Varner K J, Barman S M, Gebber G L
Department of Pharmacology and Toxicology, Michigan State University, East Lansing 48824.
Am J Physiol. 1988 Feb;254(2 Pt 2):R257-67. doi: 10.1152/ajpregu.1988.254.2.R257.
In a companion paper, we demonstrated that hypothalamic or medial thalamic lesions attenuate the reduction in inferior cardiac postganglionic sympathetic nerve discharge (SND) produced by decerebration in the anesthetized cat [Huang et al., Am. J. Physiol. 254 (Regulatory Integrative Comp. Physiol. 23): R249-R256, 1988]. This raised the possibility that these diencephalic regions contain the cell bodies of neurons that contribute to SND. The current study tested this possibility in cats anesthetized with alpha-chloralose. Spike-triggered averaging of inferior cardiac SND revealed the existence of two types of hypothalamic and medial thalamic neurons with sympathetic nerve-related activity. Recordings were made from the soma-dendritic region of these neurons, since an inflection often appeared on the rising phase of the unit action potential. The activity of type 1 neurons was synchronized to an aperiodic spikelike event in SND, whereas that of type 2 neurons was synchronized to a 2- to 6-Hz rhythmic component. Some of the type 2 neurons but none of the type 1 neurons had cardiac-related activity. Microstimulation at type 1 and type 2 unit recording sites increased SND. Our results are consistent with the possibility that hypothalamic and medial thalamic neurons contribute to the rhythmic and aperiodic components of SND in the anesthetized cat.
在一篇相关论文中，我们证明了下丘脑或丘脑内侧病变会减弱麻醉猫去大脑后下心节后交感神经放电（SND）的减少[Huang等人，《美国生理学杂志》254（调节整合生理学23）：R249 - R256，1988年]。这就提出了一种可能性，即这些间脑区域包含对SND有贡献的神经元的细胞体。本研究在α - 氯醛糖麻醉的猫身上测试了这种可能性。通过对下心SND进行触发脉冲平均，发现存在两种具有交感神经相关活动的下丘脑和丘脑内侧神经元。由于在单位动作电位的上升阶段经常出现一个拐点，所以从这些神经元的胞体 - 树突区域进行记录。1型神经元的活动与SND中一个非周期性的尖峰状事件同步，而2型神经元的活动与一个2至6赫兹的节律性成分同步。一些2型神经元但没有1型神经元具有心脏相关活动。在1型和2型单位记录位点进行微刺激会增加SND。我们的结果与下丘脑和丘脑内侧神经元对麻醉猫SND的节律性和非周期性成分有贡献的可能性一致。
