JM Bessa et al

While reading J.M. Bessa et al., I noticed that they use a modified chronic mild stress protocol. It would have been beneficial for me to know what the original CMS protocol was in order to understand the stress exposure a little better. While I can see how the mild stressors (confinement, cage tilting, food and water deprivation etc…) would model chronic stressors for the rats I feel as though the variability of the stressors, not for the rats, but more so for the experimenters’ purposes makes it difficult to distinguish what the more defined stressors for the animal are.

            Additionally, the following paradigms were interesting but also slightly confusing for me: the sucrose presence test and the novelty suppressed feeding test. It is understood that they found significance for the sucrose preference these that anhedonia was reversed significantly by imipramine, CP 156,526 and SSR 149415 and fluoxetine in the first and second weeks of treatment respectively. However they found no effect of the co-administration of MAM after repeated ANOVA. My question regarding the paradigm is whether it could have presented as a reward while measuring the baseline prior to the CMS. Furthermore, why would MAM, a cytostatic agent that blocks neurogenesis, demonstrate a null effect in this case and then demonstrate significance in the novelty suppressed feeding? In the NFS paradigm, I question several aspects of the protocol. First, the animal was starved and then placed in a novel environment, which is initially traumatic. Moreover, one food pellet is presented but then the animal is removed from the novel environment in order to be fed in its home cage? To me, this paradigm would make more sense if the animal was presented with food in the novel environment and the measurements were recorded in the novel environment only. Perhaps latency to reaching to reaching or consuming the single pellet would be a more appropriate measure of anxiety.