RESUMO
The effect of novel synthesized aminophosphonates on membrane potential and electrical conductance of internodal cells of Nitellopsis obtusa and hemolysis of erythrocytes (RBC) was studied. It was found that those the organophosphorous compounds, when present at 10-100 microM concentrations, caused depolarization and increased electrical conductance of alga membranes. They also influenced fluidity of erythrocyte membranes. When used at higher concentrations aminophosphonates caused hemolysis of RBC. The changes observed depended on structural features of the aminophosphonates, i.e., substituents at the carbon, phosphorus and nitrogen atoms, and, most probably, may be the result of direct interaction of the aminophosphonates with the lipid phase of the plasma membrane and the induced structural changes. Two modes of interaction are proposed.
Assuntos
Aminas/toxicidade , Clorófitas/efeitos dos fármacos , Cicloexilaminas/toxicidade , Hemólise/efeitos dos fármacos , Fluidez de Membrana/efeitos dos fármacos , Organofosfonatos/toxicidade , Animais , Escuridão , Condutividade Elétrica , Membrana Eritrocítica/efeitos dos fármacos , Concentração de Íons de Hidrogênio , Potenciais da Membrana/efeitos dos fármacos , Suínos , Vacúolos/efeitos dos fármacos , Vacúolos/ultraestruturaRESUMO
On the basis of Gortel & Grendel (J. Exp. Med., 1925, 41, 439-494) discovery, the importance of the lipid bilayer as an integral and indispensible component of the cell membrane is discussed. In particular, attention focuses on the interaction between membranes and amphiphilic substances. The effect on membranes of quaternary ammonium salts, both in the form of pesticides and oxidants as well as organic compounds of tin and lead are discussed in greater detail.
Assuntos
Membrana Celular/química , Membrana Celular/efeitos dos fármacos , Tensoativos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Técnicas In Vitro , Bicamadas Lipídicas/química , Modelos Moleculares , Compostos Organometálicos/química , Compostos Organometálicos/farmacologia , Praguicidas/química , Praguicidas/farmacologia , Compostos de Amônio Quaternário/química , Compostos de Amônio Quaternário/farmacologia , Eletricidade Estática , Tensoativos/químicaRESUMO
The effect of two series of amphiphilic quaternary ammonium salts on some properties of phospholipid membranes was studied. The compounds of one series, N-benzyl-N,N-dimethyl-N-alkyl ammonium bromides, exert a destructive effect on membranes and are treated as reference compounds. The compounds of the other series, N-(3,5-di-t-butyl-4-hydroxy)benzyl-N,N-dimethyl-N-alkyl ammonium bromides, are derivatives of the former ones, exhibit antioxidant properties, and do only relatively slight damage to the membranes. The aim of the work was to explain the difference in molecular interaction with membranes between the two kinds of hydrophobic compounds. Thermodynamic methods, a new mixing technique, and monolayer and quantum calculation methods were used. It has been shown that the antioxidant molecules are less hydrophobic than those of the reference compounds and disturb the membrane organization to a lesser extent. On the basis of monolayer data, we suggest that the studied antioxidant behaves like a substitutional impurity, whereas the reference behaves like an interstitial one.
