Verberne A J, Lewis S J, Worland P J, Beart P M, Jarrott B, Christie M J, Louis W J
University of Melbourne, Clinical Pharmacology and Therapeutics Unit, Heidelberg, Vic., Australia.
Brain Res. 1987 Nov 24;426(2):243-9. doi: 10.1016/0006-8993(87)90878-x.
Previous neuroanatomical studies in rats have demonstrated that the medial prefrontal cortex sends projections to the nucleus of the solitary tract which also receives the bulk of baroreceptor information from primary afferents within the IXth and Xth cranial nerves. The present study examines the influence of the prefrontal cortex on baroreceptor heart rate reflex in conscious rats. Baroreceptor reflex activity was examined in rats with bilateral excitotoxin (N-methyl-D-aspartate)-induced lesions of the medial prefrontal cortex and in control rats (artificial cerebrospinal fluid). Seventeen to eighteen days after lesioning, reflex heart rate responses were recorded following intravenous bolus doses of the pressor agent phenylephrine and the depressor agent sodium nitroprusside. Baroreceptor reflex parameters i.e., maximum and average baroreceptor reflex gain (or sensitivity): minimum and maximum heart rate plateaus; heart rate range; upper and lower reflex thresholds, were determined by sigmoidal computerized curve-fitting. Lesioning the medial prefrontal cortex did not affect resting mean arterial pressure and heart rate. However, the lesion reduced maximum and average baroreceptor reflex gain and produced a small reduction in lower reflex threshold. The other parameters were unaffected by the lesion. These observations suggest that although the medial prefrontal cortex does not exert a tonic influence on brainstem vasomotor neurons, there may be a descending excitatory projection from this brain region to medullary neurones involved in the baroreceptor reflex arc.
先前对大鼠的神经解剖学研究表明，内侧前额叶皮层向孤束核发出投射，孤束核也接收来自第九和第十对脑神经内初级传入纤维的大部分压力感受器信息。本研究考察了前额叶皮层对清醒大鼠压力感受器心率反射的影响。在双侧兴奋性毒素（N-甲基-D-天冬氨酸）诱导内侧前额叶皮层损伤的大鼠和对照大鼠（人工脑脊液）中检测压力感受器反射活动。损伤后17至18天，在静脉推注升压药去氧肾上腺素和降压药硝普钠后记录反射性心率反应。通过S形计算机曲线拟合确定压力感受器反射参数，即最大和平均压力感受器反射增益（或敏感性）、最小和最大心率平台、心率范围、上下反射阈值。内侧前额叶皮层损伤不影响静息平均动脉压和心率。然而，损伤降低了最大和平均压力感受器反射增益，并使下反射阈值略有降低。其他参数不受损伤影响。这些观察结果表明，虽然内侧前额叶皮层对脑干血管运动神经元没有紧张性影响，但该脑区可能存在一条下行兴奋性投射至参与压力感受器反射弧的延髓神经元。
