Study on Capsaicin-, Substance P-, Histamine- and Compound 48/80-induced Changes in Arterial Blood Pressure and Airway Inflammation in Non-genetic Hypertensive Sprague-Dawley Rats

• Main Authors: Su-Yu Kuo, 郭素攸
• Other Authors: Hung-Tu Huang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/88583720738420370729

碩士 === 高雄醫學大學 === 醫學研究所 === 101 === Intravenous (i.v.) application of a high dose of capsaicin (Cap), substance P (SP), or histamine produces formation of many endothelial gaps in the venules of tracheal mucosa, resulting in an extensive plasma leakage in normotensive Sprague-Dawley (SD) rats. The present study investigated whether hypertension could have an influence on Cap, SP, histamine and compound 48/80-induced plasma leakage and blood pressure. The femoral artery of spontaneously hypertensive SD rat was cannulated for monitoring arterial blood pressure and femoral vein cannulated for injecting Cap (90 microgram/ml/kg, over 2 min), SP (3 microgram/ml/kg, over 20 sec) or histamine (18 ?慆ol/ml/kg, over 2 min). The tracer dye was Evans blue (50 mg/ml/kg). Rats of control group received i.v. injection of Evans blue, over 10 sec, followed by vehicle of vasoactive drug. Five min after application of Evans blue and blood pressure recording, rats were perfused with saline and phosphate-buffered paraformaldehyde. Evans blue content in the airways, including trachea and main bronchi, was extracted with formamide and determined with an ELISA reader. Venule leakage as expressed by Evans blue content was low in Cap-treated rats, while the degree of venule leakage remained high in SP- or histamine-treated rats. The blood pressure was increased during i.v. capsaicin infusion, and decreased during substance P or histamine infusions. There was a significant change in the pulse pressure post to histamine administration, but not in capsaicin and substance P treatments. The venule leakage in trachea as expressed by Evans blue content was low in capsaicin-treated rats, while the degree of venule leakage remained high in substance P- or histamine- treated rats. Compound 48/80 is inducer of allergic inflammation. Pretreatment of Compound E dose-dependently inhibit compound 48/80-induced hypotension and increased plasma leakage. It is concluded that hypertension has inhibitory effect on Cap- and SP-induced plasma leakage in the airways, but has no effect on histamine- and compound 48/80-induced plasma leakage.