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COMPARISON OF VASOPRESSOR EFFECTS OF NITRO ARGININE IN STROKE‐PRONE SPONTANEOUSLY HYPERTENSIVE RATS AND WISTAR‐KYOTO RATS
Author(s) -
Kobayashi Yuta,
Ikeda Katsumi,
Kakizoe Eiichi,
Shinozuka Kazumasa,
Nara Yasuo,
Yamori Yukio,
Hattori Keisuke
Publication year - 1991
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.1440-1681.1991.tb01632.x
Subject(s) - endocrinology , acetylcholine , medicine , blood pressure , aorta , thoracic aorta , arginine , endothelium , relaxation (psychology) , spontaneously hypertensive rat , chemistry , vasodilation , nitroarginine , nitric oxide , nitric oxide synthase , biochemistry , amino acid
SUMMARY 1. N G ‐nitro‐L‐arginine (NO 2 Arg) is a guanidine nitro arginine derivative and an inhibitor of endothelium‐dependent vascular relaxation. Significant rise of the systolic blood pressure was observed after 1 week administration of NO 2 Arg in food (0.023% in weight, about 2.8 mg of NO 2 Arg/rat per day) in female rats of stroke‐prone spontaneously hypertensive rats (SHRSP) and normotensive Wistar‐Kyoto rats (WKY). The rises were not different between SHRSP (21 mmHg) and WKY (23 mmHg). 2. In ring preparations of the thoracic aorta of NO 2 Arg‐administered rats of both strains, relaxation by acetylcholine decreased markedly compared with those of the control rats (to 43–44%). On the contrary, glyceryltrinitrate‐induced relaxation was slightly but significantly increased in the aorta of WKY after NO 2 Arg administration and the same tendency was observed in SHRSP. 3. The rise of blood pressure and the decrease of acetylcholine‐induced relaxation suggested that NO 2 Arg inhibited the endothelium‐dependent relaxation not only in WKY but also in SHRSP. The relaxation of the thoracic aorta preparation of SHRSP by acetylcholine was much less ( ca 38%) than that of WKY; however, that of SHRSP by glyceryltrinitrate was slightly less ( ca 74%), indicating that endothelium‐dependent relaxation declined in vascular preparation of SHRSP. 4. The present results suggest that endothelium‐dependent relaxation has some contribution on blood pressure regulation in the hypertensive state, although a decline of endothelium‐dependent relaxation is evident in vascular preparation of SHRSP compared with WKY.