Acute Hypernatremia Increases Functional Connectivity of Sodium Sensing Regions in the Brain

• DOI: 10.1096/fasebj.2022.36.s1.r4696
• Publication Date: 2022-05-03T09:18:13Z
• Authors: Joseph M. Stock; Roxana G. Burciu; Jae Woo Chung; Nathan T. Romberger; Ronald K. McMillan; Darshil Patel; Ibrahim Salhab; Sean D. Stocker; William B. Farquhar
• Keywords: Hypernatremia; Lamina terminalis; Plasma osmolality; Circumventricular organs

Rodent studies have identified specialized sodium chloride (NaCl)-sensing neurons in the circumventricular organs (CVOs), which mediate NaCl-induced changes sympathetic nerve activity, arginine vasopressin (AVP), thirst, and blood pressure (BP). In humans, acute hypernatremia has been shown to increase AVP, thirst BP. However, few human investigated network of NaCl sensing regions brain using functional magnetic resonance imaging (fMRI).To determine how connectivity change during an hypernatremic perturbation.Resting-state fMRI was performed on 9 healthy young adults (29±4 yrs, 5M) at baseline a 30 min 3% intravenous infusion rate 0.15 ml/kg/min. Venous samples perceived (Likert scale, cm) were obtained before immediately following infusion. Serum electrolytes, plasma osmolality, hematocrit, hemoglobin assessed. Beat-to-beat measured continuously. Seed-based voxel-wise analysis AFNI spherical seeds placed bilaterally subfornical organ (SFO), organum vasculosum lamina terminalis (OVLT) as well cortical sensory such insula. Functional compared vs. early (min 0-15) late 16-30) p < 0.01, corrected for multiple comparisons with 3dClustSim.Thirst (∆1.9±2.0 cm), serum (∆3.2±2.1 mmol/L), osmolality (∆6.9±4.7 mOsm/kg H2 O) all increased from post-infusion (p<0.05). Head motion minimal did not throughout stages (mean = 0.11±0.10 mm, p>0.80). Hypertonic saline local between SFO OVLT (Z score baseline=0.07±0.01, Z phase=0.17+0.01, p<0.01). A similar seen insula somatosensory cortex.Acute increases within CVOs brain.