University of Delaware, Newark, DE, United States of America.
University of Minnesota, Minneapolis, MN, United States of America.
Auton Neurosci. 2024 Aug;254:103182. doi: 10.1016/j.autneu.2024.103182. Epub 2024 May 19.
Rodent studies demonstrated specialized sodium chloride (NaCl) sensing neurons in the circumventricular organs, which mediate changes in sympathetic nerve activity, arginine vasopressin, thirst, and blood pressure. However, the neural pathways involved in NaCl sensing in the human brain are incompletely understood. The purpose of this pilot study was to determine if acute hypernatremia alters the functional connectivity of NaCl-sensing regions of the brain in healthy young adults. Resting-state fMRI scans were acquired in 13 participants at baseline and during a 30 min hypertonic saline infusion (HSI). We used a seed-based approach to analyze the data, focusing on the subfornical organ (SFO) and the organum vasculosum of the lamina terminalis (OVLT) as regions of interest (ROIs). Blood chemistry and perceived thirst were assessed pre- and post-infusion. As expected, serum sodium increased from pre- to post-infusion in the HSI group. The primary finding of this pilot study was that the functional connectivity between the SFO and a cluster within the OVLT increased from baseline to the late-phase of the HSI. Bidirectional connectivity changes were found with cortical regions, with some regions showing increased connectivity with sodium-sensing regions while others showed decreased connectivity. Furthermore, the functional connectivity between the SFO and the posterior cingulate cortex (a control ROI) did not change from baseline to the late-phase of the HSI. This finding indicates a distinct response within the NaCl sensing network in the human brain specifically related to acute hypernatremia that will need to be replicated in large-scale studies.
啮齿动物研究表明，在室周器官中存在专门的氯化钠 (NaCl) 感应神经元，这些神经元介导交感神经活动、精氨酸加压素、口渴和血压的变化。然而，人类大脑中 NaCl 感应的神经通路尚不完全清楚。本初步研究的目的是确定急性高钠血症是否会改变健康年轻成年人大脑中 NaCl 感应区域的功能连接。在 13 名参与者的基线和 30 分钟高渗盐水输注 (HSI) 期间采集静息状态 fMRI 扫描。我们使用基于种子的方法分析数据，重点关注下丘脑室下器官 (SFO) 和终板血管器 (OVLT) 作为感兴趣区域 (ROI)。在输注前后评估血液化学和口渴感。正如预期的那样，HSI 组的血清钠从输注前到输注后增加。这项初步研究的主要发现是，从基线到 HSI 的后期，SFO 和 OVLT 内一个簇之间的功能连接增加。与皮质区域存在双向连接变化，一些区域与钠离子感应区域的连接增加，而其他区域的连接减少。此外，SFO 和后扣带回皮层（对照 ROI）之间的功能连接从基线到 HSI 的后期没有变化。这一发现表明，人类大脑中 NaCl 感应网络存在一种独特的反应，特别是与急性高钠血症有关，这需要在大规模研究中得到复制。
