THE MOVEMENT OF PYRIDINIUM ALDOXIMES ACROSS THE RED CELL MEMBRANE

Abstract

SummaryThe movement of 2 PAM chloride (2‐hydroxyiminomethyl‐1‐methylpyridinium chloride) across the rabbit red cell membrane was examined. The rate of uptake and efflux of the oxime through the membrane was proportional to the concentration gradient and appeared to be a process of non‐assisted diffusion. The uptake was affected by factors such as the pH and ionic strength of the medium which suggested that transport was occurring through ionic pathways in the membrane in a manner similar to that described for inorganic cations. Tempaerature had a marked effect on the rate of uptake and the energy of activation was high. However, this did not appear to be inconsistent with a process of simple diffusion. Various substances which have been shown to affect selective cation permeability in red cells were examined, but the results did not help in further indentifying the diffusion pathways. Other species of red cells were also examined; there was a reduced rate of uptake in human cells, but there was no uptake in either bovine or sheep cells.The Various salts of 2 PAM behaved in a similar manner, the iodide and methanesulphonate salt giving identical results to the chloride. There was no uptake in rabbit red cells observed with the bisquaternary compounds TMB4 [1,1′‐trimethylene bis(4‐hydroxyiminomethyl pyridinium)dibromide] and toxogonin [bis(4‐hydroxyiminomethyl pyridinium‐1‐methyl) ether dichloride]. The rate of uptake of the two non‐quaternary compounds 2‐ and 4‐hydroxyimino‐methyl pyridine was so rapid that it could not be estimated by the method employed for the quaternary compounds.