Multilevel synchronization of tubuloglomerular feedback is modulated by nitric oxide (692.10)

Abstract

Previously we showed that NO modulates synchronization of both mechanisms of renal autoregulation. We did not, however, provide a mechanism to explain TGF synchronization after L‐NAME. L‐NAME changed TGF synchronization in a way we did not understand. Here we show that TGF synchronization may become stronger within cortical lobules after L‐NAME, resulting in two mechanisms of synchronization within a synchronized cluster. Male Long‐Evans rats (N=8) were anaesthetized (isoflurane) and their left kidneys were exposed. Cortical perfusion during control and NOS inhibition (L‐NAME, 10mg/kg i.v.) was monitored by laser speckle perfusion imaging. The TGF frequency range (0.01‐0.06 Hz) was isolated with a band pass filter. Clusters of synchronized nephrons were identified based on phase coherence (PC) between all pairs of imaged pixels. During control, TGF was synchronized moderately over large areas (~5x7 mm). After L‐NAME, each cluster had areas with high PC (strong synchronization) in the center and lower, but significant, PC in the surround. When the PC reference pixel was moved systematically there was strong synchronization within smaller ~800 x 800 um areas. The position of the high PC areas was consistent with an anatomical basis for synchronization. We conclude that TGF synchronization becomes stronger within cortical lobules while remaining weakly synchronized among lobules within the larger clusters.Grant Funding Source: Supported by CIHR MOP‐102694