Influence of SFA and MUFA enrichment on insulin sensitivity in the brain and the impact on cortical and locomotor activity.
A: Attenuated tyrosine phosphorylation (PY) of IR, IRS2, and phosphorylation of AKT (S473) as well as protein expression of
AKT was analyzed by SDS-PAGE after intravenous insulin injection in overnight-fasted MUFA-, SFA-, or chow-fed animals. Densitometric
quantification of PY-IR (relative increase of PY-IR compared with insulin-stimulated control mice; n = 5–6/group; *P < 0.05) after intravenous insulin (cross-hatched bars) or vehicle (white bars) injection is presented in histograms. A representative
blot is shown. B: Analysis of basal power spectral density (indicated for delta [0.5–4 Hz], theta [4–8 Hz], alpha [8–12 Hz], and beta [12–30
Hz] frequencies) using fast Fourier transformation and estimated by ECoG in MUFA- (gray bars), SFA- (black bars), and chow-fed
(white bars) animals. Basal ECoG measurements were conducted during a 4-day period (n = 11–24/group; *P < 0.05, **P < 0.005, and ***P < 0.001 compared with controls; ##P < 0.005 and ###P < 0.001 between fat-enriched diet groups). C: An acute intracerebroventricular insulin application (cross-hatched bars) vs. vehicle (white bars) results in less pronounced
locomotor activity in SFA-fed mice. ***P < 0.001 and *P < 0.05 to vehicle. Data are mean ± SEM. Ins, insulin.