of mechanical enema and gastric intubation before surgery are still relatively high.
Collapse
Affiliation(s)
- Z J Lyu
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - W J Liang
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China; Medical College of Shantou University, Shantou, Guangdong 515000, China
| | - Z B Lin
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - G R Zhang
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - D Q Wu
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - Y W Luo
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - Q Yan
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - G F Cai
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - X Q Yao
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| | - Y Li
- Department of General Surgery, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong 510060, China
| |
Collapse
|
5
|
Chen YS, Lin XH, Li HR, Hua ZD, Lin MQ, Huang WS, Yu T, Lyu HY, Mao WP, Liang YQ, Peng XR, Chen SJ, Zheng H, Lian SQ, Hu XL, Yao XQ. [Etiological analysis and establishment of a discriminant model for lower respiratory tract infections in hospitalized patients]. Zhonghua Jie He He Hu Xi Za Zhi 2019; 40:909-914. [PMID: 29224300 DOI: 10.3760/cma.j.issn.1001-0939.2017.12.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Objective: To analyze the pathogens of lower respiratory tract infection(LRTI) including bacterial, viral and mixed infection, and to establish a discriminant model based on clinical features in order to predict the pathogens. Methods: A total of 243 hospitalized patients with lower respiratory tract infections were enrolled in Fujian Provincial Hospital from April 2012 to September 2015. The clinical data and airway (sputum and/or bronchoalveolar lavage) samples were collected. Microbes were identified by traditional culture (for bacteria), loop-mediated isothermal amplification(LAMP) and gene sequencing (for bacteria and atypical pathogen), or Real-time quantitative polymerase chain reaction (Real-time PCR)for viruses. Finally, a discriminant model was established by using the discriminant analysis methods to help to predict bacterial, viral and mixed infections. Results: Pathogens were detected in 53.9% (131/243) of the 243 cases.Bacteria accounted for 23.5%(57/243, of which 17 cases with the virus, 1 case with Mycoplasma pneumoniae and virus), mainly Pseudomonas Aeruginosa and Klebsiella Pneumonia. Atypical pathogens for 4.9% (12/243, of which 3 cases with the virus, 1 case of bacteria and viruses), all were mycoplasma pneumonia. Viruses for 34.6% (84/243, of which 17 cases of bacteria, 3 cases with Mycoplasma pneumoniae, 1 case with Mycoplasma pneumoniae and bacteria) of the cases, mainly Influenza A virus and Human Cytomegalovirus, and other virus like adenovirus, human parainfluenza virus, respiratory syncytial virus, human metapneumovirus, human boca virus were also detected fewly. Seven parameters including mental status, using antibiotics prior to admission, complications, abnormal breath sounds, neutrophil alkaline phosphatase (NAP) score, pneumonia severity index (PSI) score and CRUB-65 score were enrolled after univariate analysis, and discriminant analysis was used to establish the discriminant model by applying the identified pathogens as the dependent variable. The total positive predictive value was 64.7%(77/119), with 66.7% for bacterial infection, 78.0% for viral infection and 33.3% for the mixed infection. Conclusions: The mostly detected pathogens were Pseudomonas aeruginosa, atypitcal pathogens, Klebsiella pneumoniae, influenza A virus and human cytomegalovirus in hospitalized patients with LRTI in this hospital. The discriminant diagnostic model established by clinical features may contribute to predict the pathogens of LRTI.
Collapse
Affiliation(s)
- Y S Chen
- The Department of Respiratory and Critical Care Medicine, Fujian Province Hospital, Fuzhou 350001, China
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Kwan HY, Huang Y, Yao XQ, Leung FP. Role of cyclic nucleotides in the control of cytosolic Ca2+ levels in vascular endothelial cells. Clin Exp Pharmacol Physiol 2009; 36:857-66. [PMID: 19413591 DOI: 10.1111/j.1440-1681.2009.05199.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
1. Endothelial cells have a key role in the cardiovascular system. Most endothelial cell functions depend on changes in cytosolic Ca(2+) concentrations ([Ca(2+)](i)) to some extent and Ca2+ signalling acts to link external stimuli with the synthesis and release of regulatory factors in endothelial cells. The [Ca(2+)](i) is maintained by a well-balanced Ca(2+) flux across the endoplasmic reticulum and plasma membrane. 2. Cyclic nucleotides, such as cAMP and cGMP, are very important second messengers. The cyclic nucleotides can affect [Ca(2+)](i) directly or indirectly (via the actions of protein kinase (PK) A or PKG-mediated phosphorylation) by regulating Ca(2+) mobilization and Ca(2+) influx. Fine-tuning of [Ca(2+)](i) is also fundamental to protect endothelial cells against damaged caused by the excessive accumulation of Ca(2+). 3. Therapeutic agents that control cAMP and cGMP levels have been used to treat various cardiovascular diseases. 4. The aim of the present review is to discuss: (i) the functions of endothelial cells; (ii) the importance of [Ca(2+)](i) in endothelial cells; (iii) the impact of excessive [Ca(2+)](i) in endothelial cells; and (iv) the balanced control of [Ca(2+)](i) in endothelial cells via involvement of cyclic nucleotides (cAMP and cGMP) and their general effectors.
