Acute effect of passive Heymann nephritis on renal blood flow and glomerular filtration rate in the rat: role of the anaphylatoxin C5a and the alpha-adrenergic nervous system.

Abstract

In earlier studies, we have shown that induction of passive Heymann nephritis (PHN) by intrarenal infusion of anti-Fx1A antibodies provokes an immediate fall in renal blood flow (RBF) and glomerular filtration rate (GFR). This was probably mediated via the complement system, as infusion of the F(ab')2 fraction of anti-Fx1A did not reduce RBF and GFR. In the present study, the effects of alpha-adrenergic blockade upon the acute hemodynamic changes during induction of PHN and of C5a infusion were studied. Group 1 was infused with anti-Fx1A antibodies during blockade of the sympathetic nervous system with the alpha-blocker phentolamine; control animals were treated similarly, but infused with normal rat IgG. Group 2 was infused with the anaphylatoxin C5a, normally produced during complement activation, and compared with control animals infused with saline. In group 1, RBF did not differ from control animals after the infusion of anti-Fx1A antibodies (6.6 +/- 0.5 compared to 7.3 +/- 1.0 ml/min/g in the controls). GFR in the left, antibody-infused kidney fell compared to controls, and was 0.25 +/- 0.08 ml/min/g at the end of the experiment compared to 0.60 +/- 0.13 ml/min/g (p less than 0.05 with Student's t test, p = 0.07 with two-way analysis of variance (ANOVA). GFR in the right kidney remained unchanged compared to controls. In group 2, C5a induced a significant fall in RBF (from 7.9 +/- 0.9 to 3.1 +/- 0.4 ml/min/g kidney weight), significantly different from control animals where it fell from 8.1 +/- 0.5 to 6.8 +/- 0.7 ml/min/g (p less than 0.0001 with two-way ANOVA, p less than 0.001 with t test).(ABSTRACT TRUNCATED AT 250 WORDS)