Chloride conductance of mesangial cells. Insights into the transcellular signaling of tubuloglomerular feedback and its physiological significance.
In each nephron, a change in Cl delivered to the macula densa affects afferent arteriolar tone, and thus SNGFR. This phenomenon, called tubuloglomerular feedback (TGF), is the main function of the juxtaglomerular apparatus (JGA) and serves as the fine regulator of SNGFR. The phylogeny of the JGA strongly suggests that its physiological significance may be closely related to autoregulation of RPF and GFR and that JGA and TGF will allow maintenance of SNGFR in the face of low sodium intake. We propose that JGA, which appeared from amphibia, was a prerequisite, during evolution, for transition to terrestrial life style where abundant sodium intake was not guaranteed. In other words, our nephron is in essence a salt-conserving machinery to maintain SNGFR. Further, resetting of TGF or maladaptation of TGF in the presence of abundant salt intake may underlie the pathogenesis of essential hypertension.
Kurokawa
K
K
First Department of Internal Medicine, University of Tokyo Faculty of Medicine, Japan.
D000818:Animals; D018118:Chloride Channels; D005246:Feedback / Q000502:physiology*; D005920:Glomerular Mesangium / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007473:Ion Channels / Q000378:metabolism*; D007678:Kidney Glomerulus / Q000502:physiology*; D007684:Kidney Tubules / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
D018118:Chloride Channels; D007473:Ion Channels; D008565:Membrane Proteins