TY - JOUR
T1 - Effects of saturated long-chain N-acylethanolamines on voltage-dependent Ca 2+ fluxes in rabbit T-tubule membranes
AU - Oz, Murat
AU - Alptekin, Alp
AU - Tchugunova, Yulia
AU - Dinc, Meral
PY - 2005/2/15
Y1 - 2005/2/15
N2 - The effects of saturated long-chain (C: 16-22) N-acylethanolamines and a series of saturated fatty acids with the same length of carbon chains were investigated on depolarization-induced 45Ca 2+ fluxes mediated by voltage-dependent Ca 2+ channels in transverse tubule membrane vesicles from rabbit skeletal muscle. Vesicles were loaded with 45Ca 2+ and membrane potentials were generated by establishing potassium gradients across the vesicle using the ionophore valinomycin. Arachidonoylethanolamide and docosaenoylethanolamide but not palmitoylethanolamide and stearoylethanolamide (all 10 μM) caused a significant inhibition of depolarization-induced 45Ca 2+ fluxes and specific binding of [ 3H]Isradipine to transverse tubule membranes. On the other hand, saturated fatty acids including palmitic, stearic, arachidic, and docosanoic acids (all 10 μM) were ineffective in functional and radioligand binding experiments. Additional experiments using endocannabinoid metabolites suggested that whereas ethanolamine and arachidic acids were ineffective, arachidonoylethanolamide inhibited Ca 2+ effluxes and specific binding of [ 3H]Isradipine. Further studies indicated that only those fatty acids containing ethanolamine as a head group and having a chain length of more than 18 carbons were effective in inhibiting depolarization-induced Ca 2+ effluxes and specific binding of [ 3H]Isradipine. In conclusion, results indicate that depending on the chain length and the head group of fatty acid, N-acylethanolamines have differential effects on the function of voltage-dependent Ca 2+ channels and on the specific binding of [ 3H]Isradipine in skeletal muscle membranes.
AB - The effects of saturated long-chain (C: 16-22) N-acylethanolamines and a series of saturated fatty acids with the same length of carbon chains were investigated on depolarization-induced 45Ca 2+ fluxes mediated by voltage-dependent Ca 2+ channels in transverse tubule membrane vesicles from rabbit skeletal muscle. Vesicles were loaded with 45Ca 2+ and membrane potentials were generated by establishing potassium gradients across the vesicle using the ionophore valinomycin. Arachidonoylethanolamide and docosaenoylethanolamide but not palmitoylethanolamide and stearoylethanolamide (all 10 μM) caused a significant inhibition of depolarization-induced 45Ca 2+ fluxes and specific binding of [ 3H]Isradipine to transverse tubule membranes. On the other hand, saturated fatty acids including palmitic, stearic, arachidic, and docosanoic acids (all 10 μM) were ineffective in functional and radioligand binding experiments. Additional experiments using endocannabinoid metabolites suggested that whereas ethanolamine and arachidic acids were ineffective, arachidonoylethanolamide inhibited Ca 2+ effluxes and specific binding of [ 3H]Isradipine. Further studies indicated that only those fatty acids containing ethanolamine as a head group and having a chain length of more than 18 carbons were effective in inhibiting depolarization-induced Ca 2+ effluxes and specific binding of [ 3H]Isradipine. In conclusion, results indicate that depending on the chain length and the head group of fatty acid, N-acylethanolamines have differential effects on the function of voltage-dependent Ca 2+ channels and on the specific binding of [ 3H]Isradipine in skeletal muscle membranes.
KW - Calcium channels
KW - Endocannabinoids
KW - N-Acylethanolamines
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U2 - 10.1016/j.abb.2004.11.010
DO - 10.1016/j.abb.2004.11.010
M3 - Article
C2 - 15639235
AN - SCOPUS:11444257219
SN - 0003-9861
VL - 434
SP - 344
EP - 351
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 2
ER -