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. Author manuscript; available in PMC: 2009 Sep 11.
Published in final edited form as: Biol Psychiatry. 2008 Jul 18;64(8):691–700. doi: 10.1016/j.biopsych.2008.06.003

Figure 5.

Figure 5

RAT: Decreases in insulin receptor substrate-2 (IRS2) and AKT signaling ventral tegmental area (VTA) enhance depression-related behaviors. (A) VTA-specific reductions in IRS2 or AKT function significantly decreased the latency to immobility on Day 2 of the rat forced-swim test [F(4,98) = 9.99, p<.0001,n = 13–28], as well as (B) significantly enhanced immobility durations [F(4,98) = 9.93,p<.0001]. (C) On this day, although viral groups were no different on counts of swimming [F(4,90) = 1.78, p > .1], IRS2dn overexpressing rats displayed significantly lower climbing counts [F(4,90) = 5.57, p < .0001], and both IRS2dn and AKTdn overexpressing ratsdisplayed significantly enhanced total immobility counts [F(4,90) = 6.84, p < .0001, n = 13–28]. (D) VTA overexpression of GFP, IRS2, or AKT in rats does not significantly change the distance moved in an open field [F(4,95) = 1.01, p > .3, n = 16–23). (E) In this experiment, we tested the effects of these manipulations on five groups of rats matched for equal “pretest” sucrose preference scores [F(4,92) = .33, p> .5, n = 13–28]. Three days postsurgery, IRS2dn and AKTdn overexpression produced significantly lower sucrose preference scores [F(4,92) = 6.00, p < .001]. (F) The total fluid consumed during the sucrose preference test was not changed by viral manipulation [F(4,92) = .47, p > .5). Data are shown as mean + SEM, with * and ** indicating significant (p < .05 orp < .01, respectively) post hoc comparisons from respective control rats. AKT, thymoma viral proto-oncogene; GFP, green fluorescent protein; HSV, herpes simplex virus.