VESTIBULAR INFLUENCES ON THE SYMPATHETIC NERVOUS SYSTEM

电刺激前庭神经会引起症状的变化- 人工流出与血压(Uchino等人，1970；Ishikawa等人， 1979年)。此外，前庭损伤还会影响立位反射。 (心血管对体位改变的反应)：这种损害 极大地损害猫的血压补偿到60度倾斜(Doba和 Reis，1974；Huang等人，1977)。前庭交感神经的发生 抵消直立性低血压的反射并不是意料中事； 前庭感受器通知神经系统头部的变化 姿势，从而改变姿势。因为生理反应对 直立性低血压是交感神经流出的增加(Gauer和 Thron，1965)，对于发出变化信号的输入来说似乎是可行的 影响自主神经系统的姿势。初步研究 揭示了至少两个已知的脑干区域中的神经元含有 高密度的心脏调节神经元、延髓腹外侧部和 旁正中网状核，接受前庭输入。此外, 来自颈动脉窦和迷路的输入显示汇聚在 在这些地区的单一单位。拟议的研究将利用这两种方法 电和自然的前庭刺激，并将分析前庭 脑干心脏调节神经元的传入以及前庭诱发的 从交感神经记录到的反射。这些实验将证明 哪些下行通路将前庭信号传递给交感神经 节前神经元，并描述这些通路的输入。这 信息将揭示哪些外周内脏(半规管或 耳石器官)在产生呼吸交感反射方面很重要。 此外，来自后肢的躯体输入会聚的可能性 作为前庭-交感神经通路一部分的神经元 考虑过了。

Electrical stimulation of the vestibular nerve produces changes in sympa- thetic outflow and blood pressure (Uchino et al., 1970; Ishikawa et al., 1979). In addition, vestibular lesions affect orthostatic reflexes (cardiovascular responses to a change in body position): such lesions greatly impair blood pressure compensation to 60 deg tilt in cats (Doba and Reis, 1974; Huang et al., 1977). The occurrence of vestibule-sympathetic reflexes which counteract orthostatic hypotension is not unexpected; vestibular receptors inform the nervous system about changes in head position, and thus changes in posture. Since the physiological response to orthostatic hypotension is an increase in sympathetic outflow (Gauer and Thron, 1965), it seems practical for inputs which signal a change in posture to influence the autonomic nervous system. Preliminary studies revealed that neurons in at least two brainstem regions known to contain a high density of cardioregulatory neurons, the ventrolateral medulla and the paramedian reticular nucleus, receive vestibular inputs. In addition, inputs from the carotid sinus and labyrinth were shown to converge on single units in these regions. The proposed studies will utilize both electrical and natural vestibular stimulation and will analyze vestibular inputs to brainstem cardioregulatory neurons as well as vestibular-elicited reflexes recorded from sympathetic nerves. These experiments will show which descending pathways convey vestibular signals to sympathetic preganglionic neurons and characterize the inputs to these pathways. This information will reveal which peripheral endorgans (semicircular canals or otolith organs) are important in producing ventibulo-sympathetic reflexes. In addition, the possibility that somatic inputs from the hindlimb converge on neurons that are part of the vestibulo-sympathetic pathway will be considered.