Hye Yoom Kim1, Hye Ran Choi1, Yun Jung Lee1, Hao Zhen Cui2, Song Nan Jin3, Kyung Woo Cho1, Dae Gill Kang4, Ho Sub Lee5. 1. Hanbang Body-fluid Research Center & Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea. 2. Hanbang Body-fluid Research Center & Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea; Department of Chinese Medicine, Yanbian University, Yanji, China. 3. Institute of Materia Medica, Taishan Medical University, Taian, Shandong 271016, China. 4. Hanbang Body-fluid Research Center & Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea. Electronic address: dgkang@wku.ac.kr. 5. Hanbang Body-fluid Research Center & Professional Graduate School of Oriental Medicine, Wonkwang University, Iksan, Jeonbuk 570-749, Republic of Korea. Electronic address: host@wku.ac.kr.
Abstract
AIMS: Ursolic acid has recently been reported to increase both atrial natriuretic peptide (ANP) secretion and mechanical dynamics in rabbit atria. MAIN METHODS: The present study was designed to clarify the regulatory effects of ursolic acid on the β-adrenergic or muscarinic receptor-mediated changes in ANP secretory and contractile function allowing measurement of atrial dynamics such as pulse pressure, stroke volume, and cAMP efflux in isolated perfused beating rabbit atria. KEY FINDINGS: Pretreatment with ursolic acid significantly attenuated the isoproterenol (β-adrenergic agonist)-induced decrease in ANP secretion and increases in cAMP levels and atrial dynamics. Interestingly, ursolic acid concentration-dependently accentuated the acetylcholine-induced increase in ANP secretion and decrease in pulse pressure in the presence of isoproterenol (p<0.001). These findings indicate that acetylcholine-induced increase in ANP secretion is potentiated by ursolic acid; furthermore, acetylcholine-induced decrease in atrial dynamics is also potentiated by ursolic acid, suggesting that ursolic acid regulates muscarinic receptor-mediated secretory and contractile responses in perfused beating rabbit atria. SIGNIFICANCE: This implicates for the beneficial effects of ursolic acid in the regulation of cardiovascular and body fluid homeostasis.
AIMS: Ursolic acid has recently been reported to increase both atrial natriuretic peptide (ANP) secretion and mechanical dynamics in rabbit atria. MAIN METHODS: The present study was designed to clarify the regulatory effects of ursolic acid on the β-adrenergic or muscarinic receptor-mediated changes in ANP secretory and contractile function allowing measurement of atrial dynamics such as pulse pressure, stroke volume, and cAMP efflux in isolated perfused beating rabbit atria. KEY FINDINGS: Pretreatment with ursolic acid significantly attenuated the isoproterenol (β-adrenergic agonist)-induced decrease in ANP secretion and increases in cAMP levels and atrial dynamics. Interestingly, ursolic acid concentration-dependently accentuated the acetylcholine-induced increase in ANP secretion and decrease in pulse pressure in the presence of isoproterenol (p<0.001). These findings indicate that acetylcholine-induced increase in ANP secretion is potentiated by ursolic acid; furthermore, acetylcholine-induced decrease in atrial dynamics is also potentiated by ursolic acid, suggesting that ursolic acid regulates muscarinic receptor-mediated secretory and contractile responses in perfused beating rabbit atria. SIGNIFICANCE: This implicates for the beneficial effects of ursolic acid in the regulation of cardiovascular and body fluid homeostasis.