Collapse
Affiliation(s)
- H Y Kwan
- School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | | | | | | |
Collapse
|
7
|
Yung LM, Wong WT, Leung FP, Yao XQ, Chen ZY, Huang Y. A key role of AT1R in endothelial dysfunction during estrogen deficiency. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1119.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | - ZY Chen
- BiochemistryChinese University of Hong KongHong Kong SARPeople's Republic of China
| | | |
Collapse
|
8
|
YUNG LM, Wong WT, Tian XY, Leung FP, Chen ZY, Yao XQ, Vanhoutte PM, Huang Y. Cranberry juice consumption ameliorates endothelial dysfunction during estrogen deficiency: balance between NO and ROS. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1149.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | - ZY Chen
- BiochemistryChinese University of Hong KongHong Kong SARPeople's Republic of China
| | | | - PM Vanhoutte
- PharmacologyUniversity of Hong KongHong Kong SARPeople's Republic of China
| | | |
Collapse
|
9
|
Tang NLS, Chow CC, Ko GTC, Tai MHL, Kwok R, Yao XQ, Cockram CS. The alpha(1S) subunit of the L-type calcium channel is not a predisposition gene for thyrotoxic periodic paralysis. Clin Endocrinol (Oxf) 2007; 66:229-34. [PMID: 17223993 DOI: 10.1111/j.1365-2265.2006.02713.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Thyrotoxic periodic paralysis (TTP) has been associated with genetic variations in the gene encoding the alpha 1 subunit of the L-type calcium channel (CACNA1S). Mutations in CACNA1S are known to account for the majority of cases of familial hypokalaemic periodic paralysis (HOKPP). In this study we have examined 48 genetic polymorphisms in the CACNA1S gene and genotyped a tagging set of representative polymorphisms to determine the role of this gene in TPP. DESIGN AND PATIENTS A genetic association study was carried out with 98 TPP patients and 162 male thyrotoxic controls. Among 47 polymorphisms evaluated for linkage disequilibrium (LD) and the spectrum of haplotypes in the Chinese population, 31 were selected as tagging single-nucleotide polymorphisms (SNPs) for genotyping the whole sample. A new genotyping protocol was used to analyse an insertion/deletion (I/D) polymorphism. RESULTS We studied the LD among 47 polymorphisms in the CACNA1S gene, which comprised a set of high-density markers with an average of one SNP every 2 kb. Subsequently, 31 tagSNPs were genotyped for all the samples. The gene is composed of three LD blocks. With this block structure, we were confident that variations of the gene were comprehensively covered by the tagSNPs. No significant association was found between the polymorphisms and TPP. CONCLUSION We established the LD structure of this calcium channel subunit gene (CACNA1S) for the first time. However, its genetic variations are not associated with TPP in Chinese patients.
Collapse
Affiliation(s)
- Nelson L S Tang
- Department of Chemical Pathology, Faculty of Medicine, The Chinese Univerisity of Hong Kong SAR, China.
| | | | | | | | | | | | | |
Collapse
|
10
|
Yao XQ, Yang HE. [Clinical observation on integrated traditional Chinese and Western medicine therapy in treating patients with pelvic inflammatory disease: a report of 28 cases]. Zhong Xi Yi Jie He Xue Bao 2006; 4:199-201. [PMID: 16529700 DOI: 10.3736/jcim20060218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Affiliation(s)
- Xia-Qin Yao
- Department of Obstetrics and Gynecology, Pudong Branch, Shanghai First Maternity and Infant Health Hospital, Shanghai 200126, China.
