Renin-positive granulated Goormaghtigh cells

1989 ◽  
Vol 255 (1) ◽  
Author(s):  
J.A. Christensen ◽  
A. Bohle ◽  
E. Mikeler ◽  
R. Taugner
Keyword(s):  
Goormaghtigh Cells

Transport-coupling hypothesis of tubuloglomerular feedback signal transmission

1989 ◽  
Vol 257 (5) ◽  
pp. F882-F892 ◽  
Author(s):  
A. Rich ◽  
L. C. Moore
Keyword(s):  
Signal Transmission ◽  
Ionic Composition ◽  
Mass Conservation ◽  
Juxtaglomerular Apparatus ◽  
High Water ◽  
Tubuloglomerular Feedback ◽  
Feedback Signal ◽  
Nacl Transport ◽  
Goormaghtigh Cells ◽  
Concentration Changes

A mathematical model was used to explore the transport-coupling hypothesis of tubuloglomerular feedback (TGF) signal transmission from the macula densa (MD) to the extraglomerular mesangium (EGM) within the juxtaglomerular apparatus (JGA). The transport-coupling hypothesis supposes that changes in MD transport alter the ionic composition of the EGM interstitium, thereby stimulating the Goormaghtigh cells. This hypothesis is based on the avascularity of the EGM and the presence of a narrow cleft (JGA cleft) between the MD and Goormaghtigh cells. The model describes NaCl and water transport by MD cells and mass conservation in the JGA cleft. It calculates cleft water flow and NaCl concentration [( NaCl]). If the cleft is narrow, the model predicts that cleft [NaCl] will vary directly with luminal [NaCl] and net MD NaCl transport. With strong active NaCl transport, the MD cell plaque may act as an ionic amplifier, in that small changes in luminal [NaCl] might elicit much larger concentration changes within the cleft. Even without active NaCl transport, cleft [NaCl] could remain coupled to luminal [NaCl] if the MD cells passively secrete NaCl. With high hydraulic conductivity, cleft [NaCl] also varies with luminal osmolarity. With a wide cleft, a low diffusional resistance of the EGM interstitium, or swollen MD lateral intercellular spaces, the transport coupling between cleft and luminal [NaCl] is markedly attenuated. The predictions of our model of large changes in JGA interstitial composition agree well with published measurements made in Amphiuma. However, the low Na+-K+-ATPase content and high water permeability of mammalian MD suggest that the transport-coupling effects in mammals may be significantly less pronounced than in Amphiuma.

Phospholemman expression in extraglomerular mesangium and afferent arteriole of the juxtaglomerular apparatus

2003 ◽  
Vol 285 (1) ◽  
pp. F121-F129 ◽  
Author(s):  
Randall K. Wetzel ◽  
Kathleen J. Sweadner
Keyword(s):  
Blood Flow ◽  
Membrane Protein ◽  
Molecular Mechanisms ◽  
Juxtaglomerular Apparatus ◽  
Macula Densa ◽  
Tubuloglomerular Feedback ◽  
Afferent Arteriole ◽  
Γ Subunit ◽  
Goormaghtigh Cells

The molecular mechanisms with which the juxtaglomerular apparatus accomplishes its twin functions, acute regulation of glomerular blood flow and secretion of renin, are still not clearly understood. Least understood is the role of the extraglomerular mesangial (EM) cells, also known as lacis or Goormaghtigh cells, which lie sandwiched between the macula densa and the afferent and efferent arterioles. Here, we report that immunoreactivity for phospholemman (FXYD1), a single-span membrane protein homologous to the gamma (γ) sub-unit of the Na,K-ATPase, is found in the kidney in EM cells with the Na,K-ATPase β2-subunit and in cortical blood vessels and the afferent arteriole with Na,K-ATPase α2 and β2. Phospholemman's distribution in EM cells is distinct from that of the Na,K-ATPase γ-subunit, which is found on the basolateral surface of macula densa cells with Na,K-ATPase α1 and β1. Phospholemman is a major kinase target, and its location in the juxtaglomerular apparatus suggests that it is involved in tubuloglomerular feedback.

Sign in / Sign up

Export Citation Format

Share Document