RESUMO
A study has been carried out into the effects of procaine on the activities (Na+,K+)- and (Ca2+,Mg2+)-ATPases of the human erythrocyte membrane. In general, procaine inhibited both types of ATPases activities but with characteristic inhibition profiles and varying degrees of efficacy. In addition, the effects of procaine on the transport of K+ and phosphate ions across the membrane of the human erythrocyte were monitored and compared. Procaine was found to stimulate K+ release and to inhibit phosphate uptake. At low concentrations, both processes were found to be concentration dependent. Stimulation of K+ release and inhibition of phosphate uptake reached plateaus at concentrations of 50 and 150 mM, respectively. The antisickling effect of procaine was explained mainly in the light of the changes it induces in the activities of membrane bound ATPases and the permeability properties of the erythrocyte membrane to cations and anions.
Assuntos
Anemia Falciforme/tratamento farmacológico , ATPase de Ca(2+) e Mg(2+)/antagonistas & inibidores , Membrana Eritrocítica/efeitos dos fármacos , Procaína/uso terapêutico , Ativação Enzimática , Membrana Eritrocítica/enzimologia , Humanos , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidoresRESUMO
A study has been carried out into the effects of cetiedil on the activities of Na+, K+ and Ca2+, Mg2+-ATPases of the normal human erythrocyte membrane. In general, cetiedil inhibits both ATPases activities but with characteristic inhibition profiles and varying degrees of efficacy. The activities were inhibited non-competitively at the cetiedil concentration which caused 50% inhibition of each enzyme. In addition, the effects of cetiedil on the transport of K+ and phosphate ions across the membrane were monitored and compared. Cetiedil was found to stimulate K+ release and to inhibit phosphate uptake. At low concentrations, both processes were concentration dependent. Stimulation of K+ efflux reached a plateau at a concentration of 1.2 mM. The antisickling effect of cetiedil is explained mainly in the light of the changes it induces in the activities of membrane-bound ATPases and the permeability properties of the erythrocyte membrane to cations and anions.