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