| | | |
Collapse
|
11
|
Chan YC, Yao XQ, Lau CW, Chan FL, He GW, Bourreau JP, Huang Y. The relaxant effect of urocortin in rat pulmonary arteries. ACTA ACUST UNITED AC 2005; 121:11-8. [PMID: 15256268 DOI: 10.1016/j.regpep.2004.03.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2003] [Revised: 03/04/2004] [Accepted: 03/09/2004] [Indexed: 11/16/2022]
Abstract
Urocortin is a potent vasodilator, which plays physiological or pathophysiological roles in systemic circulation. However, little is known about its action on pulmonary circulation. The present study was aimed to characterize some cellular mechanisms underlying the relaxant effect of urocortin in isolated rat pulmonary arteries. Changes in isometric tension were measured on small vessel myographs. Urocortin inhibited U46619-induced contraction with reduction of the maximal response. Urocortin-induced relaxation was independent of the presence of endothelium. Inhibitors of nitric oxide (NO)-dependent dilator, NG-nitro-L-arginine methyl ester or 1H-[1,2,4]oxadizolo[4,3-a]quinoxalin-1-one, did not affect the relaxation. Astressin (100-500 nM), a corticotropin-releasing factor (CRF) receptor antagonist and KT5720, a protein kinase A (PKA) inhibitor reduced urocortin-induced relaxation. Urocortin produced less relaxant effect in 30 mM K+- than U46619-contracted arterial rings. Urocortin did not reduce CaCl2-induced contraction in 60 mM K+-containing solution. Ba2+ (100-500 microM) but not other K+ channel blockers reduced the relaxant responses to urocortin. Urocortin also relaxed the rings preconstricted by phorbol 12,13-diacetae in normal Krebs solution while this relaxation was less in a Ca2+-free solution. Our results show that urocortin relaxed rat pulmonary arteries via CRF receptor-mediated and PKA-dependent but endothelium/NO or voltage-gated Ca2+ channel-independent mechanisms. Stimulation of Ba2+-sensitive K+ channel may contribute to urocortin-induced relaxation. Finally, urocortin relaxed pulmonary arteries partly via inhibition of a PKC-dependent contractile mechanism.
Collapse
Affiliation(s)
- Y C Chan
- Department of Physiology, Chinese University of Hong Kong, Shatin, NT, Hong Kong, China
| | | | | | | | | | | | | |
Collapse
|
12
|
Tang NLS, Chow CC, Ko GTC, Tai MHL, Kwok R, Yao XQ, Cockram CS. No mutation in the KCNE3 potassium channel gene in Chinese thyrotoxic hypokalaemic periodic paralysis patients. Clin Endocrinol (Oxf) 2004; 61:109-12. [PMID: 15212652 DOI: 10.1111/j.1365-2265.2004.02079.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Mutation in KCNE3 gene (Isk-related family potassium voltage-gated channel member 3 gene) was recently associated with the aetiology of thyrotoxic periodic paralysis (TPP). We studied 79 Chinese TPP patients by DNA sequencing of the entire coding sequence of KCNE3 to determine if this gene is the cause of TPP in Chinese patients. DESIGN AND MEASUREMENTS A case-control genetic association study was carried out to determine the role of mutation/polymorphism in KCNE3 gene in the pathogenesis of TPP. Genomic DNA was extracted from peripheral blood samples. DNA sequencing was performed to cover the coding region of the KCNE3 gene for the TPP subjects. Restriction fragment length polymorphism was used to genotype specific sequence variants. subjects Seventy-nine TPP patients (cases) and 111 male thyrotoxic patients without history of paralysis (controls) were identified from thyroid clinic and during acute admission in a teaching hospital. RESULTS No pathogenic mutation in KCNE3 was found in the TPP patients. The reported R83H mutation was also not found in the Chinese TPP patients. In addition, another silent polymorphism, 290T/C, was also not associated with TPP. CONCLUSION The results indicate that mutation in KCNE3 is not a cause of TPP in Chinese patients.
Collapse
Affiliation(s)
- Nelson L S Tang
- Department of Chemical Pathology, Faculty of Medicine, The Chinese University of Hong Kong, Kong Kong.
