FUNCTION OF BARORECEPTOR C-FIBERS IN RABBITS AORTIC NERVE
FUNCTION OF BARORECEPTOR C-FIBERS IN RABBITS AORTIC NERVE
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DOI：
10.1111/j.1748-1716.1978.tb06048.x
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发表时间：
1978-01-01
期刊：
影响因子：
--
通讯作者：
HASWELL, BA
中科院分区：
文献类型：
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作者：
AARS, H;MYHRE, L;HASWELL, BA
在两种实验情况下，通过记录肾神经活动的变化来研究主动脉神经C纤维在压力感受性反射中的参与：左主动脉神经的A和C纤维完整，A纤维被超极化电流(阳极阻断)暂时阻断。通过手动扩张主动脉内球囊来增加压力，通过阻断颈动脉和切断右侧动脉神经来避免来自其他压力感受器区域的干扰。平均动脉压超过20毫米汞柱，达到110毫米汞柱以上，需要通过C纤维触发交感神经抑制。每升高45毫米汞柱，交感神经活动减少50%，相当于在约3赫兹时刺激主动脉神经C纤维。相反，当A纤维运作时，20-30毫米汞柱的升高会导致交感神经活动减少60%以上。根据这些对短暂压力升高的峰值反射反应的研究，主动脉神经中含有C纤维的压力感受器对压力的阈值比有髓神经中的压力感受器高得多；只有当压力远高于正常静息水平时，C纤维才有助于抑制交感神经放电的压力感受性反射。
The participation of aortic nerve C fibers in the baroreflex was investigated by recording changes in renal nerve activity in response to acute increases in arterial pressure, in 2 experimental situations: with the A and C fibers of the left aortic nerve intact, and with the A fibers temporarily blocked by a hyperpolarizing current (anodal block). Pressure was increased by manual inflation of an intra-aortic balloon, and interference from other baroreceptor areas was avoided by carotid occlusion and sectioning of the right arotic nerve. Rises in mean arterial pressure exceeding 20 mmHg, to levels above 110 mmHg, were needed to trigger sympathetic inhibition via C fibers. A rise of 45 mmHg caused 50% reduction in sympathetic activity, equal to stimulation of aortic nerve C fibers at about 3 Hz. In contrast, a rise of 20-30 mmHg evoked more than 60% reduction in sympathetic activity when the A fibers were operative. Judged by these studies of peak reflex responses to brief pressure rises, baroreceptors with C fibers in the aortic nerve have a much higher threshold to pressure than their myelinated counterparts; the C fibers contribute to the baroreflex inhibition of sympathetic discharge only when pressure is increased well above normal resting levels.