Stanek K A, Neil J J, Sawyer W B, Loewy A D
Am J Physiol. 1984 Jan;246(1 Pt 2):H44-51. doi: 10.1152/ajpheart.1984.246.1.H44.
Changes in regional blood flow and cardiac output were measured by the reference organ method in pentobarbital-anesthetized rats with radioactive microspheres (15 microns) before and after chemical stimulation of the A5 cell group with the excitatory amino acid L-glutamate an agent that excites cell bodies but not fibers of passage. This stimulation caused a decrease in mean arterial pressure, heart rate, cardiac output, and calculated stroke volume. The limb skeletal muscles showed a large increase in blood flow and decrease in vascular resistance, whereas the trunk musculature showed no change in flow or resistance. The blood flow of the entire gastrointestinal tract decreased. Blood flow in the skin decreased with no change in resistance. The cardiac muscle of the ventricles showed a decrease in flow without a change in resistance. The ipsilateral half of the brain showed a decrease in blood flow, while the contralateral side showed no change. The kidneys exhibited no change in blood flow and a decrease in resistance. A5 stimulation in guanethidine-sympathectomized rats caused no change in regional blood flow. In contrast, an increase in cardiac output was observed, and the possible interpretations for this change are discussed. Rats treated with intraventricular injections of 6-hydroxydopamine showed no changes in regional blood flow or cardiac output, indicating that catecholamine neurons are involved in these responses.
在戊巴比妥麻醉的大鼠中，使用放射性微球（15微米）通过参考器官法在化学刺激A5细胞群前后测量局部血流和心输出量，该化学刺激采用兴奋性氨基酸L-谷氨酸，一种兴奋细胞体而非传导纤维的试剂。这种刺激导致平均动脉压、心率、心输出量和计算得出的每搏输出量降低。肢体骨骼肌血流大幅增加，血管阻力降低，而躯干肌肉组织的血流和阻力无变化。整个胃肠道的血流减少。皮肤血流减少，阻力无变化。心室心肌血流减少，阻力无变化。大脑同侧半球血流减少，而对侧无变化。肾脏血流无变化，阻力降低。在胍乙啶交感神经切除的大鼠中，刺激A5未引起局部血流变化。相反，观察到心输出量增加，并讨论了对此变化的可能解释。脑室内注射6-羟基多巴胺处理的大鼠局部血流和心输出量无变化，表明儿茶酚胺能神经元参与了这些反应。
