Effects of palmitoyl carnitine and related metabolites on the avian Ca(2+)-ATPase and Ca2+ release channel

1. In birds, prolonged cold exposure induces the development of a non-shivering thermogenesis (NST) of muscular origin that may result from an increase in ATP-dependent cycling of Ca2+ between the sarcoplasmic reticulum (SR) and the cytosol. 2. Because fatty acids are thought to play a significant r...

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Bibliographic Details
Published in:The Journal of physiology 1994-08, Vol.479 (Pt 1), p.29-39
Main Authors: Dumonteil, E, Barré, H, Meissner, G
Format: Article
Language:English
Subjects:
Animals
Body Temperature Regulation - physiology
Calcium - metabolism
Calcium Channels - physiology
Calcium-Transporting ATPases - analysis
Calcium-Transporting ATPases - metabolism
Calcium-Transporting ATPases - physiology
Cold Temperature
Ducks - physiology
Male
Muscle, Skeletal - chemistry
Muscle, Skeletal - enzymology
Muscle, Skeletal - metabolism
Palmitic Acid
Palmitic Acids - pharmacology
Palmitoyl Coenzyme A - pharmacology
Palmitoylcarnitine - pharmacology
Ryanodine - metabolism
Tritium
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Summary:1. In birds, prolonged cold exposure induces the development of a non-shivering thermogenesis (NST) of muscular origin that may result from an increase in ATP-dependent cycling of Ca2+ between the sarcoplasmic reticulum (SR) and the cytosol. 2. Because fatty acids are thought to play a significant role in NST, we investigated the effects of palmitic acid and related metabolites on skeletal SR Ca2+ uptake and release in ducklings. 3. Ca(2+)-ATPase activity, 45Ca2+ release and [3H]ryanodine-binding measurements indicated that palmitic acid was without effect on the Ca(2+)-ATPase and Ca2+ release channel. Palmitoyl carnitine and palmitoyl coenzyme A inhibited the Ca(2+)-ATPase at concentrations > 20 microM whereas both activated the Ca2+ release channel at concentrations < or = 20 microM in a dose-dependent manner. 4. Palmitoyl carnitine stimulated [3H]ryanodine binding to skeletal but not cardiac SR vesicles. Induction of 45Ca2+ release was observed with long-chain (C > or = 14) but not with short-chain acyl carnitines (C < or = 12). 5. Long-chain acyl carnitines accumulated significantly in duckling skeletal muscle during cold acclimation. Accordingly, these results suggest that long-chain acyl metabolites may modulate SR Ca2+ cycling and its associated thermogenesis in vivo.
ISSN:0022-3751
1469-7793
DOI:10.1113/jphysiol.1994.sp020275