RESUMO
Rhythmic excitation of a rabbit myelin nerve increased diacylglycerol (DAG) content from 1.53 to 2.17 microg/mg lipids. Inhibition of phosphoinositide-specific phospholipase C decreased DAG content. This suggests involvement of this enzyme in processes accompanying rhythmic excitation. The increase in membrane potential of the nerve fiber (K+-depolarization) was accompanied by increase in DAG and phosphatidylinositol monophosphate and decrease in phosphatidylinositol triphosphate and phosphatidylinositol diphosphate content. Treatment of the nerve with DAG or a protein kinase C activator increased (45)Ca influx by 40%, whereas treatment with an inhibitor of this enzyme, polymyxin, inhibited this parameter by 34%. The role of phosphoinositides and protein kinase C in the regulation of Ca2+ transport during rhythmic excitation of the myelin nerve is discussed.
Assuntos
Cálcio , Diglicerídeos/metabolismo , Nervo Isquiático/metabolismo , Animais , Transporte Biológico/efeitos dos fármacos , Cálcio/metabolismo , Diglicerídeos/farmacologia , Inibidores Enzimáticos/farmacologia , Potenciais da Membrana/efeitos dos fármacos , Fluoreto de Fenilmetilsulfonil/farmacologia , Fosfatidilinositol 4,5-Difosfato/metabolismo , Fosfatos de Fosfatidilinositol/metabolismo , Proteína Quinase C/antagonistas & inibidores , Coelhos , Nervo Isquiático/efeitos dos fármacos , Nervo Isquiático/fisiologiaRESUMO
The nuclei are ejected from the pigeon erythrocytes and apoptotic vesicles form in these cells in the presence of hydrogen peroxide. Hydrogen peroxide intensifies LPO processes and changes phospholipid content. The relative content of phosphatidylcholine, sphingomyelin, and phosphatidylserine decreased, while that of phosphatidylethanolamine and lisophosphatidylcholine increased. The content of unsaturated fatty acids also decreased under these conditions. Presumably, these changes in the lipid phase of the erythrocyte membrane are a mechanism preparing the cell to nucleus ejection and apoptosis.
Assuntos
Eritrócitos/efeitos dos fármacos , Peróxido de Hidrogênio/toxicidade , Animais , Apoptose/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Columbidae , Eritrócitos/citologia , Eritrócitos/metabolismo , Técnicas In Vitro , Peroxidação de Lipídeos/efeitos dos fármacos , Lipídeos de Membrana/sangue , Fosfolipídeos/sangueRESUMO
Ligation of the sciatic nerve in rats led to reversible decrease in excitability and changes in lipid composition of myelinated nerve fiber: increase in the content of lysophosphatidylcholine, lysophosphatidylethanolamine, and free fatty acids and phospholipase A2 activity. Xymedon and laminin accelerate nerve regeneration and restore its lipid composition.