| | | | | | | | | | | | | |
Collapse
|
13
|
Chan HY, Yao XQ, He GW, Tsang SY, Wong CM, Huang Y. Short‐Term Incubation with Physiological Level of Estrogen Impairs ß
1
‐Adrenoceptor‐Mediated but Enhances ß
2
‐Adrenoceptor Mediated Coronary Relaxation. J Card Surg 2003. [DOI: 10.1046/j.1540-8191.2002.101416.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- HY Chan
- Departments of Physiology and Surgery, Chinese University of Hong Kong, Hong Kong
| | - XQ Yao
- Departments of Physiology and Surgery, Chinese University of Hong Kong, Hong Kong
| | - GW He
- Departments of Physiology and Surgery, Chinese University of Hong Kong, Hong Kong
| | - SY Tsang
- Departments of Physiology and Surgery, Chinese University of Hong Kong, Hong Kong
| | - CM Wong
- Departments of Physiology and Surgery, Chinese University of Hong Kong, Hong Kong
| | - Y Huang
- Departments of Physiology and Surgery, Chinese University of Hong Kong, Hong Kong
| |
Collapse
|
14
|
Tsang SY, Yao XQ, Wong CM, Lau CW, Huang Y. Multiplicity in the Vascular Response to Pinacidil in Rat Mesenteric Artereies. J Card Surg 2003. [DOI: 10.1046/j.1540-8191.2002.101418.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- SY Tsang
- Departments of Physiology, Chinese University of Hong Kong, Hong Kong, China
| | - XQ Yao
- Departments of Physiology, Chinese University of Hong Kong, Hong Kong, China
| | - CM Wong
- Departments of Physiology, Chinese University of Hong Kong, Hong Kong, China
| | - CW Lau
- Departments of Physiology, Chinese University of Hong Kong, Hong Kong, China
| | - Y Huang
- Departments of Physiology, Chinese University of Hong Kong, Hong Kong, China
| |
Collapse
|
15
|
Chan HY, Yao XQ, Tsang SY, Bourreau BP, Chan FL, Huang Y. Role of Endothelium/Nitric Oxide and Cyclic AMP in Isoproterenol Potentiation of 17ß‐Estradiol‐Mediated Vasorelaxation. J Card Surg 2003. [DOI: 10.1046/j.1540-8191.2002.10149.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- HY Chan
- Department of Physiology, Chinese University of Hong Kong and Hong Kong University, Hong Kong, China
| | - XQ Yao
- Department of Physiology, Chinese University of Hong Kong and Hong Kong University, Hong Kong, China
| | - SY Tsang
- Department of Physiology, Chinese University of Hong Kong and Hong Kong University, Hong Kong, China
| | - BP Bourreau
- Department of Physiology, Chinese University of Hong Kong and Hong Kong University, Hong Kong, China
| | - FL Chan
- Department of Physiology, Chinese University of Hong Kong and Hong Kong University, Hong Kong, China
| | - Y Huang
- Department of Physiology, Chinese University of Hong Kong and Hong Kong University, Hong Kong, China
| |
Collapse
|
16
|
Wong CM, Yao XQ, Tsang SY, Huang Y. Different Effects of Estrogen and Progesterone on K
+
Currents Expressed in
Xenopus
Oocytes. J Card Surg 2003. [DOI: 10.1046/j.1540-8191.2002.101419.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- CM Wong
- Department of Physiology, Chinese University of Hong Kong, Hong Kong, China
| | - XQ Yao
- Department of Physiology, Chinese University of Hong Kong, Hong Kong, China
| | - SY Tsang
- Department of Physiology, Chinese University of Hong Kong, Hong Kong, China
| | - Y Huang
- Department of Physiology, Chinese University of Hong Kong, Hong Kong, China
| |
Collapse
|
17
|
Abstract
Berberine, is an alkaloid from Hydrastis canadensis L., Chinese herb Huanglian, and many other plants. It is widely used in traditional Chinese medicine as an antimicrobial in the treatment of dysentery and infectious diarrhea. This manuscript describes cardiovascular effects of berberine and its derivatives, tetrahydroberberine and 8-oxoberberine. Berberine has positive inotropic, negative chronotropic, antiarrhythmic, and vasodilator properties. Both derivatives of berberine have antiarrhythmic activity. Some cardiovascular effects of berberine and its derivatives are attributed to the blockade of K+ channels (delayed rectifier and K(ATP)) and stimulation of Na+ -Ca(2+) exchanger. Berberine has been shown to prolong the duration of ventricular action potential. Its vasodilator activity has been attributed to multiple cellular mechanisms. The cardiovascular effects of berberine suggest its possible clinical usefulness in the treatment of arrhythmias and/or heart failure.
Collapse
Affiliation(s)
- C W Lau
- Department of Physiology, Chinese University of Hong Kong, Shatin, Hong Kong, China
| | | | | | | | | |
Collapse
|
18
|
Abstract
The modulatory effect of the protein kinase C activator was examined on contraction of rat isolated vas deferens induced by constrictive agonists, noradrenaline (NA), ATP, BaCl2 and high K+. Phorbol 12,13-diacetate (PDA, 1 micromol/l) induced a transient extracellular Ca(2+)-dependent contraction while the inactive analogue, 4alpha-phorbol (1 micromol/l) had no effect. PDA significantly enhanced the peak amplitude of the contractile response to NA (0.1-10 micromol/l), ATP (100 micromol/l), Ba2+ (3 mmol/l) or high K+ (30 mmol/l). Staurosporine at 30 nmol/l reduced the enhancing effect of PDA on the agonist-induced contraction. NA (10 micromol/l) produced a phasic contraction followed by a sustained contraction, while ATP induced monophasic contraction. Pretreatment with nifedipine (10 nmol/l) had no effect on the phasic contraction induced by NA, but it significantly reduced ATP- or high K(+)-induced contraction. Staurosporine (30 nmol/l) alone attenuated the peak contractile response induced by NA or ATP but not by Ba2+. NA produced a transient contraction in Ca(2+)-free Krebs solution, and PDA (1 micromol/l) markedly enhanced this effect. These novel data indicate that activation of a protein kinase C-dependent mechanism not only affects contraction mediated by Ca2+ influx through voltage-sensitive Ca2+ channels, but also promotes intracellular Ca2+ release or intracellular Ca(2+)-mediated contractile mechanism in rat vas deferens.
