Comparison of agonists-induced contraction between main and the third-order branches of pulmonary arteries in rats / 生理学报

This study was designed to observe the differences between main pulmonary arteries and the third-order branches of pulmonary arteries in the contractile response to phenylephrine (Phen), endothelin-1 (ET-1) and potassium chloride (KCl). The vascular tension changes of main and the third-order branches of pulmonary arteries induced by KCl, ET-1 and Phen were recorded by traditional vascular tone detection methods and microvascular ring technique, respectively. The results showed that Phen could cause a significant contraction in main pulmonary arteries, but did not induce apparent contraction in the third-order branches of pulmonary arteries. Compared with main pulmonary arteries, ET-1 contracted the third-order branches of pulmonary arteries with reduced maximal response value and PDvalue. In comparison with the main pulmonary arteries, contraction caused by KCl was enhanced in the third-order branches of pulmonary arteries. The results suggest that the vascular reactivity of main and the third-order branches of pulmonary arteries is different and it is important to study the vascular function of small branches of pulmonary arteries. This study could provide an important experimental basis for the further study on vascular function of small branches of pulmonary arteries and the functional changes in pulmonary hypertension.

Comparison of the synchronous changes of vascular tension and intracellular Casignal in third-order branches of mesenteric arteries under the different objective amplification of confocal microscope / 生理学报

This study was aimed to establish an optimized method to observe the synchronous changes of vascular tension and intracellular Casignal in the third-order branches of mesenteric arteries (sMA, diameter: 100-300 μm). The vascular tension and intracellular Casignal changes in response to potassium chloride (KCl), endothelin-1 (ET-1) and Gdwere detected using confocal wire myograph system and confocal laser scanning microscopy imaging technique, respectively. The experimental results were analyzed to explore the optimal experimental conditions. The results showed that KCl caused contraction in sMA significantly, and the intracellular Calevel of vascular smooth muscle cells (VSMCs) was also increased under 20× and 40× objective lens. Compared with those under the 40× objective lens, the Casignal change was larger and the fluorescence value was more stable under the 20× objective lens, whereas the Casignal change was not obvious under the 10× objective lens. ET-1 (1-10 nmol/L) caused concentration dependent contraction in sMA significantly, and the intracellular Casignal of VSMCs was also enhanced in a concentration dependent manner. Additionally, Gdsignificantly reduced the contraction of sMA and the intracellular Casignal of VSMCs caused by ET-1. The results suggest that the intracellular Casignal of VSMCs changes with vascular contraction or relaxation caused by the agonists or antagonists of Cachannels. We successfully recorded both changes synchronously using confocal wire myograph system and confocal laser scanning microscopy imaging technique at the same time. Based on the analysis of the experimental results, we concluded that 20× objective lens provides the best experimental condition. Compared to combination of vascular tone detection method and real-time cellular fluorescence imaging technique, the present synchronous method is convenient and helpful to reduce experimental error.