The calcium uptake of the rat heart sarcoplasmic reticulum is altered by dietary lipid

Abstract

Small amounts of dietary n-3 fatty acids can have dramatic physiological effects, including the reduction of plasma triglycerides and an elevation of cellular eicosapentanoic (EPA) and docosahexanoic acids (DHA) at the expense of arachidonic acid (AA). We investigated the effects of alterations in the fatty acid compositions of cardiac sarcoplasmic reticulum (CSR) produced by dietary manipulation on the calcium pump protein that is required for energy dependent calcium transport. CSR was isolated from rats fed menhaden oil, which is rich in n-3 fatty acids, and from control animals that were given corn oil. Relative to control membranes, those isolated from rats fed menhaden oil, had a lower content of saturated phospholipids, an increased DHA/AA ratio, and an increased ratio of n-3 to n-6 fatty acids. These changes were associated with a 30% decrease in oxalate-facilitated, ATP-dependent calcium uptake and concomitant decreased Ca-ATPase activity in the membranes from the animals fed menhaden oil. In contrast, there was no alteration in active pump sites as measured by phosphoenzyme formation. Thus, the CSR Ca-ATPase function can be altered by dietary interventions that change the composition, and possibly structure, of the phospholipid membranes thereby affecting enzyme turnover.

Dietary docosahexaenoic acid supplementation reduces SERCA Ca2+ transport efficiency in rat skeletal muscle

“…Fatty acid Control DHA PC 16:0/18:1n-9 11.8 AE 0.7 14.1 AE 0.8 16:0/18:2n-6 7.2 AE 0.2 6.4 AE 0.5 16:0/20:4n-6 16.1 AE 0.9 10.9 AE 0.3 * 18:0/18:2n-6 6.6 AE 0.7 6.3 AE 0.5 16:0/22:6n-3 8.9 AE 1.7 18.5 AE 1.5 * 18:1n-9/20:4n-6 3.6 AE 0.4 3.7 AE 0. response to DHA-supplementation is consistent with previous studies assessing SR lipid composition after DHA feeding Stubbs and Kisielewski, 1990;Taffet et al, 1993). These changes in SR membrane DHA content resulted in reduced SERCA Ca 2+ uptake, Ca 2+ -ATPase activity, and apparent coupling ratio (Fig.…”

Omega 3 polyunsaturated fatty acid modulates dihydropyridine effects on L-type Ca2+ channels, cytosolic Ca2+, and contraction in adult rat cardiac myocytes.

“…This suggests that Table 1). In conclusion, in addition to previous observations (5) (15). However, the DHA-induced modulation of DHP function described in this study may still be related to the mechanism(s) involved in fish oil protection against ischemia-reperfusion-induced intracellular Ca2+ overload associated with cardiac arrhythmias (2,3).…”

Effects of the type of dietary fat on acetylcholine-evoked amylase secretion and calcium mobilization in isolated rat pancreatic acinar cells

“…Certainly, differences in Ca-ATPase activity of heart sarcolemma have been reported after feeding animals different types of fat [3]. Dietary-induced changes in the composition, and possibly structure, of membrane phospholipids may affect Ca-ATPase turnover [33].…”