Collapse
Affiliation(s)
- Y Huang
- Department of Physiology, Chinese University of Hong Kong, Shatin, Hong Kong, China.
| | | | | | | | | | | |
Collapse
|
19
|
Huang Y, Yao XQ, Tsang SY, Lau CW, Chen ZY. Role of endothelium/nitric oxide in vascular response to flavonoids and epicatechin. Acta Pharmacol Sin 2000; 21:1119-24. [PMID: 11603286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
AIM To examine the role of endothelium in the vascular responses to flavonoids, baicalein, baicalin, cardamonin, alpinetin, and to purified jasmine green tea (-)epicatechin in the isolated rate mesenteric artery rings. METHODS The isometric contraction was measured by Grass force-displacement transducers. RESULTS Both baicalein and baicalin enhanced the phenylephrine-induced contractile response in the endothelium-intact rings. This enhancement was abolished by pretreatment with the nitric oxide inhibitor NG-nitro-L-arginine or in the absence of the endothelium. Both flavonoids also inhibited the acetylcholine-induced endothelial nitric oxide-dependent relaxation. In contrast, cardamonin, alpinetin or (-)epicatechin induced both endothelium-dependent and -independent relaxation. NG-nitro-L-arginine meyhyl ester or endothelium denudation attenuated the endothelium-dependent relaxation to the same extent. CONCLUSION Baicalein and baicalin enhanced the phenylephrine-induced contraction most likely through inhibiting production or/and release of endothelial nitric oxide. Whilst, cardamonin-, alpinetin- or (-)epicatechin-induced endothelium-dependent relaxation is primarily mediated through endothelial nitric oxide.
Collapse
Affiliation(s)
- Y Huang
- Departments of Physiology and Biochemistry, Faculty of Medicine, Chinese University of Hong Kong, Hong Kong, China.
| | | | | | | | | |
Collapse
|
20
|
Chen ZY, Law WI, Yao XQ, Lau CW, Ho WK, Huang Y. Inhibitory effects of purified green tea epicatechins on contraction and proliferation of arterial smooth muscle cells. Acta Pharmacol Sin 2000; 21:835-40. [PMID: 11501167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023] Open
Abstract
AIM The present study was aimed to examine the vasorelaxant and antiproliferative responses to purified green tea epicatechin mixture, (-)epicatechin and (-)epigallocatechin gallate on rat arterial smooth muscle cells. METHODS Changes in isometric force were measured by Grass force transducer and effects on cell proliferation were evaluated using [3H]thymidine incorporation assay. RESULTS Epicatechin mixture, (-)epicatechin and (-)epigallocatechin gallate, which we isolated and purified from jasmine green tea, concentration-dependently, reduced the contractile response to phenylephrine in rat isolated aortic rings with (-)epigallocatechin gallate being more effective. These three agents also inhibited [3H]thymidine incorporation into DNA in cultured rat aortic smooth muscle cells in a concentration-dependent manner. CONCLUSION The purified epicatechin derivatives from jasmine green tea relaxed the isolated rat arteries preconstricted by phenylephrine and inhibited aortic smooth muscle cell proliferation.
Collapse
Affiliation(s)
- Z Y Chen
- Departments of Biochemistry and Department of Physiology, Faculty of Medicine, Chinese University of Hong Kong, Shatin, Hong Kong, China
| | | | | | | | | | | |
Collapse
|
21
|
Huang Y, Yao XQ, Chan FL, Lau CW, Chan NW, Chen ZY. Abolition of endothelium-dependent relaxation in the rat aorta by tetraoctylammonium ions. Naunyn Schmiedebergs Arch Pharmacol 2000; 362:152-9. [PMID: 10961378 DOI: 10.1007/s002100000278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Quaternary ammonium ions are common pharmacological probes used to study the kinetic properties of K+ channels in smooth muscle cells. On the other hand, some ammonium compounds cause vasorelaxation through unknown mechanisms. The main aim of this study was to examine a unique role of endothelium in the vascular response to tetraoctylammonium ions (TOA+) in the isolated rat aorta. Changes in contractile force were measured by force transducers and total tissue content of cGMP was measured by radioimmunoassay. Endothelial cytosolic Ca2+ ([Ca2+]i) was assessed by laser scanning confocal microscopy.
