In the ventral tegmental area picrotoxin blocks FGIN 1-27-induced increases in sexual behavior of rats and hamsters

摘要

There are two types of benzodiazepine receptors, mitochondrial benzodiazepine receptors (MBRs), and γ-aminobutyric acid (GABAA)/benzodiazepine receptor complexes (GBRs). MBR activation increases neurosteroidogenesis. Ventral tegmental area (VTA) infusions of the MBR agonist, FGIN 1-27, increase midbrain levels of the progesterone metabolite 5α-pregnan-3α-ol-20-one (3α,5α-THP) and lordosis of rats and hamsters. Activation of GBRs leads to membrane hyperpolarization. In the VTA, infusions of GBR agonists enhance 3α,5α-THP-facilitated lordosis. Thus, if, in the VTA, MBR-mediated increases in 3α,5α-THP enhance sexual responses via actions at GBRs, then blocking GBRs with picrotoxin will reduce FGIN 1-27-induced increases in sexual behavior of female rodents.