In vivo measurement of nitric oxide on the surface of rat cremaster muscle arterioles

现已证实，一氧化氮(NO)在血管张力调节中起重要作用。然而，骨骼肌微循环中的NO浓度[NO]尚未被测定。在本研究中，我们使用非特异性微电极对大鼠提睾肌小动脉表面的[NO]进行了活体测量。用改良的Baez法对麻醉雄性Wistar-Hnorver大鼠右侧提睾肌进行外化(Baez，S，1973)。通过显微镜获得的图像被分成高速CCD摄像机和带有一对光电二极管的图像观察屏。根据Wiedeman‘s排序系统将血管分为1A、2A、3A和4A四个顺序。用安培非选择性微电极(7μm和30μm，WPI Inc.)直接测定[NO]。通过集成的电化学NO检测系统(Apollo-4000，WPI)。该电极具有0.5-5.0pA/nM的高检测灵敏度和1-3 nM的检测下限。利用显微操作器将微电极直接放置在提睾肌表面的微动脉壁上。1A型、2A型、3A型、4A型微动脉表面NO含量分别为916.4±121.6、468.4±62.5nM、583.0±131.5、245.0±138.7 nM。1A(直径50-100μm)上的[NO]显著高于4A(10-30μm)上的[NO]。随着微动脉网络的排列，小动脉壁邻近表面的NO浓度逐渐降低。

It has been established that nitric oxide (NO) plays an important role in the regulation of vascular tone. However, NO concentration [NO] in the microcirculation of skeletal muscle has not been determined. In the present study, we measured [NO] in vivo on the surface of the arterioles of the rat cremaster muscle by using NO-specific microelectrodes. The right cremaster muscles of anesthetized male Wistar-Hannover rats were surgically exteriorized using the modified Baez method (Baez S 1973). Images gained through a microscope were divided into a high speed CCD camera and into an image viewing screen with a pair of photodiodes. Vessels were classified into the order of 1A, 2A, 3A and 4A by Wiedeman's ordering system. [NO] was measured directly with a amperometric NO-selective microelectrode (7μm and 30μm, WPI Inc.) through an integrated electrochemical NO detection system (Apollo-4000, WPI). The electrode has a high detection sensitivity of 0.5 - 5.0 pA/nM and a detection limit of 1-3 nM. The microelectrode was placed immediately adjacent to the wall of arterioles on the surface of the cremaster muscle by using a micro-manipulator. [NO] was 916.4 ± 121.6 nM on the surface of 1A arterioles, 468.4 ± 62.5 nM on the 2A, 583.0 ± 131.5 nM on the 3A, and 245.0 ± 138.7 nM on the 4A arterioles. [NO] on the 1A (50 - 100μm diameter) was significantly higher than [NO] on the 4A (10- 30μm). NO concentration on the adjacent surface of the arteriolar wall gradually decreased along with the order of the arteriolar network.