[Methylation of erythrocyte membrane phospholipids: correlation with membrane viscosity. Study of normal and parkinsonian subjects].

Plasma membranes from erythrocytes were used to study various parameters: phospholipid methylation, viscosity and fragility. These parameters were analysed in 57 normal subjects (52 +/- 3 years old) and 14 patients with idiopathic Parkinson's disease without previous treatment (71 +/- 2 years old). No significant correlations were observed between the various parameters and sex or age in the normal group. No correlation was observed between fragility and methylation or viscosity. A statistically significant correlation was found between viscosity and phospholipid methylation. In the patients with Parkinson's disease, fragility is identical to the normal group but the viscosity is increased by 25 p. 100. The increase of viscosity is more obvious among the patients with a pure or predominantly akinetic form of the disease. These results favour the previously described correlation between phospholipid methylation and viscosity of the plasma membrane and suggest a modification of these parameters in Parkinson's disease. They also suggest that the increased viscosity observed in Parkinson patients could render the receptors inaccessible to their endogenous ligands.