Buller K M, Bolter C P
Department of Physiology, University of Otago, Dunedin, New Zealand.
J Auton Nerv Syst. 1997 Dec 3;67(1-2):24-30. doi: 10.1016/s0165-1838(97)00088-x.
Previous reports have suggested that a peripheral pressure-modulated reflex operates at the level of the superior cervical ganglion to alter evoked activity in the postganglionic nerves of the ganglion in both the cat and rabbit. In the present study we have examined if spontaneous activity of the external and internal carotid nerves of the rabbit superior cervical ganglion can be modulated during changes of the carotid bifurcation pressure (CBP), independent of central nervous system (CNS) integration. For external carotid nerve recordings increases in CBP resulted in a reduction in spontaneous activity while decreases in CBP were associated with an increase in spontaneous activity. For internal carotid nerve recordings similar effects were observed in the majority of recordings although a subset of recordings showed opposite effects or were not responsive to changes in pressure. To determine if vagus nerve afferents contribute to the observed pressure-modulated spontaneous activity effects, the influence of CBP on external carotid nerve recordings was examined before and after section of the vagus nerve rostral to the nodose ganglion. We found that even following section of the vagus nerve the external carotid nerve response to an increase in pressure remained intact. These results demonstrate that, after section of centrally-projecting afferent pathways from the carotid bifurcation to the CNS, changes in CBP can still modify spontaneous sympathetic activity of the rabbit superior cervical ganglion. The data reinforce previous findings related to evoked responses in the postganglionic nerves and also suggest that a pressure-modulated reflex, integrated at the level of the superior cervical ganglion, can influence ongoing sympathetic nervous outflow from the superior cervical ganglion in the rabbit.
先前的报告表明，外周压力调节反射在颈上神经节水平起作用，以改变猫和兔颈上神经节后神经的诱发活动。在本研究中，我们研究了兔颈上神经节的颈外和颈内神经的自发活动在颈动脉分叉压力（CBP）变化期间是否可以被调节，而与中枢神经系统（CNS）整合无关。对于颈外神经记录，CBP升高导致自发活动减少，而CBP降低则与自发活动增加相关。对于颈内神经记录，在大多数记录中观察到类似的效果，尽管一部分记录显示出相反的效果或对压力变化无反应。为了确定迷走神经传入是否对观察到的压力调节自发活动效应有贡献，在切断迷走神经结节神经节前方后，检查了CBP对颈外神经记录的影响。我们发现，即使在切断迷走神经后，颈外神经对压力升高的反应仍然完好。这些结果表明，在切断从颈动脉分叉到CNS的中枢投射传入通路后，CBP的变化仍然可以改变兔颈上神经节的自发交感神经活动。这些数据强化了先前与节后神经诱发反应相关的发现，也表明在颈上神经节水平整合的压力调节反射可以影响兔颈上神经节正在进行的交感神经流出。
