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EFFECT OF 8‐SULFOPHENYL THEOPHYLLINE ON ENDOGENOUS NORADRENALINE RELEASE FROM SYMPATHETIC NERVES OF THE RABBIT EAR ARTERY
Author(s) -
Ishii Reiko,
Shinozuka Kazumasa,
Kunitomo Masaru,
Hashimoto Takao,
Takeuchi Koichi
Publication year - 1996
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1996.tb02747.x
Subject(s) - theophylline , endogeny , purine , chemistry , adenosine , endocrinology , medicine , purinergic receptor , prazosin , antagonist , isoprenaline , stimulation , biochemistry , biology , receptor , enzyme
SUMMARY 1. The release of endogenous noradrenaline (NA) and adenyl purine (ATP, ADP, AMP and adenosine) from the rabbit ear artery, evoked by electrical stimulation (ES; 16Hz), was examined. 2. ES evoked a significant release of NA and adenyl purine; the ratio of the amount of total purine released to NA released was approximately 180 on a molar base. 3. ES‐evoked purine release was significantly reduced by the denudation of the endothelium and abolished by the α 1 ‐adrenoceptor antagonist, prazosin (1 μmol/L). 4. ES‐evoked NA release was significantly reduced by a P 1 ‐purinoceptor antagonist, 8‐sulfophenyl theophylline (8SPT). Purine release was slightly reduced by 8SPT. 5. These results suggest that endogenous NA released by ES results in the release of a large amount of purine, which may, in turn, increase the release of NA by acting on prejunctional purinoceptors on sympathetic nerve terminals.