Effect of Imipramine on the Membrane Anisotropy and on the Phospholipid Methylation in the Central Nervous System of the Rat

— An ex-vivo and in-vitro study of the effects of imipramine on the membrane anisotropy and phospholipid methylation in the rat cortical membranes was carried out. A comparative study of the membrane fluidity in various brain regions indicated different basal anisotropy of the areas and different reaction of these membranes to imipramine. It was found that imipramine when given to rats chronically (14 × 10 mg kg−1, i.p.) or added externally to the cortical membranes of naive rats or rats treated with a single dose of imipramine (10 mg kg−1, i.p.) decreased the anisotropy of cortical membranes. Chronic imipramine produced some changes of the membrane architecture in the cortex, whereas imipramine in different concentrations did not fluidize these membranes in-vitro. Imipramine in concentrations corresponding to its mean concentration in the rat brain after administration at a dose of 10 mg kg−1 i.p., potentiated phospholipid methylation in the cortical membranes of naive rats and rats receiving imipramine in a single dose of 10 mg kg−1 i.p. in an in-vitro study, whereas the prolonged administration of imipramine decreased the sensitivity of phospholipid methyltransferases to the stimulating effect of the drug in-vitro.