Micromolar changes in lysophosphatidylcholine concentration cause minor effects on mitochondrial permeability but major alterations in function.

Mice deficient in group 1b phospholipase A2 have decreased plasma lysophosphatidylcholine and increased hepatic oxidation that is inhibited by intraperitoneal lysophosphatidylcholine injection. This study sought to identify a mechanism for lysophosphatidylcholine-mediated inhibition of hepatic oxidative function. Results showed that in vitro incubation of isolated mitochondria with 40-200μM lysophosphatidylcholine caused cyclosporine A-resistant swelling in a concentration-dependent manner.

Activation of a novel long-chain free fatty acid generation and export system in mitochondria of diabetic rat hearts.

A number of reports indicate that a long-chain free fatty acid export system may be operating in mitochondria. In this study, we sought evidence of its existence in rat heart mitochondria. To determine its potential role, we also sought evidence of its activation or inhibition in streptozotocin (STZ)-induced diabetic rat heart mitochondria.

Gender differences in myosin heavy chain-beta and phosphorylated phospholamban in diabetic rat hearts.

The objective of this study was to determine whether a gender difference exists in myosin heavy chain (MHC) isoform or sarcoplasmic reticulum protein levels in diabetic rat hearts. As is the case with normal rodent hearts, all four chambers of the control rat hearts expressed almost 100% MHC-alpha. In 6-wk diabetic rats, MHC-beta expression in ventricles of males was significantly greater (78 +/- 7%) than in females (50 +/- 5%).

Defective intracellular Ca(2+) signaling contributes to cardiomyopathy in Type 1 diabetic rats.

The goal of the study was to determine whether defects in intracellular Ca(2+) signaling contribute to cardiomyopathy in streptozotocin (STZ)-induced diabetic rats. Depression in cardiac systolic and diastolic function was traced from live diabetic rats to isolated individual myocytes. The depression in contraction and relaxation in myocytes was found in parallel with depression in the rise and decline of intracellular free Ca(2+) concentration ([Ca(2+)](i)).

Mitochondria regulate inactivation of L-type Ca2+ channels in rat heart.

1. L-type Ca2+ channels play an important role in vital cell functions such as muscle contraction and hormone secretion. Both a voltage-dependent and a Ca2+-dependent process inactivate these channels.