Connections between rat central cardiovascular control neurons and locus coeruleus

• Main Authors: Wen-yi Wu, 吳玟誼
• Other Authors: Yueh-jan Wang
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/03756703626130803408

碩士 === 慈濟大學 === 醫學研究所 === 95 === Autonomic nerve alters its activity during the sleep-awake cycle for instance sympathetic is active when awake while parasympathetic prevails during the sleep. In the literature, there are few studies examining the connections between the sleep-awake-related nuclei and the autonomic nerve system. In light of the fact that noradrenergic neurons of the locus coeruleus (LC) are known to alter its activity during the sleep-awake cycle and that epinephrine secreted by sympathetic nerves and adrenal medulla modulates blood pressure and heart rate, we investigated whether LC neurons the sympathetic cardiovascular regulating effect though the activity of brainstem neurons of the nucleus of the solitary tract (NTS) and the ventrolateral medulla (VLM), areas known to participate in sleep-awake cycle by tracing their connections. We found that LC neurons project monosynaptically to the medial and dorsomedial subnuclei of the ipsilateral intermediate NTS (NTSi). Labeled axonal varicosities were found to appose 98% of the glutamatergic neurons located in the medial subnucleus of the NTSi which are know to receive baroreceptor input and each neuron appeared to be contacted by a few varicosities. In addition, dorsomedial subnucleus of the NTSi projected to the ipsilateral LC. Fewer LC fibers reached ipsilateral rostral VLM (RVLM) and fiber terminals were found to come close to 37% of the glutamatergic neurons of RVLM, There are also a few neurons that project from the RVLM to LC. However, there appeared to be no connection between the caudal VLM and LC. Thus, our results suggest that noradrenergic LC neurons may act through the glutamatergic NTS neurons of its medial and dorsomedial subnuclei to affect the autonomic cardiovascular control.