Tominaga M, Stekiel T A, Bosnjak Z J, Kampine J P
Department of Anesthesiology, The Medical College of Wisconsin, Milwaukee 53226, USA.
Am J Physiol. 1999 Dec;277(6):H2305-10. doi: 10.1152/ajpheart.1999.277.6.H2305.
The contribution of carotid chemoreceptors to hypercapnia-induced mesenteric venoconstriction was examined in 12 alpha-chloralose-anesthetized rabbits (1.0-1.6 kg). Surgical preparation consisted of a tracheotomy, femoral arterial and venous cannulation, and a midline laparotomy through which a 13-cm loop of ileum was exteriorized and superfused with physiological salt solution. Mesenteric vein diameter and intravenous pressure (using a servo-null measurement system) were measured in 500- to 1,000-micron mesenteric veins during 40-s periods of 15%, 20%, and 25% CO2 inhalation. Measurements were then repeated following bilateral ablation of the carotid chemoreceptors. Before denervation, mesenteric vein diameter constricted 6.5 +/- 1.1%, 11.9 +/- 1.1%, and 17.9 +/- 2.2% during the 15%, 20%, and 25% CO2 inhalation, respectively. After denervation, these values were reduced to 5.0 +/- 0.9%, 6.9 +/- 1.2%, and 8.4 +/- 1.3%, respectively. We conclude that activation of the carotid chemoreceptors by hypercapnia induces active mesenteric venoconstriction. After denervation of the carotid baroreceptors and chemoreceptors, there was also a small decrease in venule diameter proportional to the level of inspired CO2. We further conclude that noncarotid body chemoreceptor activation contributes to mesenteric venular constriction.
在12只α-氯醛糖麻醉的家兔（体重1.0 - 1.6千克）中，研究了颈动脉化学感受器在高碳酸血症诱导的肠系膜静脉收缩中的作用。手术准备包括气管切开术、股动脉和静脉插管，以及中线剖腹术，通过该手术将一段13厘米的回肠引出并灌注生理盐溶液。在吸入15%、20%和25%二氧化碳的40秒期间，测量500至1000微米肠系膜静脉的肠系膜静脉直径和静脉压（使用伺服零测量系统）。在双侧切除颈动脉化学感受器后重复测量。去神经支配前，在吸入15%、20%和25%二氧化碳期间，肠系膜静脉直径分别收缩6.5±1.1%、11.9±1.1%和17.9±2.2%。去神经支配后，这些值分别降至5.0±0.9%、6.9±1.2%和8.4±1.3%。我们得出结论，高碳酸血症激活颈动脉化学感受器可诱导肠系膜静脉主动收缩。在颈动脉压力感受器和化学感受器去神经支配后，小静脉直径也随着吸入二氧化碳水平的升高而略有下降。我们进一步得出结论，非颈动脉体化学感受器激活也有助于肠系膜小静脉收缩。
