Figure 4: MBH KATP-channel activation and VLDL-TG secretion.
(a) Schematic representation of working hypothesis. (b) Experimental protocol: independent rats received adenoviral injection of GFP or DN Kir6.2 immediately following stereotaxic surgery as indicated (f,g). MBH preinfusions of vehicle, glibenclamide (glib) or rot were commenced at −20 min, and infusions of vehicle, oleic acid, oleic acid+glib, OAG, diazoxide or diazoxide+rot were commenced at t=−10 min. (c) TG concentrations, (d) rates of appearance of VLDL-TG and (e) insulin concentrations in plasma with MBH infusion of vehicle (white open squares, n=6), oleic acid (black squares, n=8) or oleic acid+glib (grey circles, n=5). *P<0.04; **P<0.008 versus other groups. (f) Plasma TG concentrations and (g) rates of appearance of VLDL-TG in plasma in rats with prior adenoviral GFP injection following MBH infusion of oleic acid (black squares, n=7) or OAG (grey triangles, n=4) or adenoviral DN Kir6.2 injection with oleic acid (white open squares, n=4) or OAG (grey circles, n=5). *P<0.03, **P<0.001 GFP+oleic acid versus DN Kir6.2+oleic acid. †P<0.03, ††P<0.004 GFP+OAG versus DN Kir6.2+OAG. (h) TG concentrations, (i) rates of appearance of VLDL-TG and (j) insulin concentrations in plasma following MBH infusion of rot (white open squares, n=5), diazoxide (black squares, n=6) or diazoxide+rot (grey triangles, n=6). *P<0.04; **P<0.009 diazoxide, diazoxide+rot versus rot. Data are presented as mean+s.e.m. Statistical significance determined by Dunnett’s post hoc test after analysis of variance (ANOVA). For measurements over time, repeated measures ANOVA was used followed by Duncan’s post hoc test.
