title: A salivary nitrophorin (nitric-oxide-carrying hemoprotein) in the bedbug Cimex lectularius.
abstract: Salivary gland homogenate of the bedbug Cimex lectularius caused vasodilation of the preconstricted rabbit aortic ring in the absence of endothelium. Vasodilation was augmented in the presence of superoxide dismutase and inhibited in the presence of Methylene Blue. Utilization of the Griess reaction indicated the presence of reactive nitrogen equivalents of the order of 337 +/- 57 pg equivalent NO2- per pair of salivary glands (mean +/- S.E.M.; N = 3). Salivary gland homogenates have a nitrosyl-hemoprotein that releases nitric oxide in a pH-dependent manner. The fraction containing the NO-carrying hemoprotein, when separated by HPLC, caused vasodilation of the preconstricted rabbit aortic strip. Furthermore, the presence of a nitrosyl-hemoprotein in Cimex lectularius salivary gland was verified by electron paramagnetic resonance spectroscopy. It is proposed that, as in the case of Rhodnius prolixus (Triatominae), Cimex lectularius salivary glands contain a hemoprotein (nitrophorin) that carries NO from the glands to the host tissues. However, because Cimex lectularius and Rhodnius prolixus belong to different hemipteran families (Cimicidae and Reduvidae) and evolved independently to blood feeding, Cimex lectularius and Rhodnius prolixus nitrophorin may be a case of convergent evolution.
authors.affiliation: Department of Biochemistry, University of Arizona, Tucson 85721, USA.
authors.forename: J G
authors.initials: JG
authors.lastname: Valenzuela
authors.forename: F A
authors.initials: FA
authors.lastname: Walker
authors.forename: J M
authors.initials: JM
authors.lastname: Ribeiro
mesh_terms: D000818:Animals; D001011:Aorta; D001511:Bedbugs / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004578:Electron Spin Resonance Spectroscopy; D004730:Endothelium, Vascular; D006420:Hemeproteins / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008751:Methylene Blue / Q000494:pharmacology; D009126:Muscle Relaxation / Q000502:physiology; D009131:Muscle, Smooth, Vascular / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism*; D011817:Rabbits; D012469:Salivary Glands / Q000737:chemistry / Q000378:metabolism*; D012471:Salivary Proteins and Peptides / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D013482:Superoxide Dismutase / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects
chemical_list: D006420:Hemeproteins; D012471:Salivary Proteins and Peptides; C090560:nitrophorin; D009569:Nitric Oxide; D013482:Superoxide Dismutase; D008751:Methylene Blue