Age-dependent reduction in voltage-gated inward sodium current and Scn8a gene expression in murine stellate ganglia

Stellate ganglia (SG) provide sympathetic innervation to the heart and may predispose the myocardial conducting system to arrhythmias. However, little is known about age-related changes in the electrophysiology of murine SG. We investigated alterations in the electrophysiological properties of SG with aging. The loose patch clamp technique was adapted to SG tissue to investigate the voltage-gated ionic currents in its neuronal cells. We compared SG and ventricular cells from young (4 months) and aged (13 months) C57BL/6J mice to explore age-related alterations in their voltage-gated ionic currents (n > 30 patches, eight mice in each group). We observed that the voltage-gated inward sodium current (peak I_Na(Max)) was significantly decreased with aging in the SG, but not in the ventricle. Additionally, Scn8a gene expression, which encodes the Nav 1.6 channel, was decreased with aging in the SG. Application of loose patch clamp electrophysiology thus suggests that ionic current alterations with age in murine SG could contribute to cardiac autonomic dysregulation in geriatric conditions.