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