Collapse
MESH Headings
- Acetylcholine/pharmacology
- Animals
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/metabolism
- Calcimycin/pharmacology
- Calcium/metabolism
- Cations/pharmacology
- Cells, Cultured
- Cyclic GMP/metabolism
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiology
- Enzyme Inhibitors/pharmacology
- In Vitro Techniques
- Indoles/pharmacology
- Male
- Microscopy, Confocal
- Muscle Relaxation/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Nitric Oxide Synthase/antagonists & inhibitors
- Nitric Oxide Synthase Type III
- Nitroarginine/pharmacology
- Quaternary Ammonium Compounds/pharmacology
- Rats
- Rats, Sprague-Dawley
- Vasodilator Agents/pharmacology
Collapse
Affiliation(s)
- Y Huang
- Department of Physiology, The Chinese University of Hong Kong, Shatin.
| | | | | | | | | | | |
Collapse
|
22
|
Abstract
The effects of purified baicalin and baicalein from the traditional Chinese herb, Huangqin, on contractions induced by phenylephrine, U46619, and high extracellular K+ were investigated in isolated rat mesenteric arteries. Both baicalin (1-100 microM) and baicalein (1-50 microM) potentiated the contractile response to phenylephrine in a concentration-related manner. Both flavonoids (10 microM) also enhanced the U46619- or 40 mM K+-induced contractions. Baicalein (100-300 microM) reduced the phenylephrine-induced tone. Prazosin at 1 microM did not affect U46619-induced contraction in the absence and presence of baicalein or baicalin. Neither baicalin (1-100 microM) nor baicalein (1-100 microM) affected the basal tension. Removal of the functional endothelium abolished the potentiating effects of baicalin and baicalein in arteries preconstricted by both constrictors. Pretreatment of endothelium-intact rings with 100 microM N(G)-nitro-L-arginine also potentiated phenylephrine- or U46619-induced contraction but completely inhibited the effects of baicalin and baicalein. Pretreatment with 1 mM L-arginine reversed the enhancing effect of baicalin but not of baicalein on phenylephrine-evoked contraction. Pretreatment with 10 microM baicalin or 10 microM baicalein significantly reduced the endothelium-dependent relaxation induced by acetylcholine or ionomycin. These results indicate that both baicalin and baicalein potentiated the evoked contractile response, likely through inhibition of nitric oxide formation and/or release in the endothelium.
Collapse
Affiliation(s)
- S Y Tsang
- Department of Physiology, Chinese University of Hong Kong, Shatin
| | | | | | | |
Collapse
|
23
|
Abstract
The present study was intended to examine the relaxant effects of berberine in rat isolated mesenteric arteries. Berberine produced a rightward shift of the concentration-response curve to phenylephrine and significantly reduced the maximal contractile response to phenylephrine. Berberine (10(-7)-3x10(-5) M) also relaxed the phenylephrine- and 9,11-dideoxy-11alpha, 9alpha-epoxy-methanoprostaglandin F(2alpha)-precontracted arteries with respective IC(50) values of 1.48+/-0.16x10(-6) and 2.23+/-0. 22x10(-6) M. Removal of a functional endothelium significantly attenuated the berberine-induced relaxation (IC(50): 4.73+/-0. 32x10(-6) M) without affecting the maximum relaxant response. Pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME) or methylene blue reduced the relaxant effect of berberine, and L-arginine (10(-3) M) partially antagonized the effect of L-NAME. In contrast, pretreatment with 10(-6) M glibenclamide or 10(-5) M indomethacin had no effect. Berberine (10(-5) M) reduced over by 50% the transient contraction induced by caffeine or phenylephrine in endothelium-denuded rings bathed in Ca(2+)-free Krebs solution. Pretreatment with putative K(+) channel blockers, such as tetrapentylammonium ions (1-3x10(-6) M), 4-aminopyridine (10(-3) M), or Ba(2+) (3x10(-4) M), significantly attenuated the berberine-induced relaxation in endothelium-denuded arteries. In contrast, tetraethylammonium ions (3x10(-3) M), charybdotoxin (10(-7) M) or glibenclamide (10(-6) M) were without effect. Berberine reduced the high-K(+)-induced sustained contraction and the relaxant response to berberine was greater in rings with endothelium (IC(50): 4.41+/-0.47x10(-6) M) than in those without endothelium (IC(50): 8.73+/-0.74x10(-6) M). However, berberine (10(-6)-10(-4) M) did not affect the high-K(+)-induced increase of intracellular [Ca(2+)] in cultured aortic smooth muscle cells. Berberine did not affect active phorbol ester-induced contraction in Ca(2+)-free Krebs solution. In addition, berberine inhibited proliferation of cultured rat aortic smooth muscle cells with an IC(50) of 2.3+/-0.43x10(-5) M. These findings suggest that berberine could act at both endothelium and the underlying vascular smooth muscle to induce relaxation. Nitric oxide from endothelium may account primarily for the berberine-induced endothelium-dependent relaxation, while activation of tetrapentylammonium-, 4-aminopyridine- and Ba(2+)-sensitive K(+) channels, inhibition of intracellular Ca(2+) release from caffeine-sensitive pools, or a direct relaxant effect, is likely responsible for the berberine-induced endothelium-independent relaxation. Mechanisms related to either Ca(2+) influx or protein kinase C activation may not be involved. Both vasorelaxant and antiproliferative effects may contribute to a long-term benefit of berberine in the vascular system.
