Related Experiment Videos
Cardiac membrane proteins and phospholipids in L-NAME induced hypertension
J Ziaciková1, O Pechánová, I Bernátová
1Institute for Heart Research, Slovak Academy of Sciences, Bratislava, Slovak Republic.
Insights
Chronic inhibition of nitric oxide (NO) synthesis in rats using N(G)-nitro-L-arginine methyl ester (L-NAME) increased cardiac phospholipids and conjugated dienes. This suggests NO inhibition alters cardiac membrane composition without direct oxidative damage.
Area of Science:
- Cardiovascular Physiology
- Biochemistry
- Cell Biology
Background:
- Nitric oxide (NO) plays a crucial role in cardiovascular function.
- Chronic NO synthesis inhibition can lead to cardiac dysfunction.
- Understanding membrane alterations is key to elucidating these effects.
Purpose of the Study:
- To investigate qualitative changes in cardiac cell membranes following chronic NO synthesis inhibition.
- To assess the impact of N(G)-nitro-L-arginine methyl ester (L-NAME) on cardiac protein, phospholipid, and conjugated diene concentrations.
Main Methods:
- Rats were administered L-NAME (40 mg/kg/day) for 4 weeks to inhibit NO synthesis.
- Cardiac homogenates were fractionated into cytosolic and particulate components.
- Concentrations of proteins, phospholipids, and conjugated dienes (CD) were measured.
Main Results:
- Protein concentrations in cardiac fractions remained unchanged.
- Phospholipid concentration increased by 100%, and the phospholipid-to-protein ratio increased by 88%.
- Conjugated diene concentration per gram of tissue increased by 141%, but not when normalized to phospholipids, indicating no additional oxidative damage.
Conclusions:
- Chronic L-NAME treatment alters cardiac membrane composition, specifically increasing phospholipid content.
- The observed increase in conjugated dienes is attributed to elevated phospholipid levels, not direct oxidative stress.
- These findings highlight compositional changes in cardiac membranes as a consequence of NO inhibition.
Abstract:
This study deals with qualitative alterations of membranes in cardiac cells after chronic inhibition of NO synthesis in rats induced by administration of N(G)-nitro-L-arginine methyl ester (L-NAME) in a dose 40 mg/kg/day for 4 weeks. Concentration of proteins did not change either in the cytosolic fraction or in the particulate fraction of the cardiac homogenate from L-NAME treated rats. The concentration of phospholipids and consequently the ratio of phospholipids to membrane proteins increased by 100% and 88%, respectively. The concentration of conjugated dienes (CD), often used as an indirect marker for the production of free oxygen radicals, increased by 141% after calculation per gram of tissue. However, evaluation of CD concentration directly in phospholipids revealed no change, suggesting that phospholipids in cardiac tissue after L-NAME treatment were not damaged additionally, by increased level of free oxygen radicals. The increase of the CD concentration in the cardiac tissue is therefore, a consequence of the elevated phospholipid concentration.