BACKGROUND: Alpha-adrenergic activation in vivo causes constriction of coronary arterioles, but, paradoxically, in vitro these microvessels do not contract to this stimulus. We hypothesized that cardiac myocytes have a requisite role in alpha1-adrenergic coronary arteriolar constriction through the release of myocyte-derived contractile factor(s). METHODS AND RESULTS: Administration of the alpha1-adrenergic agonist phenylephrine did not constrict isolated coronary arterioles, but constriction was observed to supernatant obtained from phenylephrine-treated cardiac myocytes. Constriction to the supernatant was blocked by administration of an endothelin-A antagonist to the microvessel preparation or an alpha-adrenergic antagonist to the myocytes and was augmented after administration of an adenosine antagonist. Administration of phenylephrine to the myocytes increased endothelin-1 levels in the supernatant, but only to subthreshold concentrations. CONCLUSIONS: Cardiac myocytes have a requisite role in constriction of coronary resistance vessels to alpha1-adrenergic stimuli, which may be mediated by endothelin-1 and other unidentified myocyte-derived vasoconstrictors.
BACKGROUND: Alpha-adrenergic activation in vivo causes constriction of coronary arterioles, but, paradoxically, in vitro these microvessels do not contract to this stimulus. We hypothesized that cardiac myocytes have a requisite role in alpha1-adrenergic coronary arteriolar constriction through the release of myocyte-derived contractile factor(s). METHODS AND RESULTS: Administration of the alpha1-adrenergic agonist phenylephrine did not constrict isolated coronary arterioles, but constriction was observed to supernatant obtained from phenylephrine-treated cardiac myocytes. Constriction to the supernatant was blocked by administration of an endothelin-A antagonist to the microvessel preparation or an alpha-adrenergic antagonist to the myocytes and was augmented after administration of an adenosine antagonist. Administration of phenylephrine to the myocytes increased endothelin-1 levels in the supernatant, but only to subthreshold concentrations. CONCLUSIONS: Cardiac myocytes have a requisite role in constriction of coronary resistance vessels to alpha1-adrenergic stimuli, which may be mediated by endothelin-1 and other unidentified myocyte-derived vasoconstrictors.
Authors: Takahiko Kiyooka; Vahagn Ohanyan; Liya Yin; Yuh Fen Pung; Yeong-Renn Chen; Chwen-Lih Chen; Patrick T Kang; James P Hardwick; June Yun; Danielle Janota; Joanna Peng; Christopher Kolz; Giacinta Guarini; Glenn Wilson; Inna Shokolenko; Donte A Stevens; William M Chilian Journal: Basic Res Cardiol Date: 2022-01-17 Impact factor: 12.416
Authors: Vahagn Ohanyan; Liya Yin; Raffi Bardakjian; Christopher Kolz; Molly Enrick; Tatevik Hakobyan; John Kmetz; Ian Bratz; Jordan Luli; Masaki Nagane; Nadeem Khan; Huagang Hou; Periannan Kuppusamy; Jacqueline Graham; Frances Kwan Fu; Danielle Janota; Moses O Oyewumi; Suzanna Logan; Jonathan R Lindner; William M Chilian Journal: Circ Res Date: 2015-07-29 Impact factor: 17.367
Authors: Giacinta Guarini; Takahiko Kiyooka; Vahagn Ohanyan; Yuh Fen Pung; Mario Marzilli; Yeong Renn Chen; Chwen Lih Chen; Patrick T Kang; James P Hardwick; Christopher L Kolz; Liya Yin; Glenn L Wilson; Inna Shokolenko; James G Dobson; Richard Fenton; William M Chilian Journal: Basic Res Cardiol Date: 2016-04-04 Impact factor: 17.165
Authors: Ornella E Rimoldi; Angela J Drake-Holland; Mark I M Noble; Paolo G Camici Journal: Eur J Nucl Med Mol Imaging Date: 2006-09-02 Impact factor: 9.236