0000000000654663
AUTHOR
Elisabeth Fantini
Oxygen and substrate deprivation on isolated rat cardiac myocytes : temporal relationship between electromechanical and biochemical consequences
The effects of hypoxia and reoxygenation on action potentials (AP), contractions, and certain biochemical parameters were studied in isolated rat ventricular myocytes in monolayer culture in the presence and absence of glucose. Substrate deprivation alone had no influence on the basal properties. In the presence of glucose, a 4-h hypoxic treatment caused only a moderate decrease in AP amplitude and rate. In substrate-free conditions, hypoxia induced a gradual decline in plateau potential level and in AP duration and rate, followed by rhythm abnormalities and a failure of the electromechanical coupling. Spontaneous AP generation then ceased, and the resting potential decreased with increase…
Polyunsaturated fatty acids in cultured cardiomyocytes : effect on physiology and beta-adrenoceptor function
This study was carried out to investigate the influence of the membrane fatty acid composition on the basal electrical and contractile activities and the response to beta-adrenergic stimulation of rat cardiac muscle cells in culture. Cells were grown for 3 days in a conventional serum culture medium and then incubated for 24 h in synthetic media containing either n-6 or n-3 as the sole source of polyunsaturated fatty acids (PUFA). The n-6/n-3 ratio in the phospholipids was 0.9 in the n-3 cells and 13.1 in the n-6 cells compared with 6.3 in controls cells. Such modifications did not alter action potentials and the main parameters related to contraction, although shortening was slightly acce…