Collapse
MESH Headings
- Animals
- Aorta/cytology
- Berberine/pharmacology
- Calcimycin/pharmacology
- Calcium/metabolism
- Calcium/pharmacology
- Cell Division/drug effects
- Cells, Cultured
- Dose-Response Relationship, Drug
- In Vitro Techniques
- Male
- Mesenteric Artery, Superior/drug effects
- Mesenteric Artery, Superior/physiology
- Methylene Blue/pharmacology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- NG-Nitroarginine Methyl Ester/pharmacology
- Phorbol Esters/pharmacology
- Potassium/pharmacology
- Potassium Channel Blockers
- Rats
- Rats, Sprague-Dawley
- Vasoconstriction/drug effects
- Vasodilation/drug effects
Collapse
Affiliation(s)
- W H Ko
- Department of Physiology, Faculty of Medicine, Chinese University of Hong Kong, Shatin, Hong Kong, People's Republic of China
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Huang Y, Chan NW, Lau CW, Yao XQ, Chan FL, Chen ZY. Involvement of endothelium/nitric oxide in vasorelaxation induced by purified green tea (-)epicatechin. Biochim Biophys Acta 1999; 1427:322-8. [PMID: 10216249 DOI: 10.1016/s0304-4165(99)00034-3] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study investigated the involvement of endothelial nitric oxide in relaxation induced by purified green tea (-)epicatechin in rat isolated mesenteric arteries. (-)Epicatechin caused both endothelium-dependent and -independent relaxation. NG-Nitro-L-arginine methyl ester (L-NAME, 100 microM) and methylene blue (10 microM) significantly attenuated (-)epicatechin-induced relaxation in endothelium-intact tissues. L-Arginine (1 mM) partially antagonized the effect of L-NAME. (-)Epicatechin-induced relaxation was inhibited by Rp-guanosine 3',5'-cyclic monophosphothioate triethylamine. In contrast, indomethacin and glibenclamide had no effect. (-)Epicatechin (100 microM) significantly increased the tissue content of cyclic GMP and NG-nitro-L-arginine (100 microM) or removal of the endothelium abolished this increase. (-)Epicatechin (100 microM) induced an increase in intracellular Ca2+ levels in cultured human umbilical vein endothelial cells. Iberiotoxin at 100 nM attenuated (-)epicatechin-induced relaxation in endothelium-intact arteries and this effect was absent in the presence of 100 microM L-NAME. In summary, (-)epicatechin-induced endothelium-dependent relaxation is primarily mediated by nitric oxide and partially through nitric oxide-dependent activation of iberiotoxin-sensitive K+ channels. In addition, there may be a causal link between increased Ca2+ levels and nitric oxide release in response to (-)epicatechin.
Collapse
Affiliation(s)
- Y Huang
- Department of Physiology, Chinese University of Hong Kong, Faculty of Medicine, Shatin, Hong Kong.
| | | | | | | | | | | |
Collapse
|
25
|
Abstract
The endothelium-dependent and -independent relaxant effect of procaine was examined in isolated rat aortic rings. Procaine induced relaxation of arteries precontracted with phenylephrine or with 60 mM K+ in a concentration-dependent manner (0.01-3 mM). Procaine (1 mM) inhibited the transient contraction induced by caffeine (10 mM) in Ca2+-free Krebs solution. Removal of the endothelium caused a rightward shift of the concentration-response curve for procaine. N(G)-Nitro-L-arginine (L-NNA, 10-100 microM), N(G)-nitro-L-arginine methyl ester (L-NAME, 100 microM) and methylene blue (1-10 microM) significantly attenuated the procaine-induced relaxation without affecting the maximal response. L-Arginine (1 mM) partially but significantly antagonized the effect of L-NAME (100 microM). Pretreatment of endothelium-intact aortic rings with procaine (1 mM) or with acetylcholine (10 microM) significantly elevated the tissue contents of cyclic GMP and this increase was inhibited in the presence of 100 microM L-NNA. Tetrapentylammonium ions (1-3 microM) reduced the procaine-induced relaxation in both endothelium-intact and -denuded arteries. Tetrapentylammonium ions (3 microM) did not affect the procaine-induced relaxation of 60 mM K+-contracted arteries. Tetraethylammonium ions (3 mM) inhibited the procaine-induced relaxation. In contrast, iberiotoxin (100 nM), glibenclamide (3 microM), 4-aminopyridine (3 mM) and indomethacin (10 microM) had no effect. These results indicate that the procaine-induced relaxation may be mediated through multiple mechanisms. A substantial portion of the procaine-induced relaxation in rat aorta was caused by nitric oxide but not by other endothelium-derived factors. The activation of tetrapentylammonium- and tetraethylammonium-sensitive K+ channels contributes in part to the procaine-induced vasorelaxation. Besides, procaine may directly inhibit both external Ca2+ entry and internal Ca2+ release in aortic smooth muscle cells.
Collapse
Affiliation(s)
- Y Huang
- Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, NT.
| | | | | | | |
Collapse
|
26
|
Abstract
Effects of isoprenaline on monophasic contractions evoked by electric field stimulation were studied in rat isolated prostatic vas deferens. Isoprenaline reduced electrically evoked contractions (EC50: 0.27 +/- 0.05 microM), and propranolol concentration-dependently antagonized the effect of isoprenaline. In contrast, isoprenaline (0.3-3 microM) did not affect the contractile response induced by exogenous noradrenaline or ATP, while forskolin (100 nM) attenuated agonist-induced contraction. In some tissues, adrenergic and purinergic components of the electrically evoked contraction were isolated by exposure to alpha,beta-methylene ATP (3 microM) and prazosin (3 microM), respectively. Isoprenaline induced a greater inhibition of purinergic than adrenergic component of the electrically evoked contraction. Iberiotoxin (50 nM), glibenclamide (3 microM), 4-aminopyridine (0.3 mM) and tetraethylammonium ions (1 mM) attenuated the effect of isoprenaline. These results indicate that isoprenaline-induced inhibition of the electrically evoked (both purinergic and adrenergic) contraction was mediated primarily through activation of prejunctional beta-adrenoceptors, which probably inhibited release of contractile transmitters from sympathetic nerves supplying vas deferens. Lack of effect of isoprenaline on agonist-induced contraction does not favour a functional role of beta-adrenoceptors in vas smooth muscle.
Collapse
Affiliation(s)
- Y Huang
- Department of Anatomy, Faculty of Medicine, Chinese University of Hong Kong, Shatin.
| | | | | | | | | |
Collapse
|
27
|
Abstract
Previous studies have suggested that epididymal and sperm functions are subject to control by a local renin-angiotensin II system (RAS) in the rat epididymis. Type-1 angiotensin II receptor, AT1 and type-2 receptor, AT2 were localized in epididymal epithelium, indicating that RAS may act in a paracrine or autocrine fashion to regulate fluid secretion, probably through the basally placed membrane-bound AT1 protein as revealed by immunocytochemical and electrophysiological studies. In the present work, the expression of the angiotensin II receptor subtypes in the rat epididymis was showed by western blot analysis and reverse-transcription polymerase chain reaction (RT-PCR) using specific primers for the angiotensin II receptor subtypes. Western blot analysis showed the expression of AT1 receptor in the rat epididymis. Results from RT-PCR, using specific primers based on the corresponding angiotensin II receptor subtype genes for AT1a, AT1b and AT2 , demonstrated the differential expression of mRNAs from these receptor subtypes in the epididymides of mature and immature rats. Both the genes for AT1a and AT1b, but not that for AT2, are predominantly expressed in the epididymides of mature rat. In contrast, only AT1a and AT2 were highly expressed in the epididymides of immature rat. These results suggest that the expression of type-1 and type-2 angiotensin II receptor subtypes are developmentally regulated. Type-1 subtype may play a role in regulation of electrolyte and fluid transport in mature rat whereas type-2 subtype may be important in growth and development in the immature rat.
Collapse
Affiliation(s)
- P S Leung
- Department of Physiology, The Chinese University of Hong Kong, Shatin, NT.
| | | | | | | | | |
Collapse
|
28
|
Wang SL, Yao XQ. [Methods of controlling nursing quality]. Zhonghua Hu Li Za Zhi 1993; 28:517-9. [PMID: 8111918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
|