title: Effects of nitric oxide donors and nitric oxide synthase substrates on ciliary muscle contracted by carbachol and endothelin for possible use in myopia prevention.
abstract: Research has suggested that the development of myopia may possibly be prevented by the use of drugs which facilitate relaxation of the intraocular ciliary muscle. We examined the effects of five nitric oxide-producing agents--two nitric oxide donors, hydralazine and sodium nitrite, and three nitric oxide synthase substrates, L-arginine, L-canavanine, and N-benzoyl-L-arginine ethyl ester--on isolated bovine ciliary muscle maximally contracted with either carbachol or endothelin-1. Of these agents, hydralazine and L-canavanine produced a relaxing effect on endothelin-1-contracted muscle that was significantly greater than relaxing effect on carbachol-contracted muscle. These results indicate that hydralazine and L-canavanine could possibly be used for the prevention of myopia by relaxing the ciliary muscle with few anticholinergic and cycloplegic side effects.
authors.affiliation: Institute of Ocular Pharmacology and Department of Medical Pharmacology and Toxicology, Texas A&M University System Health Science Center, College of Medicine, College Station 77843-1114, USA.
authors.forename: C
authors.initials: C
authors.lastname: Beauregard
authors.forename: Q
authors.initials: Q
authors.lastname: Liu
authors.forename: G C
authors.initials: GC
authors.lastname: Chiou
mesh_terms: D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D002172:Canavanine / Q000494:pharmacology*; D002217:Carbachol / Q000494:pharmacology*; D002417:Cattle; D002924:Ciliary Body / Q000187:drug effects* / Q000201:enzymology; D019332:Endothelin-1 / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects* / Q000201:enzymology; D009216:Myopia / Q000517:prevention & control*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D019332:Endothelin-1; D020030:Nitric Oxide Donors; D002172:Canavanine; D002217:Carbachol; D001120:Arginine; C009727:benzoylarginine ethyl ester; D019001:Nitric Oxide Synthase