Surveying the response of transport channels of intact RBC membranes upon AgNO3 administration: an atomic force microscopy study.

BACKGROUND/AIMS Cell membranes facilitate the transport of water, ions, and necessary nutrients by hosting a great variety of transport channels that have either a 'simple' pore-like structure or more complex architecture that is based on the utilization of specific receptors. The present study reveals the impact of AgNO3, a well-known inhibitor of water channel activity, on transport channels that emerge at the membrane of intact red blood cells (iRBCs). METHODS Atomic force microscopy is employed to survey the morphological modification of all transport channels by directly comparing the respective images obtained on the exact same iRBCs prior to and after spraying the AgNO3 solution. RESULTS Small pores of mean size 50 nm that were assigned to water channels, and extended orifices of mean size 300 nm that exhibit a neck-like extracellular segment were observed at the iRBC membrane. CONCLUSION Our results reveal that AgNO3 exerts noticeable influence on all transport channels so that its selective water channel inhibitory action should be reconsidered. For low AgNO3 concentrations extended recovery of the small pore network was observed upon waiting, giving strong evidence that iRBCs have a recovery potential upon simply removing the inhibition cause without the need for specific reducing agents.