Involvement of allopregnanolone in the anti-PTSD-like effects of AC-5216

Abstract

Cholesterol import into mitochondria through the translocator protein (18 KDa) (TSPO) is the starting point and an important rate-limiting step in neurosteroidogenesis. For this reason TSPO has received increased attention in the pathophysiology of post-traumatic stress disorder (PTSD). In an effort to explore the role of TSPO in mediating the anti-PTSD effect, we first assessed the effects of the TSPO ligand AC-5216 in alleviating the enhanced anxiety and fear response in a time-dependent sensitization (TDS) procedure, a rat PTSD animal model. In the present study, we showed that chronic treatment with AC-5216 caused significant suppression of the enhanced anxiety and contextual fear induced in post-TDS rats; these effects were blocked by PK11195. Furthermore, AC-5216 treatment increased the levels of allopregnanolone in the serum, prefrontal cortex, and hippocampus of post-TDS rats, and these effects were antagonized by PK11195. These results demonstrate that AC-5216 has a clear anti-PTSD-like effect, which might be partially mediated by binding to TSPO and the subsequent synthesis of allopregnanolone.

Keywords

AC-5216 allopregnanolone post-traumatic stress disorder (PTSD)time-dependent sensitization (TDS)translocator protein 18 kDa (TSPO)

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