title: NMR investigation of the influence of procaine and its metabolites on the water exchange through human erythrocyte membranes.
abstract: The effect of procaine hydrochloride and its metabolites on the diffusional water exchange through erythrocyte membranes was investigated at 37 degrees C and at concentrations ranging between 5 X 10(-5) M and 5 X 10(-1) M by using the NMR manganese doping method. Procaine hydrochloride and 2-diethylaminoethanol have a moderate stimulating effect on the water exchange, of up to 20% at concentrations ranging between 10(-3) and 10(-2) M, while an increasing inhibitory effect was found at higher concentrations. The p-aminobenzoic acid has no effect on the water exchange up to 10(-2) M and, at higher concentrations, and apparent decreasing inhibition was noticed which is thought to be an artefact due to the uptake of Mn2+ by the cells. The temperature dependence studies suggest that procaine HCl enhances the uptake of Mn2+ by the cells. An opposite effect was found for rigid erythrocytes. The p-aminobenzoic acid and 2-diethylaminoethanol appeared to be more effective than procaine hydrochloride in increasing the uptake of Mn2+.
mesh_terms: D010129:4-Aminobenzoic Acid / Q000494:pharmacology; D001834:Body Water / Q000378:metabolism*; D004058:Diffusion; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism*; D004983:Ethanolamines / Q000494:pharmacology; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008345:Manganese / Q000097:blood; D011343:Procaine / Q000494:pharmacology*
chemical_list: D004983:Ethanolamines; D008345:Manganese; D011343:Procaine; C007369:2-diethylaminoethanol; D010129:4-Aminobenzoic Acid