Valenzuela J G, Walker F A, Ribeiro J M
Department of Biochemistry, University of Arizona, Tucson 85721, USA.
J Exp Biol. 1995 Jul;198(Pt 7):1519-26. doi: 10.1242/jeb.198.7.1519.
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.
臭虫（温带臭虫）的唾液腺匀浆在无内皮的情况下可使预先收缩的兔主动脉环舒张。超氧化物歧化酶存在时舒张作用增强，亚甲蓝存在时舒张作用受到抑制。利用格里斯反应表明，每对唾液腺中存在约337±57 pg当量NO₂⁻的活性氮等价物（平均值±标准误；N = 3）。唾液腺匀浆有一种亚硝基血红蛋白，其以pH依赖的方式释放一氧化氮。通过高效液相色谱分离的含有携带NO的血红蛋白的组分，可使预先收缩的兔主动脉条舒张。此外，通过电子顺磁共振光谱证实了温带臭虫唾液腺中存在亚硝基血红蛋白。有人提出，与长红猎蝽（锥蝽亚科）的情况一样，温带臭虫的唾液腺含有一种血红蛋白（嗜硝蛋白），它将NO从腺体转运到宿主组织。然而，由于温带臭虫和长红猎蝽属于不同的半翅目家族（臭虫科和猎蝽科），并且是独立进化为吸血的，温带臭虫和长红猎蝽的嗜硝蛋白可能是趋同进化的一个例子。
