Jpn. J. Pharmacol. 76 (1), 101-104 (1998)

Diverse Relaxation Responses of Canine Large and Small Conductive Coronary Arteries to Glyceryl Trinitrate and Nitric Oxide on the One Hand and to 8-Bromoguanosine 3':5' Cyclic Monophosphate on the Other

Toshikazu Kitagawa, Takaharu Ishibashi (*,#) and Shoichi Imai

Department of Pharmacology, Niigata University School of Medicine, Asahimachi-dori 1-757, Niigata 951, Japan
(*) To whom correspondence should be addressed.
(#) Present address for correspondence: Department of Pharmacology, Kanazawa Medical University, Uchinada, Ishikawa 920-0293, Japan

Abstract: Glyceryl trinitrate (GTN) and nitric oxide (NO) preferentially relaxed the large (2 mm in diameter) conductive coronary artery (CCA) of the dog, while 8-bromoguanosine 3':5' cyclic monophosphate preferentially relaxed the small one (0.6 mm in diameter). Nither L-cysteine nor L-acetylcysteine affected GTN-induced relaxation in small- and large-CCA. These results indicate that not different biotransformation of GTN to NO, but a process or processes operative between activation of guanylate cyclase and that of cyclic GMP-dependent protein kinase seems to be responsible for the preferential dilatation of large-CCA.

Keywords: Glyceryl trinitrate, 8-Br-cGMP, Coronary artery

Copyrightę The Japanese Pharmacological Society 1998

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