Quantitative Relationship between Neurotransmitters and Coronary Vascular Resistance during Cardiac Sympathetic Stimulation Etsuro Tanaka 1 , Hidezo Mori 1 , Minhaz U. Mohammed 1 , Kunihisa Ito 1 , Takafumi Sekka 1 , Yoshiro Shinozaki 1 , Kosuke Tobita 1 , Shuichi Haruyama 1 , Mitsuaki Chujo 1 , Akihiko Yamakawa 1 , Hiroe Nakazawa 1 1Department of Physiology, Tokai University School of Medicine Keyword: 冠循環 , ニューロペプチドY , 交感神経 , coronary circulation , neuropeptide Y , sympathetic nervous system pp.1183-1188
Published Date 1996/11/15
DOI https://doi.org/10.11477/mf.1404901369
  • Abstract
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To investigate the effects of sympathetic neurotrans-mitters on coronary vasoconstriction, we examined the quantitative relationship of norepinephrine and neur-opeptide Y (NPY) levels to coronary vascular resis-tance (CVR) in 42 anesthetized dogs under fi-adrenoce-ptor blockade in a vagotomized condition. Endogenous norepinephrine levels correlated to CVR significantly (r2=0.333) during ansae subclaviae stimulation (2 and 20 Hz) but NPY did not, where norepinephrine-overflow was 30-fold larger than NPY-overflow. Under a-and )3-blockades, NPY levels significantly correlated to CVR (r2=0.542), whereas norepinephrine did not. Exogenous norepinephrine and NPY administered into the left circumflex artery (0.001 to 0.3μg/kg/min) had a similar coronary vasoconstrictive action in potency. Neither ATP, adenosine nor calcitonin gene-related peptide affected the sympathetic vasoconstriction dur-ing ventrolateral cardiac nerve stimulation (2 to 20 Hz). During the sympathetic nerve stimulation, there-fore, the vasocontrictive actions of NPY are concealed by norepinephrine under intact α-adrenoceptor condi-tions, manifest during α-blockade.

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