title: Aerobic metabolism on muscle contraction in porcine iris sphincter.
abstract: Eyes are supplied O2through the cornea and vessels of the retina and iris, which are tissues characterized by aerobic metabolism. Meanwhile, there are no reports on the association between iris sphincter contraction and aerobic metabolism. In this paper, we studied the aforementioned association. Eyes from adult pigs of either sex were obtained from a local abattoir. A muscle strip was connected to a transducer to isometrically record the tension. O2consumption was measured using a Clark-type polarograph connected to a biological oxygen monitor. Creatine phosphate (PCr) and adenosine triphosphate (ATP) contents were measured in the muscle strips by high-performance liquid chromatography (HPLC). Iris sphincter muscles were measured in resting, contractile or hypoxic phases. Contraction was induced by hyperosmotic 65 mM KCl (H-65K+) or carbachol (CCh), and hypoxia was induced by aeration with N2instead of O2or by addition of sodium cyanide (NaCN). H-65K+- and CCh-induced muscle contraction, involved increasing O2consumption. Hypoxia and NaCN significantly decreased H-65K+- and CCh-induced muscle contraction and/or O2consumption and PCr contents. Our results suggest that the contractile behavior in porcine iris sphincter highly depends on mitogen oxidative metabolism.
authors: Laboratory of Veterinary Pharmacology, Nippon Veterinary and Life Science University, Kyonan-cho 1-chome, Musashino, Tokyo 180-862 Japan.
authors: Hidenori
authors: H
authors: Kanda
authors: Takeharu
authors: T
authors: Kaneda
authors: Asami
authors: A
authors: Kato
authors: Takuya
authors: T
authors: Yogo
authors: Yasuji
authors: Y
authors: Harada
authors: Yasusi
authors: Y
authors: Hara
authors: Norimoto
authors: N
authors: Urakawa
authors: Kazumasa
authors: K
authors: Shimizu
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002217:Carbachol / Q000494:pharmacology; D015687:Cell Hypoxia; D005260:Female; D007498:Iris / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology*; D010725:Phosphocreatine / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D012966:Sodium Cyanide / Q000494:pharmacology; D013552:Swine
chemical_list: D010725:Phosphocreatine; D011189:Potassium Chloride; D000255:Adenosine Triphosphate; D002217:Carbachol; D012966:Sodium Cyanide