Skarphedinsson J O, Delle M, Carlsson S, Bealer S L
Department of Physiology, University of Iceland, Reykjavik, Iceland.
Acta Physiol Scand. 1996 Sep;158(1):21-8. doi: 10.1046/j.1365-201X.1996.536278000.x.
Cerebral blood flow in either the cortex, thalamic region or the brain stem, as well as somatosensory evoked potentials were measured in a model of moderate cerebral ischaemia in three groups of anaesthetized spontaneously hypertensive rats. The rats were bled to reduce evoked potential amplitudes to approximately 50-60% of pre-haemorrhage control. The consequent blood pressure fall reduced blood flow to approximately 65, 80 and 85% of pre-haemorrhage control in the cortical, thalamic and brain stem regions, respectively, as measured with a laser Doppler flowmeter. Hexamethonium (10 mg kg-1 i.v.), an autonomic ganglion blocker, caused vasodilation and a slight (7-13 units of prebleeding control) increase in blood flow in all the three regions, and the somatosensory evoked potentials normalized. In addition, the latency of the first evoked potential component decreased toward prebleeding values. Heart rate decreased and a transient decrease was also observed in mean arterial pressure despite an attempt to keep it constant with a pressure regulating reservoir. It is possible that the slightly increased regional cerebral blood flow after hexamethonium injection can explain the improved cerebral function as indicated by the enhanced somatosensory evoked potentials. However, the results might also indicate an autonomic regulation of afferent sensory pathways.
在三组麻醉的自发性高血压大鼠的中度脑缺血模型中，测量了皮质、丘脑区域或脑干的脑血流量以及体感诱发电位。通过放血使大鼠的诱发电位幅度降低至出血前对照值的约50 - 60%。用激光多普勒血流仪测量发现，随之而来的血压下降分别使皮质、丘脑和脑干区域的血流量减少至出血前对照值的约65%、80%和85%。自主神经节阻滞剂六甲铵（静脉注射10 mg/kg）可引起血管舒张，并使所有三个区域的血流量轻微增加（较出血前对照增加7 - 13个单位），体感诱发电位恢复正常。此外，第一个诱发电位成分的潜伏期向出血前值缩短。尽管试图通过压力调节储液器使其保持恒定，但心率下降，平均动脉压也出现短暂下降。六甲铵注射后局部脑血流量的轻微增加可能解释了体感诱发电位增强所表明的脑功能改善。然而，这些结果也可能表明存在对传入感觉通路的自主调节。
