The present study investigated a possible mechanism for endogenous endothelin-1 (ET-1) regulation of atrial natriuretic peptide (ANP) secretion in isolated perfused acute hypoxic rabbit atria. Acute hypoxia significan...The present study investigated a possible mechanism for endogenous endothelin-1 (ET-1) regulation of atrial natriuretic peptide (ANP) secretion in isolated perfused acute hypoxic rabbit atria. Acute hypoxia significantly enhanced the release of ET-1 and the expression of the ET receptor (ETR) type A and B (ETR<sub>A</sub> and ETR<sub>B</sub>) in atrial tissues, with a concomitant increase in ANP secretion. The ETR<sub>A</sub> or ETR<sub>B</sub> antagonist, BQ123 (0.3 μmol/L) or BQ788 (0.3 μmol/L), respectively attenuated hypoxia-induced ANP secretion. Both antagonists significantly attenuated the levels of hypoxiainduced atrial phosphorylated (p)-extracellular signal-regulated kinase (ERK) and p-protein kinase B (Akt). The ERK and Akt inhibitors, PD098059 (30 μmol/L) and LY294002 (30 μmol/L), respectively mimicked the effect of the ETR antagonists. These results demonstrated that acute hypoxia- mediated atrial ET-1 regulated ANP secretion through ETR and the subsequent mitogenactivated protein kinase (MAPK)/ERK and ETR-phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathways. These pathways may mediate atrial endocrine functions under hypoxic conditions.展开更多
Our study investigated effects of C-type natriuretic peptide (CNP) on atrial dynamics and hypoxia inducible factor 1 alpha (HIF-1α) activity in perfused beating rat atria, under hypoxic conditions. Hypoxia significan...Our study investigated effects of C-type natriuretic peptide (CNP) on atrial dynamics and hypoxia inducible factor 1 alpha (HIF-1α) activity in perfused beating rat atria, under hypoxic conditions. Hypoxia significantly increased the levels of HIF-1α, concomitant with decreased trial dynamics. CNP (0.1 μmol/L) further decreased atrial dynamics under hypoxia and suppressed hypoxia-induced stimulation of HIF-1α expression. An adenylylcyclase (AC) activator, forskolin (0.1 μmol/L), significantly up-regulated atrial phosphodiesterase subtype 3A (PDE 3A) protein without affecting hypoxia-induced dynamics. In the presence of forskolin, the inhibitory effects of CNP on hypoxia-induced atrial dynamics and HIF-1α levels were significantly attenuated. Forskolin also prevented hypoxia-induced downregulation of PDE3A protein. These findings suggested that CNP inhibited atrial dynamics and HIF-1α activity in the isolated perfused beating rat atria under hypoxic conditions. Furthermore, both effects were modulated by the AC activator forskolin, through activation of CNP-PDE 3A signaling.展开更多
We propose a new method to design crossovers by employing an embedded homogeneous cylindrical lens(HCL).Compared with traditional crossover designs,this strategy introduces an HCL within the air-filled substrate-integ...We propose a new method to design crossovers by employing an embedded homogeneous cylindrical lens(HCL).Compared with traditional crossover designs,this strategy introduces an HCL within the air-filled substrate-integrated waveguide(SIW)crossover cavity to direct the incident waves in the desired direction.According to ray-tracing analysis,the added HCL can efficiently concentrate the electromagnetic wave propagating from the input to the output without increasing the fabrication complexity or footprint.展开更多
文摘The present study investigated a possible mechanism for endogenous endothelin-1 (ET-1) regulation of atrial natriuretic peptide (ANP) secretion in isolated perfused acute hypoxic rabbit atria. Acute hypoxia significantly enhanced the release of ET-1 and the expression of the ET receptor (ETR) type A and B (ETR<sub>A</sub> and ETR<sub>B</sub>) in atrial tissues, with a concomitant increase in ANP secretion. The ETR<sub>A</sub> or ETR<sub>B</sub> antagonist, BQ123 (0.3 μmol/L) or BQ788 (0.3 μmol/L), respectively attenuated hypoxia-induced ANP secretion. Both antagonists significantly attenuated the levels of hypoxiainduced atrial phosphorylated (p)-extracellular signal-regulated kinase (ERK) and p-protein kinase B (Akt). The ERK and Akt inhibitors, PD098059 (30 μmol/L) and LY294002 (30 μmol/L), respectively mimicked the effect of the ETR antagonists. These results demonstrated that acute hypoxia- mediated atrial ET-1 regulated ANP secretion through ETR and the subsequent mitogenactivated protein kinase (MAPK)/ERK and ETR-phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathways. These pathways may mediate atrial endocrine functions under hypoxic conditions.
文摘Our study investigated effects of C-type natriuretic peptide (CNP) on atrial dynamics and hypoxia inducible factor 1 alpha (HIF-1α) activity in perfused beating rat atria, under hypoxic conditions. Hypoxia significantly increased the levels of HIF-1α, concomitant with decreased trial dynamics. CNP (0.1 μmol/L) further decreased atrial dynamics under hypoxia and suppressed hypoxia-induced stimulation of HIF-1α expression. An adenylylcyclase (AC) activator, forskolin (0.1 μmol/L), significantly up-regulated atrial phosphodiesterase subtype 3A (PDE 3A) protein without affecting hypoxia-induced dynamics. In the presence of forskolin, the inhibitory effects of CNP on hypoxia-induced atrial dynamics and HIF-1α levels were significantly attenuated. Forskolin also prevented hypoxia-induced downregulation of PDE3A protein. These findings suggested that CNP inhibited atrial dynamics and HIF-1α activity in the isolated perfused beating rat atria under hypoxic conditions. Furthermore, both effects were modulated by the AC activator forskolin, through activation of CNP-PDE 3A signaling.
基金Project supported by the National Natural Science Foundation of China(Nos.62101259,62025109,and 61931021)the National Key Laboratory on Electromagnetic Environment Effects,China(No.JCKYS2019 DC4)+2 种基金the Primary Research and Development Plan of Jiangsu Province,China(No.BE2022070)the Open Research Program of the State Key Laboratory of Millimeter Waves,China(No.K202229)the Undergraduate Research Training Program of Nanjing University of Science and Technology,China(No.202210288057)。
文摘We propose a new method to design crossovers by employing an embedded homogeneous cylindrical lens(HCL).Compared with traditional crossover designs,this strategy introduces an HCL within the air-filled substrate-integrated waveguide(SIW)crossover cavity to direct the incident waves in the desired direction.According to ray-tracing analysis,the added HCL can efficiently concentrate the electromagnetic wave propagating from the input to the output without increasing the fabrication complexity or footprint.
