Chen Y, Rivers R J
Department of Anesthesiology, University of Rochester Medical Center, Rochester, NY 14642, USA.
J Vasc Res. 2001 May-Jun;38(3):219-27. doi: 10.1159/000051050.
Vascular communication functions to facilitate blood distribution within tissues and can be demonstrated as conducted vasomotor responses. This study was designed to determine if local application of sodium nitroprusside (SNP) would affect arteriolar function at remote sites. In the cheek pouch of anesthetized hamsters, local application of SNP and nifedipine caused arteriolar dilation only at the site of application (7.1 +/- 0.5 and 7.4 +/- 0.6 microm), but not at remote sites. The application of SNP enhanced subsequent remote, nitric oxide (NO)-independent dilation in response to methacholine, which was applied at a site upstream from the SNP application site (6.7 +/- 0.7 versus 4.5 +/- 0.7 microm for methacholine alone). This potentiating effect was also observed following application of 3-morpholinosydnonimine, but not following nifedipine. This nonvasomotor influence of SNP was not affected by N(omega)-nitro-L-arginine (L-NA), tetrodotoxin (TTX), Gap 27 peptide or halothane. Attenuated local dilation in response to methacholine by L-NA could be partially recovered following downstream application of SNP, suggesting that SNP-induced potentiation was associated with enhanced vasodilatory signals at the methacholine application site. Thus, our results suggest that SNP induces nonvasomotor signals in arterioles to affect the network distribution of blood flow. Intrinsic NO, TTX-sensitive Na(+) channels and gap junctional communication do not seem to play a major role in the conduction of the nonvasomotor signals.
血管通讯功能有助于促进组织内的血液分布，并可表现为传导性血管运动反应。本研究旨在确定局部应用硝普钠（SNP）是否会影响远处部位的小动脉功能。在麻醉仓鼠的颊囊中，局部应用SNP和硝苯地平仅在应用部位引起小动脉扩张（分别为7.1±0.5和7.4±0.6微米），而在远处部位则无此作用。SNP的应用增强了随后对乙酰甲胆碱的远处、不依赖一氧化氮（NO）的扩张反应，乙酰甲胆碱应用于SNP应用部位上游的一个部位（乙酰甲胆碱单独应用时为4.5±0.7微米，联合应用SNP时为6.7±0.7微米）。应用3-吗啉代 sydnonimine后也观察到这种增强作用，但应用硝苯地平后未观察到。SNP的这种非血管运动影响不受N（ω）-硝基-L-精氨酸（L-NA）、河豚毒素（TTX）、Gap 27肽或氟烷的影响。L-NA导致的对乙酰甲胆碱的局部扩张减弱在下游应用SNP后可部分恢复，这表明SNP诱导的增强作用与乙酰甲胆碱应用部位的血管舒张信号增强有关。因此，我们的结果表明，SNP在小动脉中诱导非血管运动信号以影响血流的网络分布。内源性NO、TTX敏感的Na（+）通道和缝隙连接通讯似乎在非血管运动信号的传导中不起主要作用。
