Influence of cyclandelate on in vitro red blood cell deformability

Using filtration and viscosity techniques, cyclandelate, some of its metabolites and flunarizine were evaluated to determine their ability to maintain human red blood cell (RBC) deformability. In filtration studies, RBC suspensions were metabolically depleted, which decreased the capacity of the cells to pass through narrow filter pores. In viscosity measurements performed with whole blood, metabolic depletion resulted in an increase of blood viscosity values. The results of these experiments appeared to indicate that cyclandelate, cyclandelate alcohol and flunarizine were approximately equipotent in maintaining RBC filtration and blood viscosity values. Cyclandelate acid appeared to be less active in both studies. By measuring the adenosine triphosphate content of red blood cells it has been shown that this activity is not due to an action on red blood cell energy metabolism. Finally, experiments conducted with the calcium chelator EGTA showed that the activity of cyclandelate was reduced in the absence of Ca++ ions. The results strengthen the hypothesis that cyclandelate maintains red cell deformability by inhibiting calcium entry through the red cell membrane.