Dietary fat influences electric membrane properties of neurons in cell culture.
1. SJL/J mice were maintained on semipurified diets which differed in the ratio of polyunsaturated/saturated fatty acid content (P/S). Exposure was from conception and was maintained for periods ranging from 6 to 34 weeks. 2. Neural cell cultures were prepared from dorsal root ganglia (DRG). After 6 and 20 days of culture, neuronal electric membrane properties were determined quantitatively by intracellular recording. 3. A number of significant differences were observed for the two dietary conditions. DRG from mice on the low-P/s diet had an increase in the rate of fall of both phases of repolarization which, in conjunction with the reduced action potential overshoot, led to a reduced action potential duration. This shift to shorter-duration action potentials was accompanied by a shift to more monophasic falling phases. The low-P/S neurons also exhibited a decreased afterhyperpolarization, decreased specific membrane resistance, and decreased membrane electrical time constant compared to high-P/S neurons. 4. It was concluded that the P/S ratio in the diet can have a significant effect on the electric properties of neurons. The high-P/S neurons tended to have action potentials with biphasic repolarizations and longer durations. In contrast, the low-P/S neurons tended to have action potentials with monophasic repolarizations and shorter durations. Moreover, the known ionic dependence of these two types of action potentials suggested that the low-P/S diet resulted in action potentials with a more exclusive Na dependence, while the high-P/S diet resulted in action potentials with both Na and Ca dependence.
Scott
B
B
Surrey Place Centre, Toronto, Ontario, Canada.
Lew
J
J
Clandinin
M T
MT
Cinader
B
B
D000200:Action Potentials; D000818:Animals; D002478:Cells, Cultured; D004041:Dietary Fats / Q000378:metabolism*; D005260:Female; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism* / Q000502:physiology; D008563:Membrane Lipids / Q000378:metabolism* / Q000502:physiology; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000378:metabolism* / Q000502:physiology
D004041:Dietary Fats; D008563:Membrane Lipids