Furthermore, in an LPS-induced rat model of depression, administration of ketamine and GTS-21([3-(2,4-dimethoxybenzylidene) anabaseine], a selective α7 nAChR agonist) was shown to reduce the levels of IL-1β, IL-6, and TNF-α compared to the group of rats treated with LPS alone. Here, IL6 is linked to major depressive disorder.