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The Effect of Gap Junction Blockade on Renal Autoregulation and Phase Synchronization of Autoregulation Dynamics
Author(s) -
Mitrou Nicholas,
Braam Branko,
Cupples William
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.787.2
Subject(s) - autoregulation , carbenoxolone , gap junction , tubuloglomerular feedback , blockade , perfusion , medicine , chemistry , cardiology , kidney , blood pressure , receptor , biochemistry , intracellular
Renal autoregulation is mediated by a myogenic response (MR) and tubuloglomerular feedback (TGF) both of which generate dynamics that are synchronized over macroscopic regions of the renal surface. Previously we showed that the MR is synchronized on the renal surface (Scully et al. IEEE:TBME 61(7):1989), and others have shown that the same is true for TGF (Brazhe et al. PLOS One 9(9): e105879). We hypothesized that communication within the renal vascular network is mediated by electrotonic conduction through vascular gap junctions. Thus we predicted that blockade of gap junctions would impair synchronization of autoregulation dynamics and consequently reduce the efficacy of steady state and dynamic autoregulation. In male Long‐Evans rats (N=12) we monitored renal surface perfusion with laser speckle contrast imaging (LSCI) at 25 Hz during control (CTL) and non‐selective gap junction blockade with carbenoxolone (CBX, 10 mg/kg i.v.). Both records were taken during broadband forcing of renal perfusion pressure (RPP). At the end of each record, steady state autoregulation was tested by stepwise reduction in RPP from 110‐60 mmHg. Mean phase coherence (PC), phase difference (PD) were used to assess synchronization in both MR and TGF frequency ranges. Mean RPP was not different between CTL and CBX periods, but RBF was slightly increased after CBX. The slope of MR gain reduction was reduced by CBX while the mean PC was increased. This suggests that physiological synchronization of autoregulation dynamics may have an optimal strength. Furthermore, this increase in phase synchronization appears to reduce the overall efficacy of RBF autoregulation.