Comparison of Blood Pressure Modulation by Low-Intensity Focused Ultrasound Stimulation of Carotid Sinus, Nodose Ganglion, and Vagus Nerve

Low-intensity focused ultrasound stimulation (FUS) of the vagus nerve has proven effective in lowering blood pressure (BP) in our pilot animal study, opening new possibilities for noninvasive physiotherapy for hypertension. To further explore the impact of BP regulation by FUS on other targets, we compared the BP modulation pattern when applying FUS to the left carotid sinus, nodose ganglion, and vagus nerve trunk, respectively. FUS with different acoustic intensities was applied to each target, while continuous BP waveforms were synchronously recorded in the right common carotid artery. Subsequently, systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were extracted and analyzed before, during, and after FUS. The results revealed that FUS targeting the carotid sinus and nodose ganglion could also induce reductions in BP. However, both the degree of BP reduction and the sustained duration were less than those achieved with vagus nerve stimulation. Moreover, the ultrasound stimulation intensity threshold for inducing a hypotensive effect is lower when stimulating the vagus nerve compared to stimulating the carotid sinus and nodose ganglion. This study provides compelling evidence supporting the selection of the vagus nerve as the appropriate target for FUS in regulating BP.