Effects of acetylcholine on glomerular sieving of macromolecules

Summary Using a new biomathematical model recently proposed to calculate, from glomerular sieving data for PVP¹²⁵I, the pores radius (r) and the total area per unit of path length () i.e. the parameters characterising the permeability of an ideal isoporous equivalent membrane, a mean value for the effective glomerular filtration pressure (GFP_e) in the dog has been derived from Poiseuille's law.The effects of the intra-arterial perfusion of acetylcholine have been studied. As a meanr decreased by 5%, decreased by 35% while GFP_e increased by 60% in the perfused kidney. The same effects have been noticed but less pronounced in the controlateral kidney. These changes are accompanied by an increase in effective renal plasma flow but without modification of glomerular filtration rate (GFR).The significance of these results as far as GFR autoregulation is concerned, is discussed.Supported by the National Foundation for Medical Research-Grant 1197-Belgium.