MANIPULATION OF LIPID-COMPOSITION OF RAT-HEART MYOCYTES AGED IN CULTURE AND ITS EFFECT ON ALPHA(1)-ADRENOCEPTOR STIMULATION

The fatty acid composition of the phosphoinositides was evaluated in c ultured neonatal rat cardiomyocytes during the aging-like process in v itro, comparing data obtained from control and gamma-linolenic acid su pplemented cardiomyocytes. The response to alpha(1) stimulation was ev aluated in both control and supplemented cells to verify the relations hip between the alterations of the phosphoinositide fatty acid composi tion concomitant to culture aging and the cell response to exogenous s timuli. Arachidonate level decreased as a function of age in all the p hosphoinositides, which appeared to be more saturated as cells aged in culture. Inositol phosphate production in response to alpha(1) stimul ation decreased as cells aged in culture. Supplementation of culture m edium with gamma-linolenic acid caused significant modifications in th e fatty acid pattern of the phosphoinositides, which appeared less sat urated than the corresponding fractions isolated from unsupplemented c ells during the aging-like process. The modifications induced by the s upplementation in the phosphoinositide fatty acid composition prevente d the age-related reduction of inositol phosphate production upon stim ulation. These results clearly indicate a major role for the lipid com position in determining the response to alpha(1) stimulation, suggesti ng a nutritional approach to overcome some of the impairments of molec ular events related to the process of aging. (C) 1997 Elsevier Science B.V.