EMPAGLIFLOZIN IMPROVES IMPAIRED SENSITIVITY OF AFFERENT NEURONS WITH RENAL AXONS

Abstract

Objective: Afferent renal nerve pathways likely play a role in salt sensitive hypertension. We recently reported that high salt diet (HS) impairs these afferent renal pathways in rats. Now we tested the hypothesis that during HS a decrease in sensitivity of renal afferent neurons is prevented by the SGLT2 inhibitor empagiflozin. Design and method: Respective groups of rats were put on HS containing 8% NaCl or a normal diet. Two groups (HS, controls) received empagiflozin 20 mg/kg BW/day orally. Renal neurons were retrogradely labeled with DiI. In culture, labeled dorsal root ganglion neurons (DRG Th11-L2) with renal afferents were investigated electrophysiologically using current clamp mode to assess action potential generation during current injection. Neurons were characterized as tonic highly active ( less than 5 action potentials, AP) and phasic less active neurons (more than 5 AP upon stimulation). Results: In neurons from rats on HS, the relation of tonic highly active neurons to less active phasic neurons shifted consistently towards phasic units (63,8% tonic neurons in controls vs. 42%* on HS, *p < 0.05, z-test). However, continuous treatment with empagiflozin preserved the proportion of tonic neurons as in controls (67,9% on HS with concomitant administration of empagiflozin). In controls, empagiflozin did not affect the proportion of tonic to phasic neurons (63,8% tonic neurons in controls vs. 67,9% on HS & empagliflozin, p = 0.7, z-test). Blood pressure and heart rate were not altered by HS and/or treatment with any chosen dose of empagiflozin. Conclusions: In rats, chronically elevated sodium intake (8% NaCl) reduced the sensitivity and stimulability of renal afferent DRG neurons. Under these circumstances, concomitant treatment with the SGLT2 inhibitor empagiflozin preserved the function of renal afferent DRG neurons. SGLT 2 inhibitors may help to treat dysfunction of renal innervation in cardiovascular disease.