A SALIVARY NITROPHORIN (NITRIC-OXIDE-CARRYING HEMOPROTEIN) IN THE BEDBUG CIMEX LECTULARIUS

Salivary gland homogenate of the bedbug Cimex lectularius caused vasod ilation of the preconstricted rabbit aortic ring in the absence of end othelium, Vasodilation was augmented in the presence of superoxide dis mutase and inhibited in the presence of Methylene Blue. Utilization of the Griess reaction indicated the presence of reactive nitrogen equiv alents of the order of 337 +/- 57 pg equivalent NO2- per pair of saliv ary glands (mean +/- S.E.M.; N=3), Salivary gland homogenates have a n itrosyl-hemoprotein that releases nitric oxide in a pa-dependent manne r, The fraction containing the NO-carrying hemoprotein, when separated by HPLC, caused vasodilation of the preconstricted rabbit aortic stri p. Furthermore, the presence of a nitrosyl-hemoprotein in Cimex lectul arius salivary gland was verified by electron paramagnetic resonance s pectroscopy. 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, Ho wever, because Cimex lectularius and Rhodnius prolixus belong to diffe rent hemipteran families (Cimicidae and Reduvidae) and evolved indepen dently to blood feeding, Cimex lectularius and Rhodnius prolixus nitro phorin may be a case of convergent evolution.