ISSN:
1432-2013
Keywords:
Glomerular filtration rate
;
Juxta-glomerular apparatus
;
Macula densa
;
Tubulo-glomerular feedback
;
Chloride
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract It has been concluded that tubulo-glomerular feedback mechanism is triggered by changes in NaCl concentration ([NaCl]) at the macula densa. This conclusion is based on the demonstration that changes in filtration rate produced during retrograde perfusion of the loop of Henle depend upon the perfusate [NaCl]. Experiments were performed to evaluate whether the effect on glomerular function of orthograde perfusion of the loop of Henle is consistent with this conclusion. Early proximal flow rate ( $$\dot V_{EP} $$ ), stop-flow pressure (P SF), early distal chloride concentration ([Cl]), and flow rate were measured during perfusion of the loop of Henle with mannitol solution (300 mosm kg−1), 30 mM NaCl+mannitol (300 mosm kg−1), 140 mM Na isethionate and artificial tubular fluid. When distal flow exceeded 10 nl min−1, the magnitude of the glomerular response was predictable from the [Cl]. The linear regression line, $$\Delta \dot V_{EP} = - 0.027{\text{ }}[Cl]{\text{ + 4}}{\text{.3}}$$ , did not differ from that obtained previously with the retrograde technique. Retrograde perfusion with 140 mM Na isethionate was without effect on $$\dot V_{EP} $$ . We conclude that the effect on glomerular function of perfusion of the loop of Henle in either an orthograde or a retrograde direction with these solutions depends upon the chloride concentration at the macula densa.